Abstract
O1: Assessing Cognitive Function Following Medial Prefrontal Stroke in the Rat
1University of Ottawa, Ottawa, ON, Canada, 2Canadian Partnership for Stroke Recovery, Ottawa, ON, Canada, 3University of Toronto, Toronto, ON, Canada
Cognitive impairments are prevalent following clinical stroke. However, to date, preclinical research has focused almost exclusively on motor deficits. In order to conduct systematic evaluations into the nature of post-stroke cognitive dysfunction and recovery, it is crucial to develop focal stroke models that affect cognition while leaving motor function intact. Furthermore, in order to investigate potential cognitive post-stroke treatments, it is important that deficits are persistent in the chronic phase. This experiment was performed to evaluate a focal medial prefrontal cortex (mPFC) stroke model using a battery of tests that examined a range of cognitive functions 1-4 months following stroke. Male Sprague-Dawley rats weighing 250-300 g underwent focal ischemia induced in the mPFC using bilateral intracerebral injections of endothelin-1, or sham surgery. Beginning at 1 month post-stroke, cognitive function was assessed using open field, temporal object recognition, object-context recognition, object-placement recognition, attentional set-shifting, light-dark box, spontaneous alternation, Barnes maze, and win-shift/win-stay tests. Prefrontal cortex injury resulted in bilateral damage to the prelimbic and cingulate cortices, extending typically between 4.22 to 1.34 mm anterior to bregma. Animals that underwent stroke surgery exhibited significant changes in all object recognition functions compared to Sham animals (p<0.05). Stroke animals also exhibited impaired performance on the Barnes maze (p=0.012), and took significantly more trials to learn the second rule in the win-shift/win-stay test (p=0.013). Further, they exhibited reduced anxiety-like behaviour in the open field (p=0.049). Spontaneous alternation behaviour and locomotion in the open field were not affected. The deficits observed are consistent with some of the key characteristics of prefrontal stroke in humans. Our results show that this model produces persistent deficits in multiple prefrontal cognitive functions, and therefore may be useful for identifying and developing potential therapies for improving cognitive dysfunction in the chronic phase following stroke.
O2: Improving Walking with an Implanted Pulse Generator for Hip, Knee and Ankle Control After Stroke: A Case Report
Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA
Outcome measures included the 10m walk to assess gait speed, 6 minute timed walk to evaluate fatigue, and maximum walk to measure endurance. Assessments were repeated under three conditions: 1) volitional walking at baseline, 2) volitional walking after training, and 3) walking with stimulation after training. Comparisons include evaluating the 1) therapeutic effect (baseline volitional vs. volitional after training), 2) neuroprosthetic effect (volitional after training vs. stimulation after training), and 3) total effect (baseline volitional vs. stimulation after training).
O3: Changes in Synaptic Function and Excitability in Single Neurons Following Transcranial Magnetic Stimulation
University of Otago, Dunedin, New Zealand
Repetitive transcranial magnetic stimulation, (rTMS) can non-invasively alter the activity of neural circuits for a time outlasting the stimulation period. This has been demonstrated in some studies examining changes in peripheral motor-evoked potentials (MEPs) following application of various rTMS protocols. These prolonged changes have been attributed to the induction of synaptic plasticity. At a single neuron level however, the effects of rTMS are not well understood and the induction of synaptic plasticity or prolonged changes in cellular excitability have not been demonstrated.
Using a rat model we investigated the effects of TMS on activity characteristics of single pyramidal neurons. In vivo intracellular sharp-electrode electrophysiological recordings were made from single cortical neurons in urethane-anaesthetized Wistar rats, during the application of TMS. Spontaneous neuron activity was recorded in response to single pulse and rTMS. In addition, post-synaptic potentials (PSPs) elicited using electrical or magnetic stimulation of the ipsilateral hemisphere were investigated both pre and post rTMS.
Action potentials and PSPs were reliably obtained following single pulse TMS, delivered at intensities much lower than those used in many clinical settings. During rTMS trains, spontaneous rhythmical neuronal activity was disrupted and in some cases, neuronal firing was induced. Following rTMS, neuronal excitability was altered as indicated by lasting changes in rheobase current and spontaneous activity. Furthermore, both long term potentiation (LTP) and long term depression (LTD) were observed following particular combinations of rTMS protocols.
These results provide the first indication of the effects that both single pulse and repetitive TMS have on cortical neuron excitability and synaptic plasticity. With a better understanding of these effects it is hoped rTMS protocols may be more effectively targeted to specific neural circuits, in order to optimize clinical treatment of neurological disorders.
O4: Enhancing Cortical Representational Plasticity with Non-Invasive Direct Current Stimulation to Accelerate Upper Limb Recovery in Quadriplegia
Cleveland Clinic Foundation, Cleveland, OH, USA
Current published work suggests that a minimum of 9 months of rehabilitation is required to elicit significant improvement in upper limb function following incomplete spinal cord injury (iSCI). With over 12,500 new cases and a prevalence of 337,000 in the U.S. alone, however, such extensive rehabilitation programs are impractical. Here, we tested the hypothesis that the brain and its residual descending pathways represent the most spared, and hence ideal, innovative targets for maximizing and accelerating upper limb recovery in iSCI. In particular, since loss of representation of weaker muscles in the motor cortex exaggerates muscle weakness and limits recovery following iSCI, we aimed to boost inherent adaptive plasticity of weak representations using transcranial direct current stimulation (tDCS). We hypothesized that tDCS would accelerate increases in weak muscle cortical representational plasticity while also enhancing excitability of their descending pathways to paretic limbs to ultimately maximize functional outcomes following rehabilitation. To test our hypothesis, eight patients with chronic iSCI received either upper limb rehabilitation with tDCS (2 mA anodal) to motor cortical representations of weak muscles or rehabilitation alone. Representational plasticity was measured using TMS before and after treatment and diffusion tensor magnetic resonance imaging (DTI) quantified sparing of descending tracts. Functional recovery and muscle strength was assessed before and after treatment. We found that patients who received tDCS plus rehabilitation demonstrated significant focal increases in the cortical representation of their weaker muscle, where its excitability increased by 60% (p<0.05). Representational plasticity changes were associated with gains in motor function and muscle strength. In addition, level of recovery was related to cortical tract integrity, wherein patients that demonstrated the most recovery had greatest tract sparing following their iSCI (r=0.97; p<0.0001). Our results suggest that long-term pairing with tDCS applied to the motor cortex could result in significant functional improvements by facilitating more permanent plasticity of weaker cortical representations. Further, descending tract integrity, as measured with DTI, may serve as a valuable prognostic marker of impairment and functional recovery potential.
O5: Detection and Predictive Value of Fractional Anisotropy Abnormalities in the Acute Stroke Patients
Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
T1: Use of Inertial Sensors for Determining Kinematic Characteristics of Infant Leg Movement
University of Southern California, Los Angeles, CA, USA
Our overall goal is to use inertial sensors to determine the quantity, type and quality of infants’ leg movements performed across a full-day measurement for further use in the differentiation of infants with typical, delayed or impaired neuromotor development. Here we describe an algorithm to calculate kinematic characteristics of leg movements.
Inertial sensor data were collected from 12 infants with typical development for a period of 8-13 hours per day. There were 2 months between visits and a total of 3 visits per infant. An inertial sensor was attached to each leg, recording simultaneously accelerometer and gyroscope measurements at 20Hz. In previous work, we developed and validated a threshold-based algorithm where each pause or change of direction of the limb is counted as a discrete movement. Here we determined the duration, average acceleration, and peak acceleration of each movement. The duration of each movement was computed by counting the number of samples when the acceleration magnitude was above baseline until it crossed the baseline for a second time. Consequently, acceleration magnitude was obtained for each of these samples and average acceleration and peak acceleration of each movement was calculated.
Infants produced average movement durations that ranged from 0.23 to 0.33 seconds per movement, with average accelerations ranging from 1.59 to 3.88 m/s2 and average peak accelerations from 3.10 to 8.83 m/s2.
Our results showed that there is a range of leg movement duration and acceleration values produced by infants across visits. Future work will focus on the analysis of movement features based on the age and developmental level of infants and identification of the differences between infants with typical, delayed or impaired neuromotor development.
T2: Moving Towards Clinical Integration of Accelerometers to Measure Real-World Arm Use After Stroke
1University of British Columbia, Vancouver, Canada, 2University of Melbourne, Melbourne, Australia, 3Vancouver Coastal Health Research Institute, Vancouver, Canada, 4Latrobe University, Melbourne, Australia, 5Washington University, St Louis, USA
T3: Effect of task-specific training on Eph/ephrin expression after stroke
1Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University, Seoul, Republic of Korea, 2Department of Medical Science, School of Medicine, Konkuk University, Seoul, Republic of Korea, 3Department of Rehabilitation Medicine, School of Medicine, Konkuk University, Seoul, Republic of Korea
Stroke is the leading cause of adult disability because of the brain’s limited capacity for repair. Several processes like angiogenesis, neurogenesis, axonal reorganization and synaptic plasticity act in concert to restore eurological functions after stroke. Although some degree of spontaneous axonal sprouting occurs after stroke, regeneration of lesioned axons and formation of new connection is limited. The Eph/ephrin signaling has recently been identified to play important roles in activity dependent plasticity, angiogenesis and stem cell diffenetiation in adulthood as well as axon guidance in development.
To investigate the effect of task-specific training on Eph/ephrin expression in peri-infarct area and corticospinal tract after stroke, we compared the expression of Eph receptors and ephrin ligands in cortex and corticospinal tract between control and task-specific training group.
Rats were subjected to photothrombotic infarct. Task-specific training (single pellet reaching, 300 pellets/day or 20min/day) was initiated at 5 days post-stroke and continued for 4 weeks. Behavioral tests such as single pellet reaching test, parallel bar test and cylinder test were performed at 1 day pre-stroke, 5 days post-stroke, 1 week, 2, 3, and 4 weeks post- task-specific training. The expressions of Eph receptors (EphA2 and EphA4) and ephrin ligands (ephrinA1, ephrinA2, and ephrinA5) in the peri-infarct cortex, pyramid and spinal cord at 2 and 5 weeks after stroke were determined by Western blot analysis. Eph/ephrin expression levels after stroke were compared them after task-specific training for 1 week or 4 weeks.
Task-specific training group showed significantly better recovery in the behavioral tests. The expression level of ephrinA1, ephrinA2, and ephrinA5 in the pyramid containing corticospinal tract was increased at 2 W post-stroke. Increased ephrin A1 and ephrinA5 levels at 2 W post-stroke were decreased in ipsilateral pyramid by task-specific training for 1 W. However, increased expression levels of ephrinA1, ephrinA2, and ephrinA5 in the pyramid at 5 W post-stroke have not changed by task-specific training for 4 W.
These data suggest that task-specific training alter the expression of ephrin ligands in corticospinal tract at 2 W post-stroke. Controlling expression of ephrin ligands and task-specific training may be a promising therapeutic strategy to enhance stroke recovery.
T4: Brain-Computer Interface Assisted Stroke Rehabilitation with Multimodal Feedback
1g.tec medical engineering GmbH, Schiedberg, Austria, 2Guger Technologies OG, Graz, Austria, 3g.tec neurotechnology USA Inc., Albany, USA
A brain-computer interface (BCI) allows to analyze brain activity in order to control an avatar or rehabilitation training device. Important for a successful outcome of the rehabilitation procedure is that the mental activity is paired with the avatar movements or rehabilitation device movements.
The study was performed with two patients who had a stroke 4 years earlier (P1, female, 40 years old) or 2 month earlier (P2, female, 61 years old). P1 suffered a complete paralysis of her left hand, but had normal right hand movements. The hand performance of P2 was measured with a 9 hole PEG test and showed that the right arm needed about twice as much time to complete the test.
Both patients performed the motor imagery (MI) session by imagining left or right hand movements according to an instruction on a computer screen. Then the BCI system analyzed the EEG data and controlled an avatar hand movement on the computer screen and simultaneously controlled a functional electrical stimulator (FES) that stimulated the corresponding hand. Therefore, the patients’ could see the virtual hand movement and the real hand was simultaneously also moving.
After 10 training sessions of 30 minutes each with P1 and 21 training sessions with P2 the success of the procedure could already be shown. P2 was able to move the paralyzed hand herself without the BCI and FES and P2 could perform the 9-hole PEG test with similar speed for both hands.
This shows that the training is successful and more patients are undergoing further tests currently.
T5: Awareness Assessment and Communication Tool for Patients with Disorders of Consciousness
1g.tec medical engineering GmbH, Schiedlberg, Austria, 2Guger Technologies OG, Graz, Austria, 3g.tec neurotechnology USA Inc., Albany, USA
Up to 43% of coma patients are misclassified as vegetative when actually possessing (at least minimal) conscious abilities. EEG based Brain-Computer-Interfaces (BCI) can detect command following in patients with altered states of consciousness. In this study a BCI system was used that combines three different BCI approaches - auditory P300, tactile P300 and motor imagery (MI) - in one portable tool for bedside awareness detection and (if possible) communication with the goal to enhance correct patient classification.
The electroencephalogram (EEG) yields brain wave patterns which can be assigned to a deliberate response to external stimuli or orders. These intentionally influenced states are detected by mindBEAGLE via a Mann-Whitney U test (p<0.05) and provide information about the conscious reaction of the patient. In the case of positive results, modulating these brain wave patterns on purpose allows the patient to answer YES/NO questions for communication means. This can be done by using generic classifiers or by training patient-specific classifiers (training time: P300 ~5min, MI ~20min).
Prototypes of the BCI system have already been evaluated using healthy subjects and patients with locked-in syndrome. For patients the tactile P300 paradigm yields accuracies of 80.0% (σ 33.5%) in a two-stimulator setup (YES questions) and 55.3% (σ 27.3%) in a three-stimulator setup (YES/NO questions). The MI approach gives an accuracy of 80.7% (σ 14.4%) for healthy subjects (YES/NO questions).
With the combination of three different BCI technologies to assess awareness in coma patients, mindBEAGLE is opening doors for locked-in patients to call attention to their conscious mind state and to re-enable basic communication.
T6: Two-Week Administration of Neuropathic Pain Medications Fails to Prevent the Development of Cutaneously Evoked Autonomic Dysreflexia After High Thoracic Spinal Cord Transection in Rats
Emory University/Atlanta VA, Atlanta, GA, USA
In uninjured, pentobarbital anesthetized Long Evans rats, electrical stimulation of thoracic segmental dorsal cutaneous nerves (DCNs) generates a stimulation frequency and nociceptive afferent subtype specific cardiovascular response. To varying degrees, depressor blood pressure (BP) responses and heart rate (HR) increases are seen. We previously found that cervical (C7) spinal cord crush/incomplete injury gives rise to 3 different pathophysiological BP responses to DCN stimulation at 2 weeks, a normal-like depressor response evoked by all DCNs, a dysautonomia response where mixed depressor and pressor effects are evoked from different DCNs, and a pressor response like autonomic dysreflexia (AD) evoked by all DCNs. In all 3 injury groups, the HR increases evoked by DCN stimulation showed prolonged elevation. We also found that the severity of BP pathology is positively correlated with the extent of DCN C fiber sprouting in the dorsal horn and that the prolonged HR responses are correlated with increases in DCN A fiber sprouting there.
We have now used a complete T2 spinal cord transection model to produce consistent pressor BP and increased HR responses to stimulation across all DCNs. In this model, we have continuously (twice daily for 2 weeks following injury) administered 3 neuropathic pain medications commonly used clinically in spinal cord injury (SCI). We used an opioid (Buprenorphine, 0.05 mg/kg), a non-steroidal anti-inflammatory drug (Meloxicam, 1 mg/kg), and an anti-epileptic medication (Gabapentin, 50 mg/kg) to test the hypothesis that continuously treating “pain” could perhaps limit the development of nociception induced autonomic dysfunction after severe high thoracic SCI. Following injury and treatment, segmental DCN stimulation still generated AD cardiovascular responses with pressor BP and increased HR effects in all 3 drug groups. Buprenorphine generated even greater BP increases with caudal (T12, L1) DCN activation. We are currently evaluating whether A and C fiber sprouting in the dorsal horn of these animals tracks with our physiological findings.
T7: Sildenafil for Stroke Recovery
University of Utah, Salt Lake City, USA
T8: Targeted Memory Reactivation to Improve Motor Learning
1University of Maryland School of Medicine, Department of Physical Therapy & Rehabilitation Science, Baltimore, Maryland, USA, 2University of Maryland Sleep Disorders Center, Baltimore, Maryland, USA, 3University of Maryland Medical Center, Division of Pulmonary and Critical Care Medicine, Baltimore, Maryland, USA
T9: Centralized Open-Access Research (COAR): A Database for Stroke Rehabilitation
1Auburn University, Auburn, Alabama, USA, 2University of British Columbia, Vancouver, British Columbia, Canada, 3Washington University School of Medicine, St. Louis, Missouri, USA
Prospero Registry: CRD42014009010
T10: Exercise, Cognition and Brain Imaging in Parkinsonism - Study Design
1Oregon Health & Science University, Portland, OR, USA, 2VA Portland Health Care Systems, Portland, OR, USA
T11: Freezing of Gait in Parkinson’s Disease: A Stopping Deficit?
1Oregon Health & Science University, Portland, OR, USA, 2Portland VA Medical Center, Portland, OR, USA
Recent studies suggest that patients with Parkinson’s disease (PD) with freezing of gait (FOG) are impaired in response inhibition (e.g. Stroop task, GoNoGo task). Moreover, neuroimaging studies show that patients with FOG have loss of white matter in nodes that are part of the “stopping” network, comprising the presupplementary motor area (preSMA), right inferior frontal gyrus (rIFG) and subthalamic nuclei (STN). This network is particularly important for global stopping of motor actions as assessed in stop signal reaction tasks (SSRT). We evaluated the performance of PD patients with and without FOG on the SSRT and related stopping performance to the structural integrity of the neural stopping network.
