#Underlined indicates abstract presenter.
Referent data for investigations of upper limb motor behavior: harmonized accelerometry data from three cohorts of typically-developing children
Catherine Lang, Catherine Hoyt, Jeffrey Konrad, Kayla Bell, Natasha Marrus, Marghuretta Bland, Keith Lohse, Allison Miller
Washington University School of Medicine, Saint Louis, USA
Introduction: Assessment of motor behavior in pediatric neurorehabilitation is challenging. The rise of wearable sensing technology shows promise for addressing the challenges of time-consuming, in-clinic tests, where new test versions are needed as children develop. The current pediatric wearable sensing literature is highly variable with respect to the number of sensors used, sensor placement, wearing time, and how data extracted from the sensors are analyzed. Many studies derive conceptually similar variables via different calculation methods, making it hard to compare across studies and clinical populations. In hopes of moving the field forward, this report provides referent upper limb wearable sensor data from accelerometers on 25 variables in typically-developing children, ages 3-17 years.
Methods: This is a secondary analysis using harmonized data from three pediatric cohorts of children 3-17 years of age. Participants (n=222) in the cohorts wore bilateral wrist accelerometers for 2-4 days for a total of 622 recording days. Accelerometer data were reprocessed to compute 25 variables that quantified upper limb movement duration, intensity, symmetry, and complexity. The complexity category included measures of entropy, jerk, and statistics of movement frequencies. Analyses examined the influence of hand dominance, age, gender, reliability, day-to-day stability, and the relationships between variables.
Results: The majority of variables were similar on the dominant and non-dominant sides, declined slightly with age, and were not different between boys and girls. ICC values were moderate to excellent. Variation within individuals across days generally ranged from 3% to 32%. A web-based R shiny object provides a graphical user interface for users to view the data to suit their own research and clinical needs.
Interpretation: With the use of wearable movement sensors increasing rapidly, these data provide key, referent information for researchers as they design studies, and analyze and interpret data from neurodevelopmental and other pediatric clinical populations. Upper limb accelerometry data, as an adjunct to established assessment methods, may be of high value because it can measure motor behavior: 1) over longer periods of time in the home and community; and 2) on ratio scales, which do not require different versions for different ages. These data may be of particular high value for rare or orphan diseases. Further data collection for children from 6 months to 3 years of age is underway and data sets from 6 adult cohorts are being reprocessed with the same methods. As new cohorts from our group and others are studied using a similar protocol, the field will benefit from adding these data, especially data from under-represented communities, to this harmonized database.
Categories
Motor Rehabilitation
The Neural Underpinnings and Sensory Feedback Augmentation During Split-belt Treadmill Adaptation in People with Multiple Sclerosis
Andrew Hagen, Jaclyn Stephens, Brett Fling
Colorado State University, Fort Collins, USA
Introduction: Multiple sclerosis (MS) is the most common neurodegenerative disease affecting young adults, with the average onset occurring at 31 years of age.1 The majority of people with MS (PwMS) experience significant gait asymmetries, or spatiotemporal differences between the left and right legs during walking, leading to an increased risk of falls and musculoskeletal injury.2 Split-belt treadmill adaptation, where the speed of each leg is controlled independently, alters each leg’s spatial and temporal stepping pattern and improves gait symmetry in PwMS, Parkinson’s disease, and stroke.3,4,5 Additionally, previous research has shown that lower limb sensory nerve stimulation via transcutaneous electrical nerve stimulation (TENS) improves positional awareness6 and gait coordination for PwMS.7 However, there is limited research investigating the cortical neural underpinnings of gait adaptation during split-belt treadmill walking.
Methods: In this ongoing study, PwMS and matched controls are completing two split-belt treadmill adaptation visits, one with and one without TENS, while functional near-infrared spectroscopy (fNIRS) measures changes in cortical activation at different epochs of the adaptation paradigm. We hypothesize that cortical sensorimotor integration areas will have heightened activity and that TENS will enhance gait adaptability and retention during split-belt treadmill adaptation. Further, we expect the increase in cortical activity and the effect of TENS to be greater in PwMS.
Results: To-date, we have collected fNIRS data during split-belt treadmill adaptation for ten PwMS and matched controls, and our preliminary results demonstrate increased cortical activation during split-belt treadmill walking compared to normal walking with both belts set at the same speed. Currently our data suggest that the main regions of increased activation during early adaptation include the supplementary motor areas (SMA) and the premotor cortex (PMC). An increase in activation in the SMA region was also negatively associated with step length asymmetry (SLA) change during adaptation (r = -0.931). Further, our data suggests that TENS decreases activity in the primary motor (M1) and primary somatosensory (S1) cortices during split-belt treadmill adaptation. TENS also affected gait adaptability as it elicited an increase in SLA change during the adaptation period.
Discussion: Our preliminary data suggest that there is increased input from the motor planning cortical regions during split-belt treadmill adaptation, and that TENS may enhance adaptability. Specifically, the SMA and PMC regions demonstrated the greatest increases in activity during split-belt treadmill adaptation. Because greater SMA activity was associated with decreased SLA change, this pattern of neural activity may predict poorer gait adaptability. Further, participants had greater adaptability and less activity in M1 and S1 with TENS on compared to TENS off, indicating that TENS may modulate sensory integration within these regions. Determining the neural underpinnings of split-belt treadmill adaptation may provide crucial insights to the neuroplastic changes that accompany gait symmetry adaptation in PwMS.
Categories
Multiple Sclerosis (MS)
Correlation between walking function and transcranial magnetic stimulation derived measures in spinal cord injury
Avery Foreman1, Elliot Frost2, Faith Meza2, Chad Swank3, Hui-Ting Goh1
1Texas Woman’s University, Dallas, USA. 2Baylor Scott & White Institute for Rehabilitation, Dallas, USA. 3Baylor Scott & White Research Institute, Dallas, USA
Background and purpose: Transcranial magnetic stimulation (TMS) derived measures are correlated with motor function after stroke. However, it is unclear whether neurophysiological measures derived from TMS are related to motor function in spinal cord injury (SCI). We report baseline data from an ongoing study aiming to determine the effectiveness of overground robotic exoskeleton gait training on walking recovery in individuals with motor incomplete SCI. The purpose of this analysis was to determine the relationship between gait function and TMS derived measures.
Methods: Eligible participants were within 10 days of inpatient rehabilitation admission, with a motor incomplete (ASIA Impairment Scale C or D) SCI diagnosis, and without TMS contraindications. Participants underwent structured gait training determined by the randomized controlled trial protocol. The Walking Index for Spinal Cord Injury-revised (WISCI-II) and 10 Meter Walk Test (10MWT) were used to assess walking function. TMS assessments measured resting motor threshold (RMT), and active motor threshold (AMT) of tibialis anterior (TA) and rectus femoris (RF) muscles on the stronger side. Motor-evoked potential (MEP) amplitudes at 120% RMT (resting MEP), 120% AMT (active MEP), and 100% of the stimulator output (maximal MEP) were also obtained. Additionally, short-interval intracortical inhibition and intracortical facilitation were assessed using paired pulse TMS protocols. We constructed an input-output curve for TA using 5 different intensities. Assessments were completed at admission and discharge from inpatient rehabilitation, completion of gait training, 1-month follow-up, and 9 months post injury. We performed Spearman correlational analysis between gait outcomes and TMS measures using the baseline data.
Results: Twenty-three participants (6 females and 17 males, age=46.5±20.5 years) were enrolled. At baseline, only 7 participants were ambulatory with an average gait speed of 0.16±0.43 m/s and a median WSICI-II of 0. RMT was established in TA for 10 participants (43%) and in RF for 5 participants (22%). AMTs were established in 11 participants (48%) for TA and in 9 participants (35%) for RF. The AMT of TA muscles were significantly correlated with the WISCI-II (rho= -0.62, p= .04). The AMT of both TA and RF muscles were negatively correlated with gait speed with an approaching statistical significance (rho= -0.54 and -0.57, both p= 0.09). MEP amplitudes measured under active TA contraction were significantly correlated with WISCI-II and gait speed (rho= 0.82 and 0.71 respectively). The input-output curve slope measured from TA was significantly correlated with the gait outcomes (rho= 0.66 – 0.82, ps< .05).
Discussion and Conclusion: Neurophysiological markers acquired using TMS significantly correlated with gait function, especially measurements acquired from TA muscle under active contraction. Overall, increased corticospinal excitability was associated with better gait function. Our findings implicate the role of corticospinal excitability in gait recovery after SCI.
Categories
Spinal Cord Injury (SCI)
Behavioral and Neural Correlates of Post-Stroke Fatigue: a randomized controlled trial protocol
Kuan-Chun Liao1, Isabelle Christian1, Jill Stewart2, Elaine Trudelle-Jackson1, Wanyi Wang3, Ty Shang4, Hui-Ting Goh1
1Texas Woman’s University, Dallas, USA. 2University of South Carolina, Columbus, USA. 3Texas Woman’s Univeristy, Houston, USA. 4University of Texas Southwestern Medical Center, Dallas, USA
Background: Post-stroke fatigue (PSF), defined as intensified perceived effort during activities, is a common challenge reported by people with stroke and caregivers. PSF negatively impacts functional recovery and quality of life but the underlying mechanism is largely unknown. Previous studies showed that people with PSF exhibited lower corticospinal excitability, and a recent study found that one session of anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) reduced PSF temporarily. However, whether anodal tDCS can reduce PSF with a lasting effect is unclear. Furthermore, the underlying mechanisms supporting the therapeutic effects of tDCS on PSF remains to be determined.
Purpose and hypothesis: This study aims to investigate the behavioral and neurophysiological effects of five daily sessions of anodal tDCS over M1 on PSF. We hypothesize that compared to sham tDCS, anodal tDCS will significantly reduce PSF after treatment and at one-month follow up, increase ipsilesional corticospinal excitability, and increase functional connectivity of the fronto-striatal-thalamic network.
Methods: This study is a double-blinded randomized control trial. Thirty-two people with subacute or chronic stroke who present with high fatigue (Fatigue Severity Scale > 36) will be randomized to an anodal tDCS or sham tDCS group. All participants will receive one tDCS session per day for five consecutive days. The anodal electrode will be placed over the ipsilesional M1 and the cathodal electrode will be placed over the contralateral supraorbital area. The anodal tDCS group will receive 2 mA stimulation for 20 minutes with a ramp-up and ramp-down time of 30 seconds at the beginning and end of the stimulation. The sham tDCS group will receive 20 minutes of sham stimulation. Participants will be assessed before and after the intervention and at one-month follow-up with clinical, behavioral, and neurophysiological outcomes. Severity of PSF will be quantified by self-reported clinical questionnaires, including the Fatigue Severity Scale, Fatigue Scale of Motor and Cognitive Functions, and Visual Analog Scale-Fatigue. Perceived effort during reaching, which correlates with PSF, will be measured with the Borg Rating of Perceived Exertion and Paas Mental Effort Rating Scale to assess motor behavioral effects. To determine neurophysiological effects, transcranial magnetic stimulation (TMS) and resting state fMRI will be used to assess ipsilesional corticospinal excitability and functional connectivity of the fronto-striatal-thalamic network, respectively. A 2-group (sham vs. anodal) by 3-time (baseline, post-intervention, follow-up) repeated measure analysis of variance will be used to evaluate the effect of the intervention with the α level set at 0.05.
Impact: This double-blinded randomized control trial will use a multi-modal approach to comprehensively investigate the underlying mechanisms of PSF. Our rich dataset of clinical, behavioral, neurophysiological and neuroimaging data will offer critical information for future studies to evaluate the efficacy of non-invasive brain stimulation in managing PSF.
Categories
Stroke
Advancing the Field of Neurorehabilitation through Data Harmonization: Harmonizing 10+ Years of Upper Limb Accelerometry Data
Allison Miller, Keith Lohse, Marghuretta Bland, Jeffrey Konrad, Catherine Hoyt, Catherine Lang
Washington University in St. Louis, St. Louis, USA
Introduction: Data harmonization is the process of amalgamating data from different sources into one cohesive database. Harmonizing and sharing data facilitates progress in neurorehabilitation by allowing researchers and clinicians to answer questions using large, pre-existing datasets, minimizing costs and duplication of scientific efforts, increasing statistical power through larger sample sizes, and fostering scientific collaboration. Wearable sensors are an evolving technology with enormous potential to improve the delivery and outcomes of rehabilitation care. Despite this potential, wearable sensors are primarily being deployed in the neurorehabilitation research realm in relatively small sample sizes across a small number of laboratories. To advance the field of neurorehabilitation and make wearable sensor data accessible to all, the purpose of this report is to describe our efforts to harmonize and share upper limb accelerometry data collected from numerous protocols over the past 10+ years.
Methods: Upper limb accelerometry data from eight studies from 2013 to present (n = 844 individuals over ~1,748 recording days) were harmonized into one database. Demographic and clinical variables were harmonized and named in accordance with the NINDS Common Data Elements (CDEs). In all study protocols, participants wore bilateral wrist accelerometers for at least 24 hours. Accelerometry data were summarized into 25 unique variables that reflect performance of the upper limbs in daily life.
Results: The harmonized database includes individuals with a variety of conditions, including people with stroke (n = 291), Parkinson’s disease (n = 70), orthopedic conditions (n = 45), spinal cord injury (n = 5), falls/gait instability (n = 7), autism spectrum disorder (n = 28), other medical conditions (n = 33), and healthy controls (n = 365). The database is 53% male, includes individuals from various racial backgrounds (67% White, 26% Black, 2% Asian), and spans an age range of 0 – 98 years. The 25 accelerometry variables span various aspects of motor behavior of the upper limbs, including movement duration (6 variables), intensity (7 variables), symmetry (3 variables), and complexity (e.g., variables that reflect smoothness of movement, 9 variables). At the time of this submission, we are finalizing the harmonized database and preparing a submission to the NICHD Data and Specimen Hub (DASH) repository.
Conclusions: Shifting wearable sensor data from siloed laboratories to a large, public repository will bring wearable sensor data within reach of laboratories for which the technology is unfamiliar or not available, allow the field to answer important questions in larger and more diverse sample sizes, and ultimately support the translation of wearable sensor technology from primarily the research realm into clinical care settings. This harmonized database will continue to grow as new data from our group and others are collected and added, providing an important resource for the field for years to come.
Categories
Motor Rehabilitation
Magnetic Resonance Imaging Indicators of Post-Stroke Spasticity
Katharine A. Scarlat1,2, Theodore Wein3,4,5, Marie-Hélène Boudrias2,6, Alexander Thiel3,7, Anatol G. Feldman2,8, Mindy F. Levin2,6
1Integrated Program in Neuroscience, McGill University, Montreal, Canada. 2Jewish Rehabilitation Hospital, Centre for Interdisciplinary Research in Rehabilitation, Montreal, Canada. 3Department of Neurology and Neurosurgery, McGill University, Montreal, Canada. 4McGill University Health Center, Montreal, Canada. 5St Mary’s Hospital, Montreal, Canada. 6School of Physical and Occupational Therapy, Montreal, Canada. 7Jewish General Hospital, Montreal, Canada. 8Department of Neuroscience, University of Montreal, Montreal, Canada
Stroke is a main cause of disability and post-stroke spasticity affects up to 60% of stroke survivors, limiting their recovery and functional independence. Accurate early detection of spasticity may be hampered by limitations in current clinical measures. Better detection of spasticity may help to decrease the impact of spasticity by the administration of earlier tailored treatments.
Our objective was to determine the relationship between stroke lesion location, descending tract integrity, and changes in spinal cord motoneuronal excitability using a novel measure, the Tonic Stretch Reflex Threshold (TSRT), on the development of spasticity in people with acute stroke. We hypothesized that greater stroke-related damage in the brain and descending cortico- and reticulospinal tracts would be associated with the development of a larger angular zone in which spasticity is present in the affected muscles.
Individuals were admitted into the study within one week of their stroke and assessed weekly for 12wk to evaluate sensorimotor deficits and spasticity in elbow flexors and/or ankle plantarflexors (TSRT; Modified Ashworth Scale [MAS]; etc.). Brain and spinal cord scans were done 6wk post stroke using anatomical and diffusion Magnetic Resonance Imaging (MRI). Manual lesion delineation of MRI scans was done with the FSL program, and diffusion data analysis of the reticulospinal and corticospinal tracts was done using the Spinal Cord Toolbox.
Preliminary results indicate that the TSRT is more sensitive for the early detection of spasticity than the MAS, and that there is a correlation between the reticulospinal tract radial diffusivity of the and the level of spasticity identified by the TSRT.
By improving accuracy in predicting who will develop spasticity after a stroke, more tailored treatments may be created to minimize the impact of spasticity on recovery and increase the functional independence in those living with stroke.
Categories
Stroke
Botulinum Toxin Type A vs Dry Needling in the management of lower limb spasticity in patients post-stroke: A controlled proof-of-concept trial
Joy Khayat1,2, Clara Pujol-Fuentes3, Pablo Herrero4, Wim Saeys5, Barte Eeckhaut6, Theodore Wein1, Mindy Levin1,2
1McGill University, Montreal, Canada. 2Jewish Rehabilitation Hospital, Montreal, Canada. 3Universidad Europea de Valencia, Valencia, Spain. 4IIS ARAGON, University of Zaragoza, Zaragoza, Spain. 5University of Antwerp (ANT), Wilrijk, Belgium. 6University of Antwerp, Turnhout, Belgium
Introduction: Post-stroke lower limb spasticity causes a gait disorder that results in a reduced quality of life. Two treatments used to decrease spasticity and improve walking in people with stroke are injection of botulinum neurotoxin (BTX) and dry needling (DN). As injection of BTX may have some adverse effects, it has been proposed that DN may be an effective alternative to the more invasive chemical denervation. However, there is little information about the change in tone after each of these treatments at the central (spinal) level and the duration of these effects.
Objectives: The primary objective is to determine the mechanisms of action of BTX injection and DN on lower limb post-stroke spasticity. Secondary objectives are to determine safety and feasibility of each treatment and their effects at muscle and functional levels, quality of life and cost-effectiveness.
Methodology: This is a 3-year prospective study involving 3 countries (Canada, Spain, Belgium) with 90 participants (aged >18 yr; spasticity in ankle plantarflexors (PF)). One group of subjects receive a series of 12 DN sessions and the other receives one injection of BTX in ankle PF and toe flexors. Effects of each treatment are evaluated before (3 baseline evaluations), after (for 12 weeks) and at a 4 week follow-up timepoint. Stretch reflex excitability is evaluated at the Body Structure and Function level by measuring the Tonic Stretch Reflex Threshold and its velocity sensitivity in PFs and effects on muscle are evaluatedusing ultrasound imaging and the Modified Ashworth Scale. Gait activities are measured at the Activity level and the quality of life at the Participation level. In addition, we will determine the patient acceptability and cost-effectiveness of each intervention.
Expected results: Results of this study will provide important information to help clinicians, patients and caregivers make optimal choices for the treatment of ankle post-stroke spasticity.
Categories
Stroke
Combining cerebellar transcranial direct current stimulation (tDCS) with constraint-induced language therapy (CILT) in individuals with non-fluent aphasia: a novel approach for targeting discourse
Madelyn Graham1, Marie Meysembourg1, Sharyl Saaumargia-Grivette1, Lynette Carlson1, Rebecca Gilbertson2
1University of Minnesota Duluth, Duluth, USA. 2University of Minnesota Duluth, Duluth, United States Minor Outlying Islands
Purpose: The purpose of this pilot was to determine if adding cerebellar transcranial direct current stimulation (tDCS) to CILT results in greater changes in discourse performance in individuals with non-fluent aphasia, than CILT alone. And, if this intervention leads to spectral power differences in the left frontal region.
Methods: This was a crossover, sham-controlled pilot study. Intervention conditions included 1) CILT with sham cerebellar tDCS and 2) CILT with real cerebellar tDCS. Both conditions consisted of six intervention visits, three times per week across two weeks, with a four-week washout period between conditions. Each participant was randomly assigned to either sham first or real first to control for an order effect. Intervention sessions included the application of two saline-soaked electrodes: (1) the anode placed over the right ventral-lateral cerebellar hemisphere, 1-2 cm below and 3-4 cm lateral to the inion, and (2) the cathode electrode on the right deltoid. Stimulation was set at 2mA for 20 minutes during which time, the participant engaged in CILT with a licensed, certified speech-language pathologist and a graduate student. The total intervention lasted 45 minutes: 20 minutes of combined tDCS and CILT and the final 25 minutes, CILT only. Discourse tasks and resting state EEG were collected before and after each intervention phase. Working memory was also assessed will be reported in another poster.
Results: A total of five participants completed this pilot, with no attrition and no adverse effects reported. Differences in main concept and core lexicon scores of the following discourse tasks: picture description (Broken window) and story retell (Cinderella) will be presented. In addition, correlation between the above discourse scores and spectral power of delta, gamma and alpha frequency bands will be reported.
Conclusion: Findings confirmed the feasibility of the research design. And, will provide insight to the potential of combining CILT with tDCS and will add to the current evidence of neurophysiologic and behavioral impact of cerebellar tDCS. All of which will be used to inform a larger trial.
Categories
Cognitive/Language Rehabilitation
Can working memory be impacted by combining cerebellar tDCS and Constraint-Induced Language Therapy in non-fluent aphasia?
Haley Evans, Sharyl Samargia-Grivette, Lynette Carlson, June Lee
University of Minnesota Duluth, Duluth, MN, USA
Purpose: The purpose of the study was to determine how the combined effects of cerebellar tDCS with constraint-induced language therapy (CILT) would impact individuals with non-fluent aphasia following a stroke.
Methods: This was a crossover, sham-controlled pilot study. Intervention conditions included 1) CILT with sham cerebellar anodal tDCS and 2) CILT with real cerebellar anodal tDCS. Both conditions consisted of six intervention visits, three times per week across two weeks, with a four-week washout period between conditions. Each participant was randomly assigned to either sham first or real first to control for an order effect. Intervention sessions included the application of two saline-soaked electrodes: (1) the anode placed over the right ventral-lateral cerebellar hemisphere, 1-2 cm below and 3-4 cm lateral to the inion, and (2) the cathode electrode on the right deltoid. Stimulation was set at 2mA for 20 minutes during which time, the participant engaged in CILT with a licensed, certified speech-language pathologist and a graduate student. The total intervention lasted 45 minutes: 20 minutes of combined tDCS and CILT and the final 25 minutes, CILT only. Working memory and resting state EEG were collected before and after each intervention phase, along with language tasks that will be reported in another poster.
Results: A total of five participants completed this pilot, with no attrition and no adverse effects reported. Differences in n-back accuracy and false alarms before and after intervention phases will be reported. In addition, correlation between n-back accuracy and 1) discourse and 2) spectral power of delta, gamma and alpha frequency bands from the left frontal cortex will be reported.
Conclusion: Findings confirmed the feasibility of the research design. And, provide insight to the potential of combining CILT with tDCS and will add to the current evidence of the neurophysiologic and cognitive impact of cerebellar tDCS. All of which will be used to inform a larger trial.
Categories
Cognitive/Language Rehabilitation
Within-session changes in propulsion asymmetry have minimal effect on overall gait asymmetry in individuals post-stroke
Sarah Kettlety, James Finley, Kristan Leech
University of Southern California, Los Angeles, USA
Biomechanical gait impairments are common post-stroke.1 Increasing paretic propulsion is a popular intervention objective because propulsion is associated with walking speed2 and can be successfully increased using various interventions.3 Studies that target paretic propulsion mainly focus on quantifying the changes in propulsion asymmetry and typically do not consider the intervention’s effect on overall gait asymmetry. There is an implicit assumption that reducing propulsion asymmetry will similarly reduce overall gait asymmetry, as propulsion has been related to numerous biomechanical impairments.2,4,5 However, no work has directly investigated the impact of reducing propulsion asymmetry on overall gait asymmetry. The primary aim of this study was to understand how within-session changes in propulsion asymmetry related to changes in overall gait asymmetry operationalized as the combined gait asymmetry metric (CGAM). The CGAM provides a single comprehensive and easily interpretable measure of overall kinematic and spatiotemporal gait asymmetry.6 Because of propulsion’s relationship with trailing limb angle,5 knee flexion,4 step length asymmetry,2 and sagittal kinematic gait asymmetry,7 we hypothesized that changes in propulsion asymmetry would reduce CGAM. Twenty-three participants completed a baseline treadmill walking trial, then twenty minutes of biofeedback treadmill training to increase paretic propulsion. We calculated the change in normalized paretic propulsion, change in propulsion asymmetry magnitude (Δ |PA|), and change in CGAM (Δ CGAM) from baseline during biofeedback training. We verified that increasing paretic propulsion using the biofeedback decreased propulsion asymmetry by fitting a robust linear mixed-effects model with Δ |PA| as the outcome, a fixed effect for change in normalized paretic propulsion, and a random intercept and slope for each participant. Then, we examined the relationship between propulsion asymmetry magnitude and the corresponding change in CGAM by fitting a robust linear mixed-effects model with Δ CGAM as the outcome, a fixed effect for Δ |PA|, and a random intercept and random slope for each participant. We found that increased normalized paretic propulsion was related to reduced propulsion asymmetry magnitude (β=-0.06, p<0.0001). We also found a positive association between Δ |PA| and Δ CGAM (intercept β=-1.6, p=0.49; CGAM β=3.0, p=0.002). The average change in propulsion asymmetry magnitude in our sample was -0.07, suggesting that on average, we would expect to see a CGAM reduction of 1.8. A CGAM change of 1.8 is relatively small, particularly since the average CGAM of our sample during baseline was 41.6 ± 30.1. This suggests that while propulsion biofeedback can be used to reduce propulsion asymmetry, it is unlikely to produce meaningful reductions in overall gait asymmetry. Therefore, propulsion asymmetry may not be an ideal target for biofeedback interventions designed to improve overall gait asymmetry. Future work should investigate different approaches, such as multidimensional biofeedback, to improve overall gait asymmetry.
Categories
Stroke
A Novel Approach to Patients with Maladaptive Behavior on an Acute Inpatient Rehabilitation Unit Following Acquired Brain Injury (ABI): The Utility of Applied Behavior Analysis (ABA) in the Rehabilitation Setting
Arielle Reindeau1, Michael Makley1,2, Benjamin Ingraham1, Eric Spier1,2
1Craig Rehabilitation and Research Hospital, Englewood, USA.
2University of Colorado Department of Physical Medicine and Rehabilitation, Aurora, USA
In this presentation, we will discuss a novel framework that considers behavioral disturbance after acquired brain injury (ABI) to be a temporary dysfunction of frontotemporal systems. Dysfunction of these offline neural networks leads to impaired executive function and memory encoding. These, coupled with poor insight and deficit awareness (anosognosia), lead to a loss of top down modulation of behavioral output resulting in maladaptive behavior. Consequences of such network dysfunction can range from a mildly irritable patient to one who is wildly combative with severe impulse dyscontrol. The challenge confronting the practitioner is how to get the affected patient through this temporary period of confusion, amnesia and heighted behavioral dyscontrol – also known as post traumatic amnesia (PTA) - without injury to the staff, family or patient. The physician that is directing care in acute rehabilitation centers is often asked to manage these patients’ behaviors during this period without the proper tools to manage their frontotemporal injury. To address this, we propose the use of Applied Behavior Analysis (ABA) utilizing a Board-Certified Behavior Analyst (BCBA) on the acute inpatient rehabilitation unit. BCBA directed ABA science is a validated and widely accepted approach that has been used for decades in the field of autism spectrum disorder and other developmentally challenged individuals, as well as in transitional programs specializing in persistent behavioral disorders after ABI. We believe that we are the first to bring such a program to an acute inpatient ABI specialty unit and since implementation we have seen a marked reduction in staff injury and a reduction in costs related to managing aggressive patients with frontotemporal injury. Additionally, we have seen an overall improvement in staff and family confidence in dealing with the temporary period of confusion that often follows ABI. In this presentation, we will review the basic elements of the science of ABA and the integration of a BCBA into the acute inpatient unit, followed by a discussion of both the results of our program and how these tools and techniques can generalize to other settings.
Categories
Traumatic Brain Injury (TBI)
Transition State Disorders following Moderate to Severe Brain Injury: A Novel Framework for Understanding Agitation, Confabulation, and Maladaptive Behavior after Acquired Brain Injury (ABI). A Series of 3 Case Studies
Michael Makley1,2, Eric Spier1, Matthew Loftspring1, Benjamin Ingraham1
1Craig Rehabilitation and Research Hospital, Englewood, USA.
2University of Colorado Department of Physical Medicine and Rehabilitation, Aurora, USA
Sleep disturbance after acquired brain injury is highly prevalent and some estimates put its prevalence at > 80% on an acute inpatient rehabilitation unit. In a 2005 study Baumann and colleagues found significantly lower levels of hypocretin/orexin in the CSF of patients with moderate to severe traumatic brain injury in an acute trauma center. They also found that lower levels of hypocretin/orexin correlated with deeper states of unresponsiveness. This neuropeptide is generated in the lateral hypothalamus and is thought to be critical in the “Flip/Flop Switch” model of sleep and wake cycles proposed by Saper and colleagues. In the past two decades hypocretin/orexin has been found to be either extremely low or even absent in patients with Type 1 and Type 2 Narcolepsy a clinical syndrome the hallmarks of which rest in having indistinct boundaries between states of sleep and wakefulness. The porous demarcation between these states leads to the remarkable clinical phenomena associated with this neurologic disorder such as cataplexy, hypnopompic or hypnogogic hallucinations, and sleep paralysis. REM Sleep Behavior Disorder (RBD) has also been described in these patients.
We present 3 cases of patients with moderate to severe traumatic brain injury who appear to have marked difficulty distinguishing between the dream and wakeful state on an acute inpatient rehabilitation unit. One patient with extreme agitation had many characteristics of REM Sleep Behavior Disorder with violently acting out adversarial dream state behavior. The other two patients more closely resembled subjects coming out of either hypnopompic or hypnogogic states.
In this presentation, we describe the clinical profile of these three patients and propose a classification system that could help the clinician identify similar patients with this syndrome. Established diagnostic criteria for transition state disorder after acquired brain injury will help us better understand the prevalence of this disorder in this patient population as well as help the development of appropriate treatment strategies. The authors will also offer a rational neuropharmacological approach to this syndrome.
Categories
Traumatic Brain Injury (TBI)
Bimanual and Unimanual Rehabilitative Training After Stroke: Patterns of Activity-Dependent Structural Plasticity in Peri-lesion and Contra-lesion Cortices
Victoria Nemchek, Celeste J. Hoang, Vinuthna Mallampaty, Morgan McCrea, Nikita Potdar, Vennila Satheesh, Deekshita Sundararaman, Theresa A. Jones
The University of Texas at Austin, Austin, USA
After a stroke, areas surrounding the lesion core (i.e., peri-lesion areas) experience increases in plasticity triggered by the injury. Rehabilitative training with the forelimb impaired by motor cortical stroke leads to adaptive plastic changes in the peri-lesion cortex. However, the role of plasticity in the less-affected hemisphere in recovery from stroke remains unclear. Compensatory reliance of the less-affected limb leads to maladaptive plasticity in both hemispheres. Limiting use of the less-affected limb, including physically constraining it, is a common therapeutic technique. Yet, contra-lesion plasticity appears to aid in recovery under the right conditions. This study illuminates activity-dependent plastic dynamics across hemispheres of the brain and deciphers the neural underpinnings of both impaired forelimb rehabilitation and coordinated use of both forelimbs.
Unimanual and bimanual rehabilitative training paradigms were used to compare activity-dependent structural plasticity in peri-infarct cortex and homotopic contra-lesion cortex after photothrombotic sensorimotor cortical stroke in 17 adult Thy1-GFP mice (6 female, 11 male). Bilateral cranial window implantations allowed for repeated in vivo two-photon imaging comparing dendritic spine dynamics between hemispheres for individual mice. After photothrombotic motor cortical ischemic stroke, mice either trained unimanually, bimanually, or received no training (Controls). The single seed reaching task prompts skilled reaching in a single forelimb (Unimanual) and is also used to assess impaired limb function. The Bimanual task is also a skilled reaching task but differs in that mice must use both forelimbs cooperatively to retrieve a food reward.
Rehabilitative training experiences differentially impacted activity-dependent structural plasticity in both the peri-lesion and homotopic contra-lesion cortices Mice that experienced bimanual rehabilitative training showed increased stability, decreased formation of new spines, and greater persistence of the spines formed within a week after stroke in the contra-lesion cortex. However, the bimanual group performed similarly to non-training controls on assessments of impaired limb function. The bimanual nature of the rehabilitative training was insufficient to protect from the maladaptive effects of non-impaired limb overuse after stroke. Together, these data suggest that bimanual training stabilized dendritic spines in the contra-lesion cortex and these spines likely depend on activity of the non-impaired limb during the bimanual task. Bimanual compared to unimanual training led to different patterns of plasticity in the contra-lesion cortex which underly compensatory reliance on the non-impaired limb to complete the task. These plastic changes are maladaptive and reinforce the notion of competition between mechanisms supporting the skilled use of each forelimb. Clinicians can use these findings to optimize patient rehabilitation to support maximal neural and behavioral recovery after stroke.
Categories
Stroke
Assessing the Feasibility of Collecting Reliable Center-out Reaching Measures at the Bedside and Clinic Using Accessible Single Camera Motion Capture Systems in the First Three Months Following Stroke
Megan McCune1, Julia Moon1, Tullia Lieb2, Dominica Randazzo1, Robert Matthew1
1University of California at San Francisco, San Francisco, USA.
2University of Southern California, Los Angeles, USA
Introduction: Recent recommendations from the Stroke Recovery and Rehabilitation Roundtable (SRRR) have supported the use of the planar reaching task for assessing changes in movement quality following stroke1. While the SRRR recommends the use of gold-standard marker-based methods, accessibility and the time required to apply makers challenge their use. Markerless motion capture may improve access and decrease participant burden, enabling the collection of movement metrics at the bedside and in the clinic. In this project, we assess the feasibility of collecting planar reaching movements using two single camera markerless motion capture methods: a depth camera and a webcam.
Methods: A total of 1,536 reaching movements were collected for the control (n=3, 1M/2F, 864 movements) and post-stroke (n=2, 1M/1F) groups (IRB 20-31414). Reaching movements were performed on a height adjustable table following the SRRR-recommended protocol1. Post-stroke data were collected within the first 2 weeks (T0, 320 movements) and at three months (T3, 352 movements). The Fugl Meyer Assessment: Upper Extremity2 (FMA-UE) was collected for the post-stroke group at both timepoints.
Gold-standard (240Hz), depth (30Hz), and webcam (30Hz) motion capture data were collected for all participants. OpenPose3 and custom MATLAB software were used to process all motion capture data. SRRR recommended movement variables were computed for each motion capture modality. Outlier trajectories were rejected resulting in the retention of 92%, 76%, and 62% movements respectively.
Results: Differences between the more and less affected limbs were found for the first stroke participant. At T0 (FMA-UE Proximal: 7/36), peak reaching velocities were significantly slower, (p<0.01, More affected: 21.3 ± 5.6 cm/s, Less affected: 25.9 ± 4.0 cm/s), which were not significantly different at T3 (FMA: 33/36) (p = 0.36, More affected: 27.3 ± 5.8 cm/s, Less affected: 26.6 ± 3.9 cm/s). These differences were not seen for the second participant (FMA-UE Proximal: T0: 30/36, T3: 35/36).
The depth and webcam measures had higher errors in end-point position (4.1 ± 2.3 cm, 3.3 ± 2.6 cm), heading (8.4 ± 6.6 deg, 7.3 ± 7.8 deg), and peak velocity (-2.1 ± 1.5 cm/s, -0.0 ± 1.7 cm/s) compared to the gold-standard motion capture (0.4 ± 0.2 cm, 0.6 ± 0.4 deg).
Discussion: The center out reaching task was successfully implemented using all three motion capture methods, though the metrics obtained through markerless methods had higher errors and outlier rejection rates. The webcam-derived peak velocity measure was found to have a low error, suggesting that velocity-based metrics may be more reliable than position-based measures for these single camera systems.
Conclusion: Markerless motion-capture may provide an accessible method for conducting upper-limb reaching assessments, though further studies are needed before it can replace gold-standard systems.
Categories
Stroke
Lower limb resistance exercise and treadmill training best improve walking in multiple sclerosis: Results of a systematic review and meta-analysis
Syamala Buragadda1, Syed Raza1, Abby Blaney1, Amber Critch1, Evan MacKenzie1, Sydney Hiller1, Leah Peckham1, Hannah Murphy1, Jaideep Melam2, Kristen Romme3, Michelle Ploughman1
1Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland, St.John’s, Canada. 2Prince of Wales Collegiate, St.John’s, Canada. 33Health Sciences Library, Faculty of Medicine, Memorial University of Newfoundland,, St.John’s, Canada
Objective: Despite an expanding body of literature on the effectiveness of rehabilitation exercises in MS, there is a lack of knowledge regarding optimal interventions to improve walking. This study aimed to systematically review existing evidence to estimate the impact of various exercise interventions on gait speed in people with MS.
Data sources: Electronic databases, Ovid MEDLINE, PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, Physiotherapy Evidence Database (PEDro) and the Cochrane Library were searched from March 2021 to November 2023 for relevant randomized controlled trials (RCT) of gait interventions in MS.
Study selection: Trials focusing on the impact of exercise programs, with a duration of three weeks or more, on walking speed, assessed either as a primary or secondary outcome in individuals with MS, were included.
Data extraction: Two independent reviewers conducted screening and data extraction using Covidence. Quality and risk of bias in the selected studies were evaluated using the PEDro scale. The random effects model was employed for calculating effect sizes represented as standardized difference in means (d). We used Comprehensive Meta-Analysis software (version 4) for analysis.
Results: The initial search identified 5,447 studies, with 90 RCTs meeting the inclusion criteria. Based on the type of intervention employed, studies were categorized into 10 groups: lower limb resistance, treadmill, whole body vibration, overground and robotic gait, balance, aerobic and resistance, individualized in-person physiotherapy, individualized virtual physiotherapy, home exercises and pilates and yoga. Data from 77 articles were used to calculate effect sizes (2,796 participants with MS). The overall effect size indicated a positive impact of interventions on gait speed (d=0.27; 95% confidence interval, 0.159-0.383; P=0.001). Sub-group analysis showed that lower limb resistance (d=0.68; 95% confidence interval, 0.412-0.951; P<0.001) and treadmill training (d=0.44; 95% confidence interval, 0.258-0.635; P<0.002) were most effective. Heterogeneity analysis revealed variation in the true effect size across studies (Q=210.8; df-76; p<0.001) with a variance (I2) of 64% and a prediction interval of -0.685 to -1.151. Most studies (66%) exhibited good methodological quality with a PEDro score ranging from 6 to 10.
Conclusion: Despite heterogeneity across studies, our review showed a positive but small overall effect of exercise interventions on gait speed in individuals with MS. Notably, lower limb resistance and treadmill training emerged as the most effective interventions.
Categories
Multiple Sclerosis (MS)
A Sensor-Derived Metric to Differentiate Between Upper Extremity Impairment Levels Following Stroke
Megan McCune, Robert Matthew
University of California at San Francisco, San Francisco, USA
Introduction: Our work aims to develop a sensor-derived metric to monitor changes in upper extremity (UE) motor impairment for patients with stroke based on the principles of the Fugl-Meyer Assessment-Upper Extremity (FMA-UE). The FMA-UE provides a motor impairment score primarily based on a patient’s ability to move outside of synergistic patterns and their UE range of motion1. We used inertial measurement unit (IMU) sensor data to evaluate differences in the repetition of movement patterns mimicking those assessed in the FMA-UE examination while participants performed nine tasks. We hypothesize that participants with greater UE motor impairment will perform fewer movements outside of synergistic patterns compared to those with lower UE impairment.
Methods: We utilized the publicly available PrimSeq database2, containing kinematic data from 9 upper body IMUs collected from 50 subjects with UE impairment post-stroke (n = 20 mild, 23 moderate, and 7 severe UE impairment by FMA-UE, cutoff scores from Lundquist et al.3). Each subject performed approximately 5 repetitions of 9 tasks: combing, applying deodorant, drinking, face washing, eating, donning glasses, moving objects horizontally, moving objects on a shelf, and toothbrushing. This resulted in a total of 1970 tasks (877 mild, 910 moderate, 183 severe).