T12: Upper Extremity Functional Evalulation by Virtual Fugl-Meyer Assessment Using Kinect in Hemiplegic Stroke Patients
1Department of Rehabiliation Medicine, Seoul National University Bundang Hospital, Seongnam-si, Gyeonggi-do, Republic of Korea, 2School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea
This research was supported by the MSIP (The Ministry of Science, ICT and Future Planning), Korea and Microsoft Research, under ICT/SW Creative research program supervised by the NIPA(National ICT Industry PromotionAgency) (NIPA-2014-(H0510-14-1014))
T13: Hebbian-Type Motor Cortex Stimulation Promotes Motor Learning in Chronic Stroke Patients
1Emory University, Atlanta, GA, USA, 2West Virginia University, Morgantown, WV, USA
After stroke of primary motor cortex (M1) or its corticospinal projections, plasticity in the peri-infarct tissue supports recovery of hand function. Transcranial magnetic stimulation (TMS) of ipsilesional M1 can enhance cortical plasticity and rehabilitative training-related motor learning. Hebbian-type TMS is a type of TMS that is administered concurrently with motor training. During Hebbian-type TMS, training movement-related increases in electromyographic (EMG) activity triggers subthreshold TMS over the M1 contralateral to the training hand in order to apply stimulation when M1 is involved in generating training movements. Because Hebbian-type TMS is more effective in enhancing motor learning than random TMS (Buetefisch et al., 2004; 2015), there is considerable interest to study the effect of Hebbian-type TMS in rehabilitative training of patients after stroke involving M1 or its corticospinal projections. Here we determine whether Hebbian-type TMS enhances motor training-related improvement of paretic hand function in chronic stroke. 16 patients (9M, 64.37±9.21 years) with impaired hand function due to chronic stroke involving M1 or its corticospinal projections participated in a randomized double-blinded placebo-controlled trial. Participants completed 5 days of motor training where they were asked to execute auditory paced wrist extension movements in a way that a cursor, encoding the movement’s velocity and angle, hit a target on a computer screen. Increases in movement-related EMG activity of the extensor carpi ulnaris muscle (ECU), a muscle supporting the training movement, were used to trigger TMS or sham stimulation. Therefore, training movements were paired with subthreshold Hebbian-type TMS (n=8) or sham stimulation (n=8) over the ECU hot spot of ipsilesional M1. The effects of the two interventions on movement kinematics (peak acceleration of wrist extension), motor function (Jebsen-Taylor Test) and M1 reorganization were determined before and immediately after and one month after training. To measure M1 reorganization we extracted the asymptote and slope-parameter of a stimulus response curve collected with TMS (range: 35%-80% stimulator output) over the ECU hot spot (Devanne et al., 1997). At baseline the treatment groups were comparable in respect to their main outcome measures. Participants who received Hebbian-type TMS experienced greater training-related changes in kinematics (acceleration=+74.73%), hand function (Jebsen=-19.84%) and cortical excitability (asymptote=+8.51%, slope-parameter=+14.34%) than those who received sham stimulation (acceleration=+32.42%, Jebsen=-8.72%, asymptote=+2.171%, slope-parameter=-14.50%). The improvement in hand kinematics and function persisted in both groups for 4 weeks. The results suggest that Hebbian-type TMS enhances training-related gains in hand function when applied to patients with chronic stroke affecting primary motor output. Greater functional improvements may be associated with a larger shift in M1 organization as indicated by increased excitability of the ECU representation. Prior to final analysis, 4 additional subjects will be recruited by August 2015 to meet our targeted number of 10 participants in each treatment group.
T14: Capturing Recovery Potential After Severe Stroke: How Individuality Drives the Need for a Multimodal Approach
1University of British Columbia, Vancouver, Canada, 2University of Melbourne, Melbourne, Australia
T15: Refinement of the PREP Algorithm for Predicting Recovery of Upper Limb Function After Stroke
1University of Auckland, Auckland, New Zealand, 2Auckland District Health Board, Auckland, New Zealand
The PREP algorithm was developed to predict the potential for recovery of upper limb function for individual patients within days after stroke. The original dataset included 40 people with first-ever mono-hemispheric ischemic stroke. This study tested the algorithm with a larger, more heterogeneous sample, in order to refine it prior to implementation in clinical practice. We recruited 85 patients with upper limb weakness within 3 days after stroke, and used the PREP algorithm to predict the level of upper limb function at 12 weeks. Assessments were made at baseline and 12 weeks, and upper limb therapy dose was recorded. Sixty-nine patients completed the 12 week assessments, and were categorised as having achieved the predicted level of upper limb function, over-achieved, or under-achieved. This dataset was then compared with the original dataset from 40 patients. There were three main findings that influenced the plan for subsequent clinical implementation of the algorithm. First, transcranial magnetic stimulation (TMS) could elicit motor evoked potentials in the paretic wrist extensor muscles of all patients with a Shoulder Abduction Finger Extension (SAFE) score of 5, 6 or 7. This means that patients with a SAFE score in this range can be given a prognosis for Notable recovery of upper limb function, without TMS assessment. This reduces the proportion of patients requiring TMS assessment from 58% to 40%. Second, a larger proportion of patients in this study under-achieved relative to their predicted level of upper limb function, compared with the original dataset (25% vs. 5%, P = 0.005). This effect was driven by patients with a Complete recovery prognosis (35% under-achieved vs. 6%, P = 0.035), as there were no differences between the groups for patients in other prognosis categories (all P > 0.2). Patient characteristics with a Complete prognosis were similar between the two datasets, except for a substantially lower recorded therapy dose in the present study (P < 0.001). A home exercise programme was implemented to increase therapy dose for patients in this category. Thirdly, we found that a higher proportion of patients in this study over-achieved, and exceeded their predicted recovery of upper limb function (17% vs. 8%, P > 0.05). While this was not statistically significant, it indicates that some patients can recover better than expected. Therefore when implementing the algorithm the prognosis is used to indicate the minimum level of function that the patient is likely to achieve, leaving open the possibility that they may exceed this level. The PREP algorithm is now being implemented in clinical practice with these modifications, with prognoses being provided to patients and therapy teams. Results of this implementation study are expected in 12 months.
T16: Post Stroke Sensory Loss is Associated Self-reported Functional Status and Changes in Gait Speed Following Intervention
Northwestern University, Chicago, Il, USA
T18: Is Infarct Location a Predictor of the Degree of Post-Stroke Motor Recovery?
1University of Ottawa, Ottawa, Canada, 2Canadian Partnership for Stroke Recovery, Ottawa, Canada
Stroke is a leading cause of neurological disability and a majority of patients have long-term motor impairments, often as a result of damage to the motor cortex and/or striatum. While both humans and animals show spontaneous recovery following stroke, little is known about how injury location affects the recovery process. This information is essential in order to develop new therapies to enhance recovery.
In this study we used endothelin-1 (ET-1), a potent vasoconstrictor, to produce focal infarcts in the forelimb motor cortex, the dorsolateral striatum or both the cortex and striatum in male Sprague-Dawley rats. The spontaneous recovery profile of the animals was followed over an 8-week period using four behavioural tasks assessing motor function and limb preference to identify how recovery varies depending on injury location. Infarct volumes were derived from MRI 72 hours post-stroke.
All three models resulted in functional deficits on the Montoya staircase (p < 0.002), beam (p < 0.017), and cylinder (p < 0.001) tasks but no significant impairments were seen in the adhesive removal task. The three groups demonstrated distinct patterns of recovery on the behavioural tasks with the combined cortical plus striatal group having the largest and most persistent impairments overall. There were no significant differences between groups for total hemispheric infarct volume.
These results suggest that damage to the striatum is an important predictor of the level of post-stroke motor impairment. Moreover, the pattern of recovery is not simply dependent on lesion volume but on lesion location and the behavioural test employed. All three models produce sustained motor impairments that will be valuable in assessing novel, adjunctive post-stroke therapies.
T19: Sensory-Driven Motor Recovery in Poorly Recovered Subacute Stroke Patients
1University of Kentucky, Lexington, KY, USA, 2Cardinal Hill Hospital, Lexington, KY, USA
Stroke continues to be a major public health concern in the United States. Therapeutic interventions after stroke can support motor recovery by capitalizing on neuroplastic change (reorganization of the central nervous system). Intensive, task-oriented motor training is an example of an intervention that aligns with principles governing neuroplastic change. While this type of training has been shown to effect neuroplastic change and improve motor function in stroke survivors with mild to moderate motor deficit, no proven benefit has emerged in cases of severe motor deficit (ie, virtually no wrist and finger movement). On the other hand, several lines of evidence indicate that sensory input can drive neuroplastic change and that manipulating sensory input via peripheral nerve stimulation (PNS) can enhance outcomes of motor training. Here, we report on our pioneering evidence that in cases of severe motor deficit after stroke, PNS can enhance outcomes of intensive, task-oriented training. In this double-blind, sham-controlled, randomized study, 71 subjects with subacute stroke (ie, 3-12 months from stroke onset) received 2 hours of PNS immediately prior to 3 hours of intensive, task-oriented training (18 sessions total). PNS condition (active versus sham) was the only independent variable. We evaluated motor performance according to the upper extremity motor score of the Fugl Meyer Assessment (FMA) score at baseline; immediately after completion of the total intervention period; and at 1- and 4-month follow-ups. Results indicated that active PNS can enhance outcomes of motor training significantly more than sham PNS. Also, only the active PNS group had continuous improvement evident at all longitudinal follow-ups. Our forthcoming analysis of data collected via transcranial magnetic stimulation will substantiate potential correlations between neuroplastic change and motor performance change. The overall impact of this study is to help expand effective rehabilitation options for stroke survivors with highest need. Our long-term goals include enhancing the translational potential of this paired intervention (ie, development of portable PNS for clinic and home use; streamlining PNS protocols for time-sensitive environments, such as home exercise or reimbursement-dependent settings).
T21: Does the Attentional Status Affect the Efficacy of the Neurofeedback-Based Rehabilitation?: Preliminary Analysis Using Functinoal-NIRS-Mediated (Neurofeedback) System Neural Repair Mechanisms
1Morinomiya Hospital, Osaka, Japan, 2Osaka University, Suita, Osaka, Japan
T22: Effectiveness of Active Pedaling Combined with Sensory Electrical Stimulation on Gait Performance in Subacute Stroke Patients: A Multicenter, Sham-Controlled Randomized Controlled Trial
1Nishiyamato Rehabilitation Hospital, Kanmaki-cho, Nara, Japan, 2Kio University, Koryo-cho, Nara, Japan, 3Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan, 4Kishiwada Eishinkai Hospital, Kishiwada-shi, Osaka, Japan, 5Kawamura Hospital, Gifu-shi, Gifu, Japan, 6Sumiya Rehabilitation Hospital, Wakayama-shi, Wakayama, Japan, 7Wakayama Physical Therapy College, Wakayama-shi, Wakayama, Japan, 8Terashita Hospital, Wakayama-shi, Wakayama, Japan, 9Kyowakai Hospital, Suita-shi, Osaka, Japan, 10Tokyo Bay Rehabilitation Hospital, Narashino-shi, Chiba, Japan
T23: Prevalence of Growth Hormone Deficiency in Chronic Traumatic Brain Injury
Centre for Neuro Skills, Bakersfield, CA, USA
This study examined the prevalence of growth hormone deficiency (GHD) in patients with traumatic brain injury (TBI) during the post-acute phase of recovery and whether GHD was associated with increased disability, decreased independence and depression. A secondary objective was to determine the accuracy of insulin-like growth factor-1 (IGF-1) levels in predicting GHD in patients with TBI. Anterior pituitary function was assessed in 235 adult patients with TBI through evaluation of fasting morning hormone levels. Growth hormone levels were assessed through provocative testing, specifically the glucagon stimulation test. GHD was diagnosed in a significant number of patients, with 45% falling into the severe GHD (<3 ug/L) category. IGF-1 levels were not predictive of GHD. Patients with GHD were more disabled and less independent compared to those patients who were not GHD. Those patients with more severe GHD also showed decreased levels of cortisol and testosterone. Symptoms of depression were also more prevalent in this group. In addition, patients with severe GHD had delayed admission to post-acute rehabilitation. This study confirms the high prevalence of GHD in patients with TBI and the necessity to monitor clinical symptoms and perform provocative testing to definitively diagnose GHD.
T24: Study Design: Identifying Carpal Tunnel Syndrome in Stroke Recovery using Ultrasound
Duke University, Durham, NC, USA
Patients will undergo median nerve US of bilateral median nerves, performed by trained personnel in the Duke Electromyography Laboratory, where this testing has been offered as a standard service since 2006. Our primary outcome is evidence of CTS on ultrasound, based upon pre-existing laboratory established normative values. Median nerve CSA (cross sectional area) at the distal wrist crease of 10-12mm2 will be considered at risk for CTS, while values >12mm2 and a ratio of median nerve CSA at the wrist/median nerve CSA at the forearm of >1.5 are considered consistent with CTS. The presence of intraneural blood flow will also be recorded as normal or increased. All abnormal US results will be referred back to the subject’s primary neurologist for management, including if additional electrodiagnostic tests are warranted versus treatment.
Our secondary outcome will be based on change in patient reported functional status. Patients will complete the Boston Carpal Tunnel Questionnaire (BCTQ), a widely-used self-reported functional status and symptom severity scale at baseline and during follow-up visits. Our goal enrollment is 20 patients for each study group for a goal of 80 patients. We anticipate completion of enrollment and preliminary data of hospitalized patients by October 2015.
T25: Comparing Stimulation of Bihemispheric Motor Sites on a Reaching Task in Mild and Severe Arm Impairment After Stroke
1Georgetown University, Washington, DC, USA, 2Medstar National Rehabilitation Hospital, Washington, DC, USA, 3Medstar Health Research Institute, Washington, DC, USA, 4George Mason University, Fairfax, VA, USA, 5Veterans Affairs, Washington, DC, USA
Stroke affects over 610,000 people in the United States every year and many are left permanently disabled. Chronic poststroke arm impairment is particularly disabling and existing treatments are of limited efficacy. There are sites in each hemisphere that it may be beneficial to “prime” in order to enhance the effects of a subsequently applied rehabilitation treatment . One such region is the dorsal premotor cortex (PMd). Previous research demonstrates that PMd has a role in motor control of the ipsilateral arm, direct ipsilateral and contralateral projections to the spinal cord, and the ability to flexibly compensate for asymmetries in function between hemispheres. The role of PMd in poststroke arm impairment, how it may differ from that of other cortical areas and with severity of poststroke arm impairment is not known. The hypothesis are that nlPMd, not lPMd, has a greater role in recovered reaching function in severe more than mild patients and that nlPMd, but not nlM1, has a greater role in recovered reaching function in severe patients.
30 individuals with (n=15) or without (n=15) active wrist and finger movements after poststroke arm impairment participated in a reaching task. Participants were asked to reach as quickly as possible with the affected arm to one of the targets in response to a visual ‘Go’ signal. TMS was applied between the ‘Go’ signal and movement onset. Doublepulse TMS (ISI 25 ms) was delivered to nlM1, nlPMd and lPMd at 120% of the individual’s Resting Motor Threshold (RMT) for unaffected biceps.
Change in movement time was greater with TMS applied to nlPMd than to lPMD in the severely impaired but not mildly impaired participants. A trend in the data shows an interaction effect between severity and hemisphere. Within only the severe group, change in movement time was greater with TMS applied to nlPMd but not to nlM1. Data suggest that nlPMd has a greater role in recovered arm reaching in severely impaired patients than lPMd and that this effect is not present in mildly impaired patients. Additionally, data show that this is not an effect of the contralesional hemisphere as a whole, but a site specific effect to nlPMd as shown through comparison with disruption of nlM1. This study evaluates the role of nlPMd in recovery of arm function. The results of this study lay the foundation to explore nlPMd as a potential site for upregulation as an adjuvant to traditional therapy in severe patients after stroke. Identification of sites to enhance rehabilitation outcomes of severe patients are essential as there are no currently validated treatments and longterm disability is costly to both personal quality of life and national health care costs.
T26: A Constrained Motor Connectome Characterizes Post-Stroke Upper Extremity Motor Function
University of British Columbia, Vancouver, BC, Canada
T28: Impact of Motor Practice on Neuromodulation for Stroke Rehabilitation
1Indiana University, Indianapolis, IN, USA, 2Indiana Center for Advanced Neurorehabilitation, Indianapolis, IN, USA
Neuroplasticity is an important factor for upper-extremity stroke rehabilitation. Recent trends in stroke rehabilitation research have focused on influencing neuroplasticity with neuromodulatory techniques such as repetitive transcranial magnetic stimulation (rTMS) and coupling those with motor practice. However, the amount of neuromodulation achieved with an acute session of motor practice is not fully characterized. The objective of this pilot study was to determine how engaging in motor practice with a similar time sequence as a rTMS intervention influences motor control, dexterity, and neuromodulation. Five survivors of stroke participated in this pilot study with a mean age of 60.4 (range 43-84). Each participant completed a motor practice intervention protocol with their stroke-affected arm and hand including 30 bouts of isometric contractions in a customized wrist device for 6 seconds followed by a 30 second rest. Assessments included force steadiness and electromyography during a wrist extension task, the Box and Block Test (BBT), and transcranial magnetic stimulation (TMS) before and after the intervention. The force steadiness task was two trials of at least 10 seconds at 5, 10, and 20% of the maximum voluntary contraction. The BBT is a measure of dexterity assessed as the number of small blocks moved in a minute. The TMS measures included 12 stimulations each at suprathreshold test stimulus (TS, 116% of resting motor threshold), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) with motor evoked potentials (MEP) recorded from the extensor carpi radialis (ECR) and extensor carpi ulnaris (ECU) muscles. Data were analyzed with a paired t-test. The variability of force steadiness decreased following the intervention for the 5 and 20% conditions (p < 0.05). Muscle activity increased from pre-test to post-test with significant increases during the 10% condition (p = 0.04) and a trend during the 5 and 20% conditions (p = 0.06, and 0.05, respectively). Participants were able to move significantly more blocks with their stroke-affected hand following the intervention (p < 0.02), but no changes were observed with the less-affected hand (p = 0.3). TMS data was only collected on three subjects. Two of the subjects had increases in MEP amplitude of the TS only stimulations and all three subjects had more inhibition (SICI). These results suggest that a short intervention of isometric wrist extension can influence motor control, dexterity, and neuromodulation. This demonstrates the importance of better understanding how possible rehabilitation interventions contribute to influencing neuroplasticity and promoting greater functional improvements.