Each task was divided into one-second intervals. We then developed an algorithm that uses the position and velocity of the shoulder and elbow to label the affected UE movement in each interval as flexor synergy, extensor synergy, out-of-synergy, or unknown. The number of out-of-synergy movements, normalized by time, were compared between FMA-UE impairment groups using Kruskal-Wallace tests.
Results: There was a significant difference in the number of movements with simultaneous elbow extension and shoulder flexion between individuals with mild, moderate, and severe UE impairment. This out-of-synergy movement was defined as a one-second interval with both elbow extension (mean extension velocity>5°/s, minimum angle<90°) and shoulder flexion (mean flexion velocity>5°/s, maximum angle>45°). Individuals with greater UE impairment performed a higher number of this movement pattern per second (Kruskal Wallace p<.001; mild: mean=0.129 movement pattern/second (mp/s), median=0.084mp/s, IQR=0.191mp/s; moderate: mean=0.050mp/s, median=0mp/s, IQR=0.082mp/s, severe: mean=0.038mp/s, median=0mp/s, IQR=0mp/s). Dunn’s Multiple Comparison test showed significant differences between subjects with mild and moderate impairment (p<.001), mild and severe impairment (p<.001), and moderate and severe impairment (p<.001).
Discussion: These findings support our hypothesis that individuals with greater UE impairment performed fewer out-of-synergy movements compared to those with lower UE impairment. In future work, we will utilize machine learning techniques to classify this movement pattern from raw accelerometer and gyroscope data collected from a single wrist-worn IMU. Our ultimate objective is to develop a sensor-based measurement of motor recovery, which can be integrated into a remote activity monitoring system and provide greater insight into real-world UE movement quality following stroke.
Categories
Stroke
Perception of transcranial electrical stimulation (TES) affects blinding efficacy in young children differently than young adults
Sophia Bertrand1, Tonya Rich2, Samuel Nemanich1
1Marquette, Milwaukee, USA. 2Minneapolis VA Healthcare, Minneapolis, USA
Introduction: Rehabilitation interventions for children with motor disabilities due to stroke produce limited long-term gains. Interventions combining occupational therapy and transcranial electrical stimulation (TES) could enhance motor learning and neuroplasticity, thereby improving upper limb function. However, ineffective blinding may lead to biases that impact motor performance outcomes. Novel sham protocols (ActiSham) that produce a consistent sensation of stimulation but a net-zero electric field, in contrast to traditional ramp-up/ramp-down sham protocols, have been developed to improve blinding but have not been thoroughly tested. Furthermore, in pediatric rehabilitation, children may perceive stimulation uniquely when compared to adults due to differences in sensory sensitivity, further affecting blinding. However, blinding has not been examined in pediatric populations. In this study, a systematic comparison was completed to 1) assess participant blinding during an experimental (Active) and 2 control (Sham and ActiSham) TES conditions in children and young adults, 2) evaluate changes in motor learning after single session TES, and 3) evaluate the correlation between sensory sensitivity and participant blinding.
Methods: Right-handed children (N=11, 5-14 yr, mean=9.3 yr) and young adults (N=14, 15-25 yr, mean=22.2) with typically developing cognitive and motor skills were recruited. A within-subjects single-session design was used to test motor performance after 3 TES conditions counterbalanced across participants: Active, Sham, and ActiSham. Participants practiced the Nine Hole Peg Test (NHPT) with their left hand with TES targeting the right motor cortex. After each TES condition, participants were asked if they received real or fake TES and their response confidence (0-10 scale). Two-way ANOVAs were used to determine the effects of TES condition and age on 1) blinding (weighted accuracy score) and 2) motor performance (change in NHPT time). To quantify sensory sensitivity, participants completed the child or adult version of the Sensory Profile (2nd edition), a standardized occupational therapy questionnaire that evaluates how a participant’s sensory processing affects their daily life; scores were then compared to blinding outcome.
Results: There was a significant age effect for blinding (F(1, 24)=13.2, p<0.001), such that children reported they received real TES with higher confidence compared to young adults. There were no significant improvements on the NHPT across TES conditions (F(1, 24)=0.509, p = 0.605), indicating that the active/sham TES had no effect on improving motor performance. However, motor performance improved after each condition irrespective of type of TES in the young adults but not the children. There were no significant associations between sensory sensitivity and participant blinding (all r < 0.30).
Conclusion: TES blinding was not achieved for children compared to young adults as children reported receiving real stimulation in more conditions with higher confidence. Future TES studies should include comprehensive assessments to systematically measure blinding and to consider differences in expectancy and biases for child participants.
Categories
Motor Rehabilitation
Assessment and treatment of bimanual function in children with cerebral palsy: a scoping review
Anne Claire David1, Laura Fournier-Poisson1, Maxime Robert2, Marika Demers1,3
1Université de Montréal Montreal, Montreal, Canada. 2Université Laval, Quebec, Canada. 3Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain - IURDPM, Montreal, Canada
Background: Altered upper limb function is frequent in children with cerebral palsy (CP), which can result in activity limitations, reduced participation, and quality of life.1 Children with CP are also less likely to use their more-affected upper limb while engaging in their daily activities and often use compensatory strategies to accomplish these daily activities.2 To date, most research has focus on improving unilateral upper limb function, with little attention to bimanual function.
Aim: 1) To identify the outcome measures used to capture bimanual tasks/activities in children with CP aged between 6 and 17 years, and 2) To determine which rehabilitation interventions promote bimanual activities.
Methods: We conducted a scoping review based on the five-step Arksey and O’Malley framework,3 adapted by Levac et al.4 Five different medical databases (MEDLINE, CINAHL, EMBASE, OTseeker and PEDRO) were searched using the key words and variations “child”, “rehabilitation intervention”, “cerebral palsy” and “bimanual activity”. We included publications with children with CP (aged 6-17 years old), delivering rehabilitation interventions targeting upper limb function and using valid outcome measures with at least one item assessing bimanual tasks/activities. Pharmacological or surgical interventions, reviews and expert opinions were excluded. Screening was done sequentially by two independent researchers: 1) title/abstract screen and 2) full-text screen. Data related to the study participants, interventions, outcome measures and results were extracted.
Results: The search strategy initially yielded 5074 publications and 77 included publications from 74 studies were included. For the study design, 54.5% of studies were randomized control trial and of this number 22.3% of studies did not use an active control group. The mean sample size was 26.8 (SD:18.3) participants and the mean age of participants was 9.1(1.8) years. Most (94.6%) studies included participants with hemiplegic CP and 20.3% also included participants with bilateral CP. For the outcome measures, 15 different measures were identified to capture bimanual tasks/activities, with the Assisting Hand Assessment (n=32), the ABILHAND-KIDS questionnaire (n=23) and the Bruininks–Oseretsky Test of Motor Proficiency (n=13) being the most frequently used. For the interventions, 15 interventions were identified to promote bimanual upper limb function. The five more frequent studied interventions were Constraint-induced movement therapy (CIMT; n=19), Virtual reality (n=17), Hand-Arm Bimanual Intensive Training (n=12), Bimanual intensive training (combined with CIMT: n=7, alone: n=3) and Action observation (n=5).
Significance: Multiple performance-based and self-reported measures were identified to capture bimanual activities. Similarly, multiple interventions were identified to promote bimanual activities. However, important gaps remain such as limited literature for older children with CP, small sample sizes and limited studies using an active control group, which should be addressed in future studies.
Categories
Motor Rehabilitation
Home-based Self-Delivered Prehabilitation Intervention to Proactively Reduce Fall Risk in Older Adults: A Pilot Randomized Controlled Trial of Transcranial Direct Current Stimulation and Motor Imagery
Clayton Swanson1,2, Sarah Vial1, Audrey Whiteman1, Todd Manini1, Kimberly Sibille1, David Clark1,2
1University of Florida, Gainesville, USA. 2Malcom Randall VA Medical Center, Gainesville, USA
Background: Falls and fall related injuries are a consequence of mobility decline, impacting one-third of adults over the age of 65 annually. While neurorehabilitation has shown efficacy in enhancing motor performance, achieving sustained behavioral improvement and neuroplastic adaptation poses challenges. Moreover, rehabilitation usually follows adverse health outcomes, such as injurious falls. This reactive intervention approach may be less beneficial than prevention focused interventions. This pilot study explores the feasibility, acceptability, and preliminary efficacy of a home-based, self-administered prehabilitation intervention. The intervention combines motor imagery (mentally rehearsing motor actions without physical movement) with neuromodulation (transcranial direct current stimulation, tDCS, applied to the frontal lobes) to enhance mobility performance in fall prone older adults.
Methods: Thirty older adults (79.5 ±4.7) were randomly assigned to receive either active or sham tDCS. Over a two-week period, participants completed six, 40-minute home-based, self-delivered motor imagery and tDCS intervention sessions. Motor imagery practice involved six instructional videos displaying mobility tasks reflecting activities of daily living. Simultaneously, the active tDCS group received 20 minutes of 2.0mA direct current stimulation, while the sham group received 30 seconds of stimulation. Feasibility and acceptability outcomes included rates of screening, enrollment, retention, compliance, and self-perceived acceptability of the intervention. Subjective mobility performance was evaluated using the mini-Balance Evaluation Systems Test (mBEST), which is scored between 0 and 28, with higher scores indicating better mobility. Utilizing wireless inertial sensors, objective mobility was measured as time to complete a single- and dual-task (serial sevens) Timed Up and Go (TUG) prior to and following the intervention.
Results: Recruitment averaged 20 screening calls and four enrollees per month, supporting feasibility of the intervention. Despite two participants withdrawing for non-study-related reasons, the study exhibited a retention rate of 93% and a compliance rate of 100%. Participants expressed confidence in using the tDCS device and perceived the motor imagery practice as helpful and relevant, supporting acceptability of the intervention. The subjective mBEST yielded a significant intervention effect (F(1,28)= 5.72, p=0.02, d=0.62), indicating mobility improvement in both groups. The objectively assessed single-task TUG showed no significant main effects or interactions, while the dual-task TUG demonstrated a group by intervention interaction (F(1,25)=6.5, p=0.02, d=1.01). Specifically revealing shortened TUG durations in the active tDCS group while the sham group demonstrated longer TUG durations following the intervention.
Conclusion: The feasibility and acceptability outcomes of our home-based, self-delivered motor imagery and tDCS intervention were robust. Additionally, preliminary efficacy revealed a favorable impact of motor imagery practice on overall mobility performance, with tDCS demonstrating a positive effect specifically on dual-task mobility performance. While a more extensive follow-up study is imperative, these initial results show the promising potential of enhancing mobility through the combination of motor imagery and neuromodulation.
Categories
Motor Rehabilitation
Applying Elastic Resistance Bands for Gait Training: A Simulation-Based Study to Determine How Band Configuration Affects Gait Biomechanics and Muscle Activation
Sierra Foley, Edward Washabaugh
Wayne State University, Detroit, USA
Wearable robotic exoskeletons and leg braces are desirable for gait rehabilitation because they can apply loads directly to an affected joint. Yet, they are not widely used in clinics because they are costly and complex to set up. Conversely, tethered devices, such as elastic resistance bands, are widely available in clinics, low-cost, and quick to set up. However, resistance bands will affect walking differently based on how they are configured to pull on the leg. For example, bands can be attached to different segments (e.g., the ankle, calf, or thigh) and oriented to pull in different directions (e.g., pulling forward or backward). Hence, we devised a study to determine how can a resistance band be configured to alter muscle activation and gait biomechanics based on the segment it is attached to and the angle with which it attaches. To determine this, we conducted two experiments. First, we used an open-source musculoskeletal modeling platform to emulate several configurations of an elastic band pulling on the leg. Configurations included pulling on three segments (i.e., the ankle, calf, and thigh) over sixteen angles (between 0° and 330°; 48 total configurations) during non-pathological walking. We evaluated gait biomechanics and simulated muscle activation using computed muscle control (CMC) throughout the gait cycle. From these data, we identified a subset of four configurations with potential applications for gait training. These configurations included walking with a band pulling on the ankle at 30°, ankle at 180°, calf at 180°, and thigh at 210°. In the second experiment, we conducted a human subject experiment on eight non-pathological participants who walked on a treadmill under these configurations. We collected electromyography from the lower extremity muscles to verify how these configurations altered muscle activation. Our simulation-based experiment found that muscle activity greatly varied based on the location where the elastic band was attached and the angle with which the elastic band pulled on the leg. Specifically, several configurations could be applied to increase or decrease muscle activation in the lower extremity. Our human subjects experiment confirmed these findings, indicating that an elastic band pulling on the ankle at 180° resists the quadriceps during the swing phase and the ankle plantar flexors during the stance phase. Meanwhile, pulling on the calf at 180° only resisted the ankle plantar flexors during the stance phase. Pulling forward on the ankle at 30° assisted the hamstrings during the stance phase, which was not seen in the other configurations. These results provide insight into how elastic resistance bands can be configured to provide assistance or resistance to the leg during gait training. Ultimately, this information could serve as a reference to guide clinicians when prescribing gait training with resistance bands.
Categories
Motor Rehabilitation
Perception of task duration impacts locomotor patterns and energy expenditure during split belt adaptation and de-adaptation
Samantha Jeffcoat1, Adrian Aragon2, Andrian Kuch1, Shawn Farrokhi1, Natalia Sanchez1
1Chapman University, Irvine, USA. 2Chapman University, Orange, USA
Background: Rehabilitation interventions aim to correct and restore walking behaviors toward what is commonly seen in neurotypical individuals1. This goal is achieved through a process called motor adaptation, in which a well-learned movement is adjusted to promote efficiency in a novel environment2. Motor adaptation is studied using a split-belt treadmill3,4, but the factors that drive the associated motor changes are still under debate. During adaptation, there is a reduction of energetic cost5,6, influenced by the duration of the task5, with individuals maintaining an energetic reserve during longer tasks7. Thus, we hypothesize that uncertainty of task duration will lead to a lower energetic cost and produce a faster adaptation to the split-belt when compared to knowledge of duration.
Methods: 18 healthy young participants underwent 3 walking trials: 6 minutes with the belts under each leg moving at 1 m/s (Baseline), 10 minutes with the left belt at 1.5 m/s and the right belt at 0.5 m/s (Adaptation), and again 6 minutes with the belts under each leg at 1 m/s (Post-Adaptation). Participants were assigned to either Knowledge (K) or Uncertainty (U) groups. Both groups walked for 10 minutes in the adaptation trial, however, K participants knew trial duration and received updates on time remaining while U participants were told they would be walking 30 minutes and received no updates. We measured step lengths, step length asymmetry, variability in step lengths, positive and negative work by each leg, metabolic power, and heart rate. We obtained averages for these variables during the last minute of Baseline, first, fifth and last minute of Adaptation, and first and last minute of Post-Adaptation. We used a 2x6 factorial ANOVA for statistical analyses.
Results: There were no significant differences in demographics between groups. We observed a significant main effect of time (p<0.001), and the interaction of time*group (p<0.05) for metabolic power and heart rate, with the U group showing lower exertion during both adaptation and post-adaptation, but higher heart rate during post-adaptation. We observed a significant main effect of time (p<0.001), and the interaction of time*group (p<0.05) for step lengths and positive work by the leg on the slow belt. The U group maintained shorter steps with the leg on the slow belt by the end of the post-adaptation trial relative to baseline (p=0.010) and generated a greater amount of positive work with the leg on the slow belt during post-adaptation (p<0.001).
Discussion: Uncertainty about task duration influenced walking behaviors, physiological responses, and gait mechanics during the adaptation and post-adaptation tasks, indicating that uncertainty influences adaptation and retention of locomotor behaviors. Given that uncertainty about duration can prolong the effects of adaptation and modify effort during the task, it can be used as a training variable during rehabilitation interventions.
Categories
Motor Rehabilitation
VNS-Enhanced Tactile Rehabilitation: A Pathway to Improved Somatosensation Post-Neurological Injury
Saeid Kian1,2, Michael Kilgard1,2, Seth Hays1,3, Robert Rennaker1,2,3, Joseph Epperson1,3, Kaitlyn Malley1,2, Zachary Bynum1,2, Spencer Stinson1,3, Emmanuel Adehunoluwa1,2, Rachael Hudson1,2
1Texas Biomedical Device Center, Richardson, USA. 2School of Behavioral and Brain Science, University of Texas at Dallas, Richardson, USA. 3Erik Jonsson School of Engineering and Computer Science, Richardson, USA
Chronic sensory loss is common following neurological injuries such as stroke and spinal cord injury and is associated with reduced quality of life. Novel therapeutic approaches are needed, since conventional rehabilitative strategies typically fail to fully restore sensory function after injury. Vagus nerve stimulation (VNS) during physical therapy enhances synaptic plasticity and facilitates motor recovery after stroke. The delivery of VNS during tactile therapy has emerged as a potential approach to enhance recovery of somatosensation after injury.
A case study in a man with post-stroke sensory loss reported that VNS paired with sensory therapy produced substantial gains in tactile threshold, proprioception, and stereognosis. Animal studies have revealed that pairing VNS with sensory therapy can improve sensory function long after injury. The improvement in sensory function depends on cortical release of acetylcholine and is associated with increased Arc protein expression in sensory cortex. These findings suggest that VNS paired with sensory therapy improves function by enhancing synaptic plasticity.
A plasticity-based mechanism of action is further supported by the observations that VNS must be delivered during sensory therapy and that the beneficial effects of VNS occur as an inverted-U function of VNS intensity. As in motor recovery, only moderate-intensity VNS improves somatosensory function, while lower and higher VNS intensities fail to enhance recovery.
We now seek to replicate our earlier finding that VNS paired with sensory therapy can improve somatosensation after stroke and evaluate for the first time whether it can also improve sensory loss caused by spinal cord injury. Subjects will engage in tactile therapy sessions, paired with short bursts of VNS accompanying every tactile event from simple touch to complex proprioceptive stimuli. The effectiveness of this approach will be closely assessed using advanced sensory assessment methods, including the U.S. Nottingham Sensory Assessment (US-NSA) and two-point discrimination tests, at different stages of the therapy. The study will evaluate the potential benefits observed in earlier studies, provide deeper insights into novel rehabilitation strategies for sensory recovery, and support future randomized trials.
Categories
Sensory Rehabilitation
Are there Differences in Walking Exercise Dose between Subgroups of People with Chronic Stroke?
Kiersten McCartney, Duncan Thibodeau Tulimieri, Ryan Pohlig, Darcy Reisman
University of Delaware, Newark, USA
Background: Moderate to high intensity walking exercise is highly recommended to improve walking speed and walking endurance in people with chronic stroke. Participant response to walking interventions post-stroke is multi-factorial and influenced by individual characteristics and/or variables across multiple domains. Previous studies have not examined which individual variables in the domains of baseline walking capacity, physical health, and/or psychosocial factors, impact an individual’s response to moderate to high intensity walking exercise. This study tested if there were homogeneous classes (subgroups) of people with chronic stroke that differ in the walking exercise dose achieved across an exercise intervention.
Methods: This is a secondary analysis of the larger PROWALKS clinical trial. The participants randomized into the fast walking training (FAST, n = 89) or fast walking training and step activity monitoring group (FAST + SAM, n = 80) were used for this analysis. All participants (n = 169) completed a walking exercise intervention focused on fast treadmill walking where participants walked for a maximum of 30 minutes per session for up to 36 sessions. The goal intensity for training was 70-80% of a participant’s heart rate reserve (HRR).
Eight variables were entered into a Latent Variable Mixture Modeling (LVMM) analysis to test models with 2-6 classes. A combination of model fit statistical criteria were used to identify the best fitting model. Individuals were placed into the class of their highest posterior probability. Classes were then compared on differences in each of the eight observable variable input into the model, and on differences in the number of minutes across the intervention in which the goal intensity (> 70% HRR) was met.
Results: Collectively, model fit criteria indicated the 4-class model was the optimal model. Classes differed on baseline six-minute walk test, fastest walking speed, steps per day, balance confidence, the Charlson co-morbidity index, and body mass index (p < .05). There were no differences between classes for the cumulative number of minutes at or above the goal intensity (> 70% HRR).
Discussion/Conclusions: Baseline measurements of walking capacity, walking performance, and balance confidence, as well as co-morbidity burden and body mass index differ among homogeneous subgroups of people with chronic stroke. However, these subgroups do not differ on the cumulative number of minutes of walking exercise spent at > 70% HRR, indicating these factors may not be important in differentiating the volume of exercise individuals can attain at an intensity of > 70% HRR in a walking intervention. This suggests it is possible for people with chronic stroke to exercise at this intensity regardless of their baseline characteristics. Future analyses may consider quantifying exercise dose as a continuous variable to better understand if subgroups differ on the average exercise dose attained across the intervention.
Categories
Stroke
Exploring Neuroplasticity Changes in Neurotoxin-induced Parkinson’s Disease: A Preliminary Analysis using Transcranial Magnetic Stimulation
Tomas Gomez1, Kelsey Baker2, Nawaz Hack2, Daniel Salinas2, Ramu Vadukapuram2
1University of Texas Rio Grande Valley, Brownsville, USA. 2University of Texas Rio Grande Valley - Institute of Neuroscience, Harlingen, USA
Parkinson’s disease (PD) is a neurodegenerative condition affecting movement, cognition, gait, and quality of life. Studies suggest neurotoxin pre-exposure is related to PD pathology and progressive motor/non-motor deficits, though it’s unclear how neurotoxin exposure affects neuroplasticity. This study aimed to examine neurotoxin–induced PD-associated neuroplasticity changes in relationship to mental acuity and motor functionalities.
7 voluntary participants experiencing early-stage PD symptoms with reported neurotoxin exposure were enrolled in the clinical study; 1 sex-matched, age-matched, and occupation-matched healthy subject was recruited for controlled comparative analysis (n=9). UTRGV’s Institute of Neuroscience (HION) served as study host and aided in data capture for baseline and post-2 months sessions. During baseline, participants disclosed neurotoxin pre-exposure (e.g., Agent Orange, heavy metals, insecticides, etc.). Study personnel collected outcomes related to mental acuity (SLUMS), PD-associated gait abnormalities (HY Scale), non-motor/motor experiences burdening daily life (MDS-UPDRS), and arm motor functionalities. Corticospinal excitability and neuroplasticity were evaluated using Transcranial Magnetic Stimulation (TMS). TMS was specifically applied at varying intensities to the brain region dedicated to the first dorsal interosseous (FDI), where motor evoked potentials (MEPs) were recorded at each assessed TMS intensity.
Multivariate Analysis of Covariance revealed significant mean differences in %MEP for Amplitude MEP and Area MEP after controlling for age, gender, mental status, HY ratings, motor function, and pre-stimuli EMG activity, [Pillai’s Trace = 0.24, F(18, 1358) =10.6, partial eta2 = 12%, p < .001]. Post-hoc ANOVA’s resulted significant %MEP mean differences for EMG Area MEP, [F(9, 676) =18.0, partial eta2 = 19%, p < .001], and for EMG Amplitude MEP, F(9, 676) =19.0, partial eta2 = 20%, p < .001. HY ratings alone did not reveal statistical differences in mean EMG amplitude, p > .05, however, mean EMG Amplitude for %MEP 70-180 statistically fit a sigmoid model curve, F(1, 681) = 651.2, p < .001. The sigmoid model follows the specified equation, .
Our findings suggest potential clinical implications in PD conditions related to motor function, with specific relationships between HY ratings and sigmoid model insights into physiologically observed differences. Identified differences in Amplitude MEP and Area MEP highlight the importance of multivariate approaches to understanding MEP. Application of the present study can improve a variety of areas: e.g., neurorehabilitation, neurotoxin regulation, etc.. It can be speculated that variables of age, gender, mental status, and pre-stimuli EMG activity should be carefully considered in future research on %MEP. Researchers should explore underlying mechanisms behind observed effects, interactions between variables, and clinical relevance of these findings. Specific implications depend on the context of future research, e.g. characteristics of investigated populations, field of research (e.g., neurology, motor control, clinical rehabilitation), but nevertheless researchers should consider these conclusions in the broader context of existing literature and specific goals of investigation.
Categories
Other
Vagus nerve stimulation delivered during at-home, task-specific training improves function after spinal cord injury or stroke
Kaitlyn Malley1,2, Joseph Epperson2,3, Zachary Bynum1,2, Saeid Kian1,2, Benjamin Stanislav1,2, Joel Wright2, Emmanuel Adehunoluwa1,2, David Pruitt2, Chad Swank4, Christi Stevens4, Jaime Gillespie4, Dannae Arnold4, Jane Wigginton2, Robert Rennaker1,2, Seth Hays1,3,2, Michael Kilgard1,2
1School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, USA. 2Texas Biomedical Device Center, Richardson, USA. 3Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, USA. 4Baylor Scott & White Research Institute, Dallas, USA
Vagus nerve stimulation (VNS) is a promising treatment strategy to enhance traditional neurorehabilitation and improve recovery after stroke. Preliminary data from an early feasibility study suggest that VNS paired with upper limb rehabilitation may also improve motor recovery after cervical SCI. Preclinical studies indicate that the nature of the rehabilitation combined with VNS influences the type and degree of recovery. Consequently, it would be valuable to better explore the contribution of various types of upper limb training in patients. In our initial studies, VNS was generally combined with repetitive, single-joint, upper-limb movements. In this ongoing study, we ask if VNS can promote motor recovery when combined with complex, multi-joint, activities of daily living (ADLs). VNS + ADLs was delivered in 4 individuals with incomplete spinal cord injury (SCI) and 4 individuals with stroke affecting their upper limb. Participants selected 4 to 8 ADLs and completed 36 x 1-hour long at-home sessions of VNS paired with training on these ADLs. Time to complete each ADL was recorded before, during, and after therapy. Preliminary analysis indicates that VNS can reduce time to completion for trained ADLs by 33% in individuals with SCI and by 18% in individuals with stroke. These improvements require many therapy sessions and appear to be cumulative. Benefits appear to generalize to more difficult task conditions, but not to untrained tasks. Thus, our initial data analysis suggests that VNS paired with a functional, task-based paradigm could be a promising approach to restore motor function after neurological injury. Moreover, we show that this approach can feasibly be delivered remotely.
Categories
Motor Rehabilitation
Quantifying the Effect of Trunk Postural Control on Reaching Deficits post Hemiparetic Stroke
Kathleen Suvada1, Jasjit Deol2, Julius Dewald1, Ana Maria Acosta1
1Northwestern University, Evanston, USA. 2University of Alberta, Edmonton, Canada
The trunk provides a stable base of support to the upper body and facilitates proper interaction with the environment. Damage to descending corticospinal pathways after a stroke alters performance of activities of daily living and in particular, reaching. However, despite the highly coupled nature of the trunk and arm, the impact of a stroke on coordinated trunk and arm reaching remains largely unknown. This is especially true in the context of the flexion synergy (involuntary flexion of the elbow, wrist, and fingers during shoulder abduction). The goal of this study was to quantify reaching ability post stroke when the trunk is unrestrained. We hypothesize that deficits present due to the flexion synergy will be exacerbated when actively controlling the trunk.
9 individuals post hemiparetic stroke (64.11 ± 6.57 years old; Fugl-Meyer Assessment (FMA) 7-42/66; Reaching Performance Scale (RPS) 0-32/36; and Trunk Impairment Scale (TIS) 11-20/23); and 4 age-matched controls (66.25 ± 0.96 years old) participated in the study. The trunk and arm were instrumented with motion capture markers to quantify trunk, shoulder, and elbow kinematics. Individuals sat in a Biodex chair with the trunk either restrained or unrestrained. Participants were asked to reach with their arm fixed to a robotic device capable of generating a frictionless table environment and imposing downward forces equal to 25% or 50% of their maximum shoulder abduction (SABD) force. Reaching distance (RD) was computed as the 3D distance between the 3rd metacarpophalangeal joint and the estimated glenohumeral joint1 at the end of the reach and normalized to participant limb length (LL). A generalized linear mixed effects model was used to assess the effect of load and restraint on RD. The relationship between RD and the clinical measures was evaluated using linear regression.
For the paretic arm, RD decreased with loading (p<.05) independent of trunk restraint. RD was reduced from trunk restrained to trunk unrestrained for both the paretic (Table: 85.25±15.24 vs 83.42 ±13.91 %LL; 25% SABD: 78.03±16.05 vs 74.34±15.19 %LL; 50% SABD: 77.51±16.82 %LL vs 74.66±15.34 %LL) and non-paretic (Table: 97.04±3.31 vs 94.87±3.64 %LL; 25% SABD: 96.89±3.81 vs 94.54±3.91 %LL; 50% SABD: 96.41±3.63 vs 94.30 ± 4.29 %LL) limbs (p<.05). In the paretic limb, RD was correlated with FMA and RPS for both trunk restrained and unrestrained (p<.05). Consistent with previous studies, flexion synergy is the major impairment affecting reaching, reflected in reduced reaching distance with increasing shoulder load. Nonetheless, un-restraining the trunk impacts reaching ability. Future work will examine trunk and arm muscle activation patterns to gain further insight into trunk and arm coordination after stroke.
Categories
Stroke
Repetitive transcranial magnetic stimulation combined with multi-modality aphasia therapy for chronic post-stroke aphasia: A randomized clinical trial
Trevor Low1, Kevin Lindland2, Adam Kirton1,3,4,5, Helen Carlson1,3,4,5, Ashley Harris4,5,6, Bradley Goodyear1,4,6, Oury Monchi1,4,6,7,8, Michael Hill1,4,6, Miranda Rose9, Sean Dukelow1,4,10
1Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Canada. 2Department of Allied Health, Alberta Health Services, Calgary, Canada. 3Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Canada. 4Hotchkiss Brain Institute, University of Calgary, Calgary, Canada. 5Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada. 6Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Canada. 7Centre de recherche de l’institut universitaire de gériatrie de Montréal, Montreal, Canada. 8Département de radiologie, radio-oncologie et médecine nucléaire, Faculté de médecine, Université de Montréal, Montreal, Canada. 9School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Australia. 10Division of Physical Medicine and Rehabilitation, University of Calgary, Calgary, Canada
Background: Aphasia is a common consequence of stroke and often persists into the chronic phase of recovery. Non-invasive brain stimulation techniques such as repetitive transcranial magnetic stimulation (rTMS) may improve recovery from post-stroke aphasia. Further evidence suggests that pairing rTMS with intensive speech therapy might yield even better results. This sham-controlled randomized clinical trial evaluated the efficacy of 1 Hz rTMS over the right pars triangularis combined with multi-modality aphasia therapy (M-MAT) in chronic post-stroke aphasia.
Methods: Forty-three individuals with chronic non-fluent aphasia following left middle cerebral artery stroke (>6 months from stroke) were recruited from outpatient neurorehabilitation clinics between April 2021 and May 2023. Participants were randomized to receive either rTMS (N=21) or sham stimulation (N=22) targeted over the right pars triangularis combined with 35 hours of M-MAT over 10 days. Primary outcome was the Western Aphasia Battery aphasia quotient (WAB-AQ) measured at baseline, 3-weeks and 15-weeks. Secondary outcomes included word retrieval, functional communication (Communication Effectiveness Index), multimodal communication (The Scenario Test), quality of life (Stroke Aphasia Quality of Life Scale) and mood (Stroke Aphasic Depression Questionnaire). Longitudinal analyses were performed using linear mixed models.
Results: Overall, WAB-AQ scores in both the sham and rTMS groups improved from baseline to 15-weeks (mean difference 5.33 points [95% CI, 2.9 to 7.8], p<0.001). We observed a significant group by time interaction (estimate 0.31, p=0.024) suggesting that those who received rTMS combined with M-MAT improved more over time than those who received sham. At 15 weeks, verbal fluency of the rTMS group was significantly greater compared to sham, as evidenced by lengthier and more grammatically complete utterances, less frequent word finding difficulties and fewer pauses. These differences were supported by a finding of a higher WAB-AQ scores in the rTMS group the 15-week interval (mean difference 4.1 points, [95% CI 0.6 to 7.6], p=0.022). Moreover, the change from baseline at 15-weeks was significantly greater in the rTMS group (7.6 points [95% CI 4.1 to 11.1]) compared to sham (3.0 points [95% CI -0.3 to 5.2]; mean difference 4.6 points, [95% CI 0.6 to 8.6], p=0.024). Word retrieval, functional communication and multimodal communication improved significantly from baseline to 15-weeks, however improvement on all secondary outcomes did not differ between groups.
Conclusions: Intensive administration of M-MAT alone can produce improvements in speech in chronic post-stroke aphasia. However, combining M-MAT with 1Hz rTMS promoted larger, delayed, improvements in aphasia severity. These results suggest that rTMS is a promising candidate as an adjuvant therapy to M-MAT.
Categories
Stroke
Transcallosal inhibition in recovering stroke subjects
Emily Fokas1, Myriam Taga1, Leticia Hayes1, Charalambos Charalambous1,2, Sharmila Raju1, Heidi Schambra1
1NYU Grossman School of Medicine, New York, USA. 2University of Nicosia Medical School, Nicosia, Cyprus
Introduction: Transcallosal inhibition (TI) is a neurophysiological process that may be important for precise unilateral movements. TI can be examined using transcranial magnetic stimulation (TMS), which generates an ipsilateral silent period (iSP) in a contracting muscle. Previously, we found that TI in healthy subjects was stronger in distal than proximal muscles. In chronic stroke, this segmental difference in TI was less salient. Little is known about how TI evolves segmentally in recovering stroke subjects and if TI relates to changes in motor behaviors. In this longitudinal study, we examined changes in inhibition over time by using TMS to probe a distal hand muscle (first dorsal interosseous; FDI) and a proximal muscle (biceps; BIC).
Methods: We evaluated the paretic FDI and BIC in 30 stroke subjects (F: 17; mean age: 58.7 (31 – 89) years; mean initial Fugl Meyer Assessment 57.3 (19 – 66)) at one month, three months, and six months following stroke. At each time point, we used task performance to measure motor control, electromyography to measure muscle individuation, and dynamometry to measure strength. To measure TI, we delivered TMS to a stereotactic 5x5 cm virtual grid overlying the contralesional hemisphere during standardized FDI or BIC activation. TI was indexed as the average iSP strength of the entire grid. In each muscle, we used linear mixed models to examine TI recovery and its relationship to motor behaviors.
Results: TI was stronger, on average, in the FDI than BIC of stroke subjects across the three time points (p < 0.001). For both muscles, TI did not significantly change over time (FDI: p = 0.263; BIC: p = 0.242). Stronger TI acting on the paretic FDI was related to overall better FDI motor control (p = 0.034) but also worse FDI individuation (p = 0.027); there was no relationship to overall FDI strength (p = 0.468). TI acting on the paretic BIC was unrelated to overall BIC motor control, individuation, or strength (p > 0.558). For both muscles, TI was unrelated to recovery of their motor behaviors.
Discussion: We confirmed that TI from the contralesional hemisphere is stronger for a distal than proximal muscle in stroke, consistent with previous work. We did not observe a significant change in TI during the subacute period, indicating that segmental changes may occur in chronic recovery stages. While we observed a potential role for TI in distal motor control and individuation, we did not find evidence for TI playing a role in motor recovery for either UE segment.
Categories
Stroke
Deficits in cognitive aspects of movement control differ based on the side of brain damage in chronic stroke survivors
Pramisha Thapa1, Lelti Asgedom1, Mark Folkertsma1, Scott Lunos1, Diane Chappuis2, Shanie Jayasinghe1
1University of Minnesota, Minneapolis, USA. 2Courage Kenny Rehabilitation Institute, Minneapolis, USA
Upper limb impairment post-stroke poses great challenges in achieving full recovery, and movement rehabilitation is primarily directed towards addressing deficits associated with motor execution. While we know that accurate movement also requires intact cognitive processes, there are gaps in our understanding of how lateralized cognitive processes impact functional movement. Previous studies provide evidence for deficits in cognitive aspects of movement, such as movement preparation and spatial working memory, with right brain damage and deficits in verbal working memory with left brain damage. Therefore, we hypothesized that cognitive deficits would differ based on the side of brain damage. We predicted that deficits related to cognitive aspects of movement would be larger in individuals with right brain damage (RBD) compared to those with left brain damage (LBD). We developed an upper limb reaching task with a cognitive challenge (170 trials) using the Kinereach motion capture system to examine how increased cognitive load affects ipsilesional arm movement. In our ongoing study, we have recruited 8 chronic stroke survivors with severe hemiparesis (2 females; age 52.63 years +/- 4.54 SEM; 5 RBD, 3 LBD). We placed 2 electromagnetic sensors on the hand and upper arm of the participants to record their position and orientation. In each trial, the participant was presented with a screen consisting of a set of pictorial instructions for 2 s, followed by a second screen with an array of objects. The participant had to remember the instructions from the first screen to identify and quickly reach for the correct object in the second screen within 3 s. The level of cognitive load on the participant increased over the course of the task. Our preliminary findings showed that reaction times were higher for the LBD compared to the RBD group (p = 0.0005). We also found that movement accuracy was higher for the RBD than LBD group (p = 0.0057). Therefore, LBD individuals tended to take longer to plan a movement and also had more movement errors compared to RBD individuals. While this is contradictory to our prediction, we expect that the ongoing data collection will provide further information on how cognitive deficits affect functional outcomes in this group of stroke survivors.
Categories
Motor Rehabilitation
Electrical stimulation-based treadmill training modulates spinal reflex excitability in people with stroke
Jasmine Hope1, Fisayo Aloba1, Jacob Spencer2, Catherine Mason1, Alejandro Lopez1, Trisha Kesar1
1Emory University, Atlanta, USA. 2Georgia Tech, Atlanta, USA
Stroke is a prevalent neurological injury that adversely impacts walking ability and functional independence of survivors. Besides the obvious impact of stroke on cortical motor circuits, distant spinal circuits are also altered. In conjunction with decreased corticospinal drive to the lower extremity muscles, abnormalities in spinal reflex circuitry may also contribute to post-stroke gait deficits, spasticity, and stiffness. Fast treadmill training is an evidence-supported intervention for improving post-stroke walking function. FastFES training, which pairs fast treadmill walking (Fast) with functional electrical stimulation of ankle dorsi- and plantar-flexor muscles, important for foot clearance during swing phase and push-off during late-stance, has been shown to improve walking speed and energy cost. Importantly, there is a significant knowledge gap regarding the role of spinal circuit plasticity as a neural mechanism of Fast and FastFES. In this repeated-measures crossover study, 12 participants with chronic stroke were randomized to receive 3 sessions of Fast followed by 3 sessions of FastFES training (or vice versa), with a >3-week period between the 2 training sessions. To evaluate spinal reflex excitability, paretic Soleus H-reflexes were recorded at baseline and after the 3rd training session, and Hmax/Mmax ratios were calculated. We also evaluated associations of spinal excitability with functionally relevant assessments of overground walking speed, peak ankle moment, anterior ground reaction force (AGRF), and timed up and go (TUG). Our results demonstrated that after 3 sessions of FastFES, there was a significant increase in Hmax/Mmax ratio (p=0.02, Cohen’s d=0.19), while there was no significant change after 3 sessions of Fast (p=0.27, Cohen’s d=0.48). Correlation analyses showed that a high Hmax/Mmax ratio was associated with lower paretic peak AGRF (p=0.04, r=-0.59), lower peak ankle moment (p=0.04, r=-0.61), slower gait speed (p<0.01, r=-0.83), and worse TUG score (p<0.01, r=0.79). Additionally, baseline Hmax/Mmax ratios were negatively correlated with training induced change in over-ground walking speed (p=0.03, r=-0.61) after Fast training. These results provide preliminary evidence that FastFES may induce neuroplastic changes in the spinal reflex circuitry that may be functionally relevant. Future studies would benefit from evaluating the effects of greater training dosage on spinal excitability, as well as the implication for therapeutic effects of gait training.
Categories
Stroke
Descending ipsi- and contralesional projections benefit motor behavior in chronic stroke
Myriam Taga1, Yoon N. G. Hong2, Charalambos C. Charalambous3, Sharmila Raju1, Leticia Hayes1,Jing Lin1, Yian Zhang4, Michael Houston5, Yingchun Zhang2, Pietro Mazzoni6, Jinsook Roh2, Heidi M. Schambra1
1Department of Neurology, New York University Grossman School of Medicine, New York, USA. 2Department of Biomedical Engineering, University of Houston, Houston, USA. 3Department of Neurology, Duke University School of Medicine, Durham, USA. 4Department of Population Health, New York University Grossman School of Medicine, New York, USA. 5Department of Biomedical Engineering, University of Houston,, Houston, USA. 6Department of Movement Disorders, Ohio State University, Ohio, USA
Introduction: After corticospinal tract (CST) stroke, several motor deficits in the upper extremity (UE) emerge, including diminished muscle strength, motor control, and muscle individuation. Both the ipsilesional CST and contralesional corticoreticulospinal tract (CReST) innervate the paretic UE, with possibly differential innervation of the proximal and distal UE segments. Differential innervation could predict distinct segmental relationships with motor behaviors. In this cross-sectional study, we examined two key questions in chronic stroke: (1) whether motor behaviors segmentally differ in the paretic UE, and (2) whether segmental motor behaviors differentially relate to ipsilesional CST and contralesional CReST projection strengths.
Methods: We studied 15 chronic stroke (9F/6M; mean age: 66.7 (52-89) years; mean time post-stroke: 8.6 (0.5-15) years) and 28 healthy subjects (14F/14M; mean age: 57.4 (36-81) years). We examined a proximal (biceps, BIC) and distal muscle (first dorsal interosseous, FDI) in the paretic UE (assigned in healthy). We used dynamometry to measure strength, task-based performance to measure motor control, and electromyography to measure muscle individuation. We used transcranial magnetic stimulation to measure ipsilesional CST and contralesional CReST projection strengths to these muscles. We used nonparametric testing to examine subject group and segmental differences and correlation testing to examine pathway-behavior relationships.
Results: With respect to healthy subjects, stroke subjects had comparable strength but poorer motor control (BIC, p = 0.002; FDI, p = 0.0007) and individuation (BIC, p= 0.002; FDI, p = 0.0002). In stroke subjects, motor control deficits were comparable between segments but individuation was worse in the FDI than BIC (p = 0.003). In stroke, better BIC strength related to stronger projections from both the CST (ρ = 0.525, p = 0.045) and CReST (ρ = 0.844, p < 0.0001), whereas better FDI strength related to stronger CReST projections alone (ρ = 0.785, p < 0.001). Better motor control in both segments related to stronger CST projections (BIC, ρ = 0.608, p = 0.016; FDI, ρ = 0.559, p = 0.030), but were unrelated to CReST projections. Better BIC individuation related to stronger CST and CReST projections (CST, ρ = 0.680, p = 0.005; CReST, ρ = 0.633, p = 0.011), whereas better FDI individuation related to stronger CReST projections alone (ρ = 0.538, p = 0.039).
Discussion: We did not find widespread evidence for segmental differences in chronic motor deficits. However, we confirmed the importance of the ipsilesional CST for motor control and the contralesional CReST for strength in the paretic UE. We newly found that the contralesional CReST has a positive relationship to paretic UE individuation. These findings suggest beneficial and complementary roles of these pathways in chronic motor behaviors.
Categories
Stroke
The effect of post-acute rehabilitation setting on 90-day mobility function after stroke
Margaret French1, Heather Hayes1, Joshua Johnson2, Daniel Young3, Ryan Roemmich4, Preeti Raghavan5
1University of Utah, Salt Lake City, USA. 2Cleveland Clinic, Cleveland, USA. 3University of Nevada Las Vegas, Las Vegas, USA. 4Kennedy Krieger Institute, Baltimore, USA. 5Johns Hopkins Hospital, Baltimore, USA
Background: After being discharged from the hospital for acute stroke, individuals often receive rehabilitation in one of three settings: inpatient rehabilitation facilities (IRFs), skilled nursing facilities (SNFs), or home with community services (i.e., home health or outpatient clinics). Past work has found that the initial setting in which individuals receive post-acute care (i.e., the discharge location from hospital) is related to long-term mortality and hospital readmission; however, the relationship between discharge location and changes in functional mobility remains unknown largely due to the lack of longitudinal functional data in this patient group. At Johns Hopkins Hospital, however, the same functional measure is used across the continuum of care in individuals with stroke, allowing us to examine this. Thus, the purpose of this work was to examine the impact of discharge location on the change in functional mobility between hospital discharge and 90-days post-discharge.
Methods: In this retrospective cohort study, we identified 475 individuals from the electronic health record who were admitted to Johns Hopkins Medicine with an acute stroke and who had measurements of mobility [Activity Measure for Post Acute Care Basic Mobility (AM-PAC BM)] at time of discharge from the acute hospital and 90-days after discharge. Individuals were grouped by discharge location (IRF=190, SNF=103, Home with community services=182). We used a difference-in-differences analysis to compare the change in mobility from time of discharge to 90-days post discharge between groups, controlling for demographics, clinical characteristics, and social determinants of health.
Results: After adjusting for covariates, individuals who were discharged to a SNF or Home with community services had significantly less change in AM-PAC BM from time of discharge to 90-days post discharge compared to individuals who were discharged to an IRF (SNF: β=-3.5 (1.4), p=0.01; Home with community services: β=-8.2 (1.3), p=<0.001). This finding was consistent regardless of the method used to control for the covariates.
Conclusions: These findings suggest that the initial post-acute rehabilitation setting impacts the change in mobility function at 90-days after discharge from the acute hospital. These findings support the need for high-intensity rehabilitation and for policies that facilitate the delivery of high-intensity rehabilitation after stroke.
Categories
Stroke
Machine learning reveals ipsilateral brain activation during a manual dexterity task in people with multiple sclerosis without disability
Sadman Saumik Islam, Bruna D Baldasso, Michelle Ploughman, Xianta Jiang
Memorial University of Newfoundland, St. John’s, Canada
Background: Many people with Multiple sclerosis (MS) complain of problems with hand dexterity and mental fatigue. However, in many cases, impairments are subtle and difficult to detect. Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures brain hemodynamic responses during cognitive or motor tasks. We aimed to detect potentially aberrant brain activity that could explain subjective reports of mental fatigue while completing dexterous tasks.
Methods: We recruited 15 people with MS, who did not have hand (Nine Hole Peg Test [NHPT]), mobility (fast walking speed) or cognitive (Montreal Cognitive Assessment) impairment, and 12 age- and sex-matched controls. Participants completed two types of hand motor tasks with their dominant hand, single motor (NHPT) and dual motor (NHPT + holding a ball). We analyzed fNIRS data using a machine learning framework to classify MS patients from healthy controls based on their brain activation patterns in bilateral prefrontal and sensorimotor cortices.
Results: The Random Forest classifier achieved an accuracy of 0.958 for single motor tasks and 0.957 for the more complex dual motor tasks. Further analysis of the machine learning performance using Shapley additive explanations (SHAP) values revealed that the deoxygenated blood levels and the oxygenated blood levels in the sensorimotor cortex on the ipsilateral side of the brain were the most influential features of the model performance that distinguished patients from controls.
Conclusions: We show that, even without overt hand or cognitive impairment, MS patients demonstrated inappropriate activation of brain regions ipsilateral to hand movement.
Categories
Multiple Sclerosis (MS)
Intraoperative Testing of High Frequency Electrical Motor Nerve Block in Humans: Case Report
Jayme Knutson1,2,3, Kyle Chepla1,2,3, Richard Wilson1,2,3, Michael Fu1,2,3, Emily Imka3, Shane Bender2, John Chae1,2,3, Kevin Kilgore1,2,3, Niloy Bhadra1,2,3
1The MetroHealth System, Cleveland, USA. 2Case Western Reserve University, Cleveland, USA. 3Cleveland FES Center, Cleveland, USA
Objective: If patients with significant chronic muscle spasticity could be given on-demand control of the degree of hypertonia in their upper and/or lower extremity muscles, it would revolutionize spasticity treatment for patient populations including stroke, traumatic brain injury, spinal cord injury, multiple sclerosis, and cerebral palsy. The possibility of a quick-acting patient-administered method of spasticity treatment is conceivable with electrical nerve block methods. One such method uses high frequency alternating current, which we refer to here as high frequency stimulation (HFS). HFS is being used in human studies for obesity control and pain management, but is yet to be used for blocking action potentials to muscles (i.e., inhibiting undesired or involuntary muscle contractions) The purpose of this study is to confirm that HFS can completely and/or partially block muscle contractions reversibly in humans and to determine the HFS parameters that produce complete and partial block. Here we report the first case in the study.
Methods: The participant was a 56-year old male undergoing a tendon lengthening surgery in the forearm that that exposed the anterior interosseous nerve (AIN). A nerve cuff electrode specially designed for nerve conduction block was placed around the AIN, and a stimulating probe positioned proximally near the nerve elicited muscle contractions observed as twitches or fused contractions of the pronator quadratus, i.e., pronation of the wrist. Two video cameras were used to capture the wrist movement for later video processing and quantification. Several trials of 10-sec applications of HFS were conducted using different HFS amplitudes and frequencies to characterize the effects of HFS on electrically-induced muscle twitches and fused contractions.
Results: Eight trials were conducted, all applying HFS at 20kHz and with an amplitude varying between 5 and 10 mA. HFS amplitudes of 5, 6, and 7 mA applied during electrically stimulated muscle twitches produced partial block, which was observed as a reduction in the magnitude of muscle twitch, i.e., amount of wrist pronation. The larger the HFS amplitude, the greater the degree of partial block (i.e., amount of twitch reduction). HFS amplitudes of 8 and 10 mA produced complete nerve block, observed as cessation of wrist pronation twitches. In all trials, muscle contractions resumed immediately after HFS was turned off.
Conclusion: This demonstration of high frequency electrical motor block in human is a milestone in the path toward neuromodulation technology that could become an effective treatment for spasticity.
Categories
Motor Rehabilitation
Operant conditioning of stimulus-triggered EMG evoked potentials to improve sensorimotor functions in chronic incomplete spinal cord injury
Krista Fjeld, Blair Dellenbach, Alan Phipps, Allison Lewis, Roland Cote, Aiko Thompson
Medical University of South Carolina, Charleston, USA
Spinal cord injury (SCI) results in multiple secondary sensorimotor complications. Operant conditioning of a stimulus-triggered EMG response can target beneficial plasticity to the pathway that produces the response (Prog Brain Res.2015;218:157-72). Thus, operant conditioning is a potential method to target neuroplasticity in specific neural pathways. Our overarching hypothesis is that operant conditioning of stimulus-triggered EMG evoked potentials can improve targeted pathway functions in people with SCI, leading to related improvements in sensorimotor function. Currently, we are testing this in three different applications:
1. Operant Conditioning of motor evoked potentials (MEPs) to transcranial magnetic stimulation.
We hypothesize that operant up-conditioning of the MEP can improve corticospinal function for the target muscle, thereby improving weak voluntary activation. Initial studies of tibialis anterior (TA) MEP conditioning showed that people with or without chronic incomplete SCI can increase MEP size through operant up-conditioning (J Neurophysiol.2018;120:2745-2760) leading to improved locomotion in SCI (J Neurophysiol.2019;121:853-866). We are currently examining the mechanisms of TA MEP up-conditioning (R01NS114279) and feasibility of wrist-extensor MEP conditioning in people with SCI.
2. Operant down-conditioning of the H-reflex.
We hypothesize that operant down-conditioning of the H-reflex reduces hyperexcitability of the targeted reflex pathway, which triggers beneficial plasticity in multiple spinal and supraspinal pathways, alleviating spastic movement disorders. Operant down-conditioning can decrease the soleus H-reflex size and can improve locomotion in people with chronic incomplete SCI (J Neurosci.2013;33:2365-2375; J Physiol.2021;599:2453-69). Our pilot clinical trial aims to estimate clinical effects of soleus H-reflex conditioning (U44 NS114420). The initial study of the flexor carpi radialis H-reflex down-conditioning supports the feasibility in the upper limb.
3. Operant conditioning of a cutaneous reflex to non-noxious stimuli.
We hypothesize that up-conditioning of a cutaneous reflex (a polysynaptic spinal reflex) to non-noxious stimuli is possible and affects the spinal sensorimotor function. Cutaneous reflexes from excitation of Ab-afferents contribute to motor control and are thought to interact with spinal pain processing. Until recently, reflex operant conditioning has been limited to largely monosynaptic reflex pathways, but up-conditioning of soleus cutaneous reflex has been demonstrated in one chronic, incomplete cervical SCI (Clin. Neurophysiol.2024;157:1-3). Results were accompanied by increased gait function and pain threshold of the participant, supporting that operant conditioning of a polysynaptic pathway may produce beneficial changes in multiple spinal pathways.
General methods: Standard operant conditioning protocols consists of 6 baseline and 24-30 conditioning sessions (3/week). Before and after conditioning, electrophysiological, kinematic, clinical, and functional assessments are performed. In baseline sessions, 225 control EMG responses are elicited without feedback on response size. In conditioning sessions, 225 conditioned EMG responses are elicited while participants are asked to change the EMG response size and are given immediate visual feedback as to whether the resulting response is different than a criterion value.
Categories
Spinal Cord Injury (SCI)
Relationship between resting state sensorimotor network connectivity and lower limb performance after stroke; analysis using graph theory approach
Margaret Skelly1, Sarah Carr2, Jessica McCabe1, Ahlam Salameh1, Lisa Leonhart1, Kelsey Rose Duncan1,3, Svetlana Pundik1,4
1Cleveland VA Medical Center, Cleveland, USA. 2Kings College London, London, United Kingdom. 3University Hospitals of Cleveland, Cleveland, USA. 4Case Western Reserve University school of Medicine, Cleveland, USA
Introduction: Disruption of functional connectivity in large-scale resting state brain networks has impact on upper limb motor performance. However, the relationship of gait performance and resting state functional connectivity(rsFC) is not well defined. Graph theory approach allows for detailed analysis of the complex organization of the brain. Measures of segregation such as clustering coefficient describe how neighboring neural areas are interconnected while measures of integration such as global efficiency provide details regarding how areas distant from each other are interconnected. Our purpose was to describe, using a graph theory approach, the relationship of rsFC in sensorimotor network (SMN) and clinical measures of lower limb/gait performance in a cohort of chronic stroke survivors with persistent gait deficits.
Methods: This is a cross-sectional analysis of baseline data of 37 chronic stroke survivors (>6 months) participating in an ongoing gait intervention study. Lower limb impairment and gait was assessed with Fugl-Meyer(FM) and fastest gait speed(GS) using 10-meter walk test. Data was preprocessed and denoised using standard pipelines implemented in Conn toolbox. Sensorimotor network (SMN) was defined as paramedial precentral gyrus (primary motor), precuneus, superior parietal lobule, postcentral gyrus (primary sensory), premotor cortex, supplementary motor area(SMA), posterior putamen, ventral anterior nucleus of thalamus, ventral lateral thalamic nucleus and ventral lateral posterior thalamic nucleus, cerebellum crus I-V and cerebellum crus VIII. The region of interest(ROI) to ROI Pearson correlation values were determined and used to calculate global efficiency and clustering coefficients per node. Elastic net models were tested with clinical measures as dependent variables and either clustering coefficient or global efficiency for each node within SMN as independent variables.
Results: Subjects were 64.4±8.5 years old, 5.3±4.5 years post stroke, 16.2% female, and 43.2% left hemisphere stroke. Mean gait speed was 0.69±0.41 m/s and FM was 24.1±4.0 points. Elastic net regression analysis showed that better FM score was associated with lower global efficiency in the ipsilesional primary motor, superior parietal, all thalamic sensorimotor nuclei and in the contralesional primary sensory regions (R2=0.53, root mean square error, RMSE =0.82). Faster GS was associated with lower global efficiency in the ipsilesional precuneus and in the contralesional premotor and superior parietal regions (R2=0.44, RMSE=0.9). Elastic net analysis using clustering coefficients of the SMN nodes showed that better FM was associated with higher clustering coefficients in the contralesional SMA (R2 =0.52, RMSE=0.83). Faster GS was associated with higher clustering coefficients in the contralesional superior parietal region and ipsilesional primary sensorimotor regions (R2=0.56, RMSE=0.88).
Conclusion: Faster speed and better FM scores were associated with higher regional segregation (higher clustering coefficient) and lower global integration (lower global efficiency). The sets of SMN nodes that showed a statistically significant relationship were different for GS and FM
Categories
Stroke
Fast training improves short-term motor performance of the paretic arm in chronic stroke survivors: The FAST Randomized Clinical Trial
Yannick Darmon1, Shailesh Kantak2, Hannah Cone3, Carolee Winstein1, Emily Rosario3,4, Nicolas Schweighofer1
1University of Southern California, Los Angeles, USA. 2Moss Rehabilitation Research Institute, Elkins Park, USA. 3Casa Colina Research Institute, Pomona, USA. 4USA
Despite the prevalence of upper extremity limitations after stroke, effective rehabilitation parameters are unknown. Upper extremity movements in stroke survivors are slow with multiple sub-movements, compatible with poor feedforward control. Theories of error-based learning predict that fast, but not slow, movements generate large errors that provide the necessary signal for retraining feedforward controllers.
Objectives: To compare the effects of an equivalent dose of speed vs accuracy training in chronic stroke and mild-to-moderate impairments who have no direct cerebellar damage.
Patients & methods: In this Phase-1 RCT (NCT05013762), we randomized 42 participants to either a speed or an accuracy arm-movement training condition. Each participant performed ~2080 arm movement sequences to trace complex tracks with the paretic arm in four sessions within a week. Speed was manipulated by asking participants to trace tracks of 5cm width (speed) or 1.25 cm (accuracy). We measured changes in kinematics and speed-accuracy trade-off of the paretic arm during goal-directed reaching 3-days and 1-month post-practice.
Results: Compared to accuracy training, speed training led to significantly faster and smoother movements with better symmetry of reaching velocity profile at the 3-day test, consistent with better feedforward control. Movement time and velocity symmetry of the paretic arm in the speed group post-training were comparable to those of the nonparetic arm. Speed and accuracy training led to improvement and detriment of speed-accuracy tradeoff, respectively. At 1 month, however, some gains in the two tests were lost.
Conclusion. Speed training led to greater gains in kinematics of goal-directed actions than accuracy training, notably in a 3-day post-test. To maintain longer-term gains, future trials should increase the duration of training. Nonetheless, our results suggest that training programs that include high repetitions of fast movements may improve paretic arm reaching performance.
Categories
Motor Rehabilitation
Larger infarct volume and greater lesion load of the corticospinal tracts correlate with higher fractional anisotropy of the contralesional frontal and parietal white matter
Svetlana Pundik1,2, Kelsey Rose Duncan1,3, Jessica McCabe1, Ahlam Salameh1, Margaret Skelly1, Trenley Anderson2, Pragnya Iyengar2, Lisa Leonhardt1, Terri Hisel1, Sarah Carr4
1Cleveland VA Medical Center, Cleveland, USA. 2Case Western Reserve University School of Medicine, Cleveland, USA. 3University Hospitals of Cleveland, Cleveland, USA. 4King’s College London, London, United Kingdom
Introduction: Focal stroke lesions impact whole brain function. Previous studies have suggested the contralesional hemisphere participates in functional recovery after stroke. In fact, increased activity in the contralesional hemisphere is associated with improved function especially for those with severe deficits. However, to our knowledge it is not known if there are structural changes in relation to the size of the infarct. The purpose of this analysis was to evaluate whether size of the stroke lesion has an impact on white matter integrity of the whole brain in chronic phases after stroke.
Methods: Diffusion weighted imaging (DWI) was acquired for 36 chronic (>6 months) stroke survivors with motor deficits. White matter disease score was assessed using the Fazekas scale. Left hemisphere lesions were flipped to the right-hand side. Stroke lesion volumes were manually outlined on T1 weighted and FLAIR MRI images. All MRIs were normalised to the 1mm3 MNI template brain. Lesion volume was based on the number of voxels within the lesion mask. Lesion load was calculated by estimating the number of lesion voxels that overlapped with the corticospinal tract (CST) and applying a weighting related to the maximum cross-sectional area of the entire CST divided by the cross-sectional area of the slice. DWIs were preprocessed using standard denoising techniques before calculating fractional anisotropy (FA) using FSL. In the DWIs, analysis was restricted to white matter using the Johns Hopkins University white matter atlas. Permutation testing was carried out to find associations between the lesion variables and voxel-level FA values. Lesion masks were included as regressors in the linear regression models. Percentage of the white matter region volumes showing a statistically significant result are reported.
Results: Study cohort demographics were: 64.3±8.9 y/o, 5.4±4.6 years post-stroke, 16.7% female, and 47.2% with left hemisphere stroke. Lesions were 31% cortical+subcortical and 59% subcortical only. Mean and standard deviations for lesion load and lesion volume were 25.2 ± 25.7 and 51654 ± 85413 mm3 respectively. White matter disease Fazekas score was 2.2 ± 1.4. Larger lesion volume was associated with higher FA (p < 0.05) in the contralesional superior longitudinal fasciculus (29.8% overlap between the tract and the statistically significant area), posterior thalamic radiation (20.5%), posterior (11.8%) and superior (2.0%) corona radiata. Larger lesion load was associated with higher FA (p < 0.05) in the contralesional superior longitudinal fasciculus (20.6%), anterior (12.5%), superior (1.4%) and posterior (5.0%) corona radiata. There was no association between Fazekas score and FA.
Conclusions: Greater structural integrity of the contralesional white matter is associated with larger stroke lesions. This study supports the notion that the contralesional hemisphere may have an impact on recovery post-stroke.
Categories
Stroke
APOE genotype alters cerebrovascular response to orthostasis over the course of Alzheimer’s disease progression
Jacqueline Palmer1, Carolyn Kaufman2, Alicen Whitaker-Hilbig3, Sandra Billinger2
1University of Minnesota, Minneapolis, USA. 2University of Kansas Medical Center, Kansas City, USA. 3Medical College of Wisconsin, Madison, USA
Dynamic cerebrovascular regulation is crucial to support brain function during mobility1 and is challenged under conditions that induce orthostasis, such as sit-to-stand positional transfers. Dysfunctional autonomic responses to orthostasis are associated with cognitive decline in older adults.2–4 Individuals who carry the ε4 allele of Apolipoprotein E (APOE4) show greater cerebrovascular vulnerability5–9 potentially contributing to their heightened risk for Alzheimer’s disease (AD).5 The purpose of this study was to 1) examine the effect of APOE4 genotype on cerebrovascular response during a sit-to-stand transition in cognitively-normal older adults, and 2) compare the effect of APOE4 on cerebrovascular response during sit-to-stand across stages of neurodegenerative disease progression (i.e. cognitively-normal, MCI, AD).
Methods: Older adults (n=101) with and without clinical diagnosis (cognitively-normal, n=65; MCI, n=20; AD, n=16) were genotyped as APOE4 carriers (n=41) or noncarriers (n=60). Middle cerebral artery blood velocity (MCAv) and mean arterial blood pressure (MAP) were continuously recorded using transcranial Doppler ultrasound and a finger Finometer, respectively, while participants performed a sit-to-stand transfer. The magnitude and latency of MCAv and MAP anticipatory (-30-0 cardiac beats) and post-stand responses (0-20 cardiac beats) were quantified, in which t=0 is the verbal cue to stand.
Results: Cognitively-normal APOE4 carriers showed greater anticipatory increase (p=0.018) and greater MCAv decrease immediately post-stand (p=.010) compared to noncarriers, while MAP magnitude did not differ between groups. Cognitively-normal APOE4 carriers also showed a shorter MAP response latency (p=0.007) but no difference in MCAv latency. We observed a diagnosis-by-APOE interaction in MCAv magnitude post-stand(p=0.005), in which APOE4 carriers with AD showed the most blunted MCAv decline post-stand. In contrast, noncarriers with AD showed the greatest MCAv decline post-stand. MAP responses showed a main effect of diagnosis, in which the greatest post-stand MAP reduction occurred in AD (p=0.014), regardless of genotype.
Conclusions: Greater MCAv decline in the absence of peripherally-mediated MAP differences between groups suggests cognitively-normal APOE4 carriers may possess dysfunctional cerebrovascular responses to orthostasis. Intriguingly, greater anticipatory increase in MCAv and faster MAP responses post-stand in cognitively-normal APOE4 carriers suggests potential neural compensation to counteract cerebral-specific autonomic dysfunction in preclinical stages of the disease. Further, the dissociative pattern of MCAv response change over the course of disease progression implies distinct phenotypes of cerebrovascular dysfunction may manifest in APOE4 carriers and noncarriers, and is consistent with the proposed role of autonomic dysfunction in APOE4 progression to neurodegenerative disease.2,3,11,12 These findings support a precision-medicine approach for cerebrovascular and mobility studies in aging and neurodegenerative disease.
Categories
Other
Determining the Impact of Cognitive Load on Brain-Muscle Functional Connectivity in Individuals with Chronic Stroke
Rachana Gangwani, Elizabeth Loftus, Umesh Radhakrishnan, Harshita Gudipudi, Jessica Cassidy
University of North Carolina, Chapel Hill, USA
Background: Cognitive processes like attention, memory, and executive function influence motor (re)learning, but stroke may impact these processes, thus affecting recovery outcomes. Despite evidence indicating the role of cognition in motor recovery, the underlying mechanisms that govern the interaction between cognitive and motor domains are unclear. Prior research predominantly employed neuroimaging at rest to assess connectivity between cortical regions subserving cognitive and motor function to inform cognitive-motor interplay. Building on this work, we expanded our connectivity analysis by measuring functional connectivity between the central and peripheral nervous systems during goal-directed movement to determine mechanisms subserving cognitive-motor interaction post-stroke.
Methods: Individuals with chronic (≥ 6 months) stroke completed electroencephalography (EEG) and electromyography (EMG) recordings under two experimental conditions: a submaximal isometric grip task (motor-weighted condition) and the same grip task with the Go/No-Go task (cognitive-weighted condition) which evaluates response inhibition (a component of executive function involved in goal-directed behavior). During simultaneous EEG and EMG recordings, we measured functional connectivity between brain and muscle (corticomuscular coherence; CMC). Specifically, we computed CMC between EEG leads overlying the ipsilesional primary motor cortex (M1) and frontoparietal cortex and muscle activity from EMG leads on affected bilateral biceps brachii, flexor and extensor digitorum, and first dorsal interossei muscles in cognitive- (alpha, 8-13 Hz) and motor-relevant (beta, 13-30 Hz) frequency bands. Preliminary differences in CMC between the motor- and cognitive-weighted conditions were determined using t-tests.
Results: To date, 3 individuals (mean age = 73±12 years, 2 females) were enrolled and completed procedures. Compared to the motor-weighted condition, participants demonstrated decreased CMC between the affected biceps and ipsilesional dorsal prefrontal cortex in the alpha (t=2.34, p=0.04) and low beta (t=2.38, p=0.04) frequency bands in the cognitive-weighted condition. A similar decrease in CMC was observed between the affected biceps and ipsilesional M1 in alpha (t=2.86, p=0.04), low beta (t=3.17, p=0.03), and high beta (t=2.75, p=0.03) frequency bands in the cognitive-weighted condition.
Conclusion: Preliminary findings indicate that cognitive load reduces brain-muscle functional connectivity involving cognitive and motor-relevant frequency bands and brain regions associated with cognitive and motor function. Confirming these findings in a larger clinical cohort in addition to a non-clinical cohort of unimpaired, age-matched individuals are next steps given the ongoing nature of this work. Understanding the behavioral implications of decreased CMC with increasing cognitive load using standardized cognitive and motor assessments is another future direction that we will also disseminate at the spring ASNR conference.
Categories
Stroke
Real-time feedback improves performance of vestibular rehabilitation exercises
Riley Sheehan1, Timothy Zehnbauer1, Alan Register1, Jackson Cornelius1, Nathan Pickle1, Linda D’Silva2, Karen Skop3, Paulien Roos1
1CFD Research Corporation, Huntsville, USA. 2University of Kansas Medical Center, Kansas City, USA. 3James A. Haley Veterans’ Hospital, Tampa, USA
Introduction: An estimated 35.4% of adults in the United States have vestibular dysfunction to such a level that it requires medical attention [1]. Dizziness is a common symptom in these patients and vestibular rehabilitation has been shown to be effective at reducing these symptoms. [2]. Specifically, vestibulo-ocular (VOR) exercises are often prescribed to reduce dizziness and improve gaze stability, but must be performed accurately and consistently to be most effective [3]. During at-home or remote rehabilitation programs, feedback on exercise performance can ensure that errors get corrected in a timely manner. The aim of this study was to investigate if real-time feedback during vestibular rehabilitation exercises improved exercise performance.
Methods and materials: We have developed a mobile application which provides game-based, at-home vestibular rehabilitation exercises [4], [5]. The app includes machine learning algorithms developed to identify the four most common mistakes made during VORx1 exercises: 1) making jerky instead of smooth head motions; 2) rotating the head over too large a range of motion; 3) tucking the chin (for pitch) or rolling the head (for yaw); and 4) large amounts of body movement. Real-time feedback is provided in the app when a mistake is detected. This feedback provides corrective suggestions in a visual and auditory manner.
Data was collected as part of a clinical trial (NCT05436067) where 40 patients with vestibular hypofunction (20 females; mean age 67±5.7 years) performed a rehabilitation session with the tablet, while the machine learning algorithms identified mistakes made in exercise performance. These were assessed at 7 second intervals. The percentage of trials that were corrected after feedback were identified for each of the common mistakes.
Results and discussion: For the VOR exercise in the pitch direction, participants were able to correct performance using the feedback for 50% of mistakes with jerky head motion, 40% of mistakes with range of motion, and 71.4% of mistakes with tucking of the chin. For the VOR exercise in the yaw direction, 71.4% of mistakes with jerky head motion, 62.5% of mistakes with range of motion, and 66.7% of mistakes with rolling of the head were corrected after feedback. 59% of trials in the pitch direction and 8% in the yaw direction required no real-time feedback for correct exercise performance. This suggests the pitch exercise was easiest to master for the participants. The majority of errors in exercise performance could be corrected with feedback.
Conclusions: This study showed that the use of real-time feedback during exercise games for vestibular rehabilitation exercises can effectively correct performance errors. The effect of feedback differed per exercise and may need to be improved with a larger training data set. However, initial findings show potential of the machine learning based feedback in improving exercise performance.
Categories
Other
Diagnostic accuracy of a novel motor learning test for Alzheimer’s disease screening
Alexandra Reed1, Kevin Duff2, Lee Dibble3, Sydney Schaefer1
1Arizona State University, Tempe, USA. 2Oregon Health and Science University, Portland, USA. 3University of Utah, Salt Lake City, USA
Many of the existing biomarkers for Alzheimer’s disease (AD) are cost- and time- intensive, requiring extensive resources and biomedical infrastructure that are often prohibitive for many patients (e.g., neuroimaging, phlebotomy). Thus, there is a need for affordable and rapid screening methods to support more widespread use among older adults and to make clinical trials more accessible and affordable. Our previous work has developed the quick Behavioral Exam to Advance Neuropsychological Screening (qBEANS), which evaluates learning of a functional upper limb task in ~5 minutes. In previous work, qBEANS scores have been shown to be correlated with AD pathology, brain atrophy, and functional decline. However, the specificity of the qBEANS to AD is unknown, particularly relative to movement disorders. The purpose of this study was to therefore examine the diagnostic accuracy of the qBEANS to distinguish between patients diagnosed with AD and Parkinson’s disease (PD). AD patients (n=34; mean±SE age=77.2±6.4; 56% female) were sampled from the Enriching Clinical Trials Requiring Amyloid Positivity with Practice Effects (APPE) cohort, while PD patients (n=23; mean±SE age=71.1±6.9; 52% female) were sampled from a previously published randomized clinical trial (NCT02600858). The AD and PD groups were comparable in terms of sex and education, although the AD group was significantly older than the PD group (p=.0005). A subset of cognitively unimpaired participants was also sampled from the APPE cohort (n=52; mean±SE age=72.5±4.9; 61% female) and used for comparing qBEANS score magnitude relative to the clinical samples. AD patients were classified by a board-certified neuropsychologist based on Alzheimer’s Disease Neuroimaging Initiative (ADNI) criteria, and had a mean Delayed Memory Index score of 51.7 (95% CI [47.8, 55.6]) from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). All PD patients had a modified Hoehn & Yahr score of 2, a mean MDS-UPDRS score of 30.5 on medication (45.7 off medication), and a mean RBANS Delayed Memory Index score of 93.8 (95% CI [88.4, 99.2]). Receiver Operating Characteristic (ROC) curve analysis showed an AUC = 0.83 (95%CI [0.73, 0.93]) for classifying patients as having either AD or PD, after controlling for age. Importantly, qBEANS scores for the PD group (95%CI [5.6, 7.7]) were not statistically different from the cognitively intact group in the APPE cohort (n=52; 95%CI [6.7, 10.5]), but were different from the AD group (95%CI [9.9, 14.6]), even after controlling for age (Tukey HSD p=0.0022). These data suggest that qBEANS has diagnostic accuracy for AD and not other common movement disorders, demonstrating that test scores may a viable biomarker for AD screening and clinical trial enrichment.
Categories
Motor Rehabilitation
Metabolics of a Novel Asymmetric Walking Paradigm Using a Single Belt Treadmill
Caitlin Banks1,2, Brooke Hall1, Junyao Li2,3, Jan Stenum2, Ryan Roemmich1,2
1Kennedy Krieger Institute, Baltimore, MD, USA. 2Johns Hopkins University School of Medicine, Baltimore, MD, USA. 3Northwestern University Feinberg School of Medicine, Chicago, IL, USA
Millions of people in the United States walk with asymmetric gait patterns due to a variety of neurologic and orthopedic conditions (1). Unfortunately, most rehabilitation approaches that aim to restore symmetric walking require specialized equipment that is not available in most clinics (2,3). Our lab developed a novel dynamic treadmill controller than can induce a split-belt-like adaptation using a standard single belt treadmill (4). This controller can be used to selectively modify gait parameters of importance to gait rehabilitation such as step length, trailing limb angle, and propulsion. Here, we sought to compare the metabolics of walking with the dynamic controller to that of fast walking. Our hypothesis was that the metabolic power needed for walking with the dynamic controller would fall between the power required for walking at the faster speed and walking at the slower speed, suggesting that this strategy could be used to target gait asymmetry in patients who may not be able to tolerate fast treadmill walking (a common gait rehabilitation approach for many clinical conditions).
Eleven healthy young adults (age 25±3 years, 5 male, 6 female) walked on an instrumented treadmill. The dynamic treadmill controller alternated the treadmill between 0.75 m/s and 1.50 m/s for 50% of each gait cycle, with a metronome playing to target stepping at specific time points relative to the treadmill speed change. We sampled breath-by-breath oxygen consumption and carbon dioxide production to calculate net metabolic power during the last two minutes of each walking bout. We performed a one-way ANOVA to compare net metabolic power across baseline walking at the slow speed, fast speed, and the mathematical average of the fast and slow speeds, as well as walking with the dynamic treadmill controller. Net power varied significantly by condition (F(3,30)=93.5, p<0.001) and a Tukey HSD post-hoc test revealed significant differences between all conditions (all p’s<0.001).
Net metabolic power for the dynamic treadmill condition represented a metabolic intermediate between normal walking at the fast and slow speeds. This aligns well with the split-belt treadmill literature (5). These findings, coupled with our previous work showing that this technique can drive selective changes in gait asymmetry, synergistically demonstrate that this technique has the potential for delivering asymmetric gait training at a reduced metabolic demand relative to fast walking. This dynamic treadmill controller offers clinically feasible promise for individuals with gait asymmetries, and future research will explore personalized application of the controller to subject-specific gait asymmetries. These results in healthy individuals add insight that therapeutic use of this controller may be ideal for those individuals who cannot tolerate fast walking, a popular rehabilitation strategy for individuals with better cardiovascular fitness.
Categories
Motor Rehabilitation
Developing Personalized Medicine Strategies to Increase Daily Steps for Veterans with Parkinson’s Disease: A remote gamification intervention
Kimberly Waddell1,2, S. Ryan Greysen1,2, Madison Smith2, Stephanie Wood2, James Morley1,2
1University of Pennsylvania, Philadelphia, USA. 2Crescenz VA Medical Center, Philadelphia, USA
Background: Physical activity levels are low and often decline over time for adults with Parkinson’s Disease (PD). The benefits of physical activity have mostly been observed in monitored clinical trials with supervised in-clinic programs. Strategies to increase physical activity in real life settings represent a major therapeutic opportunity and unmet need in PD treatment. Prior work has demonstrated that interventions that leverage insights from behavioral economics and scalable technologies are efficacious for increasing daily steps in many clinical populations, but the utility of these interventions in adults with PD is unknown.
Purpose: The purpose of this project is to describe a remote, behavioral intervention designed to increase daily steps in Veterans with PD and report interim results from an ongoing clinical trial.
Methods: This is a single-arm clinical trial examining the effect of gamification on daily steps for Veterans with PD. Potential participants are identified using the VA Corporate Data Warehouse. Veterans with an ICD-10 code for PD who reside within Veteran’s Integrated Service Area 4, which includes five states, are invited to participate via mailed letter and complete a telephone screen for eligibility. This trial uses Way to Health, a research technology platform that manages enrollment, survey administration, and automates daily step data collection and feedback messaging. All participants wear a Fitbit device on their hip. The trial protocol includes a two-week baseline period, a six-week gamification intervention, and a six-week follow-up period. The gamification intervention leverages insights from behavioral economics, including loss-framed points and levels, pre-commitment, and daily performance feedback to help motivate participants to meet their daily step goal. The primary trial will enroll 85 Veterans and an interim analysis was completed on 34 participants. Baseline demographics and clinical characteristics were summarized using descriptive statistics and preliminary change in daily steps from baseline was examined using linear mixed effects regression, adjusting for calendar month and baseline steps, with a participant random effect.
Results: Planned interim analyses on 34 participants demonstrated a mean (SD) age of 71 (6.1) years. Participants had a mean (SD) disease duration of 6.5 (4.4) years with a mean (SD) Unified Parkinson’s Disease Rating Scale II of 9.4 (5.6). On average, participants live 170.6 (158.4) miles from the study site. Participants averaged 4949 (2713) steps at baseline. Overall, the mean change in daily steps from baseline was 943 steps (SE 446 steps, p < 0.01) with 68% of the sample achieving their step goal > 60% of intervention days.
Conclusions: This remote, gamification intervention expanded recruitment to older adults living over 100 miles from the study site. The use of scalable technologies (wearables, remote monitoring platform) enable novel, scalable interventions that are a promising pathway for improving physical activity in older adults with PD.
Categories
Other
When complexity doesn’t equal specificity: The utility of the Boston Qualitative Scoring System for the Rey-Osterrieth Complex Figure in detecting right hemisphere stroke
Kasey Stack, Sarah Haile, Anna Seydell-Greenwald
Georgetown University Medical Center, Washington, DC, USA
Right hemisphere (RH) stroke is common in the US, as are lasting visuospatial deficits following RH stroke. One of the most prevalent deficits is constructional apraxia, which is characterized by difficulties with copying drawings or using component parts to create an overall structure. The Rey-Osterrieth Complex Figure (ROCF) is often used as a bedside diagnostic tool for constructional apraxia. However, the ROCF can be time-consuming and taxing for the testee, and the available scoring options allow for considerable subjectivity, which raises questions about the ROCF’s utility as a diagnostic tool.
Here, we investigate the ability of the Boston Qualitative Scoring System (BQSS) for the ROCF to differentiate between adults who had a RH stroke more than six months prior to the study and demographically matched controls. The BQSS is a complex and time-consuming scoring scheme that assesses the presence, accuracy, and placement of various ROCF components in the testee’s drawing,. Aspects such as fragmentation, planning, and asymmetry, which might have greater diagnostic specificity for RH stroke, are also scored. Participants (44 adults ages 20-79, 22 with RH stroke, 22 controls) were instructed to replicate the ROCF (placed in front of them) to the best of their abilities on a tablet (“copy” condition). Twenty minutes later, they were asked the recreate the figure from memory (“delayed recall” condition). Drawings were scored by a researcher blinded to group.