T29: Bilateral vs. Unilateral Therapy for Chronic Stroke Patients with Varying Degrees of Motor Impairment: A Crossover Repeated-Measures Design of Neurophysiologic Response
1Cleveland Clinic, Cleveland, Ohio, USA, 2Kent State University, Kent, Ohio, USA, 3Case Western Reserve University, Cleveland, Ohio, USA
T31: Improved Upper Limb Skilled Functional Task Performance is Predicted by Mitigated Spasticity in Response to Intensive Motor Learning Therapy in Chronic Stroke Survivors
1Case Western Reserve University, Cleveland, OH, USA, 2Cleveland VA Medical Center, Cleveland, OH, USA, 3McKnight Brain Institute, University of Florida, Gainesville, FL, USA, 4Brain Rehabilitation Research Center of Excellence VA Medical Center, Gainesville, FL, USA
T32: Contralaterally Controlled Functional Electrical Stimulation and Hand Therapy Video Games for Cerebral Palsy
1Case Western Reserve University, Cleveland, OH, USA, 2Cleveland FES Center of Excellence, Cleveland, OH, USA, 3Cleveland Clinic Children’s Hospital for Rehabilitation, Cleveland, OH, USA, 4MetroHealth Rehabilitation Institute of Ohio, Cleveland OH, USA
Contralaterally Controlled Functional Electrical Stimulation (CCFES) is a unique form of neuromuscular electrical stimulation that allows children to control the timing and amount of hand opening. A sensor glove is worn on the unimpaired hand that proportionally controls stimulation to surface electrodes on the extensors of the paretic hand. Stimulation is configured so that paretic hand opening mirrors that of the unimpaired hand. This allows children to use CCFES to assist their paretic hand while playing video games.
We developed four hand therapy video games that are controlled by impaired hand opening/closing. Each game trains different motor skills and is designed to engage children in goal-oriented training that require motor planning, control, and concentration.
Paddle Ball trains control of graded hand opening. A paddle’s vertical position is controlled by hand aperture. Difficulty is adjusted by changing paddle size and ball speed. Performance feedback is provided by score, hit rate, and motor repetitions.
Skee Ball trains control of hand opening speed. Players launch balls toward rings at speeds proportional to hand opening rate. Rings move, requiring control of hand opening speed. Difficulty is adjusted by changing ring size. Performance feedback is provided by score, accuracy, and motor repetitions.
Marble Maze trains maintenance of hand opening. Players rotate mazes to guide marbles out - often needing to hold the maze still while marbles roll. Maze rotation is proportional to hand opening angle. Difficulty is adjusted by bucket size and adding concurrent marbles. Performance is provided by completion time.
Sound Tracker trains continuous precise hand opening. Players control a cursor’s vertical motion with hand opening/closing to follow a path generated by a series of songs. Difficulty is adjusted by track width and new songs are presented with 90% accuracy. Performance feedback is provided by accuracy.
T33: Connections Between Posterior Parietal and Sensorimotor Cortices Predict Postural Adaptation in People with Multiple Sclerosis
1Oregon Health & Science University, Portland, Oregon, USA, 2VA Portland Healthcare System, Portland, Oregon, USA
T34: Activation Training Alters Corticomotor Excitability of the Gluteus Maximus
1University of Southern California, Division of Biokinesiology and Physical Therapy, Los Angeles, USA, 2Healthy Aging Center, Chang Gung University, Taoyuan, Taiwan
T35: Methodological Study to Identify Trunk and Hip Muscle Representation in Motor Cortex
usc, los Angeles/ CA, USA
T36: The Efficacy of Wii-Based Movement Therapy Upper-Limb Rehabilitation in Chronic Stroke is Accompanied by Ancillary Cardiovascular Benefits
1Neuroscience Research Australia, Sydney, NSW, Australia, 2UNSW Australia, Sydney, NSW, Australia, 3St Vincent’s Hospital, Sydney, NSW, Australia
Financial constraints in the health sector make the search for more effective and efficient post-stroke rehabilitation more urgent. Wii-based Movement Therapy (WMT) uses the Nintendo Wii and Wii Sports as a tool in a structured 14-day rehabilitation program that targets movement quality of the more-affected upper-limb and increased independence in activities of daily living. We compared dose-matched trials of Wii-based Movement Therapy (WMT) and modified Constraint-induced Movement Therapy (mCIMT) in two studies, i) an assessor-blinded randomised controlled trial of upper-limb therapy efficacy with 42 patients 2-46 months post-stroke; and ii) a post hoc analysis of the cardiovascular benefits of therapy in 46 patients receiving either WMT (n=29) or mCIMT (n=17) from 3-264 months post-stroke (mean 34.8±9.3 months) of whom 28 were studied during the RCT. Primary outcome measures for the RCT were the Wolf Motor Function Test timed-tasks (WMFT-tt) and Motor Activity Log Quality of Movement scale (MALQOM) assessed at pre-baseline (14-days pre-therapy), baseline, post-therapy, and 6-month follow-up. Patients in the cardiovascular study were assessed in the same way with the addition of peak heart rate (HRpeak) and heart rate recovery (HRR) measured during therapy sessions at early (day 2) and late (~day 13) therapy. There were no adverse events. For the RCT there were no differences at any time point between groups for the primary outcome measures. Motor-function was stable between pre-baseline and baseline assessments (p>0.05); improved with therapy between baseline and post-therapy (p<0.001); and these improvements were sustained at 6 months (p>0.05). WMFT-tt log times improved from 2.1 (1.5-2.7) to 1.7 (1.1-2.3) s after WMT and 2.6 (1.9-3.2) to 2.3 (1.7-3.0) s after mCIMT. MALQOM scores improved from 67.7 (51.1-84.4) to 102.4 (84.4-120.3) and from 64.1 (43.6-84.5) to 93.0 (76.5-109.5), respectively (mean, 95% confidence intervals). HRpeak was higher during mCIMT than WMT, but increased by late-therapy only for the WMT group (p<0.001). Similarly, HRR was always faster for mCIMT but changed significantly by later-therapy only for the WMT group (p=0.037). These data suggest that WMT provides a cardiovascular challenge that improves the cardiovascular fitness of stroke patients in the chronic phase whereas mCIMT induces a cardiovascular stress response. Patient preference and acceptance for WMT were higher than mCIMT with higher levels of sustained therapeutic activities at 6 months. Patients in the WMT cohort reported fewer falls, and greater levels of physical activity and social engagement at 6 months. This study demonstrates that WMT is as effective as mCIMT for upper-limb rehabilitation and increased independence in everyday life but WMT alone confers a cardiovascular benefit. WMT can be implemented across a broad spectrum of post-stroke impairment to provide prolonged therapy intensity and increased physical activity.
T37: Optimal Timing for Combined Neuromodulation Techniques to Enhance Motor Training in Chronic Stroke with Severe Motor Deficit
1University of Kentucky, Lexington, KY, USA, 2Cardinal Hill Rehabilitation Hospital, Lexington, KY, USA
Peripheral nerve stimulation (PNS) and transcranial direct current stimulation (tDCS) are neuromodulation techniques that can increase neuroplasticity and aid in motor recovery after stroke. Only a few studies to date have investigated the effects that tDCS combined with PNS has on outcomes of motor training after stroke. In these studies, the tDCS protocol overlapped with the end of each PNS session. It is conceivable that delivering tDCS at the start (rather than the end) of a PNS session would enhance the effects of PNS. Alternatively, delivering tDCS at the end of PNS could be optimal due to motor training taking place while the motor cortex is still depolarized from tDCS. Because no studies have investigated alternate timing configurations of tDCS combined with PNS, we conducted a proof-of-concept study in which subjects with severe post-stroke hemiparesis received 2 hours of PNS and 20 minutes of anodal tDCS concurrently. tDCS was delivered according to 1 of 2 timing configurations: 1) during the first 20 minutes of PNS (“Start” group; n=4); or 2) during the last 20 minutes of PNS (“End” group; n=6). All subjects received 2 hours of robotic-assisted upper extremity motor training immediately following stimulation. We hypothesized that the “Start” group would have greater improvements in motor function than the “End” group. Outcome measures, taken 1-7 days before starting interventions, and again at 1-7 days after completing interventions, included the upper extremity motor score of Fugl-Meyer Assessment (FMA), Stroke Impact Scale (SIS), and cortical map volume as measured by transcranial magnetic stimulation. We analyzed data using an independent sample t-test. Results indicated modest improvements in FMA for both groups, with slightly greater improvements in the Start group. Though SIS scores improved in both groups, there was a trend towards significantly greater improvement for the Start group compared with the End group (p=0.062). Cortical map volume for both hemispheres decreased in the End group, while both increased slightly in the Start group. These results suggest that delivery of tDCS at the start of PNS offers more benefit than tDCS at the end of PNS. A possible explanation is that tDCS at the end of PNS overstimulates the cortex, thus negating potentially therapeutic effects of neuromodulatory intervention. A larger study is needed to substantiate these preliminary results.
T38: Biomarkers of Stroke Recovery Study (BIOREC) Methodology
1Georgetown University, Washington, DC, USA, 2National Rehabilitation Hospital, Washington, DC, USA
Efforts to improve recovery from stroke are currently limited by a poor understanding of neural injury and repair mechanisms in humans. Here we describe the methodology for the Biomarkers of Stroke Recovery Study (BIOREC), designed to identify potential molecular markers of neural injury and repair in humans. In this pilot study, we capitalize on recent advances in the field of metabolomics to gain a window into neural remodeling after stroke. These advances have made it possible to accurately detect tiny metabolites, many of which pass through an intact blood-brain-barrier. Subjects in BIOREC undergo blood draws at 5, 15, and 30 days post-stroke - a time period during which the majority of neural recovery occurs based on stroke recovery curves. We also carefully measure functional recovery at 5, 15, 30, and 90 days post-stroke using tests of motor, speech, and cognitive abilities. Motor testing includes the upper extremity Fugl-Meyer (UE-FM), nine-hole peg test, and kinematics using the Zebris 3D-motion detector. Inclusion criteria, which are strict to reduce blood sample variability, include ischemic middle cerebral artery stroke larger than 25cc on neuroimaging, age 50-70, pre-stroke mRS < 2, and presumed cardioembolic source. BIOREC recently received IRB approval and will start recruitment at MedStar Georgetown University Hospital and MedStar Washington Hospital Center in Washington, DC. We anticipate 1 year to reach our recruitment goal of 24 stroke patients and an equal number of age-matched controls. Blood samples will be analyzed at study conclusion. BIOREC will identify novel metabolites that have a different concentration in the blood of stroke patients in comparison to age-matched controls. We suspect that metabolite changes detected early after stroke (day 5) will primarily reflect neural injury, while those detected late (day 15, 30) will reflect neural repair. This hypothesis will be tested in a larger follow up study aimed at linking specific metabolite changes with good and poor recovery using UE-FM as the primary outcome measure. This work was supported by grant 1U10NS086513-01.
T39: Investigating Dynamics of Motor Evoked Potentials During Isometric Contraction
1University of Maryland School of Medicine, Baltimore, MD, USA, 2University of Maryland Rehabilitation & Orthopedic Institute, Baltimore, MD, USA, 3University of Maryland Pepper Center, Baltimore, MD, USA, 4VA Maryland Health Care System, Baltimore, MD, USA
The amplitude of muscle potentials evoked by transcranial magnetic stimulation is often used to describe the overall state of the corticomotorneuronal system. Paired-pulse stimulation evokes potentials that allow exploration of inhibitory effects on motor cortical effectiveness. In order to tease out the effect of a behavioral condition on paired-pulse evoked potentials, it then becomes necessary to attempt to adjust for the effects of the behavior on the test and conditioning evoked activity separately. This is most often done by adjusting the stimulation intensity to match motor evoked potential amplitudes across behavioral conditions. While this method of adjustment is well established, it is limited by the presumption that the behavioral condition, such as voluntary muscle contraction, has linearly correlated effects on test and condition evoked potentials. It may also be practically difficult to match stimulus responses across non-linear recruitment curves. To overcome this limitation, we have developed a method by which a recruitment curve across stimulation intensities for one muscle is defined first, and then paired pulses are applied across stimulation intensities for both conditioning and test evoked potentials. These recruitment curves, taken at both rest and during isometric muscle contraction, can be compared, controlling for respective changes in evoked potentials and behavioral condition. This method allows us explore the dynamics of interhemispheric inhibition during unimanual isometric muscle contraction.
T40: Intensive Home-Based Prism Adaptation Treatment for Chronic Spatial Neglect: A Case Study with Bilateral Lesions
Kessler Foundation, West Orange, New Jersey, USA
Prism adaptation is a visuomotor phenomenon resulting from goal-directed limb movements toward visual stimuli while the entire visual field is shifted by prism lenses. The adaptation requires no top-down strategy and occurs automatically. Since 1990, rehabilitation researchers found prism adaptation a promising approach to treat spatial neglect. With damage primarily in the right hemisphere, affected individuals pay no or incomplete attention to the left side of the space. Candidates for prism adaptation treatment (PAT) are individuals with intact right medial temporal regions and no cerebellar lesion. However, because almost all the previous studies included only individuals with unilateral right brain damage, it is unknown whether PAT is beneficial for individuals with bilateral lesions, and the present study was designed to explore on this question.
In this study, a 69-year-old man with chronic left-sided neglect (34 months post right-brain stroke and 46 months post left-brain stroke) underwent a month-long intensive home-based PAT. The patient’s spouse was thoroughly trained to perform two PAT sessions daily on every weekday for four weeks. In the intervention period, we called the patient’s spouse weekly, and she kept a daily log recording the activities performed during each 20-min session. We assessed the patient using line bisection, Bells Test, and figure copying repeatedly on 5 consecutive days before and after PAT. In addition to paper-and-pencil outcome measures, we also included Barthel Index (BI) and Kessler Foundation Neglect Assessment Process (KF-NAP), and diffusion tensor imaging (DTI) scans before and after PAT. The patient had extensive lesions in the calcarine sulcus and lingual gyrus in the left hemisphere, and lesions from the middle frontal gyrus to the middle occipital gyrus inclusive of the superior and middle temporal gyrus, insula and caudate in the right hemisphere.
After the PAT, the patient showed improvement in line bisection (rightward bias changed from 24.2±3.4 to 10±4.2 mm, t test: p = .030), but not in Bells test (p = .850) or figure copying (p = .152). His BI scores did not change (60 pre and post-treatment). His KF-NAP scores improved from 14 to 11 but remained in the range of moderate severity. His DTI images, however, showed that diffusion in the posterior region of corona radiata changed from dorsal-ventral to anterior-posterior direction in the left hemisphere.
The present study suggests that PAT may not generate clinically meaningful improvement in individuals who had bilateral brain lesions involving regions as extensive as this case. However, the intensive PAT intervention may lead to structural changes in the relatively intact hemisphere. Further follow-ups are necessary to examine whether such changes persist over time and even promote behavioral changes.
T41: Condition-Specific Deficits in Intersegmental Coordination After Stroke
1School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada, 2Jewish Rehabilitation Hospital, Centre for Interdisciplinary Research in Rehabilitation in Greater Montreal Area (CRIR), Laval, QC, Canada, 3Bachelor in Neuroscience, McGill University, Montreal, QC, Canada, 4School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada, 5Department of Neuroscience, University of Montreal, Montreal, QC, Canada, 6School of Rehabilitation Sciences, University of Ottawa, Ottawa, ON, Canada, 7Elisabeth Bruyere Hospital, Ottawa, ON, Canada
Stroke leads to deficits such as weakness, spasticity and incoordination affecting upper-limb reaching. Reaching is also affected by stroke-related postural control problems characterised by an increase in lateral deviations of the centre of pressure (evaluated with Limits of Stability (LoS) index). Deficits in the coordination of a redundant number of degrees-of-freedom (DFs) of the body (excess DFs), may also affect reaching. We characterised reaching ability of both arms, with and without the involvement of additional trunk DFs in patients with chronic stroke (18-75yrs; Fugl-Meyer Assessment (FMA): 54.0±12.5/66; Reaching Performance Scale for Stroke (RPSS): near=15.6±2.9/18; far=15.7±3.0/18 target) and Chedoke Arm and Hand Activity Inventory (CAHAI): 47.4±12.8/63) compared to healthy age-matched controls.
Kinematics of two arm tasks involving a target located at 66% arm length were recorded in seated subjects without vision: stationary-task (maintaining finger above target) and reaching-task, while leaning the trunk forward (total of 40 trials). For each task, in 40% of trials, trunk movement was unexpectedly blocked such that movements were made with and without trunk involvement. LoS in sitting was measured in 8 directions separated by 45° intervals using a force-plate. The primary outcome measures were gain (G) for stationary-task defined as the degree to which the potential contribution of trunk displacement to hand motion was compensated by appropriate changes in arm DFs (G=1: complete compensation, G=0: no compensation); and endpoint position difference in reaching-task. Comparisons were made with Mann-Whitney U tests. Clinical measures and LoS area were correlated with primary outcomes.
G of more-affected arms was lower (G=0.49±0.19) compared to less-affected arms (G=0.69±0.14; U=20.5, p=0.02) and controls (G=0.74±0.16; U=7.00, p=0.04). There was no correlation between the more-affected arm G and FMA, CAHAI, LoS area. Endpoint position differences were similar between groups but those of the more-affected arms correlated with FMA (r=-0.76), RPSS (near: r=-0.85, far: r=-0.87) and LoS area (r=0.71).
Stroke affects the ability to compensate for additional trunk movement when the hand is held stationary. During reaching, excessive trunk movement compensates for deficits in upper limb motor function. Patients with stroke have deficits in condition-specific adjustment of intersegmental coordination. Understanding motor control deficits in managing redundant DFs will help clinicians develop targeted interventions to improve upper limb reaching ability in individuals with stroke.