Across both groups and conditions, older age was associated with lower overall presence and accuracy scores. Compared to controls, the RH stroke group had significantly lower presence scores in the copy condition, and significantly lower configural presence and accuracy scores in the delayed recall condition. In the copy condition, significantly more people in the RH stroke group had asymmetric drawings (ie. more detail on the right than the left) than controls.
Unexpectedly, there were no significant group differences for fragmentation, rotation, or overall presence and accuracy scores, even though the RH stroke group performed significantly worse on other measures of constructional apraxia (ie., the WASI II Block Design Task, the Behavioral Inattention Test Cube Drawing). Overall, group differences were small and within-group variability was large, with several controls struggling with the task despite having no indications of neurological deficits in our comprehensive testing battery and no abnormalities on neuroimaging.
Because completeness and accuracy of complex drawings are known to also be affected by left-hemisphere stroke and dementia, our findings suggest that the BQSS, and the ROCF more broadly, may not be the most efficient tools for detecting constructional deficits specific to RH stroke. Other measures with lower testee and scorer burden may not only save time and morale but may also have more clinical utility than the ROCF.
Categories
Stroke
Scalability of Asymmetric Gait Changes Induced by a Dynamic Treadmill Controller
Brooke Hall1, Caitlin Banks1,2, Ryan Roemmich1,2
1Kennedy Krieger Institute, Baltimore, USA. 2Johns Hopkins University School of Medicine, Balimore, USA
Following neurological damage, people often walk with asymmetric gait patterns (1-3). There is a need for new, customizable rehabilitation approaches for targeting various different aspects of gait asymmetry. Our lab developed a dynamic treadmill controller that alternates the treadmill speed between a fast and a slow speed, each for 50% of the gait cycle to drive asymmetric changes in several clinically relevant gait parameters depending on when the speed change occurs within the gait cycle (4). Thus far, we have only tested the dynamic treadmill controller at a fast-to-slow speed ratio of 1.5 m/s to 0.75 m/s, leaving question as to how gait changes induced by these within-stride speed changes scale across speed ratios. Here, we aimed to investigate the effects of increasing and decreasing speed ratios on gait asymmetry using the dynamic treadmill in healthy young adults. We hypothesized that the magnitude of gait changes induced will increase proportionally with speed ratio.
Fifteen healthy young participants (7 females, 8 males, age 25 ± 3 years) were randomly assigned to one of three speed ratio conditions: a two-to-one (0.5 m/s:1.0 m/s), a three-to-one (0.5 m/s:1.5 m/s), and a four-to-one (0.5 m/s:2.0 m/s) condition. Each participant first completed three baseline trials: a slow, an intermediate, and a fast speed in accordance with their speed ratio condition. Participants then walked with the dynamic treadmill controller under a condition where the treadmill accelerated from a slow to fast speed at approximately 25% of the gait cycle (based on a right limb heel-strike) such that the treadmill speed accelerated into late stance. We selected this condition because our work has previously shown it can drive asymmetries in three clinically relevant gait parameters commonly targeted during rehabilitation: step length, trailing limb angle, and peak propulsion (4).
A Kruskal-Wallis test revealed significant differences among the groups for right (H(2)=6.62, P=0.04) and left (H(2)=9.38, P=0.01) step lengths and the trailing limb angles for the right (H(2)=10.82, P<0.01) and left (H(2)=8.72, P<0.01) limbs. Post-hoc comparisons using Dunn’s test indicated significant differences between the two-to-one and three-to-one conditions for left step length (P=0.02) and left trailing limb angle (P=0.03). Lastly, we observed significant differences in left step length (P=0.02), and right trailing limb angle (P<0.01) between the two-to-one and four-to-one conditions.
These preliminary results indicate that the gait changes induced by the dynamic treadmill controller are scalable with changes in speed ratio. The ability to scale speed to target specific gait changes would enable the dynamic treadmill controller to serve as a customizable and accessible rehabilitation tool for persons with gait impairments.
Categories
Motor Rehabilitation
Cardiorespiratory fitness does not protect against changes in manual dexterity over two years in persons with multiple sclerosis (MS)
Sarah Duraid, Basel Mohamed, Nick Bray, Michelle Ploughman
Memorial University of Newfoundland and Labrador, St. John’s, Canada
Introduction: Engaging in exercise to create higher or better cardiorespiratory fitness is purported to be neuroprotective in MS,1 a central nervous system disease that arises when the immune system mistakenly attacks the myelin sheath of neurons.2 For instance, people who exercise have fewer relapses and greater preservation of the brain’s gray matter.3,4 However, few studies have examined the efficacy of exercise longitudinally. We undertook this study to determine whether cardiorespiratory fitness (VO2peak) could protect against declines in manual hand dexterity over ~2 years in persons diagnosed with MS.
Methods: We recruited 40 people with MS from a specialized MS clinic in St. John’s, NL. Participants’ disease stability was confirmed via health records. We used the Nine-Hole Peg Test (NHPT) to measure manual hand dexterity. Participants completed the NHPT twice on each hand, and the values were averaged for both the dominant and non-dominant sides. Participants also completed a recumbent stepper fitness test, and the results informed VO2peak. Outcomes were re-assessed, on average, two years later. We conducted a hierarchical regression (controlling for age, sex, global cognition, and NHPT score at baseline or T1 [Model 1]) to determine the influence of baseline fitness on change in NHPT at follow-up or T2 [Model 2]. We also conducted a paired sample t-test to investigate the change in NHPT scores from T1 to T2. A relative increase or decrease of more than 5% of the NHPT score from T1 to T2 was considered an improvement or a decline, respectively. A p-value <0.05 was considered statistically significant.
Results: Our paired t-test demonstrated no significant change in NHPT in either the dominant (p = 0.176) or non-dominant hand (p = 0.368). On the dominant hand, 19 people showed NHPT score decline, 11 were stable, and 10 showed improvement. Similarly, 20 people showed NHPT score decline for the non-dominant hand, 13 were stable, and 7 showed improvement.
When controlling for age, sex, global cognition, and T1 NHPT score, fitness at T1 did not predict NHPT score at T2 in either the dominant (Control variables R2=0.42, p<0.001, addition of fitness R2 change 0.045, p=0.095) or non-dominant hand (Control variables R2=0.77, p<0.001, addition of fitness R2 change <0.001, p=0.92).
Discussion: Despite research supporting the neuroprotective effects of exercise in animal models and humans with MS5, we found that changes in hand dexterity performance over time was not predicted by fitness assessed via VO2peak. Limitations of the study include the higher relative number of female participants and the variability in MS progression. Future research should explore the neuroprotective effects of fitness on other MS symptoms, such as cognition or leg function; the latter may be particularly insightful, given that most forms of cardiorespiratory fitness rely heavily on the lower extremities.
Categories
Multiple Sclerosis (MS)
The link between reward and movement during a music task: effects of musical composition and preliminary fMRI findings among stroke survivors
Anna Palumbo1, Eva Luna Munoz Vidal1, Karleigh Groves1, Alan Turry1, Robert Codio1, Heidi Schambra2, Gerald Voelbel1, Pablo Ripolles1
1New York University, New York City, USA. 2NYU Grossman School of Medicine, New York City, USA
Background: Music interventions for stroke rehabilitation have been demonstrated to improve motor function and mood and increase activation of sensorimotor brain networks. Reward during music playing is linked to greater motor recovery, and our previous work links music improvisation to increased enjoyment and motor response. This work also identified musical composition as significantly contributing to reward and motor responses, which bears further investigation. Research is needed to identify the neural mechanisms linking reward to motor response during music interventions following a stroke.
Objective: This study investigates the effects of 4 different music compositions on motor and affective responses during a rhythm tapping task. We will also present preliminary findings from an ongoing fMRI study investigating the neural mechanisms of the same paradigm.
Methods: Using a 2x2 crossover design, 30 healthy adults completed a rhythm tapping task on a MIDI drum while either (i) improvising or maintaining the beat and (ii) playing with live or pre-recorded piano accompaniment. All four conditions were completed with four different piano compositions written specifically for this study, including the styles of March, Waltz, Rock, and Salsa. The tempos were set to 67 bpm (March), 172 bpm (Waltz), 110 bpm (Rock), and 120 bpm (Salsa). The March and Waltz were composed with little-to-no syncopation, while the Rock and Salsa compositions included moderate and high levels of syncopation, respectively. Motor response was characterized by accelerometry and electromyography (EMG). Autonomic arousal was measured by electrodermal activity (EDA). Affective responses, including enjoyment and challenge, were measured by a 12-item 5-point Likert scale. The study is currently being replicated to include stroke survivors and measure neural response using fMRI.
Results: The March and Waltz were rated as less enjoyable and led to lower muscle activation than the Rock and Salsa compositions. The March produced less total acceleration and fewer beats played than the other compositions. The Salsa was rated as the most challenging and produced a higher tonic EDA response compared to the March. Based on these findings, the music compositions in the fMRI study were modified to all have moderate levels of syncopation and bpm in the range of 110-142.
Conclusions: Music composition modulates reward and motor response during music-playing tasks. Compositions with syncopation may increase enjoyment and motor response, while high levels of syncopation may increase challenge. Ongoing fMRI analysis will investigate neural activity linking reward during music playing to activation in sensorimotor brain regions.
Categories
Stroke
Tactile Examination at the Upper Extremity in Individuals with Stroke: A Scoping Review for Neuroengineers
Arco Paul, Karan Nayak, Lindsey Sydnor, Nahid Kalantaryardebily, Kevin Parcetich, Daniel Miner, Eileen Wafford, Jane Sullivan, Netta Gurari
Purpose. Accurate perception of tactile stimuli is essential for performing and learning activities of daily living. Through this scoping review, we sought to summarize existing tactile examination approaches at the upper extremity in individuals with stroke. The goal was to identify current limitations and future research needs for designing more comprehensive examination tools.
Methods. A scoping review was conducted in accordance with the Joanna Briggs Institute (JBI) methodological framework and the PRISMA for Scoping Reviews (PRISMA-ScR) guidelines. A database search for tactile examination approaches at the upper extremity of individuals with stroke was conducted using Medline (Ovid), The Cochrane Library (Wiley), CINAHL Plus with Full Text (Ebsco), Scopus (Elsevier), PsycInfo (Ebsco), and Proquest Dissertations and Theses Global. Original research and review articles that involved adults (18 years or older) with stroke, and performed tactile examinations at the upper extremity were eligible for inclusion. Data items of interest were extracted from the selected articles. These data items indicated: if the examination was behavioral in nature or involved neuroimaging, the nature of the task at the paretic arm of individuals with stroke, the number of possible outcomes of the evaluation, the type(s) of tactile equipment used, the location(s) along the arm examined, whether any specific peripheral nerves were targeted for examination, and if any comparison was made with the non-paretic arm or with the corresponding arms of individuals who are neurotypical.
Results. Twenty-two articles met the inclusion criteria and were accepted in this review. Most examination approaches were behavioral in nature and involved self-reporting of whether a tactile stimulus was felt while the arm remained passive (i.e., no volitional muscle activity). Typically, the number of possible outcomes with behavioral approaches were limited (2-3), whereas neuroimaging approaches had many more possible outcomes (>15). Tactile examinations were conducted mostly at the distal locations along the arm (finger or hand) and were not targeted towards any specific peripheral nerve. Although a majority of articles compared paretic and non-paretic arms, most did not compare outcomes to a control group of individuals without stroke.
Discussion. Further research is needed to develop better tactile examination tools that combine behavioral responses and neurophysiological outcomes, and allow volitional tactile exploration by subjects. Additionally, approaches that include testing of multiple body locations, provide higher resolution of outcomes, and consider normative comparisons with individuals who are neurotypical, may provide a more comprehensive understanding of the effects of these tactile deficits following stroke.
Categories
Stroke
Feasibility of passively monitoring real-world mobility and interpersonal communication among individuals with stroke using smartphone technology
Grace Bellinger1, Julie DiCarlo2, Sydney McKiernan2, Jamie Nam1, Ryan Roemmich1,3, Carolee Winstein4, Lee Schwamm5, David Lin2,6
1Johns Hopkins University School of Medicine, Baltimore, USA. 2Massachusetts General Hospital, Boston, USA. 3Kennedy Krieger Institute, Baltimore, USA. 4University of Southern California, Los Angeles, USA. 5Yale School of Medicine, New Haven, USA. 6Harvard Medical School, Boston, USA
Personalizing stroke rehabilitation using quantitative and individual-level data is limited by the challenge of gathering stroke outcomes in the real world. Current approaches to gathering functional outcomes longitudinally are time- and labor-intensive, often requiring in-person visits and placing significant burden on the patient. Remote outcomes data collection is often subjective (e.g., patient-reported outcomes) or gathered over telehealth, while still requiring active participant engagement. Gathering continuous data in a passive and scalable manner would facilitate digital phenotyping and prediction of individual recovery trajectories to inform personalized neurorehabilitation approaches. Smartphone technology such as Beiwe – a smartphone application that tracks participant mobility using GPS data and interpersonal communication via call and text message logs – offers the opportunity for remote real-world data collection without active participant engagement. The GPS data are used to calculate metrics related to real-world mobility, such as home time, distance traveled, and number of places visited. For Android devices with the application installed, Beiwe collects data on incoming and outgoing calls and text messages, which are a proxy for social interaction. The purpose of this study was to demonstrate the feasibility of remotely collecting passive smartphone-based data and calculating metrics of post-stroke mobility and communication in the real world. Forty-five adults (27 male, 18 female) admitted to Massachusetts General Hospital for acute stroke (34 ischemic, 11 hemorrhagic) enrolled in the 12-month study. On average, the participants were 61.2±8.3 years of age and 5.0±5.0 days post-stroke at enrollment. At baseline, the cohort had a median(IQR) NIH Stroke Scale of 1(1-5) and modified Rankin Scale of 3(1.5-4). Thirty-five participants (77.8%) had GPS data available for an average of 90.8±91.0 days. On an average day, this cohort spent 15.7±4.8 hours at home, traveled 23.5±38.2 total miles, and visited 2.2±1.0 places. Twenty-one participants (91.3% of Android users) had communication data available for an average of 164.1±112.2 days. For the cohort with communication data, 1.6±1.1 calls were received, 3.4±3.1 calls were placed, 11.0±15.5 text messages were received, and 7.6±10.9 text messages were sent each day. The Beiwe application offers an opportunity for passive remote monitoring that does not require participants to wear, charge, or synchronize an additional device. While phone location is only an approximation of human movement, many people carry their smartphones with them when moving both within and outside of the home. The GPS-based measures therefore provide convenient estimates of large-scale mobility for individuals with stroke. Though currently limited to Android users, the communication data may provide insight into cognitive and psychosocial health. Smartphone technology such as the Beiwe application offers promising ability to longitudinally assess post-stroke mobility and communication for digital phenotyping in a passive and scalable manner.
Categories
Stroke
Operant Up-Conditioning of the Quadriceps Motor Evoked Torque as a Means to Improve Quadriceps Function after Anterior Cruciate Ligament Reconstruction
Kazandra Rodriguez, Riann Palmieri-Smith, Chandramouli Krishnan
University of Michigan, Ann Arbor, USA
Diminished corticospinal excitability is theorized to contribute to poor quadriceps function following anterior cruciate ligament (ACL) reconstruction. However, recovery of quadriceps function may be limited as current rehabilitation methods do not directly target changes in corticospinal excitability. Operant conditioning of the motor evoked torque (MEPTORQUE) is a promising approach capable of improving corticospinal excitability.1 However, it is unknown whether increasing corticospinal excitability can improve quadriceps function following a short-term operant conditioning intervention in ACL reconstructed individuals. Therefore, the aim of this study was to evaluate whether individuals with ACL reconstruction can increase the quadriceps MEPTORQUE response with training and whether these up- conditioning effects result in improvements in quadriceps function following a two-week intervention. Twenty-two ACL reconstructed individuals (14.0 ± 5.4 months post-operative) were randomized into one of two groups for a two-week operant conditioning intervention. During training sessions, quadriceps MEPTORQUE responses elicited via transcranial magnetic stimulation (TMS) were evaluated on the reconstructed leg in both groups. While seated on a dynamometer with their reconstructed leg fixed at 60° of knee flexion, a block of 20 control TMS trials (i.e., no up-conditioning) was collected immediately before operant conditioning procedures. During the operant conditioning procedures, participants received a total of 225 TMS trials (3 blocks of 75 TMS trials), but one group received TMS and training to increase the amplitude of their MEPTORQUE responses (COND) and the other group received TMS only (SHAM-COND). The percent change in peak quadriceps MEPTORQUE amplitude from the control block to the third conditioning/sham-conditioning block was used to evaluate the changes in corticospinal excitability during training sessions. Quadriceps strength and voluntary activation were evaluated on the reconstructed leg prior to (PRE) and following (POST) the intervention to determine the effect of the operant conditioning intervention on quadriceps function. Results indicated that the COND group demonstrated a significantly higher percent increase in the amplitude of their quadriceps MEPTORQUE during training compared with the SHAM-COND group (p = 0.013, COND: 155.585 ± 10.804%, SHAM-COND: 114.171 ± 10.804% [mean ± standard error (SE)]). In addition, normalized quadriceps strength improved on the reconstructed leg, (p = 0.016, PRE: 2.397 ± 0.031 N-m/kg, POST:: 2.516 ± 0.031 N-m/kg [mean ± SE]), regardless of group. Similarly, quadriceps voluntary activation improved on the reconstructed leg (p = 0.036, PRE: 85.523 ± 1.611%, POST: 91.126 ± 1.611% [mean ± SE]), regardless of group. Together, these findings indicate that operant conditioning training can elicit within-session improvements in corticospinal excitability after ACL reconstruction. Although improvements in quadriceps function were observed, they do not appear to be solely attributed to the operant conditioning intervention.
Categories
Motor Rehabilitation
White matter disconnection predicts visually guided reaching performance in chronic stroke
Matthew Chilvers, Trevor Low, Sean Dukelow
University of Calgary, Calgary, Canada
Introduction: Stroke often results in profound impairments in upper-limb motor function. Unfortunately, upwards of 40% of people show incomplete motor recovery at six-months following stroke. Consequently, a prominent focus on neurorehabilitation research has been placed on predicting stroke outcomes, and discovering behavioural, clinical and neuroimaging biomarkers of stroke recovery. Stroke lesions can damage the white matter, which can disrupt signal transduction and cause stroke-related syndromes, including motor impairment. This white matter disruption has been termed “white matter disconnection” and can be quantified using neuroimaging. In this study, we investigated how acute white matter disconnection relates to performance and long-term impairments on a robotic visually guided reaching (VGR) task, at six-months post-stroke.
Methods: Participants with unilateral stroke (n=135) performed a VGR task in a Kinarm Exoskeleton robotic device, at six-months post-stroke (mean 191.8 ± 18.7 days post-stroke). The task required participants to make 10cm out-and-back reaching movements with their stroke-affected arm, from a central target to eight peripheral targets (2cm diameter) oriented in a circle. Performance on the VGR task was quantified using a global Task Score, which was calculated using a normative model collected from control participants without prior stroke.
Clinical neuroimaging (MRI or CT) was collected for each individual and processed using the Lesion Quantification Toolkit, to quantify three disconnection metrics: 1) the proportion of damage to 166 parcels from the automated anatomical labelling (AAL) atlas, 2) the severity of disconnection to 70 canonical white matter tracts and, 3) the severity of disconnection between every pair of AAL parcels (13695 total). Linear regressions were performed between each metric and VGR Task Scores, also accounting for overall lesion volume. Regression analyses were corrected for multiple comparisons.
Results: Six-month VGR Task Scores were notably linked to disconnection metrics, primarily centred around basal ganglia structures and motor pathways. The pallidum was the only region where the proportion of damage was associated with VGR performance. The severity of white matter disconnection was also associated with VGR performance for the: anterior commissure, corticospinal tract, corticothalamic and corticostriatal pathways, inferior fronto-occipital fasciculus and parietopontine tract. Numerous pairwise disconnections involving the pallidum also emerged as significant predictors for motor performance at six-months post-stroke.
Conclusion: This work highlights the critical role of basal ganglia structures, with a particular emphasis on pallidal involvement, and motor pathways in predicting motor outcomes up to six-months post-stroke.
Categories
Stroke
Precision control of the non-dominant left hand depends on inhibition of dominant right hand mechanisms in the left superior parietal lobule
Taewon Kim1,2,3, Samah Gassass1, Ruiwen Chen1, Alex Carter1, Ian Dobbins1, Lei Liu1, Mark McAvoy1, Zhexian Sun1, Yong Wang1, Benjamin Philip1
1Washington University School of Medicine, St. Louis, USA. 2The Pennsylvania State University, University Park, USA. 3Penn State College of Medicine, Hershey, USA
After unilateral impairment of the dominant right upper extremity, individuals must increase their reliance on the non-dominant left hand (LH). Dominant right hand (RH) performance depends on left-hemisphere specializations, but the specific neural mechanisms remain unknown, let alone how they may be recruited to improve performance with the LH. Here we used fMRI to determine which brain areas are differentially active between LH drawing vs. RH drawing, and how this differs after chronic peripheral nerve injury to the RH. We hypothesized: (1) patients would use the same brain mechanism as healthy adults; and (2) ipsilateral parietal areas would be more active during LH drawing than RH drawing because left-hemisphere specializations are ipsilateral only during LH drawing.
We addressed these hypotheses with a well-powered fMRI study of right-handed adults (n=33 total; 24 healthy controls, 9 patients with chronic peripheral nerve injury to the RH). Participants underwent functional MRI scanning while performing a precision drawing task, alternating between hands. We performed a region of interest (ROI) analysis using 10 a priori ROIs: 5 brain areas (hand region of primary motor cortex, superior parietal lobule (SPL), inferior parietal lobule (IPL), intraparietal sulcus, and dorsal premotor cortex) * 2 hemispheres (ipsilateral to movement, contralateral to movement). Within each ROI, we performed a general linear model to predict fMRI activity (drawing > rest) at the participant level, based on 7 factors: drawing hand (LH or RH), group (control or patient), age, and 4 drawing performance variables (velocity and direction smoothness, each for LH and RH).
Our models achieved a significant prediction of fMRI activity in 2/10 ROIs: SPL ipsilateral to movement (p = 0.013), with significant factors “drawing hand = LH” (t = -2.5, p = 0.015) and “RH velocity smoothness” (t = -2.7, p < .001); and IPL ipsilateral to movement, with significant factors “age” (t = -2.2, p = 0.030) and “RH velocity smoothness” (t = -2.0, p = 0.046). Therefore, high performance with the dominant RH was associated with lower activation in multiple ipsilateral parietal areas, but differences between drawing hands (LH vs RH) occurred only in ipsilateral SPL.
These results provide two conclusions about the brain mechanisms of LH precision control in right-handed adults. First, we confirmed hypothesis #1: peripheral nerve injury patients adapt to RH impairment by using the same mechanisms as healthy adults: the effect of RH performance did not depend on whether the participant was a patient (i.e. whether RH performance was injury-impaired). Second, contrary to hypothesis #2, ipsilateral SPL was less active for LH drawing than RH drawing. This suggests that LH precision drawing may require right-handed people to inhibit the left-hemisphere specializations that they would typically use when performing precision tasks with their usual RH.
Categories
Neural Repair Mechanisms
Quantitative activity assessment becomes useful when targeted at the motor skill demands following peripheral nerve injuries in the upper extermity
Samah Gassass, Ruiwen Zhou, Hattori Robin, Lei Liu, Lisa Connor, Benjamin Philip
Washington University in St. Louis, St. Louis, USA
Peripheral nerve injuries in the upper extremity (UE-PNI) account for 100-600,000 cases of chronic disability every year in the United States. Effective rehabilitation requires therapists to enable patients to engage in their preferred activities. However, it has previously been difficult to identify the impact of UE-PNI on activity participation because existing assessments of participation encompass a broad range of activities, many of which do not depend on the motor impairments involved in PNI. This measurement limitation has been addressed by a recent development in the Activity Card Sort (ACS) assessment, which now allows separate sub-scores for 12 activity “dimensions” defined by the skills needed to perform each activity. In this study, we utilized ACS dimension sub-scores to demonstrate, for the first time, that UE-PNI impacts patients’ participation. Specifically, we hypothesized that patients with unilateral UE-PNI to the dominant hand would show reduced participation for activities that require fine motor skills compared to activities that require gross motor skills or no motor skills.
In our sample of 22 individuals with unilateral UE-PNI to the dominant hand, we used a regression analysis (two-part model with random effects to account for within-subject correlations) to assess differences between 3 participation outcome variables (dimension sub-scores for fine motor, gross motor, and non-motor activities; all measured as % activities lost post-injury), and the influence of covariates including: age, months since injury, months since surgery, pain, number of OT / PT sessions, injury severity, depression, injury cause, lesion location, and nerve injured.
We found that patients with unilateral UE-PNI to the dominant hand had significantly more loss of participation in activities that required fine motor skills (z = 2.03, p = 0.042) or gross motor skills (z = 4.5, p < 1x10-4), compared to activities that required no motor skills. The only covariate associated with participation was health-related quality of life (z = -2.5, p = 0.01).
Our results demonstrate that UE-PNI affects patient life in ways that can be measured by participation assessments that focus on motor-dependent activities. Unexpectedly, we found a greater effect of UE- PNI on gross motor activities than fine motor activities. Overall, our study demonstrates that quantitative activity assessment can be useful for a wider range of conditions than previously possible, if clinicians and researchers focus their assessments on the kinds of activities relevant to the condition and important to the individual.
Categories
Motor Rehabilitation
Altered cerebellar functional connectivity differentially affects reactive stability in cognitively intact versus impaired older adults
Jessica Pitts, Lakshmi Kannan, Rudri Purohit, Tanvi Bhatt
University of Illinois Chicago, Chicago, USA
Background: Older adults with mild cognitive impairment (OAwMCI) experience twice as many falls as cognitively intact older adults (CIOA), which could be attributed to impaired reactive balance control. Our recent study found resting state functional connectivity (FC) between the cerebellum and higher cortical networks is associated with reactive stability in OAwMCI. However, the lack of control group left it unclear if the relationship between cerebellar FC and reactive balance is a product of healthy aging, or depends on cognitive status. In this exploratory analysis, we examined relationships between resting state FC, reactive balance performance, and cognition.
Methods: 26 older adults participated in the study and completed the Montreal Cognitive Assessment (MOCA). Participants underwent functional magnetic resonance imaging (fMRI) and we determined the FC within atlas, within network, and between atlas-network connections known to be associated with reactive balance4. Pre-selected atlases included cerebellum 1-10, vermis 1-10, parahippocampal gyrus, and middle frontal gyrus. Networks included default mode, sensorimotor, salience, and dorsal attention. Participants were exposed to a standing support surface perturbation to determine reactive stability (margin of stability). We used CONN software to extract FC strength and performed linear regression to analyze if FC and MOCA could predict reactive stability. We then divided participants into OAwMCI (MOCA 18-24, n=16) or CIOA (MOCA≥25, n=20) and performed t-tests to compare FC strength between groups. For each group, we also performed correlations between FC and reactive stability.
Results: MOCA significantly predicted reactive stability (β=0.056-0.173), along with cerebellum-cerebellum (β=5.761), vermis-vermis (β=11.871), default mode network-parahippocampal gyrus (β=-21.778), and middle frontal gyrus-frontal pole (β=7.713) FC (p<0.05). OAwMCI had lower cerebellum-cerebellum, vermis-vermis, and cerebellum-vermis FC than CIOA (p<0.05). OAwMCI also had lower cerebellum-sensorimotor network and cerebellum-dorsal attention network FC than CIOA, although increased cerebellum-salience insula network, vermis-default mode network, and cerebellar network-middle frontal gyrus FC (p<0.05). FC was generally more strongly correlated with reactive stability in OAwMCI (R2=0.354-0.512) than CIOA (R2=0.007-0.121).
Discussion: OAwMCI generally demonstrated reduced cerebellar FC, which could potentially impact perception of perturbation intensity and subsequent triggering of the protective stepping response, and hence reactive stability. Conversely, OAwMCI demonstrated higher FC between the cerebellum and the salience and default mode networks, which could potentially indicate altered ability to allocate attentional and vestibular resources when initiating and executing balance recovery tasks, such as reactive stepping, due to underlying vestibular and executive function deficits. While there was an apparent relationship between FC and reactive stability in OAwMCI, FC was not strongly related to reactive stability in CIOA. This could be a result of a plateau effect, where higher FC after a certain threshold is not more beneficial to plan and initiate motor responses. Further analysis is needed to explain the neural basis of increased fall incidence in OAwMCI.
Categories
Cognitive/Language Rehabilitation
Differences in motor recovery prediction based on lesion size using degree of corticospinal tract injury from acute stroke imaging
Alexander Brunfeldt, Andrew DeMarco, Matthew Edwardson
Georgetown University Medical Center, Washington DC, USA
Upper extremity motor impairment is the most common cause of disability after stroke. Compelling studies propose the degree of overlap from the acute stroke lesion with the corticospinal tract (CST) as a potential biomarker for stroke outcomes. Nevertheless, the validity of this method as a predictive tool has not been assessed in cohorts with levels of impairment reflective of entry criteria into stroke rehabilitation trials. This study aimed to validate the predictive capacity of CST injury for arm impairment in a motor rehabilitation trial cohort with mild to moderate motor impairment and compare it to a cohort more reflective of the general stroke population.
We obtained neuroimaging data and Upper-extremity Fugl-Meyer (UE-FM) scores from stroke-survivors in the CPASS trial (n=56) and the BIOREC observational study (n=39). We manually traced each patient’s lesion from MRI or CT images obtained at hospital admission. We then calculated CST injury as the number of descending corticospinal tract subsections (out of 16) with > 5% overlap with the lesion. We then performed a regression predicting UE-FM score at study endpoint (CPASS, 12 months; BIOREC, 3 months) with CST injury as the predictor.
Average lesion volume was 6.15+/-12.3cc in CPASS and 35.6+/-56.9cc in BIOREC. Across the combined cohorts, final UE-FM was associated with CST injury (N=92, R2 = 0.1, p = 0.001). There was no association with final UE-FM and CST injury in either the CPASS (R2 = 0.02, p = 0.18) or BIOREC (R2 = 0.03, p = 0.13) studies individually. Given the discrepancy in lesion size between cohorts, we then separated the combined cohort into those with large and small stroke lesions based on an arbitrary volume cutoff of 10cc. Further analysis suggested that there was no association between UE-FM at study endpoint and CST injury in patients with lesions < 10cc (N = 67, R2 = 0.0, p = 0.37), but strong associations in patients with lesions > 10cc (N = 25, R2 = 0.34, p = 0.001).
Despite being statistically significant, the weak association in the combined cohort (R2 = 0.1) does not suggest CST injury is a strong predictor of motor impairment 3-12 months post-stroke. Previous studies report R2 values greater than 0.3, up to 0.8; however, patients in those studies had lesion volumes averaging 35-80 cc, which are generally larger than our sample. We reproduced these stronger associations in patients with lesions > 10cc, but failed to do so in patients with smaller lesions. Further studies, particularly in those with levels of impairment suitable for rehabilitation trials, are needed to gauge the generalizability of measures of CST injury on acute stroke imaging to predict motor outcomes.
Categories
Stroke
Feasibility of a scalable, home-based, full-body training program in chronic stroke patients using the MindMotion GO
Spencer Arbuckle1, Anna Knill2,3, Gabriela Rozanski4, Jenna Tosto-Mancuso4, Anastasia Ford1, Louis Derungs1, Michelle Chan-Cortés1, David Putrino4, Meret Branscheidt2,5
1MindMaze, Lausanne, Switzerland. 2ETH Zurich, Zurich, Switzerland. 3Lake Lucerne Institute, Vitznau, Switzerland. 4Icahn School of Medicine at Mount Sinai, New York, USA. 5cereneo, Weggis, Switzerland
Long-term, high-dose rehabilitation can enhance functionality after an injury and prevent decline over time in chronic stroke survivors. Unfortunately, the reality is that patients generally lack access to rehabilitation, let alone long-term, high-dose programs. Reasons vary, but the primary hurdles stem from access limitations (e.g., therapist time, cost, geography) and intrinsic patient factors (e.g., motivation, compatibility with daily life). This creates a divide between evidence-based recommendations from clinical trials and medical guidelines versus what is actually delivered in real-world settings. Given the growing national shortage in therapists and the growing incidence of neurological disease, this divide will only expand.
To tackle this divide, we incorporated digital technologies into a full-body training program to help therapists augment delivered treatment dose. Specifically, we assessed the feasibility of a long-term (12-18 weeks) asynchronously-supervised training program delivered to chronic stroke patients (n=17) in their own homes and according to their own schedule. Therapy consisted of asynchronous training at home using the game-based digital therapy technologies MindMotion GO and Izar, accompanied by synchronous telerehab sessions with a physical therapist 1-3 times per week. To assess clinical efficacy, each patient completed an in-person battery of functional and physiological assessments at program start and completion.
Patients completed an average of 118 minutes of active training time (ATT) across 3 days/week for 19.5 (±2.9) weeks, with an adherence of 74% (proportion of patients who completed ≥60 min ATT, averaged across weeks). The training was full-body, with each patient spending approximately 43% (±9%), 28% (±8%), 13% (±13%), and 15% (±14%) of total ATT training focusing predominantly on the upper limbs, lower limbs, trunk, and hands. Of the total ATT, only 18% (±11%) was performed under remote, synchronous supervision with a therapist. Even so, patients showed meaningful clinically important improvements on the Fugl-Meyer UE (+6.4±5.1; p<0.01) and the Berg Balance Scale (+6.1±4.4; p<0.01), along with generally broad improvements across the battery of functional and physiological measures administered. Notably, patients enjoyed their participation, with approximately 80% expressing a desire to continue at program completion.
This program offers promise to tackle many of the primary hurdles in delivering high-dose training. First, the dosage was largely delivered asynchronously to patients, and so the dose in such a program could be more easily scaled up to better approximate evidence-based recommendations. Second, patients remained engaged in the gamified training program and were motivated to extend their participation beyond program end. Third, because this was a home-based program, patients were afforded all the conveniences of a home-based program – namely the ability to train on their own schedule and not needing to be geographically situated near a clinic. Taken together, this program represents a scalable home-based solution that can deliver long-term, higher-dose, full-body training.
Categories
Motor Rehabilitation
A data fusion approach to improve accuracy and robustness of home and community mobility assessment after stroke
George Fulk1, Karen Klingman2, Emily Peterson1
1Emory University, Atlanta, USA. 2Upstate Medical University, Syracuse, USA
Introduction: Regaining mobility is an important goal for people who have experienced a stroke. Activity monitors (AM) and self-report (S-R) are commonly used and more recently GPS has been proposed to measure granular levels of mobility in the real world. There are limitations to these approaches. The purpose of this study was to develop a novel data fusion approach that fuses all three methods to comprehensively gain insight into mobility after stroke.
Methods: Participants wore an ActivPal AM that measured mobility metrics such as steps and seated travel; a GPS device that measured geographical location coordinates; and completed a S-R trip log that provided information on when participants left/returned home and types of locations visited. Information from the three data sources were linked at the individual level to triangulate activity in and out of the home. Geographic cluster analyses were performed to identify high residency locations (and their respective location types, i.e., home, medical office, shopping center) using the DBSCAN and tidygeocoder R packages. S-R data were used to fill in data gaps that are commonly suffered by incomplete GPS data. Cluster analysis and S-R output was linked to AM data to identify areas and activities associated with high mobility levels.
Results: We found the percent of matched observations between GPS data and S-R daily activities across all individuals in the sample ranged from 0.2% to 70%. Common patterns reveal that patients with greater stroke severity primarily exhibited mobility at home and medical locations. For example, one participant with a NIHSS score of 13 had a total of 26,478 steps at home, 2,592 steps at medical visits, and 2,580 at social activities during the 5-day study period. Conversely, participants with low stroke severity exhibited more balanced patterns of mobility in and outside the home. For example, a participant with a NIHSS score of 2 had a total of 30,534 steps at home, 11,142 steps at work, and 68,466 steps shopping/social visits and recreational activities.
Discussion: These findings highlight the need to use a data fusion approach to robustly assess mobility patterns both in-and-outside the home. The proposed data fusion approach provides both broad and granular insights into participation in the community and where activity occurs across populations of patients and within individual patterns. This novel data fusion approach improves upon current methods to assess activity levels in the community by fusing data from AM, GPS, and S-R sources when each source suffers from data source specific errors and sparsity. The results of data fusion approach may be used to provide robust, accurate, and clinically useful feedback to people with stroke on their mobility levels and to discover potential barriers to increasing activity.
Categories
Stroke
Obstacle-crossing as Predictor of Future Fall Status after Stroke: Comparison of Three Obstacle conditions
Prudence Plummer, Megan Schliep, Lina Jallad, Ehsan Sinaei
MGH Institute of Health Professions, Boston, USA
Background: Stepping over an obstacle is a highly demanding and ecologically valid mobility task. For ambulatory stroke survivors, the ability to successfully step over a custom-height obstacle (10% of leg length) prior to hospital discharge has good sensitivity (67%) and very good specificity (87%) for identifying fallers and non-fallers within the first 3 months of discharge to home.
Objective: The purpose of this study was to determine whether increasing the obstacle depth could reduce the false negatives and improve the sensitivity of the test.
Methods: 46 adults receiving inpatient rehabilitation for stroke who were ambulatory with no more than minimal assistance and were being discharged home completed the custom-height obstacle test with 3 different depth dimensions (0.5 in, 1.5 in, 3.0 in) in random order. The worst of two trials was recorded for each condition on a 0-4 scale, where 0 indicated successful clearance without stopping or loss of balance, 1 indicated successful clearance after stopping, 2 indicated fail due to light contact with the obstacle, 3 indicated fail due to displacement of obstacle or loss of balance, and 4 indicated fail due to need for assistance to complete the task or recover balance. Falls diaries and phone calls were used to track falls for 3 months post discharge. Predictive accuracy of the 3 conditions was examined by dichotomizing scores as pass (0-1) or fail (2-4) and computing the sensitivity, specificity, and area under the curve (AUC) for each condition. Logistic regression estimated the probability of being a faller on each condition.
Results: 35% (n=16) of the participants were fallers (≥1 fall). The failure rates on the 0.5 in, 1.5 in, and 3.0 in obstacles were 24% (n=11), 28% (n=13), and 33% (n=15), respectively. The difference between failure rates was not significant. The subtle increase in difficulty with increased obstacle depth was not associated with improved prediction accuracy. Rather, there was an increase in the false positive rate and subsequent reduction in specificity. That is, with increasing depth, there was a trend for an increase in the number of people who failed the test but did not fall. Only the 0.5-in and 1.5-in obstacles demonstrated significant odds of falling with a failed trial, with odds ratios of 9.0 (95% CI 1.9-42.1) and 5.0 (95% CI 1.3-19.7), respectively. There was no significant difference in the AUC (95% CI) for the 3 obstacle depths: 0.70 (0.53-0.87), 0.67 (0.49-0.84), and 0.63 (0.46-0.81), respectively.
Conclusions: Subtle increases in the depth of a custom-height obstacle appeared to increase the difficulty but did not improve the predictive properties of the test. Stepping over height-customized obstacle is a good predictor of fall status at 3 months post hospital discharge in ambulatory stroke survivors returning to community living.
Categories
Stroke
Stroke impairs proactive balance control in response to predictable gait perturbations
Tara Cornwell, James Finley
University of Southern California, Los Angeles, USA
To respond to predictable gait disturbances, people rely on previous experience and awareness1 to proactively adjust their gait to maintain balance. Proactive changes to stability, such as walking with wider steps, are associated with higher energy costs2 but can reduce the reactive efforts necessary to prevent falling. People post-stroke generally walk with slower3 and wider steps4, perhaps to increase stability, but we know little about how a stroke changes proactive control. Investigating how people with and without a stroke maintain balance during regular gait disturbances could improve our understanding of how predictability informs proactive strategies and how a stroke affects balance control.
Therefore, we tested if people use proactive strategies during regular trips and how these strategies change post-stroke. Thirteen people with chronic stroke and 13 age-/sex-matched neurotypical adults walked on a dual-belt treadmill with single-belt accelerations at random (every one to five strides) and regular (every three strides) intervals. If people learn to predict the perturbation timing, we hypothesized that they could prepare kinematically by increasing the extent to which their center of mass (COM) is within their base of support, known as the margin of stability (MOS), or energetically by reducing push-off of the step before the trip. To quantify these proactive strategies, we evaluated fore-aft MOS at perturbation onset and positive work generated by the trailing leg. To quantify the effectiveness of their strategies, we evaluated the peak forward COM speed during the perturbation step. Linear mixed-effects models evaluated the effect of condition (unperturbed, regularly perturbed, and randomly perturbed) on MOS, impulse, and COM speed for each group. Then Bonferroni-corrected t-tests evaluated pairwise comparisons.
Compared to unperturbed walking, both groups increased forward COM speed during both random (stroke: 0.05 +/- 0.04 m/s, p=0.008; neurotypical: 0.07 +/- 0.03 m/s, p<0.001) and regular (stroke: 0.05 +/- 0.04 m/s, p=0.004; neurotypical: 0.05 +/- 0.03 m/s, p<0.001) perturbations. However, only neurotypical participants reduced COM speed during regular versus random trips (stroke: p=1.000; neurotypical: -0.02 +/- 0.02 m/s, p=0.031). Neither group changed their MOS before regular versus random trips (stroke: p=1.000; neurotypical: p=0.879). Instead, neurotypical participants generated less positive work on the contralateral limb before regular versus random trips (-1.0 +/- 1.2 J, p=0.032). Unlike their neurotypical peers, people post-stroke did not make energetic changes to reduce COM displacement during predictable trips, potentially exposing a proactive control impairment. Possible explanations for this difference could be damage to regions of the brain responsible for learning the pattern or generating proactive responses. Future studies should examine if proactive adjustments are modifiable post-stroke.
Categories
Stroke
Time-series clustering using gait kinematics can distinguish between neurotypical controls and subgroups of gait behaviors post-stroke
Andrian Kuch1, Alison McKenzie1, Nicolas Schweighofer2, James Finley2, Yuxin Wen1, Natalia Sánchez1
1Chapman University, Irvine, USA. 2University of Southern California, Los Angeles, USA
Background: Gait dysfunction is prevalent among stroke survivors1,2. Due to impairment heterogeneity, there is no single intervention target for gait rehabilitation3. To identify subgroups of gait behaviors that can inform on rehabilitation targets, researchers have used muscular activity4,5, peak spatiotemporal characteristics6-8, peak kinematics5-7, or peak kinetics7,8. These studies used discrete metrics, failing to capture temporal variations in the gait cycle. Identifying subgroups of gait behaviors using time-series accounts for these variations, enhancing the ability to link gait deficits to specific treatment interventions. Using this approach, we hypothesize finding several subgroups post-stroke4,6-8 and a group without gait impairment 8.
Methods: We analyzed data for 39 post-stroke and 28 age and sex-matched controls7,9. Bilateral ankle plantarflexion/dorsiflexion, ankle adduction/abduction, and knee flexion/extension were recorded during treadmill walking at self-selected speed or matched speed for controls. Average individual data over a normalized gait cycle for each joint (6x101) were input into a Temporal Convolutional Network -Convolutional Neural Network, to obtain 1D data for each participant. Then, we used the 1D data for k-means clustering. Differences between clusters were assessed with 1D statistical parametric mapping tests. We also compared walking speed and clinical assessments (Berg, ABC, FGA, FM) between clusters.
Results: Five clusters (C1-C5) were optimal. We obtained three stroke clusters (C1: n=2, C2 n=16, C4: n=16), one control cluster (C3 n=21), and one mixed cluster (C5 n=5 stroke, 7 controls). Joint angles differed between clusters during the gait cycle. We present comparisons relative to C3, dominant leg to non-paretic and non-dominant to paretic.
C1: greater paretic ankle adduction during terminal stance and swing, increased paretic plantarflexion pre-swing. C2: greater paretic knee flexion at initial contact and late swing, greater non-paretic knee flexion from initial contact to midstance, greater dorsiflexion and ankle abduction at terminal stance. C4: greater paretic ankle adduction during the entire gait cycle, increased dorsiflexion during loading response and initial swing, greater knee flexion at initial contact, from terminal stance to pre-swing and terminal swing, greater non-paretic ankle abduction and dorsiflexion from initial contact to mid-stance, greater knee flexion at pre-swing and terminal swing to mid-stance. C5: greater non-paretic ankle abduction during stance. ABC for C3 was significantly greater than C2 and C4 (both p<0.001).
Conclusion: The proposed machine-learning architecture identified four post-stroke clusters, including a mixed group, and a control group. The existence of a mixed group can be explained by the slower walking speed of controls, possibly affecting their kinematics10. Neither clinical scores nor walking speed differed between post-stroke clusters, suggesting insufficient specificity of clinical metrics to discriminate gait behavior. Analyzing the entire gait cycle provides additional information allowing clinicians to target specific phases for interventions. This pipeline is applicable to other biomechanical variables and pathological gait.
Categories
Stroke
Community Participation and Fear of Falling in Ambulatory Stroke Survivors After Hospital Discharge: A Pilot Study
Lina Jallad, Megan Schliep, Ehsan Sinaei, Prudence Plummer
MGH Institute of Health Professions, Boston, USA
Background: Fear of falling is prevalent after a stroke and can curtail community participation. Prior research has shown that fear of falling correlates with decreased community participation in chronic stroke, but the association between fear of falling and return to community participation in the transition from hospital to home is not known. Additionally, how fear of falling is influenced by whether a person falls or does not fall is unclear.
Aim: To examine the association between fear of falling at discharge from inpatient rehabilitation and self-reported community participation at 3 months post-discharge. We also examined the effect of fall status on fear of falling between hospital discharge and 3-month follow-up.
Method: 14 ambulatory stroke survivors with no prior history of falls who were being discharged home from inpatient rehabilitation completed a fear of falling questionnaire (Fall Efficacy Scale International, FES-I, scale 16-64 with higher scores indicating greater fear) at discharge and at 3 months post-discharge. Community participation at 3 months was assessed using the Community Integration Questionnaire (CIQ). Fallers (≥1 fall) and non-fallers were prospectively classified using a 3-month fall calendar. The relationship between FES-I and CIQ was assessed using Spearman’s rank correlation. A two-way mixed model ANOVA was used to examine the effect of fall status on the FES-I between discharge and 3-month follow-up.
Results: The participants had a median age of 58.5 years (range 36-75), 71% were male, and 64% were walking with an assistive device at discharge. Fifty percent of the participants fell at least once in the first 3 months. Fear of falling at discharge ranged between 16-54 (median=28), and fear of falling at follow-up ranged between 17-64 (median=23). CIQ at follow-up ranged between 6-22.75 (median=16). The correlation between FES-I at discharge and CIQ at follow-up was moderate but not statistically significant (rho=-0.50, p=0.07). There was no change in FES-I between discharge and follow-up (MD 3.4, 95% CI -3.7, 10.4). Further, there was no effect of fall status on FES-I between discharge and follow-up.
Conclusion: The findings from this pilot study suggest that fear of falling is highly variable in ambulatory adults with stroke and that it may be associated with reintegration of community participation, but this needs to be examined in a larger sample. Whether a person fell or not in the first 3 months of transition from hospital to home did not change their fear of falling.
Categories
Stroke
Diffusion Tensor Imaging correlates with Fugl-Meyer but not gait speed or other measures of clinical gait performance in chronic stroke
Jessica McCabe1, Ahlam Salameh1,2, Sarah Carr3, Kelsey Rose Duncan4, Margaret Skelly1, Trenley Anderson5, Pragnya Iyengar5, Lisa Leonhart1, Terri Hisel1, Svetlana Pundik1,5
1Cleveland VA Medical Center, Cleveland, USA. 2Kent State University, Kent, USA. 3King’s College London, London, United Kingdom. 4University Hospitals of Cleveland, Cleveland, USA. 5Case Western Reserve University School of Medicine, Cleveland, USA
Introduction: Gait is a complex motor task which can be comprehensively assessed with a battery of clinical outcomes, each contributing to the characterization of gait performance. To improve recovery of gait after stroke, it is necessary to link clinical performance and brain structure. Therefore, our purpose is to examine the relationship between clinical measures of lower limb and gait performance with structural integrity of the bilateral white matter tracts in chronic stroke survivors with persistent gait deficits.
Methods: Diffusion weighted images (DWIs) and lower limb performance measures were acquired from 36 chronic (>6 months) stroke survivors with lower limb deficits. Clinical lower extremity measures included Fugl-Meyer(FM), Gait Assessment and Intervention Tool (GAIT), timed-up-and-go (TUG) and fastest gait speed (GS).
Stroke lesions were manually outlined on the MRIs, and left hemisphere lesions were flipped about the anterior-posterior axis. DWIs were preprocessed using standard denoising techniques before calculating fractional anisotropy (FA). All MRIs were normalized to the 1mm3 MNI template brain. The analysis was confined to the white matter by masking the DWIs with the Johns Hopkins University white matter atlas. A regression model was created for each clinical variable and included lesion masks as a regressor. Permutation testing was performed to test for associations between voxel-level FA and each clinical variable. Pearson correlation was used to explore the relationship between clinical measures.
Results Participant demographics were as follows: 64.3±8.9 y/o, 16.7% female, 5.4±4.6 years post-stroke and 42.7% left hemisphere lesion. FM was 24.1±4.1. There were mild correlations between the clinical measures as follows: FM and GAIT (r = -0.33, p = 0.045) and GS (r = 0.34, p = 0.038), and GS with GAIT (r = -0.35, p = 0.036). TUG was highly correlated with GS (r = -0.93, p = 0.000). Only FM score had a statistically significant association with FA (p < 0.05). Better FM was associated with higher FA in the ipsilesional corticospinal tract and ipsilesional anterior thalamic radiation. Other clinical measures had no association with DTI measures.
Conclusion: Structural correlates relating to lower limb performance can be detected using DWI. FM, a measure of paretic limb motor control, has stronger association with corticospinal tract integrity than measures of gait performance (TUG and GS).
Categories
Stroke
Stance-phase-targeted gait training can improve lower limb function with a 10-session protocol
Lisa Leonhardt1, Jessica McCabe1, Margaret Skelly1, Ahlam Salameh1,2, Kelsey Rose Duncan3, Terri Hisel1, Elizabeth Hardin van den Bogert1, Svetlana Pundik1,4
1Cleveland VA Medical Center, Cleveland, USA. 2Kent State University, Kent, USA. 3University Hospitals of Cleveland, Cleveland, USA. 4Case Western Reserve University school of Medicine, Cleveland, USA
Introduction: Stance phase impairment contributes to the asymmetric gait pattern frequently observed after stroke. Decreased weight acceptance, limb instability due to weakness and/or dyscoordination, and a heavy reliance on assistive devices negatively impact quality and function of post-stroke gait. Treatments that specifically target discreet components of gait may lead to greater improvement in overall gait function. Our purpose was to assess efficacy of a motor learning-based treatment approach specifically targeting stance phase dysfunction in chronic stroke survivors with clinically observable stance phase deficits of the impaired limb.
Methods: 38 subjects (65.6(8.4) years old; 26.3% female; 4.5(4.2) years post-stroke) participated in 10-sessions of targeted stance phase treatment (2x/week). Therapy consisted of 30 minutes of virtual-reality obstacle clearance training on treadmill followed by 30 minutes of overground targeted stance phase training. Individuals were assigned a customized home exercise program to be completed on all non-therapy days that specifically targeted their individual stance phase gait deficits. This analysis is based on data from an ongoing double blinded randomized control trial testing adjuvant bihemispheric transcranial direct current stimulation targeting primary motor regions. Outcomes were fastest gait speed based on 10-meter walk test (10MWT), preferred gait speed during 2-minute walk test (2MWT), Fugl-Meyer (FM), Timed Up and Go (TUG), Functional Gait Assessment (FGA), and Gait Assessment and Intervention Tool (GAIT). Outcomes were collected at baseline, mid-treatment, post-treatment, and 6-week follow up. Statistical analyses included repeated measures analysis if variance (ANOVA) with Bonferroni correction.
Results: Baseline characteristics included (mean(SD)): 10MWT=0.71(0.40) m/s, 2MWT=0.55(0.28) m/s, FM=24.8(3.7), TUG =31.9(29.1) s; FGA=12.9(4.0.), GAIT=16.9(7.4). From the 1st to the 10th session, subjects significantly increased the number of obstacle clearance repetitions per session (p=3e-15) from 139±70 to 183±51, treadmill speed (p=4e-49) from 0.19±0.06 to 0.24±0.08 m/s, and distance between obstacles (p=1e-62) from 1.5±0.4 to 1.9±0.5. Statistically significant changes were observed for all outcomes. Mean changes from baseline to mid-treatment, baseline to post-treatment, and baseline to follow-up were statistically significant and as follows: 10MWT improvement (m/s) of 0.074(0.12), 0.14(0.16), and 0.13(0.17); 2MWT improvement(m/s) of 0.03(0.07), 0.04(0.08), and 0.05(0.09); FM (points) improvement of 1.9(2.1), 2.6(2.1), and 2.9(2.3); TUG improvement(s) of 2.0(5.0), 4.5(6.7), and 3.8(5.2); FGA 1.3(2.2), 2.4(2.2), and 2.4(2.3); GAIT improvement of 1.3(1.7), 2.3(2.1), and 2.6(2.3). Changes across all study measures from baseline to each of the testing time points were statistically significant.
Conclusion: A short 10-session intervention that uses a highly targeted motor learning-based treatment of the stance phase on the impaired side led to significant improvements across all outcomes and all timepoints including 6-week follow-up.
Categories
Stroke
Bi-hemispheric tDCS Paired with Contralaterally Controlled Functional Electrical Stimulation(CCFES) for Chronic Stroke Motor Recovery: A Study Protocol for a Randomized Controlled Trial
David Cunningham1,2,3, Patrick Tomko1,2, Rifeng Jin1,2, Shreya Ramani1,2, Amy Friedl2, Shannon Hogan2, Terri Hisel2, Doug Gunzler1,2, Richard Wilson1,2, Jayme Knutson1,2,3
1Case Western Reserve Univeristy, Cleveland, USA. 2MetroHealth Center for Rehabilitation Research, Cleveland, USA. 3Functional Electrical Stimulation Center, Cleveland, USA
Hemiparesis of the upper-limb is one of the most serious impairments from stroke. Paresis of the finger and thumb extensors is a frequently persisting consequence, impacting hand function. We developed contralaterally controlled functional electrical stimulation (CCFES), a neuromuscular stimulation therapy that gives the patient intimate control of both stimulation timing and intensity to their finger and thumb extensors during intention driven hand opening. Several clinical trials have reported reduced impairment, and improved function and dexterity of the affected upper-limb with CCFES. Our main objective is to build upon these therapeutic benefits of CCFES therapy for chronic stroke motor recovery. One strategy to improve rehabilitation outcomes is to combine treatments that may have synergistic effects. Therefore, this study applies transcranial direct current stimulation (tDCS) to the homologous motor cortices during CCFES to determine if the combination of the two will improve outcomes over those achieved by CCFES alone. Conventionally, tDCS has been applied to increase brain excitability and promote long-term potentiation (LTP) of the ipsilesional hemisphere with anodal stimulation and inhibit the contralesional hemisphere with cathodal stimulation; however, benefits of tDCS combined with therapy have varied. The variable results may be influenced by the dynamics of homeostatic neuroplasticity. Homeostatic neuroplasticity is defined as a relationship of neural balance between LTP, which is important for recovery, and long-term depression (LTD). When exciting the motor areas to promote LTP with tDCS, the nervous system may seek an equilibrium, potentially causing LTD during rehabilitation. In this project, we are testing the opposite approach: inhibiting the ipsilesional hemisphere to promote LTD, i.e. unconventional tDCS. We hypothesize that the nervous system will attempt to restore balance by promoting LTP during CCFES-assisted therapy, enhancing post-stroke motor recovery. We are currently conducting a randomized controlled trial (RCT) of mild to moderately impaired stroke survivors 6 to 24 months’ post-stroke (planned N = 63). They will be assigned to 12 weeks of: a) conventional tDCS during CCFES, b) unconventional tDCS during CCFES, or c) sham tDCS during CCFES. Upper extremity impairment, activity limitation and neurophysiologic assessments will be made at baseline, 6, 12, 24, and 36 weeks. This will be the first RCT of tDCS during CCFES in chronic upper extremity hemiplegia and serve to accelerate the development of treatments for reducing post-stroke hemiparesis.
Categories
Stroke
Overground slip-perturbation training among people with stroke: Associations between long-term retention of reactive balance control and physical activity and balance confidence
Rudri Purohit1, Shuaijie Wang1, Shamali Dusane2, Rachana Gangwani3, Tanvi Bhatt1
1The University of Illinois at Chicago, Chicago, USA. 2Northwestern University, Chicago, USA. 3The University of North Carolina at Chapel Hill, USA
Background: A single session of slip perturbation-based training (slip-PBT), involving repeated exposures to environmental perturbations, is known to induce short-term adaptive improvements in reactive balance control among people with chronic stroke. However, it is unclear whether such acquired improvements can be retained over long term and if they are associated with improvements in activity and participation. This randomized controlled trial aimed to examine the long-term retention of overground slip-PBT on reactive balance and clinical measures of physical activity, community-integration, and balance confidence in people with chronic hemiparetic stroke.
Methods: Sixty people with mild-to-severe motor impairment (3.60±1.2 on Chedoke McMaster Leg) were randomized to slip-PBT (n=30, 57.89±8.49yrs) or control group (n=30, 61.17 ± 12.11yrs). The slip-PBT group received 24 walking slips (a block of non-paretic slips, followed by a block of paretic slips, and mixed slips), whereas the control group received equivalent walking trials. Both groups were then tested by exposing to a paretic slip at baseline and 6 months. The primary outcome was post-slip (reactive) center of mass state stability at recovery (non-slipping) limb touchdown. Clinical assessments included physical activity (Physical Activity for the Elderly Scale, PASE), community integration (Community Integration Questionnaire, CIQ) and balance confidence (Activities Specific Balance Confidence Scale, ABC). A 2×2 ANOVA was used to examine group by time interaction (first novel paretic slip: S1 and at 6 months) on all outcomes. Linear regression was used to examine the association between reactive stability and clinical measures between the two groups at 6 months.
Results: The slip-PBT group showed greater improvements in post-slip stability from S1 to 6 months compared to the control group (p<0.05, significant group x time interaction). Additionally, the slip-PBT group demonstrated greater improvements in CIQ, ABC and PASE scales at 6 months compared to the control group (p<0.05, significant group x time interactions). Linear regressions showed group x B interaction in the relationship between stability and clinical measures (p<0.05). Greater stability values were associated with greater PASE [B=0.001, p < 0.05] and ABC scores [B=0.013, p <0.05] in the slip-PBT group, however, no associations were observed in the control group [B=0.001 for PASE, p>0.05, B=-0.001 for ABC, p>0.05].
Conclusion: One session of slip-PBT can induce adaptive improvements in reactive balance and participation-specific clinical functional measures over 6 months compared to a single-slip exposure among individuals with chronic stroke. Such long-term improvements in reactive balance also can potentially enhance balance confidence and physical activity.
Clinical Relevance: Our study highlights the potential of overground slip-PBT for acquiring and retaining fall-resisting skills crucial for recovering from slips in people with chronic hemiparetic stroke. Such training may also enhance long-term fall self-efficacy and community mobility with a potentially lower dosage (# of sessions) compared to existing balance interventions.
Categories
Stroke
Overall gait asymmetry is associated with the metabolic cost of walking in individuals with chronic stroke
Amelia Cain1, Sarah Kettlety1, Natalia Sánchez2, James Finley1, Kristan Leech1
1University of Southern California, Los Angeles, USA. 2Chapman University, Irvine, USA
Background: Chronic stroke survivors use significantly more energy than neurotypical individuals to walk the same distance. Previous studies report conflicting results regarding whether metabolic cost is associated with step length asymmetry (SLA) in stroke survivors.1,2 Importantly, reducing SLA does not change the metabolic cost of walking.3,4 SLA is only one of many spatiotemporal, kinematic, and kinetic gait parameters that are often asymmetric after stroke. The Combined Gait Asymmetry Metric (CGAM),5 incorporates temporal, kinematic, and kinetic asymmetries into a measure of overall gait asymmetry. Thus, metabolic cost may have a stronger association with CGAM than with SLA. Elucidating the relationship between CGAM and metabolic cost is a necessary first step to determine whether reducing CGAM changes metabolic cost. Here, we hypothesized that both CGAM and SLA would be positively correlated with metabolic cost, but that the association would be stronger with CGAM than with SLA.
Methods: We performed a secondary analysis of previously collected data from chronic stroke survivors who walked for five minutes on a treadmill at their self-selected speed. Throughout the walking trial, we collected kinematic, kinetic, and metabolic cost data. To capture overall gait asymmetry, we calculated CGAM using the asymmetry indices for double-limb support time, single-limb support time, circumduction, propulsion, peak swing knee angle, peak hip flexion angle, and trailing limb angle at each stride; then, we averaged CGAM across all strides for each participant. We quantified SLA as the magnitude of difference in step lengths averaged across all strides for each participant. We assessed the metabolic cost of walking using expired gas analysis data averaged for the last two, steady-state minutes of each trial, then normalized it to body mass and treadmill speed to obtain the net metabolic cost of transport (CoT). We assessed the Pearson correlations between CGAM and CoT and between SLA and CoT. We used a Pearson correlation to determine the association between SLA and CGAM.
Results: Data from 20 participants (5F/15M, ages 57 ± 11, gait speed 0.54 ± 0.19 m/s, Lower Extremity Fugl-Meyer 22 ± 6) were included in this analysis. CGAM and CoT were positively, moderately correlated (r=0.528, p=0.017). There was no significant relationship between SLA and CoT (r=- 0.311, p=0.183). SLA was not correlated with CGAM (r=-0.252, p=0.285).
Discussion: CGAM, but not SLA, is positively correlated with metabolic cost of walking after stroke. Additionally, the result that SLA is not correlated with CGAM is consistent with previous work that concludes that chronic stroke survivors exhibit inter-limb asymmetries even when walking with symmetric step lengths.6 These results indicate that CGAM may provide improved insight into how gait asymmetry impacts metabolic cost after stroke. Future work should investigate the effect of reducing CGAM on the metabolic cost of walking after stroke.
Categories
Stroke
The Influence of Risk on Decision-Making during Walking
Shreya Jain, Nicolas Schweighofer, James Finley
University of Southern California, Los Angeles, USA
Falls are commonly considered to be influenced by several risk factors. While there are assessments for intrinsic and extrinsic fall risk factors, none currently capture how the decisions we make during walking influence fall risk1,2. These decisions can have devastating consequences, particularly if they lead to risky behaviors. Decision-making under risk is studied in behavioral economics, where risk is defined as the variability in the possible outcomes of a choice3. Using this definition of risk, walking on a smooth path would have low risk, as the likelihood of losing one’s balance on any given step is near zero. In contrast, walking on uneven terrain could be considered risky as more variable outcomes, such as tripping or falling, are possible. Here, we investigated how young and older adults choose between risky alternatives while walking and applied computational models to understand the underlying decision-making processes.
Young (n = 20, 27+5 years) and older adult (n = 19, 71+5 years) participants walked on a split-belt treadmill while experiencing trip-like perturbations. They experienced two bouts of walking, each with two perturbations. One bout had perturbations of equal amplitude (“FIXED”; low risk), while the other had perturbations that differed in amplitude (“VARIABLE”; high risk). Participants then chose one of the two bouts based on this question - “If we randomly pick one trip for you to repeat, which bout should we pick it from?”.
We applied the mean-variance model of decision-making to participants’ choices to determine if their decisions were sensitive to the variance of the perturbations in each bout4,5. We used Hierarchical Bayesian modeling to estimate the population and subject-level risk-sensitivity and stochasticity parameters6,7. Positive values for risk-sensitivity indicate risk-aversion and stochasticity values near zero indicate random decisions independent of the mean and variance of the perturbations.
We found both age groups to be similarly risk-sensitive. The mean and 95% high-density intervals for the posterior distribution of the risk-sensitivity parameter for young and older adults were 1.27[0.88-1.74] and 1.17[0.83-1.51], respectively. The stochasticity parameter posterior properties were similar for young (13.05[10.86-15.10]) and older (13.13[10.23-16.43]) adults. Despite no group-level differences, some older adults appeared to be risk-neutral and made random choices, which was not observed in young adults.
These results demonstrate that we not only consider the magnitude of balance disturbances when evaluating the riskiness of a bout of walking, but we also consider the variance of the disturbances. Examining this decision-making process and understanding how it is affected by age-related factors will allow us to quantify and potentially mitigate risky behaviors in individuals who are especially prone to falls.
Categories
Motor Rehabilitation
Electrocortical dynamics during post-stroke gait: a preliminary analysis
Chang Liu1, Teng Peng1, Dorian Rose1,2,3, Daniel Ferris1
1University of Florida, Gainesville, USA. 2Brooks Rehabilitation, Jacksonville, USA. 3Malcolm Randall Veterans Affair Medical Center, Gainesville, USA
Introduction: Gait dysfunction is a prevalent outcome post-stroke that significantly impacts the quality of life [1]. One central barrier to improving gait rehabilitation is a lack of understanding of the cortical processes responsible for gait dysfunction. Recent breakthroughs in mobile imaging with high-density electroencephalography (EEG) have allowed real-time measures of active regions throughout the brain during actual walking. This ongoing study aims to quantify cortical processes tied to the biomechanics of the gait cycle for people post-stroke.
Methods: Five post-stroke participants (age: 70±13 yrs; 3M; <6 months post-stroke) and four age-matched, speed-matched older adults (age: 62±15 yrs; 1M) walked on a force-instrumented treadmill with their self-selected walking speed (100%), 120%, 80%, and 60% of their speed and four levels of body weight support. Each condition consisted of two 3-minute walking trials. Participants also completed 3-minute seated and standing resting conditions. All participants wore a dual-layer EEG cap with 120 scalp and 120 noise electrodes [2]. We attached reflective markers and inertia measurement units to the lower legs, feet, and waist. The participant wore a body-weight support harness. We processed EEG data using custom scripts and EEGLAB [3]. We removed channels with substantial noise and the motion artifacts recorded by noise electrodes from EEG data using canonical correlation analysis [2]. We applied an adaptive mixture independent component analysis to decompose EEG signals into independent components (ICs). Equivalent current dipole models that best describe the scalp topography of each IC were computed using the standard boundary-element model. We excluded ICs representing muscle activity, eye movements, heart beating, and noises and clustered brain ICs with K-means based on location. We calculated the power spectral for each brain IC during each gait cycle, linearly time-warped the spectrograms for each gait cycle, and averaged them for each cluster. We computed fluctuations from average as gait event-related spectral perturbations (ERSP).
Results and Discussion: Preliminary results show that we can localize the brain sources at the sensorimotor cortex, posterior parietal, and occipital areas. Post-stroke participants have a lower beta power at the sensorimotor cortex than neurotypical participants during walking. We also observe greater power fluctuation in ERSP in post-stroke participants at the affected sensorimotor side, which could indicate greater cognitive input during steady-state walking compared to age-matched adults. Our future analysis will explore more cleaning algorithms to remove artifacts from EEG and perform statistical comparisons of power spectral densities between post-stroke and age-matched controls. The results may provide a mechanistic understanding of how brain processes differ during gait between post-stroke and neurotypical individuals to enable novel neural targets for rehabilitation.
Categories
Stroke
Determining the role of sensory circuits for neurorehabilitation targeting after pediatric brain injury
Michelle Corkrum, Tong Wen, Jason Carmel
Columbia University, New York, USA
Unilateral brain injury in neonates results in unilateral impairment of hand function and walking in 1-2/1000 children. Most research investigating neurorehabilitation targets for movement recovery has focused on the corticospinal system. However, our previous research demonstrated that sensory circuits have a larger effect on dexterity of the more affected hand than motor circuits. The most common sensory lesion is periventricular hemorrhagic infarction, in which a bleed into the germinal matrix causes a secondary infarct of the periventricular white matter. To move the sensory tract injury association to causation, we tested the hypothesis that selective thalamocortical tract lesion would result in impaired forelimb use.Methods: An equal number of male and female Sprague-Dawley rats were used for experiments. We tested three distinct models of unilateral thalamocortical injury to determine reproducibility and specificity of sensory neural tract targeting: 1. periventricular blood injection; 2. ischemic lesion with photothrombosis (Rose Bengal); and 3. electrolytic lesion of the thalamocortical sensory tract. To trace sensory tracts, a retrograde green fluorescence protein viral vector was targeted to the primary sensory cortex. For behavioral testing, the cylinder exploration test and pasta handling test were used to test the hypothesis that sensory tract lesions correlated with impaired forelimb use.Results: For preclinical model development, we found that electrolytic lesions were the most specific and reproducible for inducing a lesion targeting the thalamocortical tract when compared to periventricular blood injections and photochemical lesions. Electrolytic lesions disrupted up to 50% of the sensory circuits, while sparing motor circuits. For our behavior experiments, we found that lesions to the thalamocortical sensory tract decreased use of the affected forelimb (contralesional) compared with the ipsilesional forelimb (n = 8, 4M and 4F, p = 0.004, paired t-test ).Conclusions: Overall, our results reveal that specific sensory system lesions of the thalamocortical tract impair forelimb use, suggesting a key role of sensory circuits as a neurorehabilitation target for movement recovery. Future experiments will be aimed at specifically manipulating the thalamocortical tract with neuromodulation interventions to demonstrate the specificity and necessity of the sensory circuits for movement recovery.
Categories
Sensory Rehabilitation
A Double-Blinded, Randomized, Sham-Controlled Trial of Vagus Nerve Stimulation Paired with Rehabilitation to Enhance Upper Limb Recovery after Spinal Cord Injury
Emmanuel Adehunoluwa1,2, Joseph Epperson1,3, Kaitlyn Malley1,2, Joel Wright1, Rachael Hudson1,2, Saeid Kian1,2, Jaime Gillespie4, Christie Stevens4, Dannae Arnold4, Chad Swank4, Richard Naftalis4, Michael Foreman4, Rita Hamilton4, David Pruitt1, Jane Wigginton1, Amy Porter1, Seth Hays1,3, Robert Rennaker1,2, Michael Kilgard1,2
1Texas Biomedical Device Center, University of Texas at Dallas, Richardson, USA. 2School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, USA. 3Erik Jonsson School of Engineering and Computer Science, University of Texas at Dallas, Richardson, USA. 4Baylor Scott & White Institute for Rehabilitation, Dallas, USA
Vagus nerve stimulation (VNS), a recently approved FDA treatment for upper limb recovery after chronic ischemic stroke, has shown promise in animal studies for enhancing upper limb recovery following spinal cord injury. Based on these outcomes, we performed a comprehensive study comprising an in-clinic early feasibility phase and a subsequent telerehabilitation phase to demonstrate the feasibility and potential benefits of VNS for individuals with chronic incomplete spinal cord injury. In this report, we present updated results from the in-clinic phase and insights from the at-home phase.
Individuals with upper limb deficits following an incomplete cervical spinal cord injury of at least 12 months duration completed 36 sessions of in-clinic therapy followed by up to 108 at-home therapy sessions. The in-clinic phase of the study was double-blinded where participants were randomly assigned to receive either active VNS paired with rehabilitation or sham stimulation with rehabilitation for the first 18 sessions. Subsequently, all participants received active stimulation with rehabilitation for the remaining 18 in-clinic sessions and throughout the at-home therapy phase. We selectively treated one of the upper limbs during the in-clinic phase and the opposite limb in the first 36 sessions of the at-home phase. Rehabilitation tasks consisted of game-based training and standard exercises. The primary outcome for upper limb recovery was the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP), conducted at baseline and after every 18 sessions of therapy.
Nineteen participants completed 36 VNS therapy sessions in the clinic. Of these 19, 8 participants have so far completed at least 36 sessions at home, 4 completed at least 72 sessions, and 2 completed 108 sessions. In the double-blinded in-clinic phase of the study, the mean change in GRASSP scores in the active VNS group was 2.4 (SEM:2.14) versus -1.44 (SEM:1.88) in the sham VNS group, which was not significantly different. The mean change in GRASSP score increased to 3.0 (SEM:2.12) after 18 therapy sessions of active VNS for those that initially received sham stimulation. In the first 36 sessions of at-home therapy, the mean change in GRASSP score was 5.49 (SEM:3.48). Notably, no serious or unexpected device-related adverse events have been reported to date.
These preliminary findings suggest that VNS is safe for individuals with spinal cord injury and is feasible both in the clinic and at home. The results also indicate that VNS paired with physical rehabilitation holds promise for improving upper limb functions in individuals with chronic incomplete spinal cord injuries, underscoring the need for a future pivotal study.
Categories
Spinal Cord Injury (SCI)
Race/ethnicity and physical activity in stroke survivors
Balsam J Alammari, Neva Kirk-Sanchez, Eduard Tiozzo, Marti Flothmann, Tatjana Rundek, Sebastian Koch, Lauri Bishop
University of Miami, Coral Gables, USA
Introduction: Non-Hispanic black (NHB) and Hispanic stroke survivors have historically been discharged from acute care with lower physical function than non-Hispanic whites (NHW).1 It is plausible that disparities in physical activity remain once individuals return home, among different race/ethnic groups. The purpose of this study is to examine the relationship between race/ethnicity and physical activity level of stroke survivors after hospital discharge.
Methods: Fifteen stroke survivors from diverse race/ethnic groups were given an activity monitor (FitBit One, Fitbit. Inc., San Francisco, CA, USA) after hospital discharge to record daily activity in their home and community setting as part of a larger study. 2 The first week (seven-day) period of physical activity after hospital discharge for each participant was used for analysis. Daily physical activity (i.e., daily step counts) was calculated by dividing the total number of daily recorded step counts by the number of days per week the device was worn. As per prior work 3,4, we further categorized participants into either a High activity ≥ 5535 (i.e., higher than group mean) or a Low activity ≤ 5535 (i.e., lower than group mean) group. A univariate, chi-square analysis was used to evaluate the relationship between race/ethnicity and physical activity level. Effect sizes and 95% confidence intervals (95% CI) are also reported.
Results: Participants’ mean (SD) age was 59 (14) years. The sample was comprised of 10 males with 20% NHW, 53% Hispanic, and 27% NHB. Six participants had a high level of physical activity (mean (SD) = 8464 (3737)), and nine participants had a low level of physical activity (3925 (1054)). There was a significant relationship between race/ethnicity, and physical activity level χ2(2) = 7.187, p < .027, Cramer’s V = 0.692, 95% CI [-0.191, 7.238].
Conclusions: The significant, moderately large effect size suggests a relationship between race/ethnicity and physical activity level among stroke survivors. Specifically, NHB and Hispanic stroke survivors had lower levels of physical activity than NHW immediately after hospital discharge.
Categories
Stroke
Effect of task-oriented arm training in standing on bimanual and unimanual arm use in stroke: a preliminary study
Rushali Pandya1, Olivia Lockhart1, Allison Lewis2, Kathryn Maxwell1, Stacy Fritz1, Jill Stewart1
1University of South Carolina, Columbia, USA. 2Medical University of South Carolina, Charleston, USA
Introduction: Task-oriented arm training leads to gains in arm function that often do not translate to gains in real-world arm use after stroke. Everyday functional activities that require the arm and hand are often done in standing. Training that incorporates the postural control demands of standing and walking during arm repetitions may provide a training environment that more closely resembles real-world function. Additionally, training often includes both unimanual and bimanual activities; understanding whether the paretic arm is active unimanually or bimanually during everyday use might provide important insight into arm use after stroke. The purpose of this preliminary study was to assess the effect of task-oriented arm training in standing on bimanual and unimanual paretic arm use after stroke.
Methods: Twelve individuals with chronic stroke (age 66.1±2, months post-stroke 45.1±24.3, Upper extremity Fugl-Meyer 48.4±3.7) completed 24, 1-hour sessions of task-oriented arm training over 8 weeks. Training included unimanual (29-83% of training repetitions across participants) and bimanual (6-61% of repetitions) tasks that targeted both proximal arm control and hand function primarily during standing and walking (81-100% of repetitions). Accelerometers (ActiGraph GT9X) were worn for a 24-hour period to capture arm use before and after training. Data was sampled at 30Hz, filtered, binned into 1 sec epochs, and converted into activity counts. The primary measures were bimanual use time (seconds where both arms were active) and unimanual paretic use time (seconds where the paretic arm was active but the nonparetic arm was not). Secondary measures included use ratio, total paretic use time, and total nonparetic use time.
Results: Analyses of the primary accelerometer variables showed no change after training (Baseline, Post (mean minutes ± std dev, (Cohen’s d)): bimanual use time 346.9±124.1, 342.0±111.7 (d=0.037); unimanual paretic use time 27.8±23.1, 26.9±15.5 (d= 0.0814). Secondary variables also showed no change with training: use ratio 0.69±0.1, 0.68±0.1 (d=0.133), total paretic arm use minutes 374.7±133.5, 368.9±115.4 (d=0.043), total nonparetic use minutes 550.9±130.9, 554.6±125.2 (d=0.025). Exploratory analyses of clinical measures of arm function found improvements that were overall small in magnitude: Action Research Arm Test: 43.8±16.7, 45.6±12.9 (d=0.436); Stroke Impact Scale Hand: 62.5±23.7, 78.2±21.4, (d=1.04). Small improvements in postural control were also found: Functional Gait Assessment: 18.4±7.9, 19.9±7.3 (d=0.648); Activity-Specific Balance Confidence Scale: 74.9±14.9, 80.1±16.7 (d=0.610).
Conclusions: Task-oriented arm training that included postural control demands did not lead to changes in bimanual or unimanual paretic arm use in this preliminary study. Other factors such as self-efficacy or social context assessed throughout the day may provide additional insight into factors that contribute to arm use after training or suggest new treatment approaches aimed at increasing arm use after stroke.
Categories
Stroke
Differential neural activations between mental imagery and action observation of slipping among healthy older adults
Rudri Purohit1, Jessica Pitts1, Lakshmi Kannan2, Tanvi Bhatt1
1The University of Illinois at Chicago, Chicago, USA. 2Northeastern University, Boston, USA
Background: Mental imagery and action observation have been incorporated into volitional and reactive balance (e.g., recovery from a slip) training for older adults, and have shown greater improvements in balance and falls self-efficacy than exercise training alone. Understanding the neural correlates associated with mental imagery and action observation could assist with tailoring balance interventions for targeting specific CNS impairments. Our previous study showed greater activations in cortical and subcortical structures during imagined versus observed slipping among young adults. This study examined differences in neural activations between these two conditions in healthy older adults.
Methods: Twenty healthy older adults (72±7 years) underwent a single session of functional magnetic resonance imaging. Participants received visual instructions to either imagine slipping (IS), observe slipping (OS), or rest with eyes open, in a randomized order. Data preprocessing including realignment and slicing, normalization, and smoothing was conducted using SPM10 in MATLAB2022 software. First level models were built using x, y, z translation realignment movement regressors and the subtraction method was used to create contrast images. Planned t-test contrasts were performed between imagined slipping minus rest (IS-Rest), observed slipping minus rest (OS-Rest) and imagined slipping minus observed slipping (IS-OS) with p uncorrected=0.05 and voxel size=80. xjview10 was used to extract the anatomical areas of activations for the three conditions. Generalized linear model was used the analyze the main effect of condition on anatomical activations across regions.
Results: Neural activations were greater in both active conditions than rest. IS-Rest showed greater activations in bilateral frontal lobes, supplementary motor area, inferior frontal gyrus, right occipital lobe, and left cerebellum. OS-Rest showed greater activations in bilateral occipital lobes, left frontal lobe, left cerebellum, corpus callosum, precentral gyrus, and middle temporal gyrus. IS-OS revealed no suprathreshold activation clusters. However, OS-IS showed greater activations in the left occipital and frontal lobe, corpus callosum, precentral gyrus, and middle temporal gyrus.