T42: Temporal and Spatial Upper-Limb Interjoint Coordination in Chronic Stroke Subjects Versus Healthy Individuals When Reaching
1School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada, 2Feil and Oberfeld Research Center, Jewish Rehabilitation Hospital, Center for Interdisciplinary Research in Rehabilitation of the Greater Montreal (CRIR), Laval, QC, Canada, 3Department of Rehabilitation, Laval University, Quebec, QC, Canada, 4Faculty of Medicine, McGill University, Montreal, QC, Canada
Movement coordination which plays a major role in upper-limb(UL) functionis commonly affectedafter stroke. We assessed UL interjoint coordination (IJC) deficits in people with stroke compared to age- and gender-matched healthy subjects and the influence of these deficits on the performance of a simple reaching task. UL kinematics were recorded using 28 markers on the arm, trunk, nose and target (Optotrak, 30s, 100Hz). Two trials of 10 movements each in which subjects (n=20) alternatively touched their nose and a target (ReachIn; ReachOut) located at 90% arm-length, as fast as possible were recorded for each arm. Healthy subjects (n=20) made the same reaching movementsat self-paced and slow speeds to match speeds of stroke subjects. Data for movements in each direction were analyzed to determine relationships between time to perform the task and arm and trunk kinematics. The relationships between temporal and spatial IJC kinematic measures and clinical scores were determined.Compared to healthy subjects, stroke subjects made more curved endpoint trajectories (Index of curvature: stroke=1.23, control=1.04, p <0.05, ReachIn) and used less shoulder horizontal abduction (stroke=11.8º, control=17.6º, p <0.001, ReachIn).Stroke subjects moved their affected arm slower than their less-affected arm (ReachIn: 18%, ReachOut: 43%; for both directions F=14.136, p<0.001) and had more curved trajectories (ReachIn: 18%, ReachOut: 27%; for both directions F=6.003, p<0.05).Interjoint coordination was similar between the two arms. Stroke severity was moderately correlated with endpoint speed (r=-0.55, p=0.006) and straightness (r=-0.47, p=0.018) but not precision. Time to perform the task correlated with endpoint straightness (r=0.77, p=0.001), temporal (r=0.63) and spatial (r=-0.61) interjoint coordination. Shoulder horizontal abduction range (β=0.127), temporal (β=0.855) and spatial (β=-0.191) interjoint coordination explained 82% of the variance in the time to perform the task. Shoulder movement and temporal and spatialinterjoint coordination were predictive of the time to perform the task, indicating the influence of UL joint configuration limitation for the performance of reaching movements after stroke.
T43: Motor Equivalence During Whole Body Reaching In Healthy Young Adults
1McGill University, School of Physical and Occupational Therapy, Montréal, Canada, 2Center for Interdisciplinary Research in Rehabilitation (CRIR)-Jewish Rehabilitation Hospital, Laval, Canada, 3Université de Montréal, Département de neuroscience, Montréal, Canada
The large number of kinematic degrees of freedom (DFs) of the body allows tasks to be accomplished using different combinations of DFs (motor equivalence). Despite this redundancy, certain movement features remain invariant. For example, hand trajectory and endpoint precision remained invariant when trunk movement was unexpectedly blocked during reaching from a sitting position. We hypothesized that hand trajectory and endpoint precision may remain invariant regardless of unexpected postural perturbations during whole body reaching from standing, which involves a larger number of DFs. Five healthy young subjects moved the hand to a remembered target located beyond the arm length with their eyes closed during standing (Free-Hip trials; FH). In randomly chosen trials, hip flexion was unexpectedly prevented by an electromagnetic device, forcing the subject to take a step while reaching (Blocked-Hip trials; BH). Reaching movements were also recorded when subjects intentionally made a step (Intentional-Step trials; IS). Upper/lower limb and trunk kinematics and ground reaction forces were recorded. Endpoint trajectory, joint kinematics and shifts in the postural center of pressure were analysed. Reaching trajectories and endpoint precision were invariant between FH and BH trials, while those of IS trials in some subjects differed. Invariance in the endpoint trajectory between FH and BH trials was maintained by changes in elbow/shoulder interjoint coordination patterns which occurred after the time of endpoint peak velocity. Stepping reactions resulting from the perturbation were also initiated after the time of the endpoint peak velocity in BH trials. Thus, unexpected recruitment of additional DFs that challenges postural stability during reaching from a standing position did not affect hand trajectories and endpoint precision. Movement adaptation occurred after the endpoint peak velocity to maintain invariance in endpoint trajectories, confirming our hypothesis that the nervous system can take advantage of the redundancy in the number of DFs to stabilize task performance, resulting in motor equivalence.
T44: Effects of Positioning Exercise On Locomotor Function After Contusive Spinal Cord Injury in Rats
1College of health science, Korea University, Seoul, Republic of Korea, 2Collge of Medicine, Korea University, Seoul, Republic of Korea, 3Department of Public Health Science, Graduate School of Korea University, Seoul, Republic of Korea
Rehabilitation exercise has been applied to prevent the progress of sensorimotor impairments in patients with spinal cord injury (SCI). In particular, most of all mainly have been focused in the effect of locomotion training. However, the effects of other rehabilitation approaches applied in patients with SCI except for locomotion training are still unclear and thus investigation for additional approaches is needed. Thus, we examined the effects of passive stretching exercise (SE) and positioning training (PT) on recovery of locomotor function. Spinal contusion was made in male Sprague-Dawley rats using NYU impactor on T12 spinal cord under anesthesia. Rats were randomly assigned to SE (n=10), PT (n=9), combined SE and PT (C, n=10) and no exercise (control, n=9). SE applied 6 muscles on hindlimb for 1 minute in each motion alternately side repeated 2 sets. PT held quadripedal posture with plantar contact for 30 min. C performed 1 set of SE and 15 min of PT. These interventions were applied 5days/week for 4weeks. Locomotion recovery was assessed by BBB open field locomotor scale and combined behavior score (CBS). Hypersensitivity after SCI was evaluated by paw withdrawal threshold (PWT) with up - down method. Average, maximum speed and travelled distance that reflect the ability of physical activity were measured by using Panlab’s smart tracking system. Luxor fast blue and cresyl violet staining was used to measure areas of cavities on epicenter.
In the PT group, BBB was significantly increased at 10, 11, 12 and 13 days after SCI, and CBS also significantly decreased at 10, 11 and 12 days after SCI compared to control. BBB and CBS in the PT group slightly increased compared to them in the SE group during intervention.
PWT in the PT group was significantly increased from 18 days to 28 days than it in the control. In all rehabilitation exercise groups, values of physical activities showed increased tendency on chronic stages and then only maximal velocity in the PT group were significantly faster than control group. Areas of epicenter cavity were no difference between each group.
These results suggest that SE was no effect to locomotion recovery whereas PT with manually partial support may be more helpful than SE to recovery of locomotor function and hypersensitivity after SCI. This study suggests positive potential for therapeutic exercise to improve locomotor function in SCI rats, though the more work related with mechanism is still needed. This research was supported by the convergence technology development program for bionic arm through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT& Future Planning (2014M2C1B2048632).
T45: Effects of Transcutaneous Electrical Nerve Stimulation (TENS) on Hand Dexterity in Chronic Acquired Brain Injury
1San Francisco VA Medical Center, San Francisco, CA, USA, 2University of California San Francisco, San Francisco, CA, USA
T46: Sensorimotor Changes After an Intervention Using a Novel Assistive System – Rein Hand: A Case Report
Northwestern University, Chicago, IL, USA
Electroencephalogram during maximum hand opening with the arm supported on a tabletop or in free space was measured before and after the 6-week intervention. These data were then used to reconstruct the cortical activity during hand opening.
Diffusion tensor images (DTI) were also acquired before and after the 6-week intervention with diffusion weighting of 1000 s/mm2 in 60 diffusion directions. DTI-tractography was used to reconstruct the corticospinal pathways between the posterior limb of the internal capsule and the cerebral peduncle.
Active range of motion, Chedoke MacMaster Stroke-assessment-hand subscale (CMcM), Semmes-Weinstein Monofilament test, the Nottingham Stereognosis Assessment (NSA) and grip strength were assessed before and after the intervention.
T47: Different Levels of Intracortical Inhibition are Involved in Bimanual Common vs. Dual-Goal Tasks and Related to Interlimb Interaction
1Department of Physical Therapy and Rehabilitation Science, School of Medicine, University of Maryland, Baltimore, MD, USA, 2Faculty of Health Sciences, Southampton, UK, 3Department of Neurology, School of Medicine, University of Maryland, Baltimore, MD, USA
Individuals following stroke have exhibited various degrees of deficits in both paretic and non-paretic arms. Nevertheless, the majority of activities of daily living require collaboration between the arms. Some tasks involve a common-goal in which two arms sharing a single focus, such as pulling out a drawer with both arms. Others involve similar but separate goals for each arm, such as picking up different items with each arm separately. The ability to restore function of both arms in bimanual tasks is crucial for stroke survivors to achieve independent living. We hypothesize that different cortical control parameters are involved in bimanual common versus dual-goal tasks, and that this difference will be demonstrated in interlimb performance interaction as well. In this pilot we determine intracortical inhibition and its relationship to interlimb interaction in bimanual common-goal vs. dual-goal isometric force tasks in young non-disabled adults.
T49: Navigated Repetitive Transcranial Magnetic Stimulation of Pre-Supplementary Motor Area on Fronto Basal Ganglia Network to Treat Frontal Lobe Stereotypy Following Traumatic Brain Injury : A Case Report
National Traffic Rehabilitation Hospital, Catholic Medical Center, Gyeonggi-do, Republic of Korea
Paracentral and cingulate sulcus depicted in high resolution T1-weighted MRI scan of the patient were used as landmark for target area of navigated rTMS. She recieved 10 sessions of 10 Hz rTMS at both pre-supplementary motor area over 2-week period at 90% of resting motor threshold. Functional reach test and balance test by measurement of the weight distribution index (WDI) using the BioRescue were performed immediately after each rTMS session. Due to stereotypy-induced poor balance, functional reach test and WDI of ischial tuberosity was evaluated in a independently sitting position.
The patient showed improvement in the functional reach test in both arms. At first, WDI was unmeasurable due to poor sitting balance. But at the last session, WDI was improved to 85%.
T50: Corticospinal Resetting of the Threshold (Referent) Position for Activation of Muscles During Motion at the Elbow Joint
1Neurosciences, Univ. De Montréal, Montreal, Quebec, Canada, 2Biomed. Engin., Univ. Paris Descartes, Paris, France, 3Inst. de génie biomédical, Univ. de Montréal, Montreal, Quebec, Canada, 4École de réadaptation, Univ. De Montréal, Montreal, Quebec, Canada, 5Sch. of Physical and Occup. Therapy, McGill University, Montreal, Quebec, Canada, 6Ctr. for Interdisciplinary Res. in Rehabil. of Greater Montreal (CRIR), Montreal, Quebec, Canada
Muscles become active when the actual position of body segments deviates from their threshold positions. Threshold positions represent the origin of the spatial frame of reference (FR) for muscle action. The level of muscle activity depends on the difference between the actual and threshold body segment positions. Voluntary motor actions result from central shifts in the threshold position, thus shifting the FR. It has been shown that the corticospinal (CS) system is involved in threshold position resetting underlying motion at the wrist joint. We investigated whether or not the CS system accomplishes threshold position resetting at the elbow joint. We also investigated how injury affecting the CS tract influences threshold position resetting. Subjects with upper limb hemiparesis after stroke (Fugl-Meyer scores: 20-65/66) and two groups of healthy controls (young: aged 20-35) and older (age-matched to the stroke group) participated in the study. All subjects voluntarily moved their elbow joint from an initial flexed to a final extended position and vice-versa for a total of 30 trials. CS influences at both positions were measured using MEPs elicited by transcranial magnetic stimulation to the biceps site in the contralateral motor cortex. Passive elbow muscle forces were compensated with an elastic band such that elbow muscle activity was approximately equalized at the two positions. Muscle activity was recorded from two elbow flexors (biceps brachii and brachioradialis) and extensors (lateral and medial heads of triceps brachii). Although the EMG activity of elbow muscles was similar, CS influences were different at the two positions. In the healthy groups, flexor MEPs were greater in the elbow flexion than the extension position and vice versa for extensors (reciprocal pattern). Similar patterns were observed only in a subgroup of patients. In the remaining patients, the pattern was either absent or reversed. Results support the notion that CS system participates in threshold position resetting underlying active motion and that this capacity may be affected by stroke. Results also reinforce previous findings suggesting that the motor cortex controls motor actions by shifting spatial FRs. Deficits in shifting spatial FRs may underlie motor deficits in stroke.
T52: Quantifying Post-Stroke Apathy with Actimeters
1Stony Brook Medicine, Stony Brook, NY, USA, 2Burke Medical Research Institute, White Plains, NY, USA
Post-stroke apathy is a syndrome of reduced goal-directed behavior and flattening of emotions that occurs in approximately 35% of patients after stroke, and is associated with slower recovery and more disability. There are no proven treatments, and clinical trials are hampered by a lack of objective quantification of apathy severity. Here we tested the hypothesis that amount of spontaneous movement can serve as a quantifiable measure of apathy severity. We studied 57 patients admitted to an acute rehabilitation unit for ischemic or hemorrhagic stroke; all had intact strength on one side, and none had a neurodegenerative movement disorder or were hypoaroused. Spontaneous movement was measured using actimeters (wrist-watch style accelerometers) attached to the wrist of subjects’ full strength arm for over 24 hours. Apathy was scored by the treating speech pathologists using the Apathy Inventory (AI; scores range 0-12 with 0 no apathy and 12 persistent and severe apathy). Using a threshold of 4 for defining clinically significant apathy, 21 (36%) of subjects had apathy. Apathetic subjects were well matched to non-apathetic subjects by age, though were typically weaker and more disabled from their stroke. We used multiple linear regression to determine the association between total movement between 9AM and 5PM and multiple predictors. We found that after accounting for motor deficit (Fugl-Meyer of the affected arm) and age, each increment of AI score correlated with 5.6 fewer minutes moving per hour (p<0.001). Motor deficit correlated weakly with minutes moving per hour (p=0.04), and age did not correlate (p=0.2). As a control analysis, we looked at movement while asleep and found no correlation between AI score and minutes moving per hour (p=0.93). Our results suggest that wrist worn actimeters may serve as an objective, quantifiable measure of post-stroke apathy in patients with an intact upper extremity. Before they can be used as a clinical trial outcome measure, we need a longitudinal study to determine their responsiveness to change in apathy severity within subjects.
T53: Effect of Creatine Supplementation on Cognition During Hypoxia in Mild Traumatic Brain Injury
Centre for Brain Research, The University of Auckland, Auckland, New Zealand
The brain relies on an uninterrupted supply of oxygen in order to function optimally. Dysfunctional oxidative metabolism occurs with many neurological conditions, including mild traumatic brain injury (mTBI). Creatine is a compound that replenishes cellular energy without oxygen and can be administered as a dietary supplement. Creatine is capable of improving cognitive functions during oxygen deprivation[1]and may have similar effects for those recovering from mTBI.
The aim of this study was to assess the effects of dietary creatine monohydrate supplementation on brain creatine and cognitive functions after mTBI. Spectroscopy was used to measure neural creatine availability. Neuropsychological assessments were conducted during a hypoxia protocol that induces cognitive impairments similar to those experienced after mTBI[2]. Neuropsychological function was measured at baseline and following 7 days of dietary creatine supplementation during the hypoxia intervention.
Participants adhered to the 7 day supplementation regime, confirmed by an 8% increase in creatine within sensorimotor cortex. Creatine improved hypoxia-induced impairments in a range of cognitive domains scores that are commonly impaired following mild TBI. Verbal, visual and composite memory domains, psychomotor speed, and an overall neurocognitive index appear to be protected from oxygen deprivation by creatine supplementation. An enhanced energy-buffering capacity associated with augmented neural creatine stores likely increases energy provision in metabolically-vulnerable brain tissue. These preclinical findings suggest that creatine has utility to improve brain function in patients recovering from mTBI.
[1] Turner CE, Byblow WD, Gant N. Creatine supplementation enhances corticomotor excitability and cognitive performance during oxygen deprivation. J Neurosci 2015; 35(4): p. 1773-1780.
[2] Turner CE, Barker-Collo SL, Connell CJ, Gant N. Acute hypoxic gas breathing severely impairs cognition and task learning in humans. Physiol Behav 2015; 142: p. 104-110.
T54: Assessment of Executive Function in Acute Rehabilitation Inpatients Using Hands-Free Cognitive Tests
University of Alabama at Birmingham(UAB), ALABAMA, USA
T55: Control of Posture and Movement with Respect to Gravity by Setting the Referent Orientation of the Body
1School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada, 2Neuroscience Program, McGill University, Montreal, QC, Canada, 3Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Laval, QC, Canada, 4Department of Neuroscience, Université de Montréal, Montreal, QC, Canada, 5School of Rehabilitation, Université de Montréal, Montreal, QC, Canada
It has been suggested that multiple muscles of the body are controlled as a coherent unit based on the difference between the referent body configuration specified by the brain and the actual, body configuration. The referent configuration is the configuration at which muscles begin to be activated. We suggest that there are referent body configurations that are used to orient actual body postures (straight or leaned) during standing and most body movements in humans and animals relative to gravity. In other words, we suggest that neural control levels can specify a referent body orientation (R) at which multiple muscles of the body reach their activity minimum. Under the influence of gravity, the body is deflected from the referent direction to a direction Q, at which the emerging muscle activity results in forces that balance gravitational forces and body stability is maintained. This hypothesis predicts that during back-and-forth movements, R and Q may momentarily coincide, bringing the activity of multiple muscles of the body to a minimum. We tested this prediction by analyzing the activity of multiple body muscles during rhythmical changes in the body orientation during standing. To manipulate R and create situations in which minima occur, participants were required to stand on 3 surface orientations, ascending, horizontal, and descending, and perform whole body sways and mini squats. EMG minima were identified from EMG signals recorded in 11 muscles across the body and the body postures at which EMG minima occurred were determined. Global minima were identified in all conditions, both in swaying and squatting movements. The EMG minima occurred in 20%-82% of movements cycles. The postures at which global EMG minima occurred were different in different conditions. Preliminary results thus confirm the hypothesis. This study contributes to the understanding of how posture and movement are controlled in the gravitational field. It also extends the previous suggestion that multiple muscles of the body are controlled as a coherent unit depending on the difference between the actual and referent configurations of the body.
T56: Improving Motor Function After Stroke by Application of Electrical Theta-Burst Stimulation via Implanted Electrodes
Department of Anatomy, Brain Health Research Centre, University of Otago, Dunedin, Otago, New Zealand
Interhemispheric inhibition (IHI) may increase following stroke, which can negatively impact on recovery. In anaesthetized rats we have previously shown that application of low-intensity electrical stimulation in an intermittent theta-burst stimulation (iTBS) pattern to the motor cortex can abolish interhemispheric inhibition (IHI) onto the opposite hemisphere, which suggests it may be beneficial if applied therapeutically for stroke.