Conclusion and Discussion: Older adults activated many similar areas as young during IS and OS than the rest condition. Unlike young, older adults demonstrated higher activations in cortico-subcortical structures during OS compared to IS, which might suggest greater neural engagement for visual information processing and interpretation of perturbation, and possibly greater demand or allocation of resources for planning, initiation and execution of coordinated movements to recover from unexpected balance loss. Alternatively, lesser activation during IS could suggest age-induced deficits in processing speed, working memory, and sensorimotor functioning, which are known to affect the ability to perform mental rehearsing tasks.
Clinical Relevance: Our study highlights task-related differences in neural structures involved in imagined slipping and observed slipping among older adults. Healthy older adults might potentially benefit more from training components of action observation than mental imagery specifically pertaining to reactive balance-related tasks (e.g., slipping).
Categories
Motor Rehabilitation
Rural Access to Pediatric Teleneuromodulation in the Home Setting
Preston Christopher1, Dorothy Farrar-Edwards2, Ellen Sutter1, Gwendolyn Nytes1, Chrysanthy Ikonomidou3, Melissa Villegas4, Daniel Lench5, Bernadette Gillick6,7
1University of Wisconsin - Madison Waisman Center, Madison, USA. 2University of Wisconsin - Madison, Madison, USA. 3University of Wisconsin - Madison Pediatric Neurology, Madison, USA. 4University of Wisconsin - Madison Pediatric Rehabilitation Medicine, Madison, USA. 5Medical University of South Carolina Department of Neurology, Charleston, USA. 6Univeristy of Wisconsin - Madison Department of Pediatrics, Madison, USA. 7Univeristy of Wisconsin - Madison Waisman Center, Madison, USA
Background: Cerebral Palsy (CP), often diagnosed after perinatal stroke or brain bleeds, can result in life-long motor impairment. Transcranial direct current stimulation (tDCS) is a neuromodulatory intervention with potential to improve the extent and rate of motor function recovery. Our laboratory has shown safe and successful performance modification when pairing tDCS with rehabilitation in children with CP. However, required access to the laboratory or clinic may increase the burden on families to complete multiple sessions, highlighting the opportunity for remotely supervised at-home interventions.
Design/Methods: The pediatric teleneuromodulation study aims to assess the feasibility, safety, and tolerability of active M1 bilateral tDCS at 1.5mA for 20 mins in the home setting under remote investigator supervision and direction. This is a 5-day serial session consisting of 1 mock, 1 sham, and 3 active 20-minute tDCS sessions. The mock session is a fully remote training session using a non-functioning device that was shipped to the participant. For the next sessions there was one study member in a videoconference call directing the participant using a prepared presentation slides and a family ambassador in the home setting whose main role was to take vitals and ensure correct use of the device. The evaluation of safety and feasibility will involve various measures, such as comparing
pre- and post-stimulation scores on the Box and Blocks test, conducting surveys to collect information about adverse events before, during, and after stimulation, and monitoring vital signs. Feasibility will also be assessed by measuring setup time, evaluating the quality of electrode contact, and tracking headgear movement during stimulation.
Results: 10 participants (10-19years old, average = 15.2yrs) have successfully completed all 5 sessions with no serious adverse events. Average set up time for active sessions has decreased 1.2 minutes on average. Box and Block scores have not significantly changed throughout participation.
Conclusion: Combining remote tDCS with telerehabilitation in children with CP may enhance therapy efficacy, offer improved intervention access, and lower cost and burden in situations of limited access to clinical facilities. This study highlights the current success of teleneuromodulation in rural settings, but also states on areas of improvement needed for remote monitoring in order to bring this intervention to home settings. Based off our current status, remote teleneuromdoulation appears to be safe and feasible.
Categories
Motor Rehabilitation
Conceptualizing Gait Initiation in Parkinson’s Disease using Linear Mixed Models
Jessica Bath, Kenneth Louie, Jannine Balakid, Hamid Fekri Azgomi, Doris Wang
University of California, San Francisco, San Francisco, USA
Patients with Parkinson’s Disease (PD) often experience postural instability, leading to difficulties with gait initiation and increased falls and reduced quality of life. To develop effective therapies, improved conceptualization of the neural circuitry involved in gait initiation, including the effects of dopamine replacement therapy, and correlates with task performance must be undertaken.
We examined cortico-pallidal network changes associated with gait initiation in five PD patients (three male, two female) implanted with an investigational bidirectional neural stimulation device (Medtronic Summit RC+S). Local field potentials (LFPs) were streamed from bilateral subdural electrodes over the cortex (premotor and primary motor areas) and deep brain stimulation (DBS) leads in the pallidum. Participants performed gait initiation trials on twin forceplates with a self-selected stepping foot in response to a visual “go” cue. Cortical and subcortical LFPs were aligned with biomechanics data quantifying anticipatory postural responses (APAs) while patients were in ON and LOW dopamine medication states while OFF DBS. Spectral power across all canonical frequency bands were averaged during task components including “quiet standing” (of which power in subsequent epochs was normalized to), “preparatory” (quiet standing end to APA onset), “postural execution” (APA onset to peak APA amplitude), and “step execution” (APA onset to stepping foot off forceplate).
LFP spectral data were aggregated for all subjects at the cortical and pallidal areas contralateral to the stepping foot using linear mixed models (LMMs) to conceptualize the influences of epoch neural power, frequency, brain location, and medication state in overall task quality metrics including APA amplitude and timing. LMMs were built with subjects as random effects and normalized epoch neural data, frequency, brain location, and/or medication state as fixed effects. Models were assessed using ANOVA and Akaike Information Criterion (AIC), variance inflation factor (VIF) and QQ plots.
LMMs were most simplistically constructed using data from the “postural execution” epoch to conceptualize APA net amplitude outcomes during gait initiation. In one optimized model, lower medication state was significantly associated with decreased APA net amplitude (p = 0.031); normalized premotor cortex (PMC) theta (4-8 Hz) power was also significantly associated with decreased APA net amplitude (p = 0.003), in addition to the random effects of patients. Other effects not reaching statistical significance in this LMM included globus pallidus internus (GPi) low beta (13-20 Hz) and low gamma (30-50 Hz) power, globus pallidus externus (GPe) low gamma power, and PMC low beta, high beta (20-30 Hz), and broadband gamma (50-200 Hz) power. (Model AIC = 1155.8, df = 11, random effect variance = 1781, residual variance = 3938; VIF 1.05-1.25). Models of varying complexity were also built with data from additional epochs, brain locations, and frequency bands to conceptualize all APA timing and amplitude metrics of task quality.
Categories
Motor Rehabilitation
A single-session of Corsi Block Tapping Task training does not improve visuospatial skills in people with chronic stroke
Giuliet Kibler1, Christina Holl1, Sarah Kettlety1, Sydney Schaefer2, Kristan Leech1
1University of Southern California, Los Angeles, USA. 2Arizona State University, Tempe, USA
Background: Visuospatial skills are fundamental for participation in daily life. Visuospatial skills are commonly impaired following a stroke.1 Studies have found that visuospatial skills are related to the retention of motor skill learning in older adults.2 This indicates that visuospatial skill impairment may limit motor rehabilitation after stroke. To date, there are few interventions to improve visuospatial skills after stroke. A recent study by Schaefer et al. demonstrated that twenty minutes of training on a visuospatial working memory task, improved visuospatial skills in a young, healthy cohort relative to a control group.3 However, the impact of this training on the visuospatial skills in individuals post-stroke is unclear. Here, we examined the effect of the same visuospatial training paradigm in people with chronic stroke (>6 months after stroke). We hypothesized that this visuospatial training would improve visuospatial skills in people post-stroke.
Methods: Participants completed baseline cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)4 and an assessment of visuospatial skills using a computerized mental rotation task.5 Participants were then randomly assigned to either the control group or training group. The control group completed 20 minutes of the 21-question Multidimensional Iowa Suggestibility Scale6 followed by a nature hike video, while the training group completed 20 minutes of the computerized Corsi Block Tapping Task, a visuospatial working memory task.7 Afterward, all participants repeated the computerized mental rotation task. To measure changes in visuospatial skills, we examined two performance metrics on the mental rotation task: reaction time on correct responses and the percent of correct responses. We ran two-tailed unpaired t-tests to compare the pre-to-post-training changes in these measures between the groups.
Results: A total of 18 participants with chronic stroke were enrolled in this study (control group: n=3F/6M, age=49±14, VCI RBANS score=80±13; training: n=4F/5, age=62±10, VCI RBANS score = 76±16). We found that neither the change in reaction time (training group = -14.1 ± 356.4ms, control group = -183.8 ± 403.5ms;p=0.36) nor the change in percent correct (training group=7.5±9.3%, control group=5.7±7.7%; p=0.67) on the mental rotation task from pre- to post-testing were different between the groups.
Discussion: The results of this preliminary study suggest that twenty minutes of visuospatial working memory training is not sufficient to improve visuospatial skills in people with chronic stroke. Differences in age between the groups may have played a role in these null results as our training group was significantly older than the control group (p=0.04). Our data collection is ongoing, and we plan to control for age in future analyses. Future studies should also test a longer training intervention to examine the effect of visuospatial training dosage in people after stroke.
Categories
Stroke
Implicit locomotor learning and retention may not be related to cognition in post-stroke individuals
Sylwia Lipior, Morgan Kelly, Amelia Cain, Kristan Leech
University of Southern California, Los Angeles, USA
Background: Stroke is a major cause of long-term disability, often resulting in gait dysfunction. Many chronic stroke survivors also experience post-stroke cognitive impairment (PSCI, i.e., a new cognitive deficit in at least one domain that cannot be explained by another condition1), which may impact motor learning due to shared neural resources between cognition and motor processes.2 Cognitive abilities are related to acquisition and retention of new locomotor patterns that are learned through cognitively demanding motor learning processes in people with chronic stroke.3 However, the relationship between post-stroke cognition and the capacity to learn a new walking pattern through a more implicit, less cognitively demanding motor learning task (e.g., split-belt adaptation) is unknown. We aim to investigate this relationship and hypothesize that cognition will not explain a significant portion of the variance in implicit locomotor learning and retention.
Methods: Participants with chronic stroke (>6 months) completed an implicit locomotor learning task that consisted of a two-minute baseline trial at half of their fastest comfortable walking speed, four four-minute split-belt walking trials (with a 2:1 belt speed ratio), and a four-minute de-adaptation trial at the baseline gait speed. Kinematic data were collected throughout each trial and used to calculate step length asymmetry (SLA = short step length – long step length / short step length + long step length) changes throughout the experiment. Cognition and motor impairment were assessed with the Repeatable Battery for Assessment of Neuropsychological Status (RBANS) and the lower extremity portion of the Fugl-Meyer Assessment (FM-LE), respectively. To capture the rate of learning and un-learning of the implicitly learned walking pattern, we examined the magnitude of step length asymmetry during strides 6–30 of the adaptation and de-adaptation trials (early change: mean SLA during strides 6–30).4 Separate linear regression analyses were performed with these motor outcome measures as the dependent variables, the RBANS composite score as the primary independent variable, and FM-LE included as a control variable.
Results: Fifteen participants with chronic stroke (n = 4F/11M, ages 58.87±10.44) completed the experiment. There was a notable degree of inter-individual variability in rate at which the participants implicitly learned and unlearned a new walking pattern. However, our preliminary analyses suggest that implicit locomotor learning and unlearning rates are not related to cognitive or motor impairment after stroke (adaptation early change: R2=0.168, p=0.331; de-adaptation early change: R2=0.088, p=0.573). Data collection is ongoing.
Discussion: This preliminary study suggests cognitive abilities may not strongly predict implicit locomotor learning rate in post-stroke individuals. This work highlights the potential utility of integrating implicit learning processes into rehabilitation for people with cognitive impairment. Further research should further explore the dynamics of motor learning in post-stroke gait rehabilitation, considering the interplay between cognitive function and recovery outcomes.
Categories
Stroke
Disproportionate deficits in spatial working memory compared to verbal working memory in adults with chronic right hemisphere stroke
Sarah Haile, Kasey Stack, Anna Seydell-Greenwald
Georgetown University Medical Center, District of Columbia, USA
Stroke survivors often experience deficits in their working memory and report lapses in storing short term information. While both verbal and spatial memory deficits are associated with strokes in general, spatial memory deficits in particular are greatly associated with right-hemisphere damage, in line with the known dominance of the right hemisphere for visuospatial processing in the vast majority of neurologically healthy adults. The purpose of this study was to directly compare the differences in verbal and spatial memory spans in adult survivors of right hemisphere strokes relative to demographically matched neurologically healthy controls. We predicted that spatial working memory span would be more severely affected by right-hemisphere stroke than verbal working memory span.
To test this hypothesis, the study used two maximally similar measures of verbal and spatial working memory, respectively: the Digit Span task and the Corsi block-tapping task. In the Digit Span task, participants have to verbally reproduce digit sequences presented audibly by the experimenter. In the Corsi block-tapping task, participants are shown a configuration of nine blocks and the experimenter taps a subset of them in a certain order that then has to be reproduced by the participant. In both tasks, sequences are presented at a rate of one item (digit or block tap) per second, sequence length increases by one item every other trial, and testing is terminated when the participant fails to reproduce both sequences of a given length. Here, we used an electronic version of the Corsi tapping task in which the blocks were represented by nine squares on a touch screen that lit up in a certain order. We tested 45 participants ages 20-79 (22 participants who had had a right-hemisphere stroke more than 6 months prior to the study, and 23 controls). A trained tester administered the Digit Span and the e-Corsi task in randomized order as part of a larger testing battery. Both tasks were scored by multiplying the number of items in the longest correctly recalled sequence by the number of correctly recalled sequences.
As expected, participants with right-hemisphere lesions scored significantly lower than matched controls on the Corsi task. Their Digit Span scores were also lower, but this difference did not reach statistical significance. Crucially, the relative difference between Digit Span and Corsi scores was significantly larger in the stroke group compared to the control group, revealing a disproportionate effect of right-hemisphere stroke on spatial relative to verbal working memory. These findings support previous research demonstrating that acquired right-hemisphere lesions in adults are associated with deficits in spatial more than verbal working memory.
Categories
Stroke
Biopsychosocial factors and cognitive reserve predict return-to-work or disability after stroke
Caitlin Dulay1, Veronica Burton2, Mario Dulay2,3, Timea Hodics2
1Texas A & M University, College Station, USA. 2Houston Methodist Neurological Institute, Houston, USA. 3The Houston Institute for Neuropsychological Knowledge (THINK) lab
Background: We examined associations and predictors of return-to-work (RTW) after cerebrovascular accident (CVA). Stroke is a leading cause of disability. There is evidence that up to 60% of CVA survivors remain permanently disabled from employment. Several barriers to RTW found in previous research included stroke severity, job type, ethnicity, older age, persistence of cognitive deficits, comorbidities (sleep deprivation, severe fatigue), and poststroke depression (PSD).
Methods: Participants of this IRB approved study included 314 stroke survivors (52% women, average age of 60.1 years; range 18-87) who underwent an outpatient neuropsychological evaluation approximately 8 months after unilateral focal CVA. A subset of patients (N=72) were retested an average of 18 months after CVA. Exclusion criteria included a diagnosis of dementia, comprehension issues, bilateral CVA, and inpatients. Associations of RTW included in logistic regression analyses were biological (side and location of stroke), psychological (psychiatric disorders, apathy, pseudobulbar affect [PBA], psychiatric treatment before CVA), social and demographic (age, marriage status), and cognitive (memory, executive function, cognitive reserve level). Cognitive-Reserve-Index questionnaire estimated cognitive reserve using pre-stroke education level, cognitive load of occupation, and level of leisure engagement (Nucci et al., 2012). Depression and anxiety were defined by DSM-5 criteria. Apathy was defined as diminished goal-directed behavior and decreased interest that impacted daily life more than expected from physical issues after CVA (family and self-report using the Frontal Systems Behavior Scale and Tay et al., 2021 guidelines). PBA was defined by the Center for Neurologic Study-Lability Scale and clinical judgment.
Results: At month 8 after CVA, 27% of individuals had returned-to-work, 50% had not returned to work, and 23% were not working before or after the CVA. Eighteen months after CVA, 35% of individuals had returned-to-work and 47% had not returned, and 18% were not working before or after the CVA. At month 8 with cross-sectional data, patients who experienced post-stroke apathy were 6.8 times more likely to not RTW after stroke (p=0.003), those with memory loss were 6.3 times more likely to not RTW (p=0.004), those who suffered from PSD were 5.2 times more likely to not RTW (p=0.02), and those with greater cognitive reserve were 4.3 times more likely to RTW (p=0.04). In the smaller sample (N=72) test-retest predictors of RTW by month 18 analysis, month 8 apathy level, memory loss and greater cognitive reserve remained the strongest predictors of RTW.
Conclusions: Results replicate the finding that barriers of return-to-work include residual cognitive and emotional deficits after CVA and extends previous research by showing that cognitive reserve may facilitate return-to-work. Results highlight the importance of quantifying post-stroke apathy and PSD in a standard neuropsychological work-up after stroke to identify candidates for services to facilitate RTW efforts (e.g., interventions for apathy, vocational rehabilitation services, psychotherapy,).
Categories
Stroke
Understanding the influence of action observation on error reduction during movement in stroke
Layla Abdullatif1, Maria Lindsey1, Veronica Rowe2, Lewis Wheaton1
1Georgia Institute of Technology, Atlanta, USA. 2Georgia State University, Atlanta, USA
Someone in the United States has a stroke every 40 seconds. Almost 70% of people who have a stroke experience the loss of arm and hand movement which ultimately decreases daily function and contributes to poor quality of life. Thus, there is a great need for rehabilitation in the stroke population. Action observation (AO) and has emerged as a potentially powerful therapeutic tool to improve stroke rehabilitation by allowing a stroke survivor to learn how to use their arm and hand again by watching and attempting to replicate “normal” arm and hand movements. AO training in patients with amputations revealed that their movement is improved when they focus their eye gaze on specific aspects of the movement in the video that may maximally benefit the patient. It is unknown if these eye gaze patterns may serve as a mechanism behind AO and how stroke severity impacts these gaze patterns.
Purpose: In this study, we sought to identify a relationship between gaze patterns in the AO phase to performance during the action execution (AE) phase in stroke survivors with varying levels of impairment.
Methods: We recruited 20 stroke survivors with upper limb impairment into the study with Fugl-Meyer Scores ranging from 23 to 54, involving repeated trials where patients observed, then performed, a task that entails picking up a small, round disc, transporting the disc across and above a barrier before placing the disc correctly in the designated colored, circular slot. We hypothesized that AO augments visuomotor strategies causing changes in differing gaze strategies over time between varying stroke severities across the two different limbs, more affected and less affected.
Results: For the more affected side, gaze during AO was commonly focused on the hand of the actor performing the task, which was associated with the most decrease error during the AE phase. Gaze focused on the task board or disc did not associate with decreases in movement error. Considering severity of impairment (based on the Fugl-Meyer), this effect was most pronounced in the moderate group (FM-UE score of 29-42) compared to the mild group (FM-UE score of 43-66).It believed that AO can be predictive of task performance. A similar effect was seen in the less affected side, however, there were significantly fewer errors in the less affected versus more affected, limiting interpretations.
Conclusion: This suggests that AO impacts the perception of observed movement based on severity, which may contribute to increased motor control (decrease task error) in the more affected limb.
Categories
Stroke
Characterization of bilateral reaching abilities in typically developing children using computer vision and augmented reality assessments
Shelby Ziccardi, Stephen Guy, Rachel Hawe
University of Minnesota, Minneapolis, USA
Introduction: Bilateral coordination is impaired across multiple neurodevelopmental conditions including cerebral palsy, autism spectrum disorder, and developmental coordination disorder. We currently lack clinical assessments that can quantify bilateral coordination. The goals of this work were to 1) determine the feasibility of using computer vision and augmented reality to assess bilateral reaching abilities in children in a clinically feasible manner; and 2) characterize the development of bilateral reaching abilities in typically developing children in order to be able to detect impairments in clinical populations.
Methods: We designed an augmented reality game in which participants viewed a mirror image of themselves on a computer monitor along with virtual target objects to reach with both of their hands simultaneously. Video data from a single webcam was used for pose estimation using MediaPipe, allowing for individuals to interact with the targets and collect kinematic data. Data was collected at the 2023 Minnesota State Fair, where 151 children ages 6-17 were recruited with no history of orthopedic or neurologic conditions that would limit the ability to move their arms. Following practice trials, children had 50 seconds to reach as many targets as possible. Participants completed two assessment tasks in which the targets were placed to require either symmetrical or asymmetrical movements between the arms. Outcome measures were the number of targets reached in each task and the time lag between the two hands reaching the targets. Participants also completed a survey on their past video game experience to determine if gaming experience influences performance.
Results: Performance on both tasks improved with age. Children reached significantly more targets on the symmetrical compared to asymmetrical tasks, however, the difference between the tasks remained constant across the age range. The time lag decreased with age, and was smaller for the symmetrical compared to asymmetrical tasks. We found that performance on the tasks was not related to prior video game experience.
Discussion: Our results demonstrate the ability to use computer vision and augmented reality to measure bilateral reaching abilities in a clinically feasible manner requiring less than five minutes and only a single webcam. Our normative data also characterizes the development of symmetrical and asymmetrical bilateral reaching abilities, which are both seen to improve through adolescence. This assessment and normative data can be used to identify impairments in individuals with neurodevelopmental conditions, and our approach can be expanded to adult populations such as stroke. Additionally, the use of computer vision and augmented reality games can be adapted to be an intervention to allow for intensive practice of bilateral upper limb movements.
Categories
Motor Rehabilitation
Home-based, Wearable Myoelectric Interface for Neurorehabilitation (MINT) Conditioning to Improve Arm Function in Chronic Stroke: A Randomized Controlled Trial
Abed Khorasani1, Vivek Paul1, Cynthia Gorski1, Joel Hulsizer1, Prashanth Prakash2, Marc Slutzky1,3,4,5
1Department of Neurology, Northwestern University, CHICAGO, USA. 2Department of Neurology, Northwestern University, CHICAGO. 3Department of Physical Medicine & Rehabilitation, Northwestern University, CHICAGO, USA. 4Department of Neuroscience, Northwestern University, CHICAGO, USA. 5Department of Biomedical Engineering, Northwestern University, CHICAGO, USA
Individuals with moderate to severe upper limb impairment from stroke often show limited improvement with conventional rehabilitation in the chronic phase. Our previous research suggested that training with a myoelectric computer interface (MyoCI) designed to counteract abnormal co-activation patterns in the laboratory has the potential to reduce this co-activation and improve arm function. This therapy provides intuitive feedback to the user about the EMG activations in each of the trained muscles, enabling them to reduce this co-activation. Here, we present the results of a randomized controlled trial investigating the efficacy of a wearable version of MyoCI featuring home-based training called myoelectric interface for neurorehabilitation (MINT). MINT has the advantage of being home-based, enabling a high number of repetitions and motivation.
Participants were randomly assigned to train with different MINT variations (targeting and providing feedback about 2 or 3 muscles simultaneously) or a sham control group (providing feedback on only one muscle at a time to control for a non-use effect). All groups engaged in 90-minute daily sessions, 6 days per week for 6 weeks. Fifty-six chronic stroke survivors (mostly severely impaired) completed the training. Analysis revealed that participants in all experimental groups improved by a mean of 3.9 s in the primary outcome, the Wolf Motor Function Test after 6 weeks compared to baseline (paired t-test, p = 0.001), exceeding the minimal clinically important difference (MCID) of 1.5 seconds. Additionally, participants in the training with 3 muscles simultaneously improved by 7.03 seconds compared to baseline (paired t-test, p = 0.01), while the sham group did not significantly change from baseline (paired t-test, p = 0.35). Furthermore, participants training with 3 muscles simultaneously improved at 6 weeks by significantly more than the sham group (7.03 seconds vs. 1.5 seconds, p = 0.03, unpaired t-test) and increased this improvement 4 weeks later (9.7 seconds vs. 3.3 seconds, p = 0.02, unpaired t-test). Notably, even individuals with severe impairment improved significantly with MINT conditioning. Experimental groups also improved their reaching range of motion, while those in the sham group did not, indicating that improvement was due to arm movement, not compensatory. These findings indicate that MINT conditioning can improve arm function in chronic stroke survivors with moderate to severe impairment.
Categories
Stroke
A randomized, double-blind, placebo-controlled study of ReStore, a novel implantable vagus nerve stimulator for stroke recovery
Joseph Epperson1,2, Amy Porter1,2, Emmanuel Adehunoluwa1,2, Holle Gallaway1,2, Nate Bleker1,2, Michael Foreman3, Richard Naftalis3, David Pruitt1,2, Katharine Wigginton1,2, Chad Swank3,2, Christie Stevens3, Jaime Gillespie3, Dannae Arnold3, Rita Hamilton3, Jane Wigginton1, Joel Wright1, Rachael Hudson1,2, Michael Kilgard1,2, Seth Hays1,2, Robert Rennaker1,2
1Texas Biomedical Device Center, Richardson, USA. 2University of Texas at Dallas, Richardson, USA. 3Baylor Scott and White, Dallas, USA
Many stroke survivors are left with chronic upper limb motor and sensory disability, but a novel neurorehabilitation strategy is now available. Paired VNS was recently approved by the U.S. Food and Drug Administration for the treatment of upper extremity motor deficits associated with chronic ischemic stroke. The technique uses brief pulses of vagus nerve stimulation to engage pro-plasticity neuromodulatory circuits during rehabilitative movements. Three clinical trials indicate that vagus nerve stimulation (VNS) combined with supervised physical rehabilitation after stroke leads to increased recovery of upper limb motor function in the clinic. Building on this success, we have developed a next-generation, minimally-invasive VNS system that can be paired with novel rehabilitative tools for high-repetition physical and occupational therapy.
Open-loop stimulation with the conventional VNS system allows long-term accumulation of benefits and offers an opportunity to further enhance recovery with closed-loop stimulation. We have developed ReStore, an implantable, minimally invasive vagus nerve stimulator that can be implanted approximately 40 minutes faster than the conventional device, is 50x smaller, does not have a battery or leads, is MRI compatible up to 3T, and facilitates unsupervised closed-loop stimulation. The device is programmable and can be integrated into novel high-repetition gaming systems for high levels of spatial and temporal stimulation timing control.
Here, we report the safety, feasibility, and early efficacy outcomes in a randomized double-blind placebo-controlled study of 15 participants with ischemic stroke and 2 participants with hemorrhagic stroke Participants received 18 sessions of Active VNS or Placebo VNS. Participants in the Placebo VNS group crossed over to the Active VNS group, where all participants received an additional 18 sessions of Active VNS with rehabilitative exercise. There were no severe device-related adverse events, participants received approximately 400 stimulations per therapy session and saw an average UEFM change of 6.18 +/- 1.04 points in 36 sessions of therapy. These results indicate that continued investigation of the ReStore system is viable and may improve overall patient outcomes.
Clinical Trial ID: NCT04534556
Categories
Stroke
Investigating the lateralized role of posterior parietal cortex for fine motor control during a tablet-based tracing task using HD-tDCS
Sydney Sharp, Jessica Manning, Brooke Dexheimer
Department of Occupational Therapy, Virginia Commonwealth University, Richmond, VA, USA
The posterior parietal cortex (PPC) is believed to have a role in numerous mechanisms supporting motor control, including visuospatial perception, multi-sensory integration, and visual attention.1 Lesion and neuromodulation studies have also suggested that these processes are lateralized.2,3,4 Our previous research using an excitatory, non-invasive electrical stimulation: anodal high-definition transcranial direct current stimulation (HD-tDCS), showed that transfer of motor learning to the opposite, untrained arm during a motor adaptation task is enhanced when anodal HD-tDCS is applied to left PPC.5
Precision drawing tasks, such as handwriting, are believed to occur via different neural mechanisms from motor adaptation. However, research has implicated PPC for these mechanisms as well, although it remains unclear the extent to which these mechanisms are lateralized.6,7 An enhanced understanding of lateralized PPC contributions to precision drawing has immense clinical implications, especially for those with motor deficits due to central or peripheral nervous system damage.
In this pilot study, fifteen neurologically intact participants completed a tablet-based tracing task with their dominant right hand. During this task, we applied anodal HD-tDCS (15 min., 2 mA), over left PPC, right PPC, or under sham conditions. We quantified tracing error as the Euclidean distance between the stylus tip and on-screen shape outline at every sampling timepoint. Immediately after this task, participants switched to their non-dominant hand and completed the same tracing procedures (no stimulation delivered). We hypothesized that anodal HD-tDCS over left (but not right) PPC during dominant hand learning would coincide with significantly greater transfer of learning to the non-dominant hand (i.e. significantly lower tracing error).
All groups increased their tracing error when switching to the non-dominant hand (p < .001). Opposite of our expectations, the largest error increases occurred for the left PPC stimulation group (1.52 pixels ± .12 SE; p < .001). Sham group participants increased trial duration when switching to their non-dominant hand (706 ms ± 112; p < .001), while those in the left and right PPC groups did not. To further quantify performance, we used Fast Fourier Transformations (FFTs) within each trial to decompose continuous tracing error into distinct frequency components. Our preliminary analysis shows significant differences in low-frequency spectral power (0.5 to 1.5 Hz) between the hands (p < .001), with no differences between the stimulation groups (p = .33). In summary, when switching to their non-dominant hand, participants performed at similar speeds but with significantly higher tracing error and greater proportions of low-frequency (0.5 to 1.5 Hz) oscillatory stylus movements when compared to their dominant hand. The left PPC stimulation group demonstrated the highest increase in tracing error.
While these results are preliminary, they suggest that PPC contributions to the neural mechanisms underlying precision drawing are lateralized and distinct from the underlying neural mechanisms for motor adaptation.
Categories
Motor Rehabilitation
Accuracy of the Berg Balance Scale, Functional Gait Assessment, and Mini-BESTest for Predicting Future Post-stroke Fallers at Discharge from Inpatient Rehabilitation
Ehsan Sinaei, Lina Jallad, Megan Schliep, Prudence Plummer
MGH Institute of Health Professions, Boston, USA
Background: Individuals post stroke are at high risk for falls, with 35-73% falling within the first 6 months of discharge from hospital. The Berg Balance Scale (BBS) and Functional Gait Assessment (FGA) are recommended instruments to evaluate balance and infer fall risk in this population. However, the BBS has only fair sensitivity (63%) and specificity (65%) for predicting post-stroke fallers after inpatient rehabilitation, and the predictive properties of the FGA in the inpatient setting are unknown. The BBS may be limited in predicting future fallers due to the absence of any gait activities.
Objective: To compare the discriminative accuracy of BBS, FGA, and Mini-BESTest at discharge and their ability to predict fall status 3 months post discharge among ambulatory stroke survivors being discharged to home. Whereas the BBS has no gait items, the FGA has exclusively gait items, and the Mini-BESTest includes both gait and non-gait components.
Methods: 36 stroke survivors being discharged home from inpatient rehabilitation (mean ±SD: 64.1 ±12.3 years old, 28.5 ±18.1 days post stroke, 50% female) were assessed on the BBS, FGA, and Mini-BESTest 1.8 ±1.2 days prior to hospital discharge. Participants were given a falls diary to track falls for 3 months. Predictive accuracy was examined by dichotomizing scores based on cut-off points and computing the sensitivity, specificity, and area under the curve (AUC) for each test. Differences between fallers and non-fallers on all 3 tests as well as the four subscales of mini-BESTest (anticipatory postural control, reactive postural control, sensory orientation, and dynamic gait) were examined using Mann-Whitney U test.
Results: 36% (n=13) of the participants were fallers (≥1 fall). The median/maximum possible (range) for BBS, FGA, and Mini-BESTest were 12/28 (1-27), 40.5/56 (0-56), and 10/30 (0-30), respectively. There were significant differences in BBS and Mini-BESTest scores at hospital discharge between would-be fallers and non-fallers, but not for the FGA, which had a 27% floor effect. Anticipatory postural control and dynamic gait sections of the Mini-BEST at hospital discharge significantly differentiated future fallers and non-fallers. The sensitivity was very good for the BBS (92% [95% CI 64-100]), FGA (100% [95% CI 75-100)], and Mini-BESTest (100% [95% CI 75-10]). However, the specificity was poor due to high false positive rates: BBS (48% [95% CI 27-69]), FGA (10% [95% CI 1-32)], and Mini-BESTest (39% [95% CI 20-61]). The AUC (95% CI) for BBS, FGA, and Mini-BESTest were 0.71 (0.54-0.89), 0.55 (0.35-0.75), and 0.68 (0.49-0.86), respectively.
Conclusion: While the BBS, FGA, and Mini-BESTest are feasible in the inpatient rehabilitation setting and may inform areas for treatment, they lack accuracy in predicting future fallers after discharge. There is a need for a more accurate assessment for predicting post-stroke fallers in the critical transition from hospital to home.
Categories
Stroke
Corticospinal contribution to the control of bilateral intermuscular coordination in healthy and post-stroke subjects
Shiva Nouri1,2, Ti-No Ho2,3, Carl Tchoumi1,2, Anatol G. Feldman2,3, Mindy F. Levin1,2
1McGill University, Montreal, Canada. 2Centre for Interdisciplinary Research in Rehabilitation, Montreal, Canada. 3University of Montreal, Montreal, Canada
Introduction: Coordination of bilateral upper limb (UL) movements is a crucial skill for the accomplishment of daily life activities. Damage to the primary motor area (M1) after stroke alters the ability to produce bilateral coordinated movements. However, which brain and spinal cord structures/pathways are involved in the control of bilateral movement, and to what extent they are disrupted in patients with stroke is still unclear.
Objective 1: Determine the roles of the ipsilateral and contralateral corticospinal tracts (iCST, cCST) in the regulation of bilateral wrist movement in healthy subjects. By equalizing electromyographic (EMG) activity at different wrist positions, we will test the hypothesis that M1 controls motoneuronal activity indirectly, by influencing the hand threshold position at which proprioceptive and stretch reflexes begin to act (Raptis et al. 2010).
Objective 2: Determine the roles of iCST and cCST on regulation of bilateral wrist movement in patients with chronic stroke. We hypothesize that the contribution to muscle activation from the iCST and cCST will be disrupted in patients with chronic stroke.
Methodology: 18 healthy and 18 people with chronic ischemic/hemorrhagic stroke (≥3mo, 18-75yr) will be recruited. Subjects are excluded if they are prone to seizure or have contraindications to Transcranial Magnetic Stimulation (TMS). Subjects with stroke undergo one clinical evaluation session (i.e., sensation, muscle strength, spasticity, etc.) and all subjects participate in one experimental session. From a sitting position, the subject’s arms are supported on a smooth horizontal surface and each hand is placed in a wrist manipulandum permitting free flexion/extension movements in the horizontal plane. The subject specifies 4 wrist positions: 1) right wrist extension-left wrist flexion; 2) right wrist flexion–left wrist extension; 3) right and left wrist flexion; and 4) right and left wrist extension. For each position, TMS (12 stimuli) is applied over M1 of ipsi- and contralateral hemisphere after equalizing background EMG activity in homonymous muscle pairs. EMG is recorded from 5 wrist muscles per arm and TMS-elicited Motor Evoked Potential (MEP) amplitudes are compared for each position within- and between groups.
Results: In healthy subjects, iCST and cCST stimulation evokes MEPs of different amplitudes in wrist flexors and extensors according to the wrist positions. For iCST, there is a tendency for more responses in wrist extensors than wrist flexors regardless of position. In contrast, MEP responses were delayed and smaller in participants with stroke. However, they occurred with greater frequency in both wrist flexors and extensors during iCST.
Significance: Results of this study will enhance our understanding of the role of corticospinal pathways in bilateral coordination in healthy subjects that may lead to improvements in UL neurorehabilitation of stroke survivors.
Categories
Motor Rehabilitation
Conversion from MEP- to MEP+ relates to upper extremity dexterity improvements after acute neurologic injury: a case study of recovery from cervical spinal cord injury due to meningitis-induced tonsillar herniation
Kristi Emerson1, Sydney McKiernan1, Kelly Rishe1,2,3, Sara Cavanagh1,2,4, Josephine Buclez1, Maria Nazarova5, Isha Vora6, Denis Balaban1, Teresa Kimberley6, Ziv Williams1, Leigh Hochberg1,2,7, David Lin1
1Massachusetts General Hospital, Boston, USA. 2Veterans Affairs Providence Healthcare System, Providence, USA. 3Medical University of South Carolina, Charleston, USA. 4Harvard John A Paulson School of Engineering and Applied Sciences, Cambridge, USA. 5Aaolto University, Espoo, Finland. 6MGH Institue of Health Professions, Boston, USA. 7Brown University, Providence, USA
Acute neurologic injury to descending motor pathways allows for the examination of relationships between neurophysiology and motor behavior. Here we present a remarkable neurologic case of a young woman with spinal cord injury resulting from tonsillar herniation after viral meningitis. We performed motor assessments, neuroimaging, and TMS neurophysiology acutely and repeated motor assessments with neurophysiology 20 months later.
A 24-year-old woman presented with headache, neck pain, and photophobia. Initial testing including cerebrospinal fluid and MR neuroimaging were suggestive of meningitis. In the following days her condition rapidly worsened and repeat imaging showed tonsillar descent. In the intensive care unit, she was tetraplegic. She underwent suboccipital craniectomy and C1 laminectomy. Transcranial magnetic stimulation (TMS) performed on day 20 after initial injury showed the presence of a motor-evoked potential (MEP) in the left abductor pollicis brevis (APB) and the absence of an MEP in the right APB. Forty days after initial injury she discharged from the acute hospital. At this time, she could follow commands, nod yes/no, demonstrated Medical Research Council (MRC) grade 1 out of 5 strength in both arms, and had triple flexion in her legs in response to noxious stimuli. She was transferred from the acute hospital to an inpatient rehabilitation hospital where she underwent standard rehabilitation protocols for 2.5 months and then returned home with ongoing outpatient therapy thereafter. In her initial outpatient therapy evaluation she regained bilateral arm strength to a grade of at least 3/5 in her right upper extremity and 4/5 in her left. She performed 9 Hole Peg testing that revealed a large deviation from normal, particularly in the R hand.
She was then seen for follow-up 20 months after initial injury. Strength testing showed at least 4/5 strength without gross asymmetry between upper extremities. 9-Hole Peg revealed that the right upper extremity had made substantial improvement but still had more deficits than left. Proximal dexterity (assessed by Mahalobis distance of a 2D center-out reaching trajectory from a healthy population) demonstrated that bilateral arms performed just below age-matched norms, with the right arm exhibiting less dexterity. TMS results showed presence of MEPs in bilateral APBs demonstrating conversion in right APB from MEP- at baseline.
This 24-year-old woman demonstrated a remarkable recovery course. Her RUE which showed the most dexterous improvement over the course of this study, notably was found to have converted from MEP- to MEP+ from hospital to follow up. This increase in dexterity coupled with MEP conversion is likely indicative of recovery of the corticospinal tract over this time period. Altogether, our case highlights the value of detailed longitudinal assessment in patients with acute neurologic injury to further understand relationships between neurophysiology and motor behavior.