We have now shown that in the rat photothrombotic model, similar application of iTBS via an implanted electrode in the contralesional homologous motor cortex can improve functional recovery. In our study, one three-minute session of TBS or sham stimulation was applied twice weekly for three weeks commencing either 3, 10, or 31 days after stroke induction and recovery of forelimb function was assessed throughout using a grid walking test. A further group of rats received five three-minute sessions of TBS, each spaced by 10 minutes, five days a week for three weeks. After behavioural assessments, all rats were anaesthetized with urethane, and in vivo intracellular sharp electrode recordings were made in the peri-lesional motor cortex to measure IHI and excitability.
Application of intermittent TBS (iTBS) beginning 3 days after stroke improved forelimb function compared to both sham stimulation and continuous TBS (cTBS) (P<0.05; n=8 per group). Early implantation of electrodes after stroke and acute commencement of stimulation may not be desirable in the clinical setting. Therefore two further groups received stimulation starting at later time points. Commencing iTBS 10 days after stroke trended towards enhanced early recovery compared to cTBS and sham stimulation (n=6-8 per group). No differences were seen between groups (n= 7 per group) when stimulation began 31 days after stroke induction. However, preliminary data obtained by applying stimulation more intensively indicates that within-session repetitions of TBS can further enhance the effects on recovery, when stimulation is commenced 10 days following stroke induction.
These data show that applying infrequent contralesional electrical TBS early after stroke can enhance recovery but its effectiveness reduces with increasing delay in commencement. However, our preliminary data involving more intensive application of stimulation at more clinically translatable time points shows enhancement of recovery of motor function, consistent with enhanced effects on motor function by repeated applications of TBS applied using magnetic stimulation.
F1: Anxiety and Depression in Patients with Malformations of Cortical Development and Incomplete Hippocampal Inversion
Madras Medical College, chennai, India
2) To compare the anxiety and depression levels in patients with intractable epilepsy with structural abnormalities (MCD & IHI) and without structural abnormalities.
F2: Increased Interhemispheric Coherence During Transcallosal Inhibition Assessment in Chronic Stroke: A Preliminary TMS-EEG Investigation
1Emory University, Atlanta, Georgia, USA, 2Georgia Institute of Technology, Atlanta, Georgia, USA, 3University of British Columbia, Vancouver, British Columbia, Canada
All data pre-processing steps were performed in EEGLAB. Epochs were extracted for each participant and concatenated within each group for IC analysis. Post-TMS (0-300ms) IC values between electrodes overlying M1 (C3, C4) bilaterally were calculated within the beta frequency band (15-30Hz) as the primary dependent measure of interhemispheric IC. Secondary analyses subdivided the stroke group based on lesion hemisphere. Level of physical impairment was evaluated using the upper extremity portion of the Fugl-Meyer (FM) Assessment.
F3: Effect of Resveratrol on Relapsing-Remitting Multiple Sclerosis
1Harry S. Truman Memorial Veterans Hospital, 2University of Missouri School of Medicine, Columbia, MO, USA
The use of meta-analysis in basic biomedical research has increased in recent years due to differences in genetically modified mice producing inconsistent results. Resveratrol (RSV) is a naturally occurring polyphenol that has been shown to affect numerous biological pathways, leading to many health benefits. Several of these benefits include anti-inflammatory and neuroprotective properties that have implicated RSV as a possible therapy for relapsing remitting multiple sclerosis (RRMS). Recent research with RSV has been focused on a mouse model of MS called experimental autoimmune encephalomyelitis (EAE), but results have not been consistent. In the present study, we performed a meta-analysis of the data related to the effect of RSV on RRMS. The meta-analysis revealed a slight delay in the onset and progression of EAE in mice treated with resveratrol, as well as a decrease in peak symptom severity determined by a clinical scale score. Overall, mice treated with EAE showed a slower disease progression, including the number of days to reach peak clinical score and the number of days it took for the mice to reach minimum relapse score. This study suggests that, despite many positive effects, RSV has not shown statistically significant results as treatment for regulating the clinical presentation of EAE. Meta-analysis will be run on other aspects of the effect of RSV on RRMS before presentation, including its neuroprotective effect, quantified by level of retinal ganglion cell (RGC) axon damage and number of spinal cord lesions with preliminary analysis indicating a significant positive effect following treatment.
F4: The Effect of Antispasmodic Medications on Recovery During Inpatient Rehabilitation After Acute Traumatic Spinal Cord Injury
1New York Institute of Technology, Old Westbury, NY, USA, 2Icahn School of Medicine at Mount Sinai, New York, NY, USA, 3Craig Hospital, Englewood, CO, USA, 4James J. Peters VA Medical Center, Bronx, NY, USA
During acute inpatient rehabilitation, 686 patients (49.9%) received at least 5 doses of antispasmodic medications. Patients with cervical injuries were more likely to receive antispasmodic medications (58.1%) than those with thoracic (37.6%) or lumbosacral (35.4%) injuries.
After controlling for baseline injury severity and level at inpatient admission, motor FIM scores at inpatient discharge were significantly higher in patients not given antispasmodic medications (53.8, 95% CI 52.7-54.9) than in those who received antispasmodic medications (48.5, 95% CI 47.4-49.6) (p<0.0005). Likewise, motor FIM scores at one-year follow-up were significantly higher in patients not given antispasmodic medications: 63.9 (95% CI 62.3-65.5) versus 59.9 (95% CI 58.2-61.5) (p=0.001). These effects persisted after performing Rasch transformation - baseline-adjusted, Rasch-transformed FIM motor scores were higher in those not given antispasmodic medication: at discharge, 48.4 (95% CI 47.7-49.1) versus 45.4 (95% CI 44.7-46.2) (p<0.0005); at one year, 57.5 (95% CI 56.2-58.9) versus 55.3 (95% CI 53.9-56.6) (p=0.022). Antispasmodic medication did not significantly affect discharge ISNCSCI grade.
F5: Paired Stimulation to Increase Cortical Transmission to Hand Muscles
1James J. Peters VA Medical Center, Bronx, NY, USA, 2Icahn School of Medicine at Mount Sinai, New York, NY, USA, 3Burke Medical Research Institute, White Plains, NY, USA
F6: Threshold Position Resetting Suppressing both Stretch Reflexes and Background Muscle Activity in Response to Prolong Muscle Lengthening
1Department of Neuroscience, Université de Montréal, Montréal, Canada, 2School of Physical and Occupational Therapy, McGill University, Montréal, Canada, 3Center for Interdisciplinary Research in Rehabilitation of Greater Montreal, Montréal, Canada
Since the work of Sherrington (1906), it has been recognized that, together with other proprioceptive reflexes, the stretch reflex (SR), i.e. position- and velocity-dependent resistance to muscle lengthening, plays a fundamental role in the control and stability of posture and movement. The spatial threshold of the SR, i.e. the muscle length or respective joint angle at which the SR begins to act is broadly regulated by spinal and supra-spinal systems in a task-specific way. We tested the hypothesis that the SR threshold can be reset to suppress both SR reactions and background muscle activity in response to high amplitude lengthening, thus preventing overstretching active sarcomeres. The forearm and hand of subjects (n=12) were placed on a horizontal manipulandum. Elbow flexor or extensor muscles were pre-activated by compensating an external load (1-3 Nm) applied to the manipulandum by a torque motor. The muscles were stretched by rotating the manipulandum by 60 ° at different velocities (8-120°/s) randomly selected for each trial. EMG signals (biceps brachii, brachioradialis, triceps brachii lateralis and medialis), displacement and velocity were recorded. In training trials and subsequent experimental trials, subjects were instructed to abstain from intentionally modifying their responses to perturbations. Trials in which subjects changed EMG levels prior to stretch onset were excluded. SR responses to muscle stretch (lengthening), if present, were minimal and occurred at latencies of 25-35 ms and after about 70 ms the EMG activity was suppressed for about 80 ms. After that the stretched muscles were reactivated during the ongoing muscle lengthening. Results are consistent with the notion of resetting of spatial thresholds for muscle activation, rather than with suppression (gating) of the SR in time. In general, threshold resetting is used not only to prevent muscle overstretching but also in the control of intentional movement. By doing so, the nervous system converts posture-stabilizing to movement-producing mechanisms, thus solving the classical posture-movement problem. Spatial threshold resetting can also be used to prevent falls in subjects standing on a platform that is suddenly tilted. The possible relationship between the notion of SR threshold resetting and the clasp-knife phenomenon in some neurological conditions is discussed.
F7: Track-Weighted Functional Connectivity in the Sensory Discrimination Network Correlates with Haptic Performance: A Preliminary Study in Stroke
The Ohio State University, Columbus, OH, USA
F8: Does Delayed Peroneal Activation in Response to a Sudden Underfoot Perturbation during Gait Predict Injurious Falls in the Elderly with Diabetic Peripheral Neuropathy?
1University of Michigan, Department of Mechanical Engineering, Ann Arbor, MI, USA, 2University of Michigan Health System, Department of Physical Medicine & Rehabilitation, Ann Arbor, MI, USA, 3National Rehabilitation Center, Seoul, Republic of Korea, 4Hôpitaux Universitaires de Genève, Geneva, Switzerland
This study was supported by grants from the National Institutes of Health (R01 AG026569-01) and the Public Health Service (P30AG024824).
F9: Neural Correlates of Attentional Demands Associated with Dual-Task Walking
1Jewish Rehabilitation Hospital, Feil/Oberfeld/CRIR Research Centre, Laval, Quebec, Canada, 2Chiba University, Chiba, Japan, 3McGill University, School of Physical and Occupational Therapy, Montreal, Quebec, Canada
Walking while simultaneously performing another task requires divided attention, e.g. holding a cup without spilling. Stability control during gait alone requires attention, which may be compromised as the cognitive demand increases. The impact of dual-tasking on biomechanical and neural components is yet to be explored. Our primary goal was to investigate gait pattern changes and the neural correlates of complex dual-task walking using functional near-infrared spectroscopy (fNIRS). Healthy young adults (n=11) and a stroke participant walked on a 3m long force-sensing treadmill (CMill, Motek-Forcelink). Cortical activation was acquired with a NIRScout system (NIRx) using a custom-built cap covering the frontal cortex. The protocol included repeated block trials consisting of four alternating blocks of standing (20s) and walking (25s) at a comfortable speed determined prior to the experiment. Five walking trials were performed, each consisting of four randomized conditions including holding a Styrofoam cup that was empty or filled with water, jelly or hot liquid. Participants held the cup in the dominant or non-paretic hand. Primary outcomes included stride length, step width, stride duration, center of pressure displacements and gait variability (% coefficient of variation in stride duration). The cortical hemodynamic response was quantified by concentration changes of oxygenated hemoglobin (oxyHb) in the frontal cortex. Cortical response maps were determined based on the general linear model using SPM (nirsLAB). Walking with a cup filled with hot liquid was associated with a slight decrease in step width and gait variability in all healthy participants but not the stroke individual. The decrease in step width suggests that all subjects adapted to the back-and-forth slosh frequency of the fluid by adjusting their gait so as to suppress the resonant slosh frequency thereby preventing any spillage. In healthy controls, walking while holding jelly was associated with activation of the supplementary motor area (SMA), whereas holding hot liquid resulted in activation of the premotor cortex (PMC) and dorsolateral prefrontal cortex (DLPFC), which are associated with selective attention. Cortical activation in the stroke participant demonstrated increased activation in the contralesional DLPFC and medial SMA while walking and holding either jelly or water. Absence of significant changes in biomechanical gait parameters suggests that during complex dual-task locomotion, the brain can allocate the required cortical resources to account for increased attentional demands without modifying the inherent locomotor pattern.
F10: Intensive Upper Limb Neurorehabilitation with Virtual Reality in Chronic Stroke: A Case Report
1Laboratory of Cognitive Neuroscience, Brain-Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Center for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 3MindMaze SA, Ecublens, Switzerland, 4Clinique Romande de Réadaptation, Sion, Switzerland, 5Chair in Brain-Machine Interface, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
Upper limb motor deficits are a frequent consequence of stroke, limiting patients in their daily life activities. The recovery process is slow and long, including several months or even years of rehabilitation, with the risk of diminishing patient motivation and involvement. Intensive therapy has been shown beneficial, improving the speed of recovery and the degree of independence. In this context, virtual reality (VR) based motor rehabilitation systems provide a potential complement to current therapy in order to intensify the therapy dose and to maintain patients motivation. This study was aimed at evaluating the rehabilitation dose and effect of a VR-based system (MindMotionPRO, MindMaze SA) that enables intensive training adapted to impaired upper limb motor skills in a game-like scenario. The interactive exercises engaged patient’s shoulder, elbow and wrist movements with various levels of difficulty. The system provides real-time feedback of patient’s performance, with an avatar reproducing his movements on the screen while performing different motor tasks (pointing, reaching, grasping).
A 50-year-old right-handed man, who had a left ischemic stroke 26 months earlier, was recruited for this study. He discontinued the conventional physiotherapy (once per week) in January 2015. At the time of recruitment (NIHSS=3), deficits in his right upper limb were notable in coordinating arm movements, with a Fugl-Meyer Assessment Upper Extremity (FMA-UE) score of 47/66 (Reflexes=4/4; Flexor synergy=9/12; Extensor synergy=5/6; Movement combining synergy=4/6; Movement out of synergy=5/6; Wrist=9/10; Hand=7/14; Coordination/Speed-Finger=4/6). One-hour sessions of intensive VR-based therapy were administered twice per week for five consecutive weeks (10 sessions in total) at the Clinique Romande de Réadaptation (Sion, Switzerland), starting on 21 April 2015. On average, the patient performed 804 goal-directed movements per session with his affected limb. Interestingly, the therapy dose continuously increased from 519 (session 1) to 809 (session 10) repetitions per day. In complement to the training, the patient engaged in daily sport activities. Post-treatment assessments showed an increase of 7 points in FMA-UE score (54/66), with improvements in proximal upper limb control and arm coordination (Flexor synergy=10/12; Extensor synergy=6/6; Movement combining synergy=6/6; Hand=9/14; Coordination/Speed-Finger=5/6). Moreover, the patient reported a positive experience with the technology and showed high levels of engagement during the sessions.
Based on this case report, we surmise that the use of the MindMotionPRO in clinical settings increases the feasibility of adjusting the rehabilitation dose upwards to speed up the recovery. The patient received one-hour intensive VR-based therapy twice a week in addition to sport activities, which contributed to an improvement in his motor outcomes. Intensive VR-based therapy brings thus promising perspectives for maximizing the efficacy of motor rehabilitation in stroke patients.
F11: Task-Oriented Arm Training in Standing Improves Both Anticipatory Postural Control and Upper Extremity Functional Outcomes in Stroke Patients
University of Maryland Baltimore, Baltimore, MD, USA
F13: Improvements in Visual Search Contribute to Visuomotor Learning
1University of South Carolina, Columbia, SC, USA, 2University of Trento, Trento, Italy
F14: Comparing Three Dual-Task Methods and the Relationship to Physical and Cognitive Impairment in People With MS and Controls
Memorial University, St. John’s, Canada
F15: An Interprofessional Case Study: Training Health Profession Students in Clinical Exercise Therapy for People with Parkinson’s Disease
Long Island University (LIU), Brooklyn, NY, USA
Educational institutions that provide clinical training to health profession students are either mandated or strongly encouraged to provide interprofessional education (IPE) opportunities for students. Successful integration of appropriate faculty, students and community participants into sustainable interprofessional clinical training is challenging. This case study aims to describe a successful IPE model involving people with Parkinson’s disease (PWP) that is currently operational at a major NYC university, and to identify the strengths and limitations of the model. Our IPE model is adapted from Hirsh’s (2011) recommendations for community based health care for PWP. It requires integration of four elements: (1) committed faculty members from various health professions; (2) community participants with mild to moderate idiopathic PD who consistently participate in exercise; (3) a university gym area with dual action resistance machines and space for group cardiovascular exercise; and (4) health profession students from diverse disciplines who enroll in an elective 3-credit course entitled Exercise Training in Individuals with Parkinson’s Disease (ETIPD). The ETIPD course was offered in academic year 2014-15 and will continue in 2015-16. Twenty-four students from the Departments of Athletic Training, Health & Exercise Science (ATHES), and Respiratory Therapy have participated in the course which is growing in popularity. The faculty currently includes professors from Physical Therapy, ATHES and Nursing who complete a physical assessment of the PWP three times a year in an on-going prospective cohort research project on the effectiveness of consistent exercise in PWP. The faculty also supervises the bi-weekly exercise sessions. One faculty member (A.R.) has primary responsibility for the didactic lectures in the course with the other professors presenting selected didactic modules. One faculty member (R.S.) heads the research efforts. The nurse faculty member (T.S) has had specialized training in Parkinson’s disease sponsored by the Parkinson’s Disease Foundation Edmond J. Safra Visiting Nurse Faculty Program. The PWP were referred to the exercise program through a community Parkinson’ s support group. All sessions are offered for free to individuals with PD with the backing of the investigators’ university and the community support group. The current cohort numbers 27 PWP who consistently exercise two times a week for 10 weeks a semester during the academic year. The strengths of the model include the attachment of the exercise sessions to a university sponsored course, the collegial and friendly atmosphere of the exercise sessions, the strong support of the university and the community Parkinson’s group, and, perhaps most importantly, the strong conviction of all involved that consistent exercise slows the progression of Parkinson’s disease and helps the participants maintain self sufficiency. The major limitation of the model is the challenge of presenting the full 20-session the summer module when the exercise sessions are not part of the ETIPD course.
F16: Evidence for Interhemispheric Reorganization in Sensory Cortex Following Unilateral Upper Extremity Amputation in Humans
1Washington University, St. Louis, MO, USA, 2University of Missouri, Columbia, MO, USA
Deafferenting injuries (e.g. limb amputation) lead to reorganization of the somatosensory cortex, but the functional relevance of these changes remains unknown. Classic work in primate somatosensory cortex (S1) identified immediate and precise reorganizational changes in S1 ipsilateral to deafferentation, following reorganization in contralateral S1 after small deafferenting injuries (Calford and Tweedale 1990). Furthermore, following unilateral rat forepaw deafferentiation, stimulation of the radial nerve from the intact side is associated with bilateral increases in the blood oxygen-level dependent (BOLD) response in S1, which appears to reflect disruptions in interhemispheric functional connectivity (Pawela et al. 2010). Human unilateral amputees exhibit bilateral increases in cortical sensorimotor hand areas during use of the intact limb (Bogdanov et al. 2012), but it remains unknown whether such effects depend on reductions in interhemispheric inhibition between motor and/or sensory regions.