Categories
Motor Rehabilitation
Sharing and aggregation of transcranial magnetic stimulation (TMS) derived data through common data elements: Improved functionality of the TMS Analysis Toolbox
Patrick Tomko1,2, Rifeng Jin1,2, Shreya Ramani1,2, David Cunningham1,2,3
1Case Western Reserve University, Cleveland, USA. 2MetroHealth Center for Rehabilitation Research, Cleveland, USA. 3Cleveland Functional Electrical Stimulation Center, Cleveland, USA
For over thirty years, the field of neurorehabilitation have utilized single and paired-pulse TMS to understand adaptive and maladaptive neuroplasticity following neurological injuries and to predict recovery. TMS employs electromagnetic induction to stimulate upper motor neurons, generating action potentials that propagate to the targeted muscle. These experiments measure the resulting compound muscle action potential (motor evoked potentials) and the suppression of muscle activity (silent periods) using electromyography at the specific muscle site. Recently, the National Institutes of Health (NIH) has focused on an initiative to promote open data access and sharing. However, the field of neurorehabilitation encounters various challenges stemming from the use of diverse data acquisition software, experimental protocols, naming conventions, and analysis algorithms. The absence of a framework enabling integration from various sources limits the full utilization of the extensive data available in the field. In response to the NIH open access initiative, we have improved our open-source TMS Analysis Toolbox to facilitate data sharing. The toolbox can import whole multi-channel files from various data acquisition systems, comprising the majority of the field, and subsequently export the data in a uniform format. We have adopted common data elements (CDEs) during importing of datasets to better define data and improved organization when exporting datasets and results. The goal of the CDEs is to create a more consistent file naming structure, while improving research team’s accessibility of shared data and provide a clear understanding of the study protocol and conditions through the naming convention. The TMS Analysis Toolbox’s features are in line with the NIH initiatives for open source data access and multi-site clinical trials, ensuring its capability to accommodate diverse research studies. The toolbox’s potential to aggregate multiple datasets from diverse research sites in a repository has broad implications for disseminating data, enabling research teams to collaborate without being limited by diverse data acquisition software, experimental protocols and naming conventions. We illustrate the flow of preliminary data collected from poster “Jin et al. The impact of post-stroke motor overflow modulation on unilateral and bilateral asymmetric force production” – from formatting, organization, and making the data accessible to other research.
Categories
Other
Assessing Spinal Reflex Excitability of Post-Stroke Stiff-Knee Gait During Locomotion
J. Sebastian Correa1,2, Ricardo Siu1,2, Shreya Ramani1,2, David Cunningham1,2, James Sulzer1,2
1Case Western Reserve University, Cleveland, USA. 2The MetroHealth System, Cleveland, USA
Introduction: Stiff-Knee Gait (SKG) is a common disability following stroke often defined by a reduced swing phase knee flexion angle that puts individuals at higher risk of falls and joint pain. A common hypothesis states SKG is caused by quadriceps reflex hyperexcitability. However, interventions aimed at reducing quadriceps activity are inconsistently effective, leading to questions about the overall spinal contributions towards hyperreflexia in SKG. The overall goal of this study is to assess the excitability of spinal circuits controlling quadriceps activation in people with SKG. Here, we characterize potential mechanisms of hyperreflexia using a novel technique by assessing the heteronymous facilitation (HF) of the femoral nerve to the tibial nerve during locomotion in non-disabled participants. We hypothesize increased facilitation in both the paretic and non-paretic legs of people with post-stroke SKG, compared to non-disabled age-similar individuals.
Methods: HF was assessed using the H-reflex of the vastus medialis and soleus to innervate the femoral and tibial nerves in non-disabled participants (n=2; A: 23M, B: 22F), respectively. H-reflexes were elicited with transcutaneous electrical stimulation and recorded with surface electromyography. To elicit maximal facilitation, timing between nerve stimulations was first optimized at rest in supine position. The tibial nerve was stimulated before the femoral nerve using an inter-stimulus interval of 5 – 8 ms with a 0.25 ms step size. The interval that yielded the largest facilitation of the soleus H-reflex was used to elicit a conditioned H-reflex during locomotion. In this abstract we present data from pre-swing defined by when the contralateral leg to the dominant/tested leg supported greater than 25% of body weight following swing. HF during locomotion was assessed on an instrumented treadmill as participants walked at 1 m/s. Conditioned reflexes were normalized using control trials to find the ratio of facilitation at pre-swing.
Results: For the non-disabled participants, peak facilitation was found at an inter-stimulus interval of A: 5.75 ms and B: 6 ms. This result is similar to intervals described in earlier literature of 6-7 ms. For Participant A the facilitation ratio during pre-swing was 1.52±0.26 while B yielded 0.55±0.28. These results indicate varied facilitation of the soleus by the quadriceps depending on the participant. Some variance is expected due to the declining soleus activity pre-swing found in previous literature. Further data is needed to verify these findings before comparing to post-stoke SKG.
Conclusion: In this study we aim to understand the spinal mechanisms driving quadriceps hyperreflexia in post-stroke SKG. Preliminary result show varying modulation of the soleus by the quadriceps at pre-swing. Future work will investigate this in people with post-stroke SKG to help determine the locomotion phase dependent spinal contributions of quadriceps spasticity.
Categories
Stroke
Efficiency of unimanual dexterous performance and task factors influence arm nonuse in chronic stroke survivors
Shauna Zodrow1, Brandon Knight1, Shailesh Kantak1,2, Laurel Buxbaum1
1Moss Rehabilitation Research Institute, Thomas Jefferson University, Elkins Park, USA. 2Department of Physical Therapy, Arcadia University, Glenside, USA
Background and purpose: Almost 40-80% of stroke survivors fail to use their paretic arm during daily activities despite having the capacity to do so. This use-capacity disparity (UCD), also referred to as arm nonuse is a perplexing disorder that lies at the interface of sensorimotor, cognitive and affective processing. Despite its clinical significance in stroke rehabilitation, factors that predict UCD in chronic stroke survivors remain unknown. In this study, our aim was to determine if sensory, motor and affective deficits after unilateral stroke are predictive of UCD.
Methods: Twenty-one participants with mild-to-moderate stroke (upper extremity Fugl-Meyer (UEFM) score>30; 11 LCVA, 10 RCVA) completed the Actual Amount of Use Test (AAUT) which measures the disparity between amount of paretic arm use under spontaneous versus forced conditions during a variety of unimanual and bimanual tasks. The normalized difference in the paretic arm use between spontaneous and forced conditions provided a quantitative index of UCD or nonuse. Participants were also assessed on measures of motor capacity UEFM, unilateral gross manual dexterity (Box and Block test), tactile sensations (Semmes Weinstein monofilament test), proprioception, and self-efficacy (confidence in arm and hand, CAHM). We used stepwise multiple regression analyses to determine which motor, sensory and affective measures were predictive of the UCD scores on the AAUT. We further assessed if there was a difference in UCD scores between unimanual and bimanual tasks of the AAUT.
Results: Of all the variables tested in the model, the difference in Box and Block test performance between the paretic and nonparetic arms significantly predicted the degree of UCD (p=0.001; R2 adj= 0.526; Pearson’s correlation r= 0.745). Scores on the CAHM showed high negative correlation with UCD scores (r= -681, p=0.001), but did not explain additional variance in UCD scores over and above Box and Block test. Further, there was a significant difference in UCD scores between the unimanual (mean UCD score= 0.53+0.34) and bimanual (mean UCD score= 0.32+ 0.23) tasks of the AAUT (p= 0.03) such that the paretic arm was more spontaneously engaged during bimanual actions compared to unimanual actions.
Conclusions and discussion: Our results suggest that the relative efficiency (speed) of dexterous paretic arm performance, self-efficacy and task factors influence arm nonuse in chronic stroke survivors. Novel to this study, greater movement speed difference between paretic and nonparetic arms may bias stroke survivors to choose their nonparetic arm during functional tasks. Clinically, these findings imply that box and block test, a relatively quick assessment of unimanual dexterity may serve as an important predictor of arm nonuse after stroke. Further, strategies that incorporate bimanual tasks and promote movement speed during practice-based interventions may help reduce arm nonuse in stroke survivors.
Categories
Stroke
Assessing Physical Activity Levels and Sedentary Behavior of Stroke Survivors living in the US-Mexican Border: a mix-method pilot study
Leonardo Teixeira Tomé da Silva1, Jessica Hoffman1, Angel Melendez1, Adrian Chavarria1, Lindy Miller1, Taylor Chevalier1, Georgina Sanchez-Garcia1, Ana Jéssica Pinto2, Janaine Polese3, Camila Torriani-Pasin1
1The University of Texas at El Paso, El Paso, USA. 2University of Colorado Anschutz Medical Campus, Denver, USA. 3Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
Introduction: This study addresses the scarcity of data on sedentary behavior (SB) and physical activity (PA) levels among Hispanic/Latin stroke survivors residing on the US-Mexican border. While physical and psychosocial factors influencing SB and PA are reported in the literature, tailored intervention strategies for this specific population are lacking.
Aim: Our pilot study aims to assess SB and PA among stroke survivors on the US-Mexican border, identifying associated physical and psychosocial factors.
Methods: This study was approved by IRB under the number: 00001224. Employing a cross-sectional mixed-method design, we collected quantitative and qualitative data over three visits. Objective measures include wearable activity monitors (ActivPal and ActiGraph) worn by each participant for 7 days, performance-based tests (Timed Up and Go – TUG; 10 Meter Walking Test – 10MWT), self-reported questionnaires (Sedentary Behavior Questionnaire – SBQ; Self-Efficacy to Reduce Sedentary Behavior – SRSB), and a one-on-one interview. A diary log was also used to capture contextual aspects of SB and PA. Data analysis involved descriptive and inferential statistics, integrating interview results with quantitative data to further explore relationships between variables. The open-ended interview questions were analyzed using NVivo. A thematic analysis approach was employed to identify recurring themes, patterns, and insights related to factors influencing participants’ PA levels and SB. Transcripts of the interviews were coded, and themes emerged through an iterative process of data coding and categorization. This analysis provided insights into the subjective experiences and perspectives of participants, helping to enrich the understanding of their behaviors.
Results: Eight stroke survivors were enrolled in the study, being white Hispanic/Latino, with a mean age 62.88 (SD = 7.1), 50% are male, 75% have experienced one stroke (Mean = 1.63 / SD = 1.40), and 75% had an ischemic episode. Participants spent 10.18 hours/day (SD = 3.10) in seated positions, 1.03 hours/day (SD = 0.63) in Light Physical Activity (LPA), and 0.19 hours/day (SD = 0.40) in Moderate to Vigorous Physical Activity (MVPA). The average transitions from sitting to standing were 42.14 times/day with an average step count of 5300 steps/day (SD = 4435). SBQ findings aligned with wearable sensor data, revealing an underestimation of SB. Unexpectedly, uninterrupted sedentary time was 7.67 hours/day (SD = 4.54). SRSB indicated awareness but insufficient self-efficacy to reduce SB. Interviews highlighted the importance of educational information, self-efficacy, and motivation, each of which is vital for improving PA levels and reducing SB.
Conclusions: Our data indicates significant SB among stroke survivors, with limited engagement in LPA and MVPA. Patterns differ on weekdays and weekends, with common activities being TV watching and resting. Educational information, self-efficacy, motivation, and family support are critical for promoting PA engagement. Hispanic/Latino stroke survivors exhibit higher SB levels than reported in white American literature.
Categories
Stroke
Distinct Influence of Beta- and Gamma-tACS on Grip Force Regulation in Chronic Stroke
Syed Qadri1, Seraphina Culp2, Megan Grainger3, Peter Lum4, Shashwati Geed5
1MedStar National Rehabilitation Hospital, Washington, D.C., USA. 2The Catholic University of America, Washington, D.C., USA. 3MedStar National Rehabilitation Hospital, Washington D.C., USA. 4The Catholic University of America, Washington D.C., USA. 5The University of Texas at El Paso, El Paso, TX, USA
Background: Synchronized firing of excitatory/inhibitory interneurons gives rise to cortical oscillations in the beta (13-30Hz), gamma (30-100Hz) bands. We tested if transcranial alternating current stimulation (tACS) in beta/gamma bands leads to systematic changes in different aspects of grip force regulation. We hypothesized that beta-tACS decreases the rate of rise and release of grip force whereas gamma-tACS increases the rates of grip force rise and release.
Methods: Seven adults with chronic stroke (3 male; mean age±SD=58±12.3-yrs, mean Action research Arm Test (ARAT) score±SD=27±19.7) were tested; all had prior ischemic stroke. Patients received twenty minutes of beta (20Hz), gamma (70Hz), or sham-tACS using M1-contralateral-supraorbital montage (intensity just under threshold for phosphenes) during three visits spaced one week apart. Participants performed 80 go/no-go grip-force-matching trials to a target force before and after tACS. Grip forces were processed into (1) grip onset reaction time; (2) rise time: duration to reach steady-state target grip force; (3) peak grip force velocity during rise; (4) reaction time to grip offset; (5) release time: duration to release grip to baseline. Paired-sample statistics were computed using the Wilcoxon signed-rank tests.
Results: Grip forces showed small increase in reaction time (+72.9ms) following beta-tACS; slightly smaller increase with gamma-tACS (+40.4ms) and no significant difference with sham stimulation. While beta and sham stimulation showed small differences in the duration of grip force increase, gamma stimulation led to shortening of the duration of grip force reaction time (-166.89ms). No difference was observed in the peak grip force amplitude. We observed no differences in the reaction time to grip offset, but slight increase in the duration of grip force release in gamma stimulation (44.41ms) and sham (45.82ms).
Discussion: Our task allows us to dissociate different aspects of grip force regulation, in particular, reaction time from the time for dynamic adjustments to desired grip force. tACS was tolerated well by individuals with stroke. Beta- and gamma-tACS led to slight increases in reaction times. Gamma-tACS also led to shortening of the time needed for grip force matching, indicating faster times to ramping up the grip force. Data collection is ongoing, results from a larger sample of individuals with chronic strokes and healthy controls will be presented.
Conclusion: Gamma and beta-tACS are safe and tolerable for individuals with chronic stroke and may lead to significant changes in grip force modulation.
Categories
Stroke
Soft wearable inflatable robot for supporting the shoulder improves arm function in people post-stroke
Prabhat Pathak1, James Arnold1, John Paul Bonadonna1, Carolin Lehmacher1, Conor McCann1, Tanguy Lewko1, Sarah Cavanagh1,2,3, David Pont-Esteban1, Kelly Rishe2,3,4, David Lin2,3, Conor Walsh1
1John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA. 2Department of Neurology, Division of Neurocritical Care and Stroke Service, Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. 3Department of Veterans Affairs, Rehabilitation Research and Development Service, Center for Neurorestoration and Neurotechnology, Providence, RI, USA. 4Stroke Recovery Research Center, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA
Stroke-induced motor impairments limit the ability of people post-stroke to elevate their arm while also causing involuntary shoulder and distal joint movements, and a reduction in end-effector movement quality [1,2]. An effective strategy employed in the field of rehabilitation to practice functional arm use is to offload the arm against gravity [3]. This study evaluated the potential for a soft wearable robot that uses a pneumatic actuator to offload the weight of the arm [4] to improve arm function. The wearable robot consists of an actuator that is attached to a custom-made shirt and a control unit that can be worn by the users. A controller uses the real-time residual shoulder movement recorded using inertial motion unit (IMU) and capacitive deformation sensors to tune the level of support to the user’s movement.
We recruited three individuals with upper extremity motor impairment after stroke (age = 56.0±19.5 years, years since stroke = 4.7±2.1 years, FMA scores = 45±9.2) and asked the participants to lift their arm against gravity by lifting it to 90 degrees flexion, while keeping their elbow straight, three times each when the robot was turned on and off. We used an optical motion capture system to track upper-limb movement and evaluate arm function by calculating 1) maximum shoulder elevation, 2) involuntary joint movement (horizontal shoulder abduction, shoulder hike, and elbow flexion), and 3) end-effector movement quality (hand-to-path ratio of the three-dimensional hand center of mass trajectory).
We found that the soft wearable robot increased the maximum shoulder elevation, on average, by 11.1±3.3°, while reducing involuntary joint movement by decreasing shoulder horizontal abduction, elbow flexion, and shoulder hike by 8.2±3.6°, 6.0±1.8°, 8±3.4%, respectively, for the three participants. Additionally, the robot improved end-effector movement quality by reducing hand-path-ratio, on average, by 41.0±9.9%. Considering the efficacy of the device in improving arm function for single-joint movement, in future studies we plan to assess the efficacy of our device in improving arm function during multi-joint functional activities and its usefulness as a tool for upper extremity motor rehabilitation.
Categories
Stroke
One-week test-retest reliability of an unsupervised, online version of the digit symbol modalities task among older adults
Andrew Hooyman1, Kevin Duff2, Sydney Schaefer1
1Arizona State University, Tempe, USA. 2Oregon Health and Science University, Portland, USA
Measuring individual cognitive ability is critical for the diagnosis of neurodegenerative disease and prognosis of neurorehabilitation. Ideally, individual cognitive ability is achieved through an in-person neuropsychological assessment by a trained and licensed clinician. However, there are several barriers that may prevent a prospective patient from being assessed (e.g., lack of transportation, reduced access to qualified professionals, etc.). Furthermore, the growing number of older adults in need of such evaluations will likely exceed the number of available clinicians that can administer such tests. Thus, we developed an online, unsupervised version of the digit symbol modalities task (DSMT), a subtest of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) that measures individual processing speed. Importantly, the DSMT is the only RBANS subtest (out of 12) that has not been validated for remote assessment following the COVID-19 pandemic. Tasks like DSMT have also been linked to medical comorbidities and even mortality (refs). The online DSMT used in this experiment was adapted from a previously published version of the DSMT that has been validated among older adults with and without mild cognitive impairment (Galvin et al. 2020) and is neither copyrighted nor requires payment to be used. The online DSMT can be performed both via a computer or touchscreen device. The purpose of this experiment was to examine the one-week test-retest reliability of the online DSMT among a group of adults 55 years and older. Sixty-eight adults (mean age = 59.6 ± 4.8; female = 14, computer/touchscreen = 68/0) completed the initial and one-week assessment of the online DSMT. Participants were presented with an instructional video on how to complete the assessment and a limited practice set of the DSMT to become familiarized. Presentation of symbol order was the same across each assessment day and between participants. A one-way model of intraclass correlation for consistency was used to calculate the intraclass correlation coefficient (ICC). Results indicated an ICC = .68 (p<.001, 95% CI = [.52; .79]). Furthermore, a dependent t-test between the initial test (mean = 29.2+/-10.6) and the one-week test (mean = 30.8+/-11.5) was not statistically significant (p = .16), which indicates that performance was relatively stable between time-points. This result is consistent with prior examinations of ‘good’ test-retest reliability of the DSMT administered in-person. Overall, these results indicate that online, unsupervised DSMT performance is consistent across a one-week period among adults 55 years and older. Furthermore, the transformation of what is commonly a paper-and-pencil test into an online assessment allows for the engineering of digital based performance features that may serve as potential digital biomarkers of neurodegeneration. Future research will validate online DSMT performance with other indicators of neurodegenerative disease.
Categories
Cognitive/Language Rehabilitation
Estimating Trunk and Forearm Movements in Healthy Controls and Patients with Unilateral Weakness due to recent Stroke using Wearable Sensors
Jack Pettit1, Catherine Dang2, Paige Hepple1, Linda Riek3, Ania Busza1
1University of Rochester, Rochester, USA. 2Vanderbilt University, Rochester, USA. 3University of Nazareth, Rochester, USA
Title: Estimating Trunk and Forearm Movements in Healthy Controls and Patients with Unilateral Weakness due to recent Stroke using Wearable Sensors
Background: Repetitive exercises are the cornerstone of current treatment for upper extremity (UE) motor impairment after stroke. Studies suggest that for some patients, permitting compensatory movements of the trunk or shoulder may lead to less effective or even harmful effects of treatment. 1,2
However, it is still unclear whether all compensatory movements are detrimental, and whether specific types of patients are at higher risk for the negative effects of compensation. Currently, research is limited due to a lack of easily available automated systems for measuring compensatory movements during rehabilitation therapies. Wearable sensors may provide a method for automatically tracking compensatory movements during rehabilitation exercises. 3,4
Objective: To investigate the use of wearable sensors for measuring trunk and forearm movements during rehabilitation exercises.
Design: Healthy controls and subjects with UE weakness due to recent (<6 weeks) unilateral stroke performed a set of functional UE activities (cup stacking, wiping, radial motion, and using a rolling pin) while wearing sensors on the chest and both UEs that collect accelerometry and gyroscope data.
Sessions were video recorded to provide information about the time and duration of activities performed, and data from the sensors were synchronized to each exercise component. Total degrees traversed per exercise component can be estimated from gyroscope data and can then be compared between paretic and nonparetic UE and between subjects with and without history of recent stroke.
Results: Our preliminary results using gyroscopy from a wearable sensor placed on the chest found that degree of truncal movement varies greatly between individuals with UE weakness due to stroke.
When compared to healthy controls, subjects with UE weakness due to stroke show more total trunk flexion during the exercises we examined. Furthermore, the amount of trunk flexion varies depending on exercise phase, with the greatest trunk movement occurring when the exercise requires greater arm extension. Ongoing analysis includes incorporating accelerometry data, as well as examining gyroscope data from sensors placed on the forearm and dorsum of the hand.
Conclusion/Future Direction: Our results suggest that data from wearable sensors can provide information about truncal movements during UE exercises, and that degree of compensatory trunk movement varies between subjects with UE weakness due to stroke. Future analysis will include additional subjects, as well as investigating the use of a wearable sensor system automatically track the degree of compensatory truncal movement during post-stroke rehabilitation in order to ultimately better study the effect of compensatory movements during the post-stroke recovery period.
Categories
Motor Rehabilitation
Motor Evoked Potential Operant Conditioning of Wrist Extensors in Individuals with Chronic Stroke: A Case Series
Blair Dellenbach1, Manuel Portilla-Jiménez2, Allison Lewis1, Roland Cote1, Jinsook Roh2, Aiko Thompson1
1Medical University of South Carolina, Charleston, USA. 2University of Houston, Houston, USA
About 50% of individuals with stroke will have lasting upper extremity (UE) impairment1, which impacts participation in meaningful activities. Previous studies have shown that operant up-conditioning of the ankle dorsiflexor motor evoked potential (MEP) can increase the size of the ankle dorsiflexor MEP, dorsiflexor activity during walking, and can improve gait function in people with SCI2,3. Based on those promising findings in lower extremity, we have started investigating the applicability of MEP operant conditioning in UE of individuals with CNS disorders. As one of the first steps in such effort, this study tests the hypothesis that extensor carpi radialis (ECR) MEP up-conditioning can improve wrist extensor activity and UE function in individuals with chronic stroke.
Three adults with moderate UE impairment and weak wrist extension due to ischemic subcortical stroke have been studied with ECR MEP up-conditioning: a 67-year-old female 6 years post-stroke (P1); a 56-year-old female 2.5 years post-stroke (P2); a 57-year-old male 3 years post-stroke (P3). Participants were exposed to 6 baseline and 24 MEP up-conditioning sessions (3 sessions/wk over 10 wks). In all 225 MEP trials of baseline sessions and the first 20 trials of each conditioning session, the participant received no feedback as to MEP size. Then, in 225 conditioning trials of each conditioning session, the participant was asked to increase MEP size and received immediate feedback as to whether MEP was larger than a criterion (i.e., whether the trial was a success). EMG amplitude during the maximum isometric voluntary contraction (MVC) and silent period (SP) after MEP were measured in each of the 6 baseline and 30 conditioning sessions. The Fugl-Meyer Upper Extremity Motor Assessment (FMA-UE), Action Research Arm Test (ARAT), and Box and Block Test (BBT) were administered at baseline and after 24 conditioning sessions.
Changes in EMG and function measures after 24 conditioning sessions are as follows. P1: +25% in MEP, +20% in MVC, -6.2% in SP duration, from 39 to 49 in FMA-UE, from 21 to 33 in ARAT, and from 14 to 18 in BBT. P2: -13% in MEP, +70% in MVC, -44.5% in SP, from 40 to 48 in FMA-UE, from 32 to 32 in ARAT, from 11 to 17 in BBT. P3: -36% in MEP, +71% in MVC, non- measurable at baseline to measurable SP after, from 34 to 42 in FMA-UE, from 28 to 34 in ARAT, from 13 to 16 in BBT.
These early results support our hypothesis that MEP up-conditioning can improve voluntary activation of wrist extensors and improve UE function in chronic stroke. Currently, we are studying additional participants and examining neurophysiological changes and time course of change in individuals with chronic stroke.
Categories
Motor Rehabilitation
Alterations in Brain White Matter Tract Integrity Across the Severity Spectrum in Chronic Stroke Survivors: A Tract-Based Spatial Statistics (TBSS) Analysis Approach
Jia Liu1, Ken Sakaie1, Xin Li1, Kelsey Potter-Baker2, David Cunningham3,4, Mark Lowe1, Akhil Mohan1, Kyle O’laughlin1, Morgan Widina1, Jayme Knutson3,4, Ela Plow1
1Cleveland Clinic, Cleveland, USA. 2University of Texas Rio Grande Valley, Edinburg, USA. 3MetroHealth Center for Rehabilitation Research, Cleveland, USA. 4Case Western Reserve University, Cleveland, USA
Background: A majority of stroke survivors experience chronic upper extremity (UE) paresis, with 37%-50% of them facing severe limitations. Current UE rehabilitative outcomes are unsatisfactory, leading to restricted functional independence of affected individuals to perform activities of daily living and self-care tasks. Recent evidence underscores the essential role of white matter integrity of corticospinal tracts and other brain areas in facilitating post-stroke recovery. Stroke survivors with varying severity levels of UE impairment likely display distinct white matter damage profiles, calling the need for severity-specific neurorestorative targets for precise rehabilitation. However, no studies have characterized variations in brain white matter integrity in stroke survivors across the spectrum of UE impairment severity. This study was to compare whole-brain white matter integrity in chronic stroke survivors along the UE impairment severity spectrum.
Methods: We studied 77 chronic stroke participants (>=6 months) and 15 age-matched neurotypical adults. Stroke participants were categorized as mild (N=16), moderate (N=29), or severe (N=33) based on their UE Fugl Meyer (UEFM) scores (maximum 66). UEFM score >47 signifies mild UE motor impairment, 20 - 47 (inclusive) moderate, and ≤ 19 severe. 3T diffusion-weighted imaging was collected in all participants and white matter integrity was quantified using an unitless measure called tractional anisotropy (FA). We employed a tract-based spatial statistics (TBSS) approach to compare the integrity of white matter tracts throughout the entire brain among four participant groups (F-test and Bonferroni-corrected multiple t-tests, p<0.05). Significant group differences were labeled using the JHU ICBM-DTI-81 white matter atlas. Associations between UEFM scores and white matter tract integrity were analyzed using Pearson’s correlations (p<0.01).
Results: Compared to neurotypical individuals, mildly impaired stroke survivors (UEFM mean±SD: 55.6±3.8) had significant FA decreases in the lesioned hemisphere, primarily in the anterior limb of internal capsule and the superior longitudinal fasciculus. However, moderately (UEFM: 33.4±8.4) and severely (UEFM:14.8±3.2) impaired participants showed more extensive FA decreases in both the lesioned and non-lesioned hemispheres compared to neurotypical adults. These areas included corpus callosum, cerebral white matter, corona radiata, cingulum, corticospinal tracts, internal capsule, and superior and inferior longitudinal fasciculi, suggesting a widespread white matter degeneration following moderate and severe strokes. Correlation analyses identified positive associations of UEFM scores with FA values of the anterior corona radiata in the non-lesioned hemisphere for severely impaired participants, and with FA values of the cingulum in the lesioned hemisphere for moderately impaired persons.
Conclusion: The extent and site of white matter integrity loss after stroke differ across the severity spectrum of UE impairment, with more pronounced bilateral degeneration following moderate and severe strokes. Our study, for the first time, identified white-matter structures linked to distinct levels of UE impairment, emphasizing the need for severity-specific neurorestorative targets for precise rehabilitation.
Categories
Stroke
Pairing Intensive Training with Neuromodulation to Augment Hand Function in Persons with Hemiparesis
Susan Duff1,2,3, Alison McKenzie1, Brooke Stein1, Bailey Advincula1, Isaac Ian1, Annie Jeon1, Casey McWilliam1, Will Potter1, Virginia Ruano1, Paulina Vokulich1, Rahul Soangra1
1Chapman University, Irvine, USA. 2Rancho Research Institute, Downey, USA. 3Cedar Sinai Medical Center, Los Angeles, USA
Background. Activity-based training can improve hand function in persons with hemiparesis. Yet, it is not clear if function could be further augmented with transcutaneous spinal cord stimulation (tSCS) due to the modulatory effect it has on spinal and supraspinal networks. Our primary aim was to determine if a 4-week hand and arm training program would improve function in persons with hemiparesis. The secondary aim was to determine if use of tSCS in a second 4-week training period would further improve function. This is a pre-posttest, controlled trial for persons 10-75 years old (yo), >6 months post-stroke or with unilateral cerebral palsy.
Methods. Eight individuals 19 to 72 yo (mean 36 yo) with hemiparesis participated in a 4-week training period without tSCS, 3x/week for 2 hours/day. Two persons engaged in an additional 4-week training period augmented with low frequency tSCS to the C5-T1 spinal region using the Chattanooga® Continuum™ (Dallas, TX). Both periods included aerobic priming, strengthening, and unimanual/ bimanual activities. Stimulation intensity for tSCS was based on muscle activation using surface electromyography (SEMG) during 3 tasks: 1) grip dynamometry; 2) grip-lift (ATI force transducers, Apex, NC); and 3) target pointing. Outcome measures at pre- and post-training were: Canadian Occupational Performance Measure (COPM), Box and Block test (BBT), grip/pinch dynamometry, Upper Extremity Fugl-Meyer (UEFM), sensibility tests, hand/arm SEMG (Delsys Trigno, Natick, MA), Stroke Impact Scale, interlimb coordination measures and daylong arm use ratio (paretic/non-paretic arm) using APDM Opal inertial sensors (Portland, OR). Wilcoxen tests compared median outcomes pre- and post-training after the 1st period. Individual means were used to compare outcomes pre- and post-training after the 2nd period.
Results: Findings revealed significant improvement in COPM performance and satisfaction for each individual’s most important task (p<0.05), after the 1st training period. Most (7/8) improved individual grip strength and UEFM after the 1st training period, yet changes were not significant. While greater than 50% of all participants showed individual improvement in the BBT, 2-point discrimination (2PD), SEMG activation for the 3 tasks, fingertip force coordination during the grip-lift task, interlimb coordination, and daylong arm use ratio; changes were not significant. The 2 participants in the 2nd training period with tSCS did show individual improvement in grip strength, UEFM, 2PD, and SEMG during the 3 tasks.
Discussion/Conclusion: Age and targeted training positively influenced outcomes after the 1st training period yet, participant number and variability likely contributed to statistical results. Modest improvements were noted after the 2nd training period with tSCS, suggesting it could further improve function. With more participants, inclusion of tSCS using a commercially available device, during training may be found to significantly augment hand function in persons with hemiparesis.
Acknowledgments: Scholarly/Creative Grant Fund, Chapman University.
Categories
Stroke
Exploring Machine Learning Approaches for Predicting Parkinsonian Gait: A Focus on Synthetic Minority Over-sampling Technique (SMOTE)
Daniel Salinas, Gerardo Medellin, Katherine Bolado, Tomas Gomez, Dr. Nawaz Khan Abdul Hack, Dr. Ramu Vadukapuram, Dr. Igor Zwir, Dr. Kelsey Baker
University of Texas Rio Grande Valley, Edinburg, USA
Background: Parkinson’s Disease (PD) is characterized by both motor and non-motor symptoms, and its diagnosis primarily relies on clinical presentation. There is a growing need for diagnostic tools to identify the early signs of PD, particularly the initial motor impairments often manifested as gait abnormalities. Here we seek to present preliminary findings to address this need. Our study focuses on using Machine Learning techniques (ML) to predict the PD clinical stage most efficiently and accurately. Specifically, we have sought to evaluate how spatiotemporal characteristics and other locomotor performance variables obtained on a walkway system can be utilized to identify the Hoehn and Yahr (HY) score in PD.
Methods: Seven individuals with PD and 9 Healthy individuals participated in the study. PD patients were classified on the HY scale by a physician (score range 0-5). Participants completed eight passes on the Zeno Walkway while Protokinetics Movement Analysis Software recorded and calculated the temporal, spatial, and pressure measurements of within-step recordings. Data preprocessing and predictive modeling were analyzed using R. Multiple regression, utilizing predictors such as gait speed, left and right steps, and walking methods (socks, shoes, and barefoot), were employed to normalize the data. The data was split 80% for training and 20% for testing, using three repeated 10-fold cross-validations. HY ratings on the training data were balanced using the Synthetic Minority Over-sampling Technique (SMOTE), and an original set of training data was retained for comparison. Models included Random Forest, Neural Networks, Naive Bayes, Support Vector Machines with Linear Kernel (SVM), and Penalized Multinomial Logistic Regression. The model performance between SMOTE and real training data was compared in terms of 128-core processing computational efficiency, model accuracy, interclass balanced accuracy, kappa, and weighted averages of the area under the curve (AUC).
Results: Analysis across SMOTE and real training data suggests that the Neural Network outperformed other algorithms, achieving an overall real data model accuracy of 98.7%, interclass balanced accuracy of 99.2%, Kappa of 97.6%, weighted AUC of 53.9%, and a model learning time of 11.4 seconds. Additionally, algorithms trained with SMOTE exhibited greater performance, with improvements in Accuracy (d = .19), Balanced Accuracy (d = .30), Kappa (d = .18), and AUC (d = .27). However, the use of SMOTE resulted in an increase in the cost of computational time (d = 1.34).
Discussion: Our results suggest that ML techniques can be used to predict HY scores in a PD population, although the accuracy and efficiency of ML techniques vary and should be optimized to provide real-time clinically relevant feedback. Future work will seek to explore the economic feasibility of early detection of PD using the gait mat and ML strategies.
Categories
Other
Exploring reference frame utilization and aging effects in a traditional y-maze spatial navigation task
Emily Cui1, Yasmine Bassil2, Michael Borich3
1Department of Neuroscience and Behavioral Biology, Emory University, Atlanta, USA. 2Neuroscience Graduate Program, Emory University, Atlanta, USA. 3Department of Rehabilitation Medicine, School of Medicine, School of Physical Therapy, Emory University, Atlanta, USA
Background: Impaired spatial navigation is one of the first indicators of aging-related cognitive decline and potentially the earliest marker of future neurodegeneration. During navigation, spatial information is processed through egocentric reference frames (i.e., first-person, route-centered information) (ERFs) and allocentric (i.e., third-person, world-centered information) (ARFs). Older adults show decreased utilization of ARFs, resulting in an ERF bias, often classified using a y-maze task. While the effects of RF utilization and aging on navigation have been broadly investigated, the two effects on y-maze performance require further research. Therefore, we compared y-maze performance between ERF and ARF classified individuals, as well as between younger and older adults (YAs, OAs). We hypothesized that OAs would preferentially show ERF bias and lower navigational performance in the y-maze compared to YAs.
Methods: YAs (N = 18; mean age 23.7±4.5 years) and OAs (N = 12; mean age: 65.2±6.7 years) completed a computerized y-maze with 5 unique environments. In each environment, participants navigated down a pathway (with associated landmarks) paired with a positive auditory cue 5 consecutive times (“non-probe” trials, NPTs). Afterwards, a shift in landmarks occurred (“probe” trial). RF classification was determined by the navigational choices made in the probe trials. Outcome measures included completion time, distance traveled, and speed for all trials and number of NPTs per environment. Probe-cost ratios (PCRs) (probe / last non-probe outcome measures) were also calculated. T-tests were performed for all outcome measures to assess performance differences between RF groups and between age groups.
Results: There were no significant RF classification effects on y-maze performance, irrespective of age group. No significant differences were found across all outcome measures of participants classified with ERF versus ARF (all p > 0.05).
Significant aging effects were found on y-maze performance, irrespective of RF characterization. Time to complete was lower and speed was higher for both probe and non-probe trials in YAs compared to OAs (all p < 0.005). Distance, number of NPTs, and PCRs were not significantly different (all p > 0.05).
When categorizing individuals by RF classification and age group, 75% of OAs were classified with ERF, while 46% of YAs were classified with ERF. Preliminary visual trends show OAs classified with ERF showed the lowest y-maze performance.
Discussion: Findings suggest that OAs have lower y-maze navigation performance than YAs, especially the OA-ERF cohort. The y-maze may not be able to detect differences in navigation ability through RF classification alone, but may be able to capture aging-related changes in navigation ability through the interaction of RF and aging. Thus, it may serve as a potential clinical tool to detect aging-related declines in navigation ability and as a predictor of future cognitive impairment.
Categories
Cognitive/Language Rehabilitation
Association of functional motor performance with hand muscle motor evoked potential post-stroke
Jenna Blaschke1, Christian Schranz1, Ja’Quann Gallant1, Arianna Alston1, Na Jin Seo1,2
1Medical University of South Carolina, Charleston, USA. 2Ralph H. Johnson VA Healthcare System, Charleston, USA
Background: Many stroke survivors experience chronic motor impairments. Of these more than half suffer from upper extremity hand and arm impairments. To study the neurological function and recovery of stroke survivors with hand impairments researchers often study the corticospinal motor pathways using components of motor evoked potential (MEP). When studying MEP for hand impairments researchers often study MEP in the abductor pollicis brevis (APB). The objective of this research was to determine which muscles of the hand best indicate the participants current hand functional motor performance as indicated by three primary components of MEP: (1) peak-to-peak amplitude; (2) latency; (3) duration.
Methods: Twenty-six stroke survivors completed a pre-assessment before undergoing standardized hand task practice. This study investigated how upper extremity MEP components of four primary hand muscles correlated with motor function performance. Motor function performance was quantified using Wolf-Motor Function Test (WMFT) times. The four primary muscles in the hand that were investigated were: APB, First Dorsal Interosseous (FDI), Flexor Digitorum Superficialis (FDS), and EDC. MEP was measured using transcranial magnetic stimulation. Three MEP components were observed: amplitude, latency, and duration. Correlation analysis was used to investigate the association between WMFT times and the APB, FDI, FDS, and EDC MEP measures.
Results: There were no significant associations between WMFT times and any of the APB MEP components. A higher FDI MEP amplitude was associated with a shorter time to complete the WMFT, but there was no association between WMFT times and FDI latency or duration. A longer FDS MEP duration was associated with a shorter time to complete the WMFT, but there was no association between WMFT times and FDS latency or amplitude. Increases in both the MEP amplitude and duration were associated with a shorter time to complete WMFT.
Discussion: While EDC MEP amplitude and duration were associated with WMFT times, none of the APB MEP components had a significant relationship with WMFT times. EDC is the only muscle of the four muscle groups studied that are required in all WMFT hand tasks. APB MEP is commonly affected post-stroke but can be compensated for using alternative pinches and/or muscles, such as FDI. Pinches used in several WMFT tasks (towel, checkers, etc.) can all be successfully compensated for using FDI instead of APB to perform lateral pinch without affecting the WMFT time. These findings highlight the importance of considering the primary muscles and possible compensatory muscles of motor function assessments when conducting MEP analysis. While collecting and integrating data from multiple muscle groups, even if they are not typically the primary muscle groups utilized for a task, may require additional resources, the complex interactions between upper limb muscle groups, may require this comprehensive approach for accurate findings.
Categories
Stroke
Timing matters: Investigating the optimal period for baseline motor assessments in stroke recovery trials
Sydney McKiernan1, Julie A. DiCarlo1, Jennifer D. Hebert1,2, Perman Gochyyev3,1, David J. Lin1,2
1Massachusetts General Hospital, Boston, USA. 2Veterans Affairs Providence Healthcare System Center, Providence, USA. 3Massachusetts General Hospital Institute of Health Professions, Boston, USA
Introduction: The first few days after acute stroke are characterized by multiple and complex biological processes resulting in dramatic changes in patient presentation. Given this dynamic early change, there is a lack of clarity on when to gather baseline motor assessments for recovery trials. Here, we aimed to characterize early change in global and upper limb motor impairment as measured by the National Institute of Health Stroke Scale (NIHSS) to determine when stroke related deficits stabilize and recovery begins. We also aimed to test the hypothesis that upper limb motor impairment at distinct timepoints during acute hospitalization would differentially explain long-term motor outcomes.
Methods: Ninety-eight individuals with upper limb motor impairment after acute stroke were prospectively enrolled in a motor rehabilitation study (NCT03485040). NIHSS (total and motor sub-score) were collected at four timepoints during the acute hospitalization: admission (<6 hours), 24 hours, 72 hours (from symptom onset), and discharge. A mixed-effects regression model was used to assess mean change between timepoints. Multiple linear regression was performed to determine potential factors (acute stroke therapies, medical comorbidities, premorbid function, baseline NIHSS score) that explained change in total NIHSS between timepoints. Long-term upper limb motor impairment was measured by the Fugl-Meyer assessment 90 days post-stroke, and linear regression analyses were performed to determine which timepoints explained the most variance in outcome.
Results: The 98 participants (mean age 64.2 ± 13.1, 49% female) had an average acute stroke hospitalization length of 7.6 ± 5.0 days. On initial presentation, the cohort had an average total NIHSS score of 11 ± 7.0 and motor subscore of 2 ± 1.5. Total NIHSSadmission-24hr had a significantly larger mean magnitude of change (5.54 ± 4.89 points) compared to the later change windows: Total NIHSS24-72hr (2.33 ± 2.15) and Total NIHSS72hr-discharge (3.06 ± 2.34), indicating that the greatest change occurred in the first 24 hours after stroke. Endovascular therapy and diabetes were predictive of total change from admission to 24 hours (p <0.001). Premorbid cardiac disease predicted change from 72 hours to discharge (p <0.001). Multiple linear regression analyses demonstrated that 24, 72, and discharge NIHSS motor scores were significant predictors of 3-month Fugl-Meyer (p=0.001 for all three), while admission motor score was not.
Discussion: The most change (improvement and deterioration) happened from admission to 24-hours post-stroke. Distinct factors explained change in different time windows during the acute stroke hospitalization. Motor scores gathered at or after 24 hours predicted 90-day motor outcome, suggesting long-term motor recovery processes can be captured within this early time frame. Taken together, these results highlight distinct biological windows after acute stroke and provide insight into timing for baseline motor assessment.
Categories
Stroke
Impacts of exoskeleton on movement characteristics during multi-directional reaching tasks in healthy adults
Yi-Ning Wu, Hannah Allgood, Cooper Ferrari, Lian Orifice
University of Massachusetts Lowell, Lowell, USA
Introduction: Human reaching relies on intricate motor programs (synergies) that can be disrupted by neurological disorders or aging. While assistive exoskeletons have the potential for rehabilitation, their impact on reaching, due to added weight, mechanical restriction or applied force, remains unclear. In this study, we aimed to investigate how these interferences alter reaching movements.
Methods: Nine healthy participants at the age of 20.6 ± 1.6 years were included in this study. None of them had experience working with an exoskeleton before participating in the study. A commercial exoskeleton (Myomo Pro) controlled by muscle activations was used in this study. Each participant performed reach-and-grasp tasks at three conditions using the right arm: natural reaching without wearing the exoskeleton (NoExo), reaching while wearing the exoskeleton with power off (ExoOff), or power on (ExoOn). During the tasks, participants were asked to reach and grasp the object (an aluminum can) placed in one of the three locations (10 times at each location ordered randomly), including in the front of the participant (forward reach), and 45 degrees to the left (medial reach) and to the right (lateral reach). To characterize the reaching movements, we derived the variables in reaching and returning phases, including the distance between travelled trajectory and the straight line connecting the starting and target locations (DIS), transport time (TT), and travelled trajectory (TRJ), constituting six dependent variables. To examine the differences among conditions, we conducted the two-way repeated measures analysis of variance (ANOVA) with the level of significance set at p<0.05 and Bonferroni tests for multiple comparisons when appropriate.
Results: During the medial reach, ExoOn had a significantly larger DIS in both reaching and returning phases when compared to NoExo (p=0.037 and p=0.044). The TT in ExoOff and ExoOn were significantly longer compared to TT in NoExo during the medial reach (p=0.008 and p=0.014) and the lateral reach (p=0.001 and p=0.03). During the reaching phase of forward reach, NoExo had a significantly shorter TT than ExoOff and ExoOn (p=0.005 and p=0.012) and ExoOff had a significantly shorter TT than ExoOn (p=0.005). When compared to NoEXO, ExoOn took significantly longer time to return from the medial, forward, and lateral reaches (p=0.006, 0.002 and 0.002). It also took longer time for ExoOn to return from the forward reach when compared to ExoOff.
Discussion: The exoskeleton assistance (ExoOn) might encumber the motion while the added weight or mechanical restriction of the exoskeleton (ExoOff) might have less effect on reaching. The larger distance deviated from the straight line seems more evident in the medial reach when the exoskeleton was powered.
Conclusion: Human reaching performance might vary depending on the directions. The design or adoption of the exoskeleton for movement assistance should consider task requirements for better outcome.
Categories
Other
Proximal Upper Extremity Motor Control Analysis in Stroke Patients: A Comparative Study of Principal Component Analysis-Mahalanobis Distance (PCA-MD) and Dynamic Time Warping (DTW)
Liqi Shu1, Sarah K. Cavanagh2,3,4, Perman Gochyyev5, Nicole Dusang6, Karen L. Furie1, Dagmar Sternad7, Leigh Hochberg2,3,6, David J. Lin2,3,5
1Department of Neurology, Warren Alpert Medical School of Brown University, Providence, USA. 2Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, USA. 3VA RR&D Center for Neurorestoration and Neurotechnology, Veterans Affairs Providence Healthcare System, Providence, USA. 4Harvard John A Paulson School of Engineering and Applied Sciences, Cambridge, USA. 5Department of Rehabilitation Sciences, MGH Institute of Health Professions, Boston, USA. 6Carney Institute for Brain Science and School of Engineering, Brown University, Providence, USA. 7Departments of Biology, Electrical and Computer Engineering, and Physics at Northeastern University, Boston, USA
Background: Proximal motor control deficits are a core feature of upper extremity (UE) hemiparesis following stroke. Principal Component Analysis and Mahalanobis distance (PCA-MD) have been previously used to quantify these deficits by measuring deviation from healthy motion patterns. However, this method does not account for the temporal aspect of motor control, as they assess movements irrespective of time. This study introduces Dynamic Time Warping (DTW), an approach accounting for temporal component, and compares it with PCA-MD in stroke patients. We focus on the methodological significance of temporal elements in motor control evaluation and correlating the outputs of each method with conventional motor outcome assessments.
Methods: Twenty-two participants with UE motor impairment after acute stroke (4.6 ± 1.9 days poststroke, Fugl-Meyer range [7-65]) completed 80 trials of a planar reaching in a center-out task (8 directions) with their more affected UE on the Bionik InMotion2® Arm Therapy System, a clinical rehabilitation robotic system. A control population of 22 able-bodied adults completed the same planar reaching task. We computed both the PCA-MD and DTW scores of stroke planar reaching trials in relation to reaching trials of the able-bodied population. We investigated the relationship between both methods and UE outcome measures (Fugl-Meyer Assessment Upper Extremity [FMA-UE], Box and Block Test, and Nine Hole Peg Test). Spearman correlations were used to evaluate the relations between the PCA-MD and DTW methods, as well as between the methods and UE outcome measures.
Results: DTW demonstrated high correlation with PCA-MD score (Spearman correlation: r=0.91, p<0.001), despite differences in temporal data handling. Both PCA-MD and DTW scores showed strong correlations with functional outcomes (Box and Block Test, Nine-Hole Peg Test). Correlations between PCA-MD and DTW scores with FMA-UE were statistically significant, but weaker (Spearman correlation: r=0.46, p=0.031, and r=0.47, p=0.028, respectively). While significantly correlated with elbow extension (Spearman correlation: r=0.55, p=0.010, and r=0.55, p=0.010, respectively) and grip strength (Spearman correlation: r=0.45, p=0.035, and r=0.42, p=0.049, respectively), PCA-MD and DTW scores were not correlated with elbow flexion, shoulder abduction or finger extension (p>0.05).
Conclusion: This study establishes DTW as a methodologic alternative to PCA-MD for quantitatively evaluating motor control deficit. The strong correlation of both methods with functional outcomes not only reinforces their utility in understanding motor impairments, but also highlights that the temporal aspect of movement might not significantly influence these correlations during two-dimensional planar reaching. Additionally, certain components of the FMA-UE were not significantly correlated indicating that the planar reaching kinematics do not capture the full motor control deficit in stroke. Future studies will focus on extending methods to kinematics in three dimensions and to diverse patient populations to enrich neurologic motor outcome assessment.
Categories
Motor Rehabilitation
Influence of Participant Characteristics on Temporary Deafferentation Effectiveness to the Proximal Upper Limb
Maria Lozano Bonilla, Hunter Butler, Jared Hensley, Daniel Salinas, Monica Lozano Garcia, Chelsea Erazo, Ashley Tijerina, Abdallah Gallah, Victoria Cuello, Kelsey Baker
University of Texas Rio Grande Valley School of Medicine, Harlingen, USA
Background: Temporary deafferentation (TD) has been used in neurorehabilitation to improve motor and sensory recovery. TD involves the use of anesthesia to reduce dominant signals with the purpose of unmasking inhibited neural pathways. Different methods have been used to induce temporary deafferentation, such as ischemic, injected nerve blocks, and topical techniques. Topical anesthetics have shown promise at being the preferred method of application, as they reduce patient discomfort, are readily available, and can be applied by the patient upon receiving simple instructions. Unfortunately, there is a lack of studies demonstrating the best approach to achieve maximum effectiveness. Here, we conducted a study evaluating the effectiveness of 5% lidocaine cream in achieving temporal deafferentation, and identified potential factors that could influence the level of TD.
Methods: Eighteen volunteers without any history of upper limb injury and neurological disorders participated in this optimization study. We utilized commercially available lidocaine cream for TD in this study. Specifically, following enrollment, 10 cc of lidocaine cream (5%) was topically applied to the right biceps. Sensation was assessed every 15 minutes, up to 75 minutes, using von Frey monofilaments. We utilized several filaments (range: 2.26-5.07) that spanned the sensitivity thresholds of the monofilaments, including: normal sensation, light touch sensation and protective sensation. At each time point we assessed the level of sensation by placing the monofilament on 9 random locations of the biceps. The percent sensitivity was evaluated at each time point. Prior to and following 75 minutes of temporary deafferentation, all participants completed the nine-hole peg test (NHPT), proximal limb strength test and pinch/grip strength assessment. We also collected body mass index (BMI), age, body-fat percentage, arm width and sex for each enrolled participant.
Results: Overall, we found that participants achieved maximum loss of biceps sensitivity with TD after 60 minutes. We observed that the level of normal sensation loss (filament 5.07) and light touch sensation (filament 4.31) following TD was significantly influenced by BMI, with individuals with a higher BMI showing higher sensitivity (less TD) over 75 minutes. Interestingly, we found that underweight/normal weight individuals were quicker to achieve TD, while obese and overweight individuals achieved the same loss of sensitivity, but often took 2X the amount of time. In contrast, age was most related to the loss of protective sensation (filament 3.84, 3.62, 3.22), with a higher age achieving more loss of sensation.
Conclusions: Our results demonstrate that peak deafferentation can be achieved approximately 60 minutes after application, but the level of TD is influenced by BMI, age, and arm width. Further work will assess the impact of temporary deafferentation in a singular session compared to multiple sessions.
Categories
Motor Rehabilitation
Assessing Functional Connectivity and its Relationship to Functional Recovery Post-Stroke: Preliminary Findings from a Randomized Controlled Trial of Backwards Walking Training
Dorian Rose1,2,3, Abigail Waters1,2, Kelly Hawkins1,2, Ronald Cohen1,2, John Williamson1,2
1Malcom Randall VAMC, Gainesville, USA. 2University of Florida, Gainesville, USA. 3Brooks Rehabilitation, Jacksonville, USA
Objective. Backwards Walking Training (BWT) is increasingly implemented in post-stroke rehabilitation to improve gait and balance, important targets for reducing falls and hospitalizations. BWT may foster greater engagement of prefrontal networks through its more novel and less automatic gait pattern that creates unique postural and lower extremity motor control demands without the advantage of visual flow. Here we present preliminary findings on the association between baseline resting-state functional MRI (rs-fMRI) prior to BWT and improved physical functioning post-BWT.
Participants and Methods. In this ongoing randomized control trial of BWT dosage, individuals 2- 4-months post-stroke (N = 6) with unilateral paresis and gait and balance deficits (Berg Balance Scale < 45/56, 10-Meter gait speed < 0.8 m/s) were randomized into two BWT dose groups (18- or 27-sessions; Ngroup= 3). The sample mean age was 53.0 (SD = 14.8), with majority right-sided lesion in each group. Ten-Meter Walk Test, Functional Gait Assessment (FGA), and Berg Balance Scale (BBS) were conducted at baseline and post-intervention. Participants underwent a structural MRI (1mm3 T1-Weighted; 1.12mm3 FLAIR) and rs-fMRI (2.5mm3, TR = 1.5) at 125.7±42.8 days post-stroke, prior to BWT. Lesion masks were generated with ITK-SNAP, images were pre-processed and co-registered with FMRIPREP, and Region Of Interest-to-Region Of Interest functional connectivity (FC) analyses were performed in CONN with Threshold Free Cluster Enhancement (pFDR < 0.05). Following baseline assessment, participants engaged in BWT, each session consisting of 20 minutes on a treadmill with body-weight support and 20 minutes of over-ground training.
Results. There were no FC differences between groups at baseline. Stronger FC between superior sensorimotor network and right prefrontal cortex [F(1,2) = 1455.58, pFDR < 0.001] was associated with improvement on the FGA in the 18-session (mean change: 28%) but not the 27-session group (mean change: 167%). In contrast, stronger FC between right putamen and right supplementary motor area [F(1,2) = 2709.54, pFDR < 0.001] was associated with improvement on the BBS in the 27-session (mean change: 27%) but not the 18-session group (mean change:16%). Gait speed improvement was associated with stronger FC between left posterior parietal cortex and left prefrontal cortex in the 18-session (mean change: 16%), but not the 27-session group (mean change: 9%). However, this relationship did not survive correction for multiple comparisons [F(1,2) = 477.57, punc = 0.002].
Conclusions. Consistent with previous work, these preliminary data suggest BWT is an effective intervention to effect change in gait and balance deficits post-stroke. The addition of brain imaging extends this work, providing new evidence that increased dosage of BWT may offset the impact of frontal control region FC, at baseline, on recovery of gait. Future research is needed to explore the relationship between FC and rehabilitation response, to tailor rehabilitation interventions and improve prognosis.
Categories
Stroke
Alteration in intermuscular coordination patterns after stroke varies depending on biomechanical conditions in the arm
Manuel Portilla-Jiménez, Yoon N. G. Hong, Jinsook Roh
University of Houston, Houston, USA
Stroke is one of the leading causes of permanent disability. Every year in the USA, around 0.8M people suffer a stroke event, and 80% of survivors experience motor impairments [1], including abnormal neuromuscular coordination. Many studies have described altered intermuscular coordination in the arm as stroke-induced abnormalities in different biomechanical conditions (e.g., isometric force control, kinematic reaching, or grasping) [2]. Nevertheless, how neuromuscular coordination strategies after stroke vary under different biomechanical conditions, such as static and kinematic conditions in the arm, remains unknown. Thus, this study examined how stroke alters intermuscular coordination during isometric force generation and point-to-point reaching within a 3D space in the human arm.
Four chronic hemiparetic volunteers with a single unilateral stroke and four neurologically intact, age-matched individuals participated in this study. We recorded surface electromyographic (EMG) signals from eight arm muscles while participants performed 3D isometric and point-to-point reaching tasks, respectively, using the paretic arm for stroke and the dominant arm for healthy control. The direction of force generation and reaching as well as the upper extremity posture of the two motor tasks were matched. A non-negative matrix factorization was applied to the EMG signals to identify intermuscular coordination patterns, also known as muscle synergies. The similarity of muscle synergies between the two tasks was obtained by calculating the scalar product of the best-matching pairs of muscle synergy patterns.
In both stroke and control groups, four synergies were identified for the isometric task. However, for the point-to-point reaching, the age-matched control group required five synergies while the stroke group did four. Moreover, the composition of the four synergies in stroke was similar between the two motor tasks (mean ± SD; *, p<0.05): Elbow flexor (0.90 ± 0.04*), elbow extensor (0.95 ± 0.06*), shoulder flexor/adductor (0.94 ± 0.05*), and shoulder extensor/abductor (0.89 ± 0.14*).
The increase in the number of muscle synergies necessary to execute point-to-point reaching, compared to isometric force control, in health suggests that performing kinematic reaching involves a higher complexity of neuromotor control than isometric force generation. In contrast, stroke survivors required the same number of muscle synergies for both isometric and kinematic tasks, indicating a decrease in the number of synergies in kinematic but not in isometric motor performance after stroke. This finding suggests that stroke alters intermuscular coordination, but the underlying mechanism of the alteration can vary depending on biomechanical conditions (static vs. kinetic) in the upper extremity. Moreover, the similarity of the muscle synergy composition between the two tasks suggests that the central nervous system after stroke will recruit the same intermuscular coordination patterns but with different activation profiles to perform different motor tasks. Overall, the current study suggests that poststroke alteration in neuromuscular coordination in the arm can vary depending on biomechanical conditions.
Categories
Stroke
Estimating the effect of age on one-year change in individual motor skill among a large, remote online cohort
Andrew Hooyman, Sydney Schaefer
Arizona State University, Tempe, USA
Monitoring the onset of Alzheimer’s Disease and related dementias (ADRD) is primarily dependent on the amount of cognitive and functional change a patient experiences relative to established normative values. However, with a growing aging population and a shrinking number of primary care providers that can routinely evaluate patients, the ability to longitudinally track individuals is a public health challenge. Recent research suggests that motor skill can be a sensitive measure to ADRD progression in its early stages. With advances in measuring motor skill online, we have shown that quantifying motor skill remotely from large and diverse groups of people without supervision through personal internet connected devices (e.g., smartphones, tablets) is feasible and reliable. We therefore now aim to determine how much change in motor skill is typical in non-disabled individuals as a function of age. Three hundred forty-nine participants from a total of 41 states were recruited through Amazon Mechanical Turk to participate in this study. Mean age was 40.04±11.02 years, and 46% of the sample was female (n=162), 72% was non-Hispanic White (n=252), 40% had less than a bachelor’s degree (n=141). Following informed consent, participants completed a survey that collected demographic, lifestyle, and health history data, followed by 75 trials of Super G, our online motor skill game in which participants attempted to land a rate-controlled cursor into a target area using either their touchscreen or arrows keys of their device. If the participant landed and maintained the cursor position in the target area for one continuous second, then a reward tone was played. A dependent t-test demonstrated that participants improved their mean time in target by 101 ms (p<.001) from baseline (537±251) to one-year follow-up (638±241). Multivariable linear regression demonstrated that individual change in time in target was negatively associated with age (βage = -1.75, 95% CI = [-3.12; -.38], p=.01), while controlling for sex, education, race, and ethnicity, meaning that the amount of improvement in Super G performance due to test-retest from baseline to one-year decreased with age. These estimates provide the expected one-year change in motor skill among non-disabled adults, establishing normative data to which clinical samples can be compared in the future.
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Other
Associations between neuroimaging predictors and changes in arm impairment in a phase 3 stroke recovery trial of vagus nerve stimulation
Anne Schwarz1,2, Marc Feldman2, Vu Le1, Jesse Dawson3, Charles Y Liu4,5, Gerard E Francisco6,7, Steven L Wolf8, Anand Dixit9, Jen Alexander3, Rushna Ali10, Benjamin L Brown11, Wuwei Feng12, Louis DeMark13, Leigh R Hochberg14,15,16, Steven A Kautz17,18, Arshad Majid19,20, Michael W O’Dell21, Jessica Redgrave19, Duncan L Turner22, Teresa J Kimberley23, Steven C. Cramer1,2
1Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. 2California Rehabilitation Institute, Los Angeles, CA, USA. 3Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom. 4USC Neurorestoration Center and Department of Neurological Surgery, USC Keck School of Medicine, Los Angeles, CA, USA. 5Rancho Los Amigos National Rehabilitation Center, Downey, CA, USA. 6Department of Physical Medicine and Rehabilitation, The University of Texas Health Science Center McGovern Medical School, Houston, Texas, USA. 7The Institute for Rehabilitation and Research (TIRR) Memorial Hermann Hospital, Houston, Texas, USA. 8Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University School of Medicine, Atlanta, GA, USA. 9Stroke Service, The Newcastle Upon Tyne Hospitals National Health Service Foundation Trust, Newcastle, United Kingdom. 10Department of Neurosurgery, Mayo Clinic, Rochester, MN, USA. 11Department of Neurosurgery, Ochsner Neuroscience Institute, Covington, LA, USA. 12Department of Neurology, Duke University School of Medicine, Durham, NC, USA. 13Brooks Rehabilitation, Jacksonville, FL, USA. 14Department of Neurology, Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. 15School of Engineering and Carney Institute for Brain Science, Brown University, Providence, RI, USA. 16VA RR&D Center for Neurorestoration and Neurotechnology, VA Medical Center, Providence, RI, USA. 17Ralph H Johnson VA Medical Center, Charleston, SC, USA. 18Department of Health Sciences and Research, Medical University of South Carolina, Charleston, SC, USA. 19Sheffield Institute for Neurological Sciences (SITraN), University of Sheffield, Sheffield, United Kingdom. 20Sheffield Teaching Hospitals National Health Service Foundation Trust, Sheffield, United Kingdom. 21Clinical Rehabilitation Medicine, Weill Cornell Medicine, New York City, NY, USA. 22School of Health, Sport and Bioscience, University of East London, London, United Kingdom. 23Department of Physical Therapy, MGH Institute of Health Professions, Boston, MA, USA
Introduction – Impairments of arm movement after stroke are common and often debilitating. A recent phase 3 clinical trial supported the efficacy of vagus nerve stimulation (VNS) for such deficits, but the response was variable and the characteristics of treatment responders remain to be identified. VNS improves motor status by modulating function throughout the cerebrum, and so this study tested the hypothesis that treatment-induced change in arm motor impairment is predicted by baseline differences in both regional motor system injury and global brain measures.
Methods – Subject data were included from the VNS-REHAB trial (Lancet. 397:1545). Stroke lesions were manually traced on T1-weighted images and used to derive brain measures of regional brain motor system injury (CSTM1, precentral gyrus, postcentral gyrus). Global brain measures extracted from scans were degree of white matter disease (WMD; Fazekas scale) and volume of each thalamus, cerebrospinal fluid, cortical grey matter (GM), and white matter. Models used treatment group, age, and gender as covariates and the trial’s primary endpoint (change in arm motor Fugl-Meyer (FM) score from baseline to end of 6-weeks of treatment) as the dependent variable. Models were repeated for the VNS group only. Spatial associations between lesions and motor impairment were examined using voxel-based lesion symptom mapping (VLSM).
Results – MRIs were available from 80 patients (age 59.8 ±9.5 years, 29 females). Infarct volumes ranged from 0.4 to 319.5ml. Lesions affected the precentral gyrus in 37.5% and the corticospinal tract in 83.8%. Across all patients, the regression model for predicting change in FM score included factors for degree of WMD (p = 0.014), GM volume (p = 0.014), and treatment group (p = 0.026); R^2 = 20.9% (p = 0.001). For the VNS-group only, WMD (p=0.004), ipsilesional thalamus volume (p = 0.051), and dominant hand (p = 0.044) were predictors of FM changes; R^2 = 34.5% (p = 0.003). The VLSM including all patients found that lesion cluster in the ipsilesional thalamus significantly correlate with FM baseline (Z = -2.7), while lesion-clusters in primary motor cortex significantly correlated with FM change (Z = -1.6).
Conclusion – In this phase 3 VNS trial, global brain measures such as severity of WMD, cortical grey matter volume, and thalamic volume, predicted motor gains, findings that are concordant with VNS mechanism of action. Results support the value of neuroimaging measures as biomarkers for patient selection and to gain insight into treatment mechanisms. Results require external validation. The low-moderate predictive strength of current models suggests that additional, non-neuroanatomic factors may also be important. This study findings may be useful for patient selection, subgroup stratification, and personalized medicine in stroke rehabilitation.
Categories
Stroke
Spontaneous Movements and Cortical Activity during Early Infancy
Xiwen Su, HyunJoon Kim, Evan Yarnall, Marie Kelly, Claudio Ferre
Boston University, Boston, USA
Spontaneous movements predominate the newborn motor repertoire. Assessment of the presence and quality of spontaneous movements serves as a critical tool for the identification of infants at high-risk (AR) for cerebral palsy (CP). Spontaneous movements during infancy also serve as a potentially rich source of experience for developing sensory systems. However, how exploratory movements shape brain development, both in typically developing (TD) and AR infants, remains relatively unknown. Understanding mechanisms underlying co-development of brain function and motor behavior might provide important foundational knowledge that could contribute to the development of targeted therapies for children with neurological impairment. Functional near-infrared spectroscopy (fNIRS), an optical imaging tool, is an infant-friendly technique that enables measurements of brain activity during performance of movements in naturalistic conditions. fNIRS is robust with respect to signal artifacts and can be used to map hemodynamic responses to cortical activity with relatively precise spatial precision. The objective of our study is to longitudinally track development of spontaneous, exploratory movements in relation to cortical activity. Here we present preliminary data from a sample of TD infants (n=15) and infants AR for CP (n=2). Infants were observed performing spontaneous movements while lying supine at monthly intervals from 2 to 6 months. Movements were recorded using inertial measuring units (BioStamp, USA) synched to fNIRS signals (NIRx, Germany). Movement bouts were analyzed using an established algorithm for infant movements. We calculated duration of movement bouts by limb, proportion of time spent moving, and patterns of symmetric vs. asymmetric bilateral movements. An fNIRS probe containing 8 sources and 12 detectors was placed bilaterally over the scalp in areas covering sensorimotor cortex. In our TD group, we observed a trend of increased duration of movement bouts over time, however there was large interindividual variability. Bouts of limb movements elicited contralateral cortical activity of sensorimotor areas. Duration of bouts and proportion of time moving were markedly reduced in our pilot AR group. The AR group also demonstrated marked asymmetry of bilateral movements. AR infants demonstrated aberrant and reduced patterns of cortical activation. Our preliminary data suggest that there are pronounced movement differences, and resulting cortical activity, that characterize typical and atypical motor development trajectories. The relation between spontaneous, exploratory movements and brain activity suggests a potential activity-dependent mechanism that may help shape motor circuits early in development. Thorough descriptions of the interrelation between spontaneous movements and developing cortical function could provide insights into potential therapeutic targets for infants AR for CP.
Categories
Motor Rehabilitation
Corticomuscular connectivity after rehabilitation training in subacute stroke
Soha Saleh1, Michael Glassen1, Gregory Ames2, Kiran Karunakarn2, Karen Nolan2
1Rutgers university, Newark, USA. 2Kessler Foundation, West Orange, USA
The principles of neuroplasticity suggest that progressive task-specific training can help with the recovery of function and neural adaptations after a stroke. However, there is still limited understanding of the neural adaptations that take place in the central nervous system and neuromuscular system during walking tasks in subacute stroke, and how these changes relate to functional recovery. This study aims to investigate the impact of progressive and intensive exoskeleton-assisted walking (RE) training compared to standard-of-care (SOC) walking training on clinical and functional outcomes, as well as neural adaptations with corticomuscular connectivity (CMC) during walking being the primary outcome.
Assistive walking robots are used in physical therapy programs for stroke patients in the early stage of recovery, which is typically within 40 days post-stroke. During this period, many patients find it challenging to participate in high-dose PT. However, this is also the time when the injured Central Nervous System is highly responsive to repetitive goal-directed physical activities. Along with mobility assessments, 64-channels EEG is used as a mobile imaging technique to study brain activation and CMC during walking. Participants perform standing and walking tasks for 10 trials while EEG and EMG data are collected. The primary outcome measure is cortico-muscular coherence during the swing and double support phases of walking. After 30 sessions of training over 10 10-week periods, changes in these measures are also measured.
In a preliminary sample of 7 subjects in the RE training group (2F, 5M, 57±10.7 years) and 8 subjects in the SOC training group (3F, 5M, 65±12 years) who completed all 30 sessions of training and assessments at baseline, post-training, and follow-up, all subjects showed improvement in mobility assessments when comparing post-training to baseline; Fugl Meyer assessment of lower extremity function (increase in 2.25 ±14.4 points in SOC group and 4.3±3.6 in RE group), timed up and go (-14.7±17.7 seconds in SOC vs. -13.2±16 seconds in RE), and Dynamic Gait Index (10.4±7.5 in SOC vs. 5.4±4.3 in RE).
In terms of neural adaptations, several subjects showed no change while others showed increase in CMC between the Cz EEG channel and the affected gastrocnemius muscle. This increase occurred during the heel strike phase of the gait cycle, indicating higher cortical engagement or cognitive effort to control the loading of the affected limb during walking. This is the first report of change in CMC during walking in subacute stroke.
This analysis of dynamic CMC will be compared to TMS-based measures of primary motor cortex excitability (static CMC) to further understand if there is a relationship between M1 excitability at rest and CMC during walking and if dynamic CMC can potentially be a biomarker of motor recovery post-stroke.
Categories
Stroke
A Review of Post-Stroke Motor Fatigability
Adarsh Mavathaveedu1, Paige Hepple2, David Cunningham3, Ania Busza2
1University of Rochester Medical Center, Rochester, USA. 2Department of Neurology, University of Rochester, Rochester, USA. 3Department of Physical Medicine and Rehabilitation, Case Western Reserve University, Cleveland, USA
Background: After a stroke, many people experience various motor control impairments which contribute to post-stroke disability. One key impairment is Post-stroke Motor Fatigability (PSMF), defined as a decline in one or more aspects of repetitive or sustained motor performance. PSMF can affect the ability to perform repetitive activities of daily life post-stroke. Despite its significance, PSMF remains highly understudied due to differences in terminology, methodology, and assessment. Additionally, deficits in performance may stem from central and/or peripheral origins, which may also be altered post-stroke. In this literature review, we aim to summarize and clarify existing literature on PSMF by establishing clear definitions, distinguishing it from the subjective feeling of “post-stroke fatigue”, and evaluating various tools used to identify the impairment and its source.
Objective: To summarize existing literature on PSMF and evaluate various neurophysiologic tools and assessments used to study PSMF.
Design: Papers published between 2012-2022 were identified through Elsevier and Pubmed databases. Key search terms included “stroke” “motor” “fatigue”. Of these results, 41 studies were selected, which described deficits in motor performance post-stroke utilizing any fatiguing protocol (repetitive maximal contractions, sustained submaximal contractions, walking, etc.) The references of these papers were also examined for additional findings.
Results: Despite some suggested connections to the subjective feeling of fatigue after stroke (termed post-stroke fatigue), PSMF appears to be an independent impairment and requires independent testing. Existing methodologies will be categorized into four groups including functional, indirect, direct, and diagnostic tests, with the latter two being more descriptive of PSMF and its source. We will review results of prior studies, some of which suggest that the source of fatigability may be limb-specific, with peripheral origins on the non-paretic limb and central origins on the paretic limb. We will also suggest ideas for future studies to help further clarify the mechanisms underlying PSMF.
Conclusion/Future Direction: Current PSMF literature suggests that sustained motor performance is impaired post-stroke and may have different origins across limbs. Further investigations, preferably with direct and diagnostic tests, may improve our understanding of PSMF development. Ultimately, more studies on PSMF may contribute to the development of effective therapies for PSMF and help patients adjust to the repetitive and often sustained activities of daily life.
Categories
Motor Rehabilitation
A Preliminary Study of Repetitive Grip Strength Testing in Subjects with Weakness due to Stroke
Klaury Youchom-Tagheu1, Adarsh Mavathaveedu2, Paige Hepple3, Ania Busza3
1University of Delaware, Newark, DE, USA. 2University of Rochester, Rochester, NY, USA. 3Department of Neurology, University of Rochester, Rochester, NY, USA
Background: Motor Fatiguability, defined as decreases in sustained or repetitive motor performances, has been described in subjects with motor impairment after stroke. However, the incidence, emergence, and associated factors have not been determined. We hypothesized that a subgroup of patients with upper extremity (UE) motor impairment after stroke would exhibit serially decreasing grip strength, and that this decrease in strength over serial testing would improve over the first 6 months post stroke.
Objective: To use repetitive hand grip strength testing to study the incidence and evolution of motor fatiguability after stroke.
Design: Subjects with upper extremity (UE) impairment due to recent (<10 days post-stroke) unilateral ischemic or hemorrhagic stroke were enrolled as part of a larger longitudinal study (Motor Abnormalities Post Stroke (MAPS) study). Grip strength was tested at baseline, 1 month, 3 months, and 6 months after stroke. To assess motor fatiguability, a dynamometer was used to measure maximal hand grip strength (in kg) in both paretic and non-paretic hands 5 times consecutively. We then performed linear regression analysis on the grip force data to approximate a straight line through the data points. The slope of this line was compared between paretic and non-paretic arms, and between subjects. To assess intra-individual consistency, similar data were also collected from healthy controls across a span of 2-4 days.
Preliminary Results: At baseline study visit (<10 days post-stroke) subjects with UE motor impairment due to stroke display a wider range of slopes with their paretic hand, with some subjects displaying decreased grip strength over repetitive testing (suggesting motor fatiguability) and others displaying increasing strength over serial grip strength testing (range: -14 to15). In comparison, serial testing of the nonparetic limb exhibited a narrower range of slopes (range: -2.7 to 4.6). During subsequent visits, the range of slopes in the paretic UE decreased, and at 6 months the range in slopes of the paretic UE is similar to that of the nonparetic limbs.
Conclusion/Future Direction: Our data supports that some patients after stroke exhibit motor fatiguability in their affected UE early post-stroke and that this improves over the first 6 months of stroke recovery. However, other patients appear to show improved strength with serial activation. Whether these two phenomena represent distinct subgroups of motor impairment after stroke, or if patients post-stroke have more overall variability in serial grip strength, remains to be determined. Ultimately, we hope to use the information gained in this longitudinal study to develop personalized, impairment-specific interventions for motor recovery.
Categories
Stroke
Motor Control Abnormalities in the First 6 Months After Stroke – An Ongoing Longitudinal Study
Paige Hepple1, Adarsh Mavathaveedu2, David Cunningham3, Ania Busza1
1Department of Neurology, University of Rochester, Rochester, NY, USA. 2University of Rochester, Rochester, NY, USA. 3Department of Physical Medicine and Rehabilitation, Case Western Reserve University, Cleveland, OH, USA
Background: Upper extremity (UE) disability is common after stroke. Prior studies in individuals with hemiparesis due to stroke have identified 4 distinct impairments of motor control: (1) decreased maximal muscle activation, (2) delayed muscle activation, (3) motor fatigability, and (4) abnormal co-activation of antagonistic muscle groups. However, the timing, trajectory, and risk factors of developing specific motor control abnormalities are unclear. We have developed a gamified electromyographic (EMG) computer interface to collect surface EMG data from wrist flexor and extensor muscle groups from subjects performing multiple isometric muscle contractions at precise time points, in order to be able to measure individual motor control abnormalities across multiple time points.
Objective: To study the development and progression of UE motor impairments after stroke and identify early markers predicting specific motor control abnormalities in the chronic phase post stroke.
Design: Subjects with upper extremity (UE) impairment due to recent (<10 days) unilateral ischemic or hemorrhagic stroke are enrolled from the inpatient stroke and rehabilitation services. Patients are evaluated with bedside assessments, as well as behavioral and neurophysiological testing at baseline (<10d post-stroke), 1 month, 3 months, and 6 months after stroke. In addition, demographic, medical, and neuroimaging data is collected for each subject. Further testing with our previously developed gamified electromyographic (EMG) computer interface is used to collect surface EMG data from wrist flexor and extensor muscle groups performing multiple muscle contractions at precise time points.
Results: At the time of abstract submission, we are 18 months into our study and have enrolled 28 subjects. Preliminary results suggest that subjects early (<10 days) after stroke exhibit decreased EMG amplitude and increased variability in activation onset of wrist flexor and extensors in their affected UE as compared to their less impaired UE. Some participants also show increased co-activation in their paretic arm. We will present our results thus far comparing maximum EMG value, activation delay, and co-activation of antagonist muscle groups between subjects impaired and less impaired arms, and investigate the evolution of these findings over the first 6 months after stroke. We will also describe several challenges with our data collection strategy, including antagonist muscle co-activation impacting game control, and difficulties related to impaired focus/stamina of subjects during the early post-stroke period.
Conclusion/Future Direction: Our EMG-controlled computer interface can be used to collect EMG data across multiple time points. With our current longitudinal study, we will assess the prevalence and individual trajectory of each motor impairment over the first 6 months post-stroke. Ultimately, we hope to use the information gained in this longitudinal study to develop personalized, impairment-specific interventions for motor recovery.
Categories
Stroke
Between thinking and doing: Investigating the relationship between cognition and upper limb motor function after stroke
Julie DiCarlo1,2, Abhishek Jaywant3, Sydney McKiernan1, Steven Cramer4,5, Nathan Ward2, David Lin1
1Massachusetts General Hospital, Boston, USA. 2Tufts University, Medford, USA. 3Weill Cornell Medicine, New York, USA. 4University of California, Los Angeles, USA. 5California Rehabilitation Hospital, Los Angeles, USA
Stroke often leads to deficits in motor function. The evaluation of motor function involves various outcome measures with differing task requirements, ranging from ballistic movements to sustained, goal-directed actions. Concurrently, cognitive impairments frequently manifest post-stroke, but are typically investigated and treated independently. Cognitive domains such as visuospatial, attention, language, and memory may be affected. In this study, we investigated the relationships between motor and cognitive deficits post-stroke. We hypothesized that specific cognitive domains, namely visuospatial and attention, play a crucial role in goal-directed motor actions compared to language and memory. Finally, we tested the hypothesis that common brain regions underlie both impaired cognition and motor. In this prospective study, individuals with upper limb (UL) hemiparesis were assessed 3-months post-stroke. Various outcomes measuring UL motor function: strength (grip dynamometry), manual dexterity (9-hole-peg, box&blocks ), and synergies (Fugl-Meyer) were scored. Global cognition was measured using the Montreal Cognitive Assessment (MoCA) from which four sub-scales representing visuospatial, attention, language, and memory impairment were extracted. Linear regression explored the association between global cognitive impairment and each motor outcome. Confirmatory factor analysis (CFA) created a composite motor score. This score was used to examine how each MoCA sub-scale was associated with overall UL hemiparesis. Linear regression further delved into the relationships between attentional impairments and performance on goal-directed and ballistic tasks. Voxel-based lesion-symptom mapping (VLSM) investigated brain regions associated with both attention and motor impairments. Fifty-four individuals (age 58.1±14.3, 68.5% males) with UL hemiparesis were assessed. Global cognition significantly explained variance in all motor outcomes: strength (R2=0.14, p=0.014), dexterity (9-hole-peg, R2=0.19, p=0.003; box&blocks, R2=0.22, p=0.001) and synergies (R2=0.27, p<0.001). The CFA model demonstrated a good fit (CFI=1) and global cognition significantly (p<0.001) explained 26% of variance in this composite motor score. Visuospatial (p<0.001) and attention (p=0.015) explained 24% and 13% of the variance, respectively, while language (p=0.30) and memory (p=0.18) showed no association with UL motor impairment. Attention explained significant variance in outcomes requiring goal-directed movements, 9-hole-peg (R2=0.08, p=0.05), box&blocks (R2=0.10, p=0.03) and Fugl-Meyer (R2=0.17, p=0.004) but not in the ballistic assessment of grip strength (p=0.07). VLSM revealed substantial overlap (42.93%) between injury patterns linked to attention and goal-directed motor impairments, primarily centered in cortical brain regions including the dorsolateral frontal cortex and anterior insula. Supporting our hypothesis, cognition has a substantial association with outcomes measuring motor function post-stroke. Notably, the attention sub-scale of the MoCA exhibited significant associations with performance on goal-directed motor tasks but not strength. VLSM revealed substantial overlap between injury patterns associated with attentional and motor impairments. This suggests shared neural substrates including regions specifically implicated in attentional skills. These links between cognitive and motor dysfunction, and their shared neural basis, suggest targeted interventions could enhance both functions.
Categories
Motor Rehabilitation