In an effort to determine whether similar effects occur in human S1, we developed an fMRI-compatible system to deliver cutaneous stimulation to the fingers of the intact hand, as well as the left or right sides of the lower face, of 15 unilateral traumatic amputees and 28 healthy adults matched for age, gender, and handedness. Amputees showed greater activity than controls in left (ipsilateral to stimulation) S1 during stimulation of the intact left hand. Activity in the former hand territory showed no between-groups difference in response to facial stimulation, nor any statistically significant correlations with phantom limb pain or time since amputation. To our knowledge, this is the first demonstration of interhemispheric transfer of plasticity in human primary somatosensory cortex. This phenomenon may allow physicians to influence deafferented cortex (e.g. contralateral to a hand with nerve injury) by therapies targeting the intact hand or cortex, thereby opening new avenues toward rehabilitation of patients with unilateral upper limb disability.
F17: Manual Asymmetry During a Bilateral Reach and Hold Task
1University of Maryland School of Medicine, Baltimore, MD, USA, 2University of Southampton, Southampton, England, UK, 3Penn State Milton S. Hershey Medical Center and College of Medicine, Hershey, Pennsylvania, USA, 4Penn State University, University Park, Pennsylvania, USA
We have previously characterized interlimb and interhemispheric asymmetries for unilateral coordination tasks. This work has led to a model of motor lateralization in which one hemisphere is specialized for impedance control that is robust to unstable environmental conditions, while the other hemisphere is specialized for predictive mechanisms that can specify efficient and smooth trajectories under stable environmental conditions. We hypothesize that these two specializations are distributed across the arms during everyday bilateral tasks that involve holding and manipulating, such as when holding a baguette with one hand to slice it with the other hand. We predict that each hand should demonstrate different specializations for each of these task elements during bilateral behaviors. In order to test this hypothesis, we designed an experimental equivalent of the hold and slice task. In this task, performed in a virtual environment with the unseen arms supported by frictionless air-sleds, the arms are connected by a spring, while one hand maintains its position at the origin of the task, and the other moves to a series of targets distributed across a range of directions. Thereby, the reaching hand is required to take account of the spring load to make smooth and accurate trajectories, while the stabilizer hand must impede the spring load to keep a constant position. Right-handed subjects performed each of two sessions of this task, with the order of the sessions counterbalanced between groups. In one session, the right hand reached while the left hand stabilized, and the second session the left hand reached while the right hand stabilized. Our very preliminary results indicate a hand by task component interaction, such that the right hand showed better reaching performance, with faster and smoother (Jerk) reaching. In contrast, the left hand stabilized better, showing less displacement than the right hand. These findings suggest that the specializations of each cerebral hemisphere for impedance and predictive mechanisms are expressed during bilateral interactive tasks, such as the reach and hold task. To date, this is the first demonstration of the dynamic dominance hypothesis within the context of an asymmetric bilateral task. Further, once evaluated in non-disabled adults, future investigations within patients post-stroke could provide knowledge for the development of novel functional bilateral rehabilitation approaches.
F18: Modulating Transcallosal and Intrahemispheric Brain Connectivity with Transcranial Direct Current Stimulation (tDCS)
Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
F19: Right Hemisphere Structures Predict Post-Stroke Speech Fluency
Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA
F20: Effectiveness of Modified Constraint Induced Movement Therapy in a Group Setting as Compared to Individual on the Quality and Quantity of Upper Extremity Movement Recovery After Stroke
1Universidad de La Frontera, Departamento de Especialidades Médicas, Temuco, Chile, 2Clínica Alemana Temuco, Servicio de Medicina Física y Rehabilitación, Temuco, Chile, 3Universidad de La Frontera, Departamento de Pediatría y Cirugía Infantil, Temuco, Chile, 4Universidad de La Frontera, Departamento de Psicología, Temuco, Chile, 5Rehabilitation Center, Emory University, Atlanta, USA
F21: Is Structural Connectivity of Basal Ganglia Associated with Learned Non-Use in Chronic Stroke?
1Division of Biokinesiology and Physical Therapy at University of Southern California, Los Angeles, CA, USA, 2Neuroscience Graduate Program at University of Southern California, Los Angeles, CA, USA, 3Ming Hsieh Department of Electrical Engineering at University of Southern California, Los Angeles, CA, USA, 4Brain and Creativity Institute at University of Southern California, Los Angeles, CA, USA
In those with mild to moderate stroke impairment, there can be a discrepancy between movement capability and daily use of the affected arm and hand. This is captured by the phrase, “he can, but does he?” This phenomenon may be a consequence of negative reinforcement resulting from affected arm use and positive reinforcement for less-affected arm use. The basal ganglia (BG), especially ventral striatum, are considered the neural reward center for reinforcement learning. Thus, the BG may have an important role in mediating the learned non-use phenomenon in chronic stroke. The primary aim is to investigate whether the structural connectivity of BG to other sensorimotor brain areas is associated with affected arm use. This study is part of a larger longitudinal Phase-I clinical trial of rehabilitation in chronic stroke (ClinicalTrials.gov ID: NCT 01749358). Individuals with mild to moderate motor impairment after stroke participated (N=24, average chronicity= 3.04 years). Structural brain images (T1-weighted MRI and DTI) were acquired, and processed using BrainSuite14a (http://brainsuite.org/). A total of twenty-four cortical or subcortical sensorimotor areas (Twelve regions of interests [ROIs] in each hemisphere) and a cerebellum ROI were chosen to construct a structural network. We calculated the Fractional anisotropy (FA) of each tractography between each ROI pair. A 25 X 25 FA matrix was generated to produce an undirected weighted graph. A weighted communicability graph was also computed from the raw FA matrix. Network metrics, including strength and degree, were calculated from FA and communicability graphs for each ROI. We calculated an asymmetric index (AI) of each network metric between an ROI and its homologous ROI in the other hemisphere. Motor Activity Log (MAL) was used to quantify the paretic arm use in daily activities. Linear regression analyses were used to test the relationship between connectivity metrics and MAL score. Significance level was set using Bonferroni correction for multipe comparisons (alpha=0.05/12=0.00417). There was no significant linear relationship between any network metrics and MAL score. However, the communicability strength AI (CSAI) of caudate nucleus showed the highest effect size on the MAL score among twelve CSAIs. 17% of variance in MAL score was explained by the caudate CSAI (p=0.024, Effect size [Cohen’s f2] = 0.21). Other ROIs’ CSAI had smaller effect size than caudate CSAI on the MAL score (Cohen’s f2 < 0.10). This result provides partial support for our hypothesis that structural connectivity of BG is associated with affected arm use in chronic stroke. People with a higher caudate CSAI demonstrated less use of the affected arm in daily activities than those with a lower caudate CSAI. Future work should test whether a reduced structural connectivity of ipsilesional caudate nuclei is predictive of learned non-use, or is simply the result of affected arm non-use.
F22: Toward a Self-Calibrating Brain-Computer Interface for People with Tetraplegia
1Brown University, Providence, RI, USA, 2Dept. of VA Medical Center, Providence, RI, USA, 3Massachusetts General Hospital, Boston, MA, USA, 4Stanford University, Stanford, CA, USA, 5Harvard Medical School, Boston, MA, USA
Brain-computer interfaces (BCIs) aim to restore communication and independence to people with severe motor disabilities by translating decoded neural activity directly into control of a computer cursor. However, nonstationarities in recorded brain activity can degrade the quality of neural decoding over time. Periodically interrupting ongoing use of the BCI to perform decoder recalibration tasks is time-consuming and impractical. In the ongoing pilot clinical trial of the investigational BrainGate2 Neural Interface System, we previously showed that typing performance in a self-paced, neurally controlled point-and-click communication interface can be maintained for hours, despite underlying signal nonstationarities, without requiring the user to pause to perform disruptive calibration tasks. This was accomplished using 3 innovations that address different aspects of neural signal nonstationarities: feature mean and variance tracking, decoder output bias correction, and retrospective target inference-based (RTI) decoder calibration, which uses data acquired during practical, ongoing BCI use to recalibrate the decoder. The current study extends self-calibration of the BCI to multiple days. On day 1, a BrainGate participant diagnosed with amyotrophic lateral sclerosis (ALS) (participant T6) performed the standard “center-out” decoder calibration task with presented targets, and then proceeded to self-paced typing. Then, on days 3, 5, 14, 35, and 42, with the aid of feature tracking and bias correction, the participant was able to proceed directly into self-paced typing using the previous session’s last directional and click decoders. The decoders were updated periodically over the course of the day using RTI decoder calibration, without ever requiring the participant to perform explicit calibration tasks again after day 1. By eliminating the need for the user to perform daily calibration tasks with prescribed targets, despite nonstationarities in the underlying neural signals, this approach advances the potential clinical utility of intracortical BCIs for individuals with severe motor disability.
F23: Imperceptible Random Vibration Applied to Wrist Skin Increased EEG Evoked Potential for Fingertip Touch
1Medical University of South Carolina, Charleston SC, USA, 2University of Wisconsin-Milwaukee, Milwaukee WI, USA, 3Marquette University, Milwaukee WI, USA
The objective of this study was to investigate if cortical activity for sensing touch stimuli on the fingertip is affected by imperceptible white-noise vibration applied to wrist skin. Recent studies have demonstrated that fingertip tactile sensory thresholds improved with continuous, imperceptible, white-noise vibration applied to different locations in the upper extremity such as wrist, forearm, dorsum of the hand, or base of the palm in healthy adults as well as chronic stroke survivors. As such, vibration can be used to manipulate sensory feedback and improve dexterity, particularly during neurological rehabilitation. Nonetheless, the neurological bases for remote vibration enhanced sensory feedback are yet poorly understood. This study examined how imperceptible random vibration applied to the wrist changes cortical activity for fingertip sensation in healthy adults using electroencephalogram (EEG). We employed somatosensory evoked potential to assess peak-to-peak evoked response to light touch of the index fingertip with applied wrist vibration versus without. The peak-to-peak somatosensory evoked potential in response to fingertip touch significantly increased (p < .05). In addition, increased neural recruitment of the somatosensory, motor, and premotor cortex with wrist vibration was observed, corroborating an enhanced cortical-level sensory response motivated by vibration. It is possible that the cortical modulation observed here is the result of the establishment of transient networks for improved perception. This study results support the modulation of cortical-level of somatosensory processing using remote imperceptible vibration, providing the neurobiological basis for its further use in rehabilitation.
F24: From Noise to Music: Using Bayesian Statistical Parameter Estimation to Model Intra-Individual MEP Variability Before and After TBS for More Dynamic Biomarkers of Plasticity
1Laboratory for Cognition and Neural Stimulation, University of Pennsylvania, Philadelphia, PA, USA, 2Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA, 3Moss Rehabilitation Research Institute, Elkins Park, PA, USA
Continuous theta burst stimulation (cTBS), an inhibitory subtype of repetitive transcranial magnetic stimulation (rTMS), is thought to induce plasticity in the stimulated cortical region and thus is frequently investigated as a treatment for neural injury. Cortical excitability and neuroplastic changes therein are measured by assessing increases or decreases in the mean amplitude of motor evoked potential (MEPs), the motor response to TMS. However, the therapeutic utility of rTMS (including cTBS) has been curtailed by a high degree of variability in responses to repetitive stimulation, even among healthy individuals.[1] Despite advances in understanding several factors contributing to inter-individual variability in the rTMS response, much less is known about the variability of MEP amplitudes within individuals, which may itself constitute a dynamic factor affecting the induction of plasticity. A more precise characterization of the intrinsic variability of MEP amplitudes during collection may add a valuable new dimension to hierarchical models predicting individual neuroplasticity responses to rTMS.[2]
This study used Bayesian Data Analysis (BDA) methods to explore the possibility that the induction of plasticity may be accompanied by changes in the shape of the distribution of sampled MEPs within a block, independently of changes to mean MEP amplitude. To enable simultaneous estimation of multiple descriptive parameters for sets of collected MEPs besides the mean (i.e., mode, spread, normality, and skewness), we employed Bayesian statistics to estimate parameter values and examine changes in the distributions of sampled MEPs peak-to-peak amplitudes collected before versus after cTBS. 30-35 MEPs were obtained from the right dorsal interosseous muscle of 31 healthy individuals using single-pulse, aperiodic TMS to motor cortex (M1). TMS pulse-strength levels were individually determined as the ratio of percent machine output required to elicit 1mV MEP amplitudes to resting motor threshold (rMT), and remained constant throughout the experiment. After baseline MEP collection, cTBS was administered for 40s (50-Hz triplets delivered at 5-Hz; 80% active motor threshold), followed by post-stimulation MEP blocks sampled at 0-min, 20-min, and 30-min.
Our results suggest that shape of the distribution of MEP amplitudes might be a dynamic variable in itself. For example, MEP amplitudes were not normally distributed and at baseline, and shape parameters (spread, normality, skewness) varied as a function of TMS pulse-strength, but not the mode. Following cTBS, TMS pulse-strength no longer predicts distribution shape parameters, which instead appeared to vary as a function of the mode MEP amplitude in a subset of subjects. Importantly, BDA does not assume that the data are normally distributed a priori. Rather, it precisely estimates central tendency and shape parameters without discarding “outlier” values, which are often eliminated for statistical expediency despite being potentially meaningful datapoints.[3] Accordingly, BDA outputs more faithful representations of intra-individual MEP variability for integration into inter-individual variability predictions.
F25: Paired Brain and Spinal Cord Stimulation to Strengthen Corticospinal Responses
1Burke Medical Research Institute, White Plains, NY, USA, 2Weill Cornell Medical College, New York, NY, USA
Spinal epidural stimulation has emerged as a powerful tool to raise the excitability of spinal cord circuits and to strengthen voluntary movement after injury. We sought to augment excitability of the corticospinal motor tract by pairing stimulation of its origin in motor cortex with stimulation of its end in the cervical spinal cord. All of the experiments were conducted in intact, anesthetized adult rats. We measured excitability of the motor system by electrically stimulating motor cortex and recording EMG in the contralateral biceps muscle. We created response curves by stimulating cortex at increasing intensity and compared curve under different conditions. We delivered epidural stimulation on the dorsum of the cervical spinal cord. We conducted 3 experiments. In the first experiment, we measured the effects of tonic 40Hz spinal epidural stimulation on EMG responses. We hypothesized that, like lumber epidural stimulation, tonic cervical spinal cord stimulation would augment EMG responses in a manner dependent on the intensity, polarity, and stimulation location. Indeed, tonic stimulation directed at the cervical enlargement produced robust augmentation of EMG with both cathodal and biphasic stimulation that increased with intensity. In the second experiment, we hypothesized that a single pulse of spinal epidural stimulation at discrete intervals after cortex stimulation would augment EMG responses. Latency was a crucial determinant, with 11ms being optimal. This timing coincides with the timing of the spinal cord dorsum potential recorded in the cervical cord after motor cortex stimulation, suggesting synergistic effects of corticospinal and large diameter sensory afferent stimulation. Finally, we asked whether repeatedly pairing of cortex and spinal cord stimulation at the optimal latency would induce learning in the spinal cord. We created a baseline response curve and also measured the spinal stimulation necessary to provoke EMG responses. We then delivered motor cortex stimulation followed 11 ms later by a single biphasic spinal cord pulse and repeated this every 2 seconds for 5 minutes for a total of 150 paired stimuli. We recorded a response curve and spinal thresholds immediately after the pairings and every 10 minutes thereafter. Paired stimulation caused a dramatic (>100%) increase in motor responses and the spinal threshold also decreased. Thus, we demonstrate plasticity in the intact corticospinal motor tract by repetitive pairing of brain and spinal cord stimulation that occurs at the level of spinal cord.
F26: Impaired Multi-Finger Synergies in Individuals with Multiple Sclerosis
1Pennsylvania State University, State College, PA, USA, 2Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA, USA, 3University of Delaware, Newark, DE, USA
Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that can result in impaired hand function. An important component of everyday hand actions is to ensure controlled stability of the combined action by a set of digits. We investigated multi-finger synergies stabilizing total force during a pressing task in twelve participants with mild and moderate MS and 12 age- and gender-matched control subjects. All subjects were tested during performance with their dominant and non-dominant hands. The subjects produced an accurate constant force level by pressing with four fingers on individual force sensors followed by a self-paced force pulse into a target. Finger inter-dependence (enslaving, E) was quantified using ramp force tasks performed by each finger. The uncontrolled manifold approach was used to compute a multi-finger synergy index during steady state and changes in this index (anticipatory synergy adjustments, ASA) in preparation to the force pulse. The MS group showed significantly lower maximal finger forces for both hands and higher enslaving among fingers when the lateral fingers (index and little fingers) were the task fingers. The MS group was also slower as compared to controls in the time to force peak. MS subjects showed significantly lower synergy indices than the controls during the steady-state phase and also demonstrated smaller and delayed ASA in preparation to the force pulse. These findings indicate that MS affects several aspects of multi-finger coordination including lower finger individuation, weaker force-stabilizing synergies, and decreased anticipatory adjustments in preparation to a quick action. These changes could be related to the impaired hand function observed in this population. Given that similar synergy changes are observed in patients with Parkinson’s disease and multi-system atrophy, additional analysis is needed to explore possible differences in the indices of synergy in MS subjects with involvement of different pathways within the central nervous system.
F27: Training a Complex Arm Skill Transfers to Improved Simple Reaching Tasks and Modulates Corticospinal Excitability in Patients With Stroke
Moss Rehabilitation Research Institute, Elkins Park, PA, USA
Motor skill training involves acquiring novel movement capabilities through practice that leads to an improvement in the speed-accuracy tradeoff function, akin to acquiring real-world skills. Recent evidence indicates that skill learning is behaviorally and neuroanatomically distinct from motor adaptation and sequence learning. In this study we investigated the practice effects of a complex arm motor skill on change in speed-accuracy tradeoff (learning) as well transfer to a simpler functional reaching task. In a subset of patients, we explored the neural mechanisms of skill learning using transcranial magnetic stimulation (TMS). Specifically, we assessed the pre-post change in TMS-evoked recruitment curve and transcortical inhibition targeting the paretic triceps brachii. Participants with moderate stroke (n=10) practiced a complex motor task the goal of which was to navigate a cursor with their paretic arm through a virtual track as fast as possible without crossing the borders of the track. Performance changes during practice were characterized by improvements in accuracy while practicing within the prescribed movement time ranges. Learning was indexed by changes in the speed-accuracy tradeoff function measured at baseline, a day and approximately a month after practice ended. To assess the transfer to a non-practiced task, we examined the pre-post changes in goal-directed reaching to three different targets placed in front of the patient. All patients improved their performance on the practiced task. Following practice, there were improvements in the speed-accuracy tradeoff function that were retained over a month. Importantly, there was a significant improvement in the performance and control of non-practiced functional reaching task as evidenced by reduced movement times, higher peak velocities and shorter time-to-peak velocities after practice. Improved motor control was also reflected in improved efficiency indicated by decrease in the number of submovements during execution of the practiced as well as the non-practiced task. Neurophysiological data indicated an increase in the corticospinal excitability and decrease in transcallosal inhibition with training. Patients with stroke demonstrate improved performance and control of the trained paretic arm following practice of a complex arm motor task. This improved performance is accompanied by changes in the corticospinal and interhemispheric mechanisms. The most novel finding of our study is that learning of the complex task transfers to improved performance on an untrained simpler task. These findings have significant clinical implications suggesting that complex task practice may be helpful in driving performance and control improvements for simple tasks, particularly if the two (complex and simple tasks) share similar control processes. Corticospinal and interhemispheric changes likely underlie the efficient motor performance.
F28: Effects of Metformin and Enriched Rehabilitation on Recovery Following Neonatal Hypoxia-Ischemia
1University of Ottawa, Ottawa, Canada, 2University of Toronto, Toronto, Canada, 3Canadian Partnership for Stroke Recovery, Ottawa, Canada
Neonatal hypoxia-ischemia (HI) is one of the most common causes of mortality and morbidity in children, often leaving survivors with profound physical and cognitive disabilities. Effective treatments capable of supporting long-term recovery and reducing the severity of these disabilities are needed. Previous research using adult animal models of stroke has shown that metformin, an antidiabetic drug, promotes neurogenesis, oligogenesis and angiogenesis to enhance motor and cognitive function following injury. This study aims to determine whether metformin, enriched rehabilitation (ER) or a combination of the two could provide a clinically relevant therapeutic option for enhancing motor function following neonatal HI.
At post-natal day (PND) 7, Sprague-Dawley rats were assigned to two groups: sham (n=7) or hypoxia-ischemia (n=22). The Rice-Vannucci model was used to induce unilateral injury, in which HI animals had their left carotid artery permanently ligated prior to being placed in a hypoxia chamber (8% O2) for 90 minutes. At weaning (PND 21), animals assigned to ER were housed in an enriched environment and received reach training for 4 weeks. All other animals were standard housed. Once weaned, pups received subcutaneous metformin (200mg/kg/day) or saline injections for 4 weeks. Motor function was assessed pre- and post-combined therapy using the following tests: ladder-walking, adhesive-strip removal and Montoya staircase.
Following four weeks of treatment, hypoxia-ischemia animals receiving ER made 45% fewer errors with their impaired forelimb and 17% fewer errors with their impaired hindlimb on the ladder-walking test compared to standard housed HI animals. ER animals also displayed a decreased latency to contact the adhesive strip on their impaired forelimb. In addition, animals receiving either metformin or enriched rehabilitation showed enhanced motor learning on the Montoya staircase.
In conclusion, enriched rehabilitation promoted motor recovery following HI, while both ER and metformin accelerated acquisition of a skilled reaching task. Work in progress is examining the effects of metformin and enriched rehabilitation on cognitive function following HI.
F29: Effects of Limb Non-Use on Resting Functional Connectivity
Washington University School of Medicine, Saint Louis, MO, USA
F30: Short-Term Practice Effects Predict Longer-Term Upper Extremity Motor Learning in Older Adults With and Without Mild Cognitive Impairment
1Utah State University, Logan, UT, USA, 2University of Utah, Salt Lake City, UT, USA
While dose-response studies have suggested that larger doses of neurorehabilitation lead to better outcomes, there may be value in using shorter-term ‘practice effects’ to predict responsiveness to a clinical intervention. Recent work in older adults has demonstrated the utility of practice effects after one week of cognitive training, but has focused primarily on explicit memory tasks. We have begun exploring motor tasks that require implicit memory formation (i.e. procedural learning) that may, in concert, provide a more comprehensive assessment of cognitive function in older adults. The purpose of this study was to compare short-term improvements due to practice on a complex upper extremity motor task between samples of young (n=28) and older (n=29) adults. Within the older adult sample, 55% had cognitive scores below the normative cutoff (Montreal Cognitive Assessment, MoCA). All subjects were free of known neurological or musculoskeletal conditions. We hypothesized that over four practice trials within a single session, the rate of improvement would be greatest for the young adults and smallest for the older adults with cognitive impairment. Performance on each trial was measured as the time to complete the motor task, with shorter times indicating better performance. Analyses of variance (ANOVAs) and correlation coefficients showed, however, that all three groups had comparable rates of improvement, despite having significantly different baseline performances on the motor task itself (p<.0001). The young adults completed trial 1 in the shortest amount of time, and the cognitively-impaired older adults took the longest. To test the sensitivity of our motor task in discriminating age and cognitive status, we fit Receiver Operating Characteristic (ROC) curves to baseline data (trial 1) as well as improvement data (normalized change from baseline to trial 4). Although ROC curves moderately discriminated young and impaired subjects based on their baseline performance (AUC = 0.75), they were unable to do so above chance based on the amount of improvement from baseline (AUC = 0.55). Collectively our data showed comparable improvement after four practice trials, regardless of age or cognitive status. Moreover, these short-term practice effects were significantly related to 1) the amount of learning achieved by the older adults after completing a much larger dose of practice (150 trials over 3 days) (Spearman’s r=0.49; p=.018), and 2) the amount retained one month later (r=0.41; p=.05). We do acknowledge that the MoCA is a gross measure of global cognition, and does not specifically test implicit memory; thus, despite some of the older adult group presenting with cognitive impairment, they may have relatively intact implicit memory function. Nevertheless, these results provide preliminary evidence of how short-term practice effects may have predictive value in determining responsiveness to longer-term procedural learning interventions in neurorehabilitation.
F31: Differential Effects of Moderate and High Intensity Exercise on Corticomotor Excitability, Intracortical Inhibition and Intracortical Facilitation
1Northwestern University, Chicago, IL, USA, 2University of Illinois at Chicago, Chicago, IL, USA
F32: Reduced Ankle Muscle Co-Contraction after Robot-Guided Therapy in Children with Cerebral Palsy
1University of Massachusetts Lowell, Lowell, MA, USA, 2Rehabilitation Institute of Chicago, Chicago, IL, USA, 3Northwestern University, Chicago, IL, USA
F33: Comparing Mirror Visual Feedback and Actual Visual Feedback Post Stroke
1New York University School of Medicine, New York, USA, 2the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China, 3NewYork University, New York, USA, 4University of Medicine and Dentistry of New Jersey, New Jersey, USA, 5Johns Hopkins University, Maryland, USA
Mirror visual feedback (MVF) is a non-invasive technique where visualization of movements of the unaffected side can potentially stimulate neural circuits on the affected side for enhanced motor performance. MVF has been used in the rehabilitation of upper limb function after stroke; however the mechanisms by which it affects motor control are not yet fully understood. Thirteen subjects between 27-63 years (mean 45.3, SD =13.2), at least 6 months post stroke performed wrist extension movements using a custom-made wrist trainer in two separate experiments. In the unimanual experiment, subjects moved their affected wrist with (1) MVF provided using a mirror reflection of the movements of the unaffected side on the screen in front of them and (2) actual visual feedback (AVF) by looking at the affected side moving. In the bimanual experiment, subjects moved both wrists simultaneously with (1) MVF provided using mirror reflection of the unaffected side in a mirror between the two arms, and (2) AVF by looking at the affected side moving. Motor impairment, wrist kinematics and surface EMG activity of the wrist extensors and flexors were measured. Due to large differences in the Fugl-Meyer scores and baseline wrist kinematics, the subjects were divided into high performance (n=7) and low performance (n=6) groups for further statistical analysis. During unimanual movements, the high performance group showed increased wrist extension with AVF compared to MVF, but used a feedback strategy where the deceleration time of wrist extension was increased. There was no significant difference in EMG activation or co-activation across the wrist flexors and extensors. On the other hand, the low performance group showed no significant differences in wrist extension between AVF and MVF, but also used a feedback strategy with AVF and showed increased wrist flexor, extensor and flexor-extensor co-activation compared with MVF. During bimanual movements, the high performance group used a feedforward strategy with MVF with higher acceleration times compared with AVF, but no other differences in performance were noted. The low performance group, showed lower wrist flexor activation and co-activation with MVF compared to AVF. The results suggest that actual visual feedback from looking at the affected hand moving improves wrist extension using a feedback strategy in the high performance group, whereas mirror visual feedback reduces co-activation in the low performance group which may be helpful to promote easier movement in this group. It is necessary to stratify subjects based on their performance in order to understand motor control patterns and develop evidence-based personalized training strategies post stroke.
F34: Discriminating Visuospatial Neglect from Proprioceptive Impairment using Robotics
1University of Calgary, Calgary, AB, Canada, 2Hotchkiss Brain Institute, Calgary, AB, Canada, 3Queen’s University, Kingston, ON, Canada, 4University of South Carolina, Columbia, South Carolina, USA
Visuospatial neglect commonly occurs after stroke and results in impaired attention to locations, objects and limbs in contralesional space. Neglect typically leads to increased recovery times and poorer outcomes following stroke. Typically, neglect is identified based on clinical impression which is supplemented with pen and paper assessments, such as the Behavioral Inattention Test (BIT). Our group has previously reported that a high percentage of stroke survivors who perform poorly on the BIT also perform poorly on robotic testing of proprioception. However, we have also seen a number of anecdotal cases of individuals with poor proprioception who appear to be have been misdiagnosed by clinicians as having neglect. We sought to compare the clinician’s impression of the presence of neglect in acute stroke subjects, performance on the BIT and robotic proprioceptive testing. Determining specific impairments can guide therapists to deliver targeted interventions.
Hospital charts of 252 subjects with subacute stroke were reviewed to determine whether clinicians (physicians, occupational and physiotherapists) had identified neglect as a presenting symptom on their initial assessment. Subjects were assessed in the research laboratory using the conventional sub-tests of the BIT and underwent robotic assessment of position sense (PM: sense of limb location) and kinesthesia (KIN: sense of movement) on the KINARM exoskeleton . Failure on each of the robotic tests was determined via comparison to the 95% limits of normative control data.
Seventy subjects were determined by clinicians to have neglect versus 56 subjects that were identified as having neglect through the BIT. One-hundred twenty-six subjects failed PM, while 163 failed KIN. The majority of subjects that failed the BIT also had clinician identified neglect (C+, BIT+ N=40). However, 30 subjects identified by clinicians actually passed the BIT (> 129) (C+,BIT-). Many subjects who failed the BIT were not identified by clinicians (C-,BIT+, N=16). We found that nearly all subjects in the C+,BIT+ and C-,BIT+ groups had significantly impaired PM (C+,BIT+=90% N=36, C-,BIT+=75%, N=12) and KIN (C+,BIT+=98% N=39, C-,BIT+=100%, N=16). We found that many subjects in the C+BIT- group had significant proprioceptive impairments (PM=57%, N=17, KIN=73%, N=22). When we compared the proportion of C+BIT- subjects with proprioceptive impairments to those subjects with normal BIT and no clinician-identified neglect (C-,BIT- N = 166, PM=37%, KIN=52%), we found a 20% higher proportion of subjects failing proprioceptive tasks in the C+BIT- group.
We found that many individuals identified by clinicians as having neglect with negative testing on the BIT had significant proprioceptive impairments according to performance on robotic measures of proprioception. We question whether clinicians are misidentifying proprioceptive loss as visuospatial neglect. This speaks to the necessity for better and more sensitive assessments of post-stroke impairments.
F35: Transcranial Direct Current Stimulation Lessens Dual Task Cost in People with Parkinson’s Disease
Texas Woman’s University, Dallas, TX, USA
F36: Characterizing Impairments in Digit Angular Excursion and Individuation in Different Shoulder Positions Post-Stroke
1New York University School of Medicine, New York, New York, USA, 2Columbia University, New York, New York, USA, 3New York University Physical Therapy, New York, New York, USA
The ability to move the fingers independently is necessary to perform everyday tasks such as typing, grasping objects of different shapes and playing music. A stroke invariably leads to impaired finger independence particularly for finger extension. It has been suggested that arm posture and orientation can affect finger independence. Here we characterize finger independence in the affected hand in subjects with chronic stroke and determine its relationship to arm posture. Thirteen subjects, 28-81 years, with chronic hemiparesis at least 6 months post-stroke participated in the study. The degree of upper limb motor impairment was assessed using the Fugl-Meyer Scale (FMS). Subjects were asked to perform three 15-second cyclical maximal flexion-extension movements of an instructed finger from the MCP joints of the affected and unaffected hands, while keeping all the other fingers as still as possible in three different shoulder positions: (1) shoulder neutral and elbow flexed to 90 degrees, (2) shoulder flexed to 90 degrees, and (3) shoulder abducted to 90 degrees. The forearm was supported in all three positions. The angular displacement, frequency and distance travelled by the fingers were recorded using an instrumented glove (Cyberglove, Immersion Corp., San Jose, CA). We computed the frequency of finger excursions, the extent of finger flexion and extension, and the individuation index which reflects the degree to which the instructed finger moves while keeping all the other fingers still. The metrics were compared across the three shoulder positions. We found that the frequency of finger excursions and the degree of flexion were greater in the shoulder neutral position across most subjects. The degree of finger extension and individuation varied across individuals: subjects with severe motor impairment (FMS<20) showed greater finger extension and individuation in the shoulder neutral position, whereas subjects with moderate motor impairment (FMS=20-50) showed higher finger individuation and/or finger extension in the shoulder flexed or abducted position. The results suggest that the effect of shoulder position on finger independence depends on the stage of recovery likely due to the effect of arm posture on potentiation of spasticity and synergy patterns. Using shoulder positions that inhibit spasticity may be helpful in training finger individuation and/or extension.
F37: Statin Medication Use and Nosocomial Infection Risk in the Acute Phase of Stroke
1St. Luke’s Rehabilitation Institute, Spokane, WA, USA, 2Providence Sacred Heart Medical Center, Spokane, WA, USA
F38: Use of the GesAircraft Video Game for Upper Limb Rehabilitation in Stroke: A Pilot Study
1Burke Medical Research Institute, White Plains, NY, USA, 2Cornell University, New York, NY, USA, 3GesTherapy, Inc, Brooklyn, NY, USA
F39: Reactive and Voluntary Stepping in Individuals With Stroke: A Comparison Between Paretic and Nonparetic Leg Responses
1University of Maryland Baltimore, Baltimore, MD, USA, 2Ritsumeikan University, Kusatsu, Japan
F40: Towards Assessing Mobility in Parkinson’s Disease Patients Using a Single 3D Sensor
1Integrated Media Systems Center, University of Southern California, Los Angeles, CA, USA, 2Division of Biokinesiology and Physical Therapy University of Southern California, Los Angeles, CA, USA
For number of disabilities, e.g., Parkinson’s Disease (PD), optimized medication and rehabilitation plans require reliable and frequent mobility assessments. Current clinical scales, e.g., the Unified Parkinson’s Disease Rating Scale (UPDRS) lack resolution and rely on subjective visual observation. Our Point of Care Mobility Monitoring (POCM2) system uses Kinect to monitor a patient who performs a standardized task. As such POCM2 has the potential to provide an objective assessment solution that can be deployed in the home. We discuss preliminary results of a study where POCM2 was used to characterize the medication state of 14 PD patients, as suggested by the observation that gait in persons with PD can be improved by medication. We report results of a dual-task walking task (i.e., walking in a figure-of-eight pattern while counting backward) for which the Kinect sensor was most accurate while the cognitive task introduces an additional challenge that accentuates the differences between on and off medication conditions. At each timestamp, we considered a subset of 15 nodes (head, neck, torso, shoulders, elbows, hands, hips, knees and feet) of the skeleton that Kinect produces in conjunction with the self-reported most affected side. Steps and strides were automatically segmented (we excluded turns and measurements on segments of the trajectory where the sensor did not have a good viewing angle). Subsequently, steps and strides were used to derive linear and angular kinematic measurements. In the process, post-processing was applied to recover left and right side of the body (Kinect assumes the person is facing the sensor), and limit the maximum extent of joints (Kinect does not constrain joint angles). Each variable was measured multiple times over the course of two trials and the average was used for the statistical analysis. The statistical analysis indicated that left step length and step length grouped by most affected side were both statistically significant (p<0.05). For least affected steps, standard deviation of most affected shoulder angle (p=.003), least affected shoulder angle (p=.001), most affected hip angle (p=.009) and least affected hip angle (p=.002), and for most affected steps, the average least affected hip angle (p=.011), standard deviation of most affected knee angle (p=.008), least affected shoulder angle (p=.001), most affected shoulder angle (p=.008), least affected hip angle (p=.001) and most affected hip angle (p=.001) were statistically significantly different. These statistical results validate the feasibility of using Kinect to objectively assess the medical state in PD patients. Future work includes completing the study with additional patients to achieve significance for other variables, extending to use additional individual information, using insights from the statistical analysis to inform feature selection for machine learning approaches and extending to use data obtained from wearable sensors to ultimately provide fine grained automated mobility assessment methods.
F41: Rehabilitation-Based Motor Pattern Differences after Biological and Bionic Therapies in Spinal Cord Injury (SCI)
1Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia,PA, USA, 2Biomedical Engineering, Drexel University, Philadelphia, PA, USA
The goal of this work was to investigate the underlying organization of muscle activations for locomotion during complete SCI (cSCI) rehabilitation. The clinical utility of multi-modal rehabilitation approaches is a growing area of investigation. For example, epidural stimulation (ES) used in combination with rehabilitation training has recently driven improved motor function in patients recovering from severe SCI. Here, we investigate the combined therapies of robot rehabilitation and Adeno-associated viral delivery of Brain-derived neurotrophic factor (AAV5-BDNF) for locomotive rehabilitation following cSCI in a rat model, followed by addition of robot-driven epidural stimulation. We use information-based techniques (i.e., Independent Component Analysis or ICA) to decompose multi-site muscle recordings to examine dimensionality, identify underlying motor modules, and monitor module structure throughout rehabilitation. SD rats (n=3) were implanted with nine intramuscular EMGs in the right hindlimb, from which baseline EMG recordings were made prior to complete transection (T10) and implantation with stimulating electrodes placed on the spinal cord surface (L2 and S2). All rats received AAV5-BDNF microinjections caudal to injury into the ventral horn of the cord, eliciting spontaneous reflex stepping. After recovery, animals were treadmill trained with robotic pelvic rehabilitation therapy (20 min/session) for three weeks, followed by a second phase of robot-driven (as needed) ES for another three weeks. Throughout training, 2 minutes of perineal stimulation was used to elicit strong stepping every other training session. ICA was used to decompose these EMG recordings into informationally distinct underlying motor modules, and to examine the specific contributions of muscles to each of the modules. Weight matrices were compared among sessions across the training period using correlation. These weight matrix correlations revealed distinct groupings across time. First, there were higher correlations in the weeks before epidural stimulation. Spinalized rats initially showed weak local correlations between weight matrices, and intact rat modules, which then strengthened over this period. ES applied subsequently altered these correlations, suggesting a transition in control and modularity occurred between the two rehabilitation phases. The modules no longer correlated as well with intact rats, even after achieving internal stability with a return to high correlations among days achieved in the final two weeks. The modules after ES training correlated less well with the intact rat modules compared to the AAV5-BDNF rehab phase. In sum, contributions of muscle activity to these decompositions appear to be different between the No ES and ES phases of the rehabilitation. These data suggest that early spontaneous locomotive recovery aided by AAV5-BDNF elicits contributions of muscle activations to locomotive recovery that more closely resemble pre-transection patterns than do those observed during ES. Furthermore, dimensionality and muscle contributions alter throughout rehabilitation but different modalities of therapy appear not to elicit the same spinal muscular groupings / activations during recovery.
Support for this research provided by the Brody Family Medical Trust Fund Fellowship in “Incurable diseases” of The Philadelphia Foundation.
F42: Associations Between Foot Cutaneous Sensation and Muscle Activation Patterns During Unexpected Lateral Perturbations After Stroke
University of Maryland, Baltimore, USA
A protective step is commonly used as a strategy to recover and stabilize the body when one’s balance is disturbed. After a stroke, balance recovery is difficult with many falls occurring as weight is transferred laterally. Foot plantar sensation may normally be an important sensory input contributing to the sensorimotor control of protective stepping that can be disrupted following stroke. The purpose of this study was to determine the associations between foot plantar cutaneous sensation and muscle activation patterns during protective stepping in response to an unexpected lateral waist-pull to the paretic and non-paretic side in persons with chronic stroke.
Fourteen community dwelling individuals who were > 6 months post-stroke participated in the study. Participants were fitted into a safety harness and were tested using a lateral waist-pull system to induce steps. There were 18 randomly ordered trials and participants were instructed to react naturally and prevent themselves from falling. The electromyographic (EMG) activity was recorded bilaterally from the adductor magnus (AD), gluteus medius (GM), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and soleus (SOL) muscles with surface electrodes during 18 lateral waist-pull trials. Cutaneous sensation was assessed on the plantar aspect of the foot with monofilaments. Correlation coefficients (r) were calculated to determine the strength of associations between the EMG onset and magnitude and cutaneous sensation.
The first recovery step was initiated by the non-paretic leg 63. 4% of the time and 36.6% by the paretic leg. For non-paretic leg stepping, greater impairments in cutaneous sensation of the paretic foot were correlated with an increased EMG area of the GM (r=0.27; p=0.003), RF (r=0.40; p<0.001) and TA (r=0.26; p=0.003) muscles. The EMG area was increased by 27.7% in the GM, 61.4% in the RF and 51.5% in the TA muscles during the first recovery step. For the paretic limb steps, greater impairments in cutaneous sensation were correlated with the initiation time of the AD (r=0.28; p=0.05), GM (r=0.40; p=0.002) and TA (r=0.34; p=0.01) muscles. However, significant differences from the non-paretic limb in the initiation time were only found in the paretic AD (p=0.002) and GM (p=.008) muscles, with a delay of 130 and 110 ms.
The results indicated that persons with more severe sensory impairments of the paretic foot compensate with increased muscle activity when recovering balance with the non-paretic limb. They also, have a delayed onset of muscle activity in the paretic hip muscles when the first step used to recover balance was the paretic leg. This demonstrates the importance of plantarflexor cutaneous sensation and the role it plays in the ability to recover balance from an expected perturbation after a stroke.
Grant Support: AHA 14CRP19880025; NIDRR H133F140027; NIDRR H133P100014
F43: Towards a Low-Cost Alternative for BCI-aided Neurorehabilitation: A Comparison of the Emotiv Epoc to a Clinical EEG System
1University of California, Irvine, Irvine, California, USA, 2Purdue University, West Lafayette, Indiana, USA
Brain-computer interfacing (BCI) is a form of human-machine interaction with potential to enhance rehabilitation therapy after neurological injuries. The most common method used to capture data in BCI is electroencephalography (EEG). In EEG, electrodes embedded in a non-invasive cap detect electrical signals over the user’s scalp. The BCI then decodes these signals to control an external device, such as a wheelchair or exoskeleton robot.
Although EEG has proven useful for neurorehabilitation, typical systems are very expensive, limiting their use to clinical and research settings. In recent years, low-cost alternatives, such as the Epoc by Emotiv©, have targeted widespread use of BCI including bringing BCI into the home.
In this study, we compared the low-cost Epoc headset to a more expensive clinical grade EEG system: the EGI Clinical Geodesic hydrocel. The Epoc consists of 14 dry electrodes and samples at 128 Hz, while the EGI uses 256 electrodes and samples at 1000 Hz. We collected data from six (N=6) unimpaired subjects (4 right-handed, 5 Female) using their left hand to play a musical computer game, similar to Guitar Hero©. Participants received robotic assistance from the Finger Individuated Grasping Exercise Robot (FINGER). We used a two factor, two level factorial design where the factors were robot assistance (on or off) and overt motor activity by the subject (active or passive) resulting in 4 experimental conditions. Participants completed a total of 62 trials in each condition.
We investigated the ability of each EEG system to reliably detect Event Related Desynchronization (ERD), a commonly used signal for BCI-contingent robot therapy. ERD refers to the reduction in amplitude of mu (8-13 Hz) oscillations over the sensorimotor cortex, known to precede both overt and imagined movement.
The more expensive EGI headset detected significant ERD in all subjects and all movement conditions when compared to passive recording (t-test, p < 0.01). The less expensive Epoc detected ERD for only one subject when the participant was active (within-subject MANOVA, p = 0.0383). The magnitude of ERD was also significantly greater with the EGI headset (t-test, active subject, p < 0.01).
The importance of the sensorimotor cortex in neurorehabilitation means that any EEG system used for BCI must reliably detect motor signals such as ERD. The 14 channels of the Epoc do not adequately cover the scalp, most closely approaching sensorimotor cortex with electrodes at F3/F4 and FC5/FC6. It is likely that the Epoc detected ERD in these nearby channels in one subject through volume conduction, as evidenced by the reduction in ERD magnitude. Although the Epoc shows promise in its ability to detect raw EEG, its electrode placement meant it was unable to reliably detect ERD, thus limiting its potential for applications in robotically assisted therapy.
F44: Employing Patient’s Individual Characteristics to Derive Personalized Brain Stimulation Therapies
1Cleveland Clinic, Cleveland/Ohio, USA, 2Sao Paulo University, Sao Paulo, Brazil
F45: Compensatory Stepping in People with Multiple Sclerosis
1Veterans Affairs Portland Health Care System, Portland, OR, USA, 2Oregon Health & Science University, Portland, OR, USA, 3University of Kansas Medical Center, Kansas City, KS, USA
F46: Changes in Corticomuscular Coherence Associated with Different Levels of Isometric Hand Force Production Using MEG
1School of Physical & Occupational Therapy, McGill University, Montreal, Quebec, Canada, 2McConnell Brain Imaging Centre, Montreal Neurological Institute, Montreal, Quebec, Canada
TF: M1 and SMA exhibit an increase in beta activity during the holding periods (low and high) that decreases during the ramp period. Similar behaviour was observed for the FDI, ECU and EDC muscle signals, as previously reported [1]. The 20-50% condition exhibited the greater modulation with force.
CMC: An increase in CMC was found in the beta range between MEG and EMG signals during the two holding periods. In particular, M1 and EDC, showed the greatest coherence. This effect diminishes when higher forces were produced.
[1] Kilner et al.,The Journal of Neuroscience, December 1, 2000, 20(23):8838-8845
F47: Distribution of Corrective Movements Differ in People Post Stroke During Paretic Arm Reaching
1Veterans Affairs Medical Center, Washington, District of Columbia, USA, 2MedStar Health Research Institute, Washington, District of Columbia, USA, 3MedStar National Rehabilitation Hospital, Washington, District of Columbia, USA, 4Georgetown University, Washington, District of Columbia, USA, 5George Mason University, Fairfax, Virginia, USA
Following stroke, individuals with severe movement impairments commonly have difficulty reaching. To optimize rehabilitation paradigms to improve reaching movements of people post stroke, it is crucial to characterize how reaching in this population differs from those with more mild movement impairments. Movement units (reversals in tangential velocity of the hand during a reach) have been previously used to describe reaching in people post stroke, however this measure may not fully capture differences between functional groups.
The purpose of this study was to develop a novel analysis technique to describe forward reaching by utilizing the onset of corrective movements in people post stroke. We hypothesized that the distribution of corrective movements in people with severe movement impairment would differ compared to people with mild arm impairment post stroke.
Upper extremity function was categorized by score on the Upper Extremity Fugl-Meyer [UEFM] (Severe: score <30; Mild: UEFM score >35). Twenty-five people post stroke (14 mild UEFM: 52.3+9.7; 11 severe UEFM: 17.8+8.4) completed a forward reach task with the paretic limb. Participants completed forward reaching movements with the paretic arm in response to a visual ‘Go’ cue to targets located at 80% of their maximum voluntary reach distance.
Reach duration was normalized to one hundred data points for each trial. Movement units were identified by significant positive peaks in x-y (horizontal plane) tangential velocity of the hand. Peaks were considered significant if the height of a peak exceeded 15% of the maximum peak velocity. This analysis included 131 forward reaches by people with mild movement impairment and 99 forward reaches by participants with severe arm movement impairment. Analysis was conducted using custom Matlab programs with a significance level identified a priori at p<0.05.
A two-sample Kolmogorov-Smirnov test was used to compare the cumulative distribution functions (CDFs) of movement units throughout time-normalized reach in people with mild or severe impairment. The null hypothesis that movement units in mildly- and severely-affected stroke patients are similarly distributed during reach was rejected (test statistic 0.201, p = 0.004). The results indicate the onsets of corrective movements are unequally distributed in time during reaching in people with mild and severe arm impairment post stroke.
These results suggest that people with severe arm impairment initiate corrective movements at the mid-point of the forward reach, suggesting a greater dependence on visual feedback. Individuals with mild arm impairment had greater occurrence of corrective movements in the final 10% of the time-normalized reach suggesting a more smooth velocity profile with a corrective movement to make contact with the target. Further analyses are necessary to describe corrective movements during a forward reach in people with severe arm impairment.
F48: Clinical Characteristics Changes of Phantom Phenomen After Traumatic Limb Amputation
Department of Rehebilitation Medicine, Faculty Of Medicine, University Of Indonesia, Jakarta, Indonesia, Indonesia
F49: Electrophysiological Mechanisms Underlying Visual Feedback in Prism Adaptation
1Dalhousie University, Halifax, Nova Scotia, Canada, 2University of Victoria, Victoria, British Columbia, Canada
F50: The Control of Grasp Force for Individuals Who Suffered a Stroke and Age-Matched Controls
Wayne State University, Detroit, MI, USA
We acknowledge support for this study Blue Cross Blue Shield of Michigan Foundation
F51: Validation of Reaching Movements Made in a 2D Virtual Environment in Typically Developing Children
1Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada, 2Center for interdisciplinary research in rehabilitation of greater montreal, Montreal, Quebec, Canada, 3School of Physical and Occupational Therapy, McGill University, Montreal, Quebec, Canada
The ultimate goal of rehabilitation is to improve movement kinematics which can be described at two levels: movement quality and motor performance. Measurement of change in movement quality and performance over time is also a method to identify motor learning. Motor learning is based on different principles which can be manipulated in treatment interventions by a therapist or through the use of interactive computer technology, such as virtual reality. Our aim was to compare the kinematics of movements in a physical environment to a similar virtual environment in typically-developing children. Participants (children; 8-17yrs) completed the Edinburgh Handedness Inventory to identify the dominant arm. They practiced reaching in the virtual environment to become familiar with the task. Then, they performed a series of 3 gestures (frontal, vertical and sagittal arm movements) in two environments: virtual and physical environments for a total of 6 gestures. 3D movement kinematics of the arm and trunk were recorded with 6 wireless electromagnetic sensors (G4, Polhemus, Vermont, 120Hz). Participants completed 15 trials of each gesture in each environment (45 trials per environment, for a total of 90 trials). The virtual environment consisted of an interactive game controlled by arm and hand movements (Jintronix, Montreal) projected on a computer monitor. Movements throughout the arm workspace were recorded with a Microsoft Kinect camera and projected into the game scene. Movements made in the virtual environment were less precise, slower and shorter in comparison to those made in the physical environment. In the virtual environment, participants used less trunk displacement in comparison to the physical environment. There were no significant differences between the two environments with respect to the range of motion of the elbow and the shoulder. Differences between movements made in each environment can be explained by less precise body position tracking in the virtual environment, decreased quality of the visual scene and differences in depth perception cues. The overall similarities of movements made in the two environments suggest that training in 2D game-like virtual reality environments may be feasible for motor rehabilitation of children.
F52: Alterations in Cortical Laterality Among Individuals at Risk for Stroke: A Functional MRI Study in Controls and Patients
Medical University of South Carolina, Charleston, USA
F53: Avoidance Strategies in Response to Animate and Inanimate Obstacles in Young Healthy Individuals Walking in a Virtual Reality Environment
1McGill University, School of Physical and Occupational Therapy, Montreal, Quebec/QC, Canada, 2McGill University, Integrated Program in Neuroscience, Montreal, Quebec/QC, Canada, 3Feil and Oberfeld Research Center, Jewish Rehabilitation Hospital, Laval, Quebec/QC, Canada
Many studies have described obstacle avoidance strategies while walking, either in physical or virtual environments. These studies, however, were limited to the avoidance of inanimate objects (e.g. cylinders) or failed to address the influence of the visual and auditory properties of the obstacle in shaping avoidance strategies. This study aims to describe the extent to which three different types of obstacles (cylinder, visual human-like avatar and visual human-like avatar with footsteps sounds) affect the inherent avoidance strategies in young healthy individuals. Healthy young adults (n=4, 50% male, aged 24.7 ±3.5 years (mean ±1SD)) were tested while walking over ground and viewing a virtual environment (VE) displayed in a helmet mounted display (HMD) unit (nVisor SX60). The VE, controlled in Caren-3 (Motek medical), simulated a large room that included a target located 11m straight ahead. In addition, three identical obstacles were positioned 7m ahead in three locations facing the subject (40° right, 40° left, and straight ahead). As the subjects walked 0.5m, one of the three obstacles approached them by walking/moving towards a theoretical point of collision located 3.5m ahead at the midline. Meanwhile, the two remaining obstacles moved/walked away from the participants. The ability of the subjects to steer toward the target while avoiding the obstacles was characterized using the 3D position and orientation of the head recorded from reflective markers (Vicon) placed on the HMD. Preliminary findings show a trend towards smaller minimal distances in all directions when interacting with human-like avatars (left: 1.25±0.47; center: 1.22±0.20; right: 1.31±0.24) as compared to cylinders (left: 1.49±0.26; center: 1.29±0.12; right: 1.52±0.17). The addition of footstep sounds to human-like avatars did not modify minimal distance values compared to when no footstep sounds were provided (left: 1.20±0.39; center: 1.71±0.14; right: 1.31±0.28). Onset times of avoidance strategies were similar across all conditions. These findings suggest that participants had equivalent movement perception of the obstacles regardless of the condition displayed. They also indicate that smaller clearances in the presence of human-like entities may occur due to an inherent real life perception of the avatars resulting in actions that rely on strategies applied during daily locomotion. Finally, the similarity of results following the addition of footstep sounds to the visual human-like avatar condition suggests that avoidance strategies may primarily rely on visual cues.
F54: Muscle Fatigability and Subsequent Torque Decline During Isometric and Isokinetic Knee-Extension Generated by Sequential Electrical Stimulation
1Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada, 2Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
F55: Subcortical Influences on Paired-pulse TMS-induced I-waves in Humans
1University of Auckland, Auckland, New Zealand, 2University of Pittsburgh, Pittsburgh, PA, USA, 3University of Miami, Miami, FL, USA
Paired-pulse transcranial magnetic stimulation (TMS) of the human motor cortex results in consecutive facilitatory motor evoked potential (MEP) peaks in surface electromyography, allowing the possibility to make non-invasive inferences about the physiology of indirect (I) waves. Using paired-pulse TMS over the hand motor cortex of intact humans and individuals with incomplete cervical spinal cord injury (SCI), we examined early (first) and late (second and third) MEP peaks in a resting finger muscle. In uninjured subjects, we demonstrate a reduced amplitude and duration of the third peak compared with the second, irrespective of test (S1) intensity. A higher conditioning (S2) intensity increased the amplitude of the third but not second peak. No difference in amplitude and duration was found between the first and second peaks. A threshold electrical S2 over the cervicomedullary junction facilitated the second and third but not the first peak similarly to TMS. In SCI subjects, we found a decreased amplitude for all MEP peaks compared with controls. The onset of the second and third peaks were delayed, with the third peak also showing an increased duration. The delay of the third peak was smaller than in controls at a lower stimulation intensity, suggesting lesser influence of decreased corticospinal inputs. A mathematical model showed that the third peak aberrantly contributed to spinal motoneurone recruitment after SCI, irrespective of motor unit threshold. Additionally, temporal and spatial aspects of late peaks in SCI subjects correlated with MEP size and hand motor output. Our results indicate that TMS-induced MEP peaks undergo distinct modulation after SCI, with the third peak likely reflecting a decreased ability to summate descending volleys at the spinal level. We argue that subcortical pathways contribute to late TMS-induced peaks in humans with and without SCI.
F56: Memantine Treatment for Post-stroke Aphasia: A Case Control Study
Burke Rehabilitation Hospital, White Plains, NY, USA