Date Presented Accepted for AOTA INSPIRE 2021 but unable to be presented due to online event limitations.
Upper extremity (UE) functional recovery after stroke requires the integration of motor and sensory systems. We describe the relationship among recovery of somatosensation, motor impairment, and manual dexterity from acute to 3 months poststroke. Sensory retraining emphasized in conjunction with motor interventions after stroke may improve functional UE outcomes.
Primary Author and Speaker: Isha Vora
Contributing Authors: David Lin, Julie DiCarlo, Jessica Ranford, and Teresa J. Kimberley
PURPOSE: One of the fundamental challenges in stroke rehabilitation is a limited understanding of how to enhance individual recovery beyond natural restitution of function. Thus, people are often left with life-altering impairments after stroke. By some estimates, 50% of people have upper extremity (UE) sensory deficits post stroke. Current practice focuses largely on training the motor system, with relatively little regard to the important effects of the somatosensory system on motor performance. It is well known that the motor system is highly influenced by sensory inputs, and research has begun to show that sensory retraining is associated with improved motor outcomes. Understanding the relationship between the recovery of UE somatosensation, motor impairment, and dexterity is an important first step in developing optimally effective intervention strategies for clients after stroke.
DESIGN: Cohort data were obtained from a longitudinal and observational Stroke Motor Recovery natural history Study (SMaHRT; NCT03485040) at an academic hospital in Boston, Massachusetts. Participant characteristics, medical history and a battery of clinical and research assessments were collected by clinicians or trained study staff during the acute hospitalization, and at approximately 3 months post-stroke.
METHOD: This is an exploratory, retrospective, cohort analysis using data from an observational, longitudinal stroke recovery study. Upper extremity motor impairment [Upper Extremity Fugl-Meyer Assessment (FMA-UE); 9 Hole Peg Test (9HPT)] and somatosensory impairment (NIH Stroke Scale-Item 8) were measured. The NIH Stroke Scale-Item 8 rates pinprick on a 0, 1, or 2-point scale, indicating normal sensation, mild-moderate, or severe-total sensory loss, respectively. Participants were divided into two sensory groups (Normal, Impaired). People in the normal sensory group had normal sensation by 3 months post stroke. People in the impaired sensory group had impaired sensation at 3 months post stroke. Participants were also grouped according to baseline UE motor impairment severity (Mild, Moderate, Severe) determined by FMA-UE. While our analysis looked at all groups, we primarily focused on people with baseline moderate motor impairment (FMA-UE >20 and <47). Our dependent variable was the change in FMA-UE and 9HPT scores between acute hospitalization and 3 months. Mean differences were calculated between sensory groups and effect size differences were compared between groups.
RESULTS: Twelve participants with moderate baseline motor impairment were included in this preliminary analysis. Participants in the normal sensory group had a change in FMA-UE score of 26.17 ± 9.45 (mean ± SD) and a change in 9HPT score of -113.83 ± 9.45 seconds from acute hospitalization to 3 months. Participants in the impaired sensory group had a change in FMA-UE of 24.00 ± 9.96 and a change in 9HPT scores of -55.22 ± 64.54 seconds from acute hospitalization to 3 months. There was a large effect in 9HPT change scores between those with normal vs impaired sensation, T(10) = -1.84, p = 0.096, d = -5.80.
CONCLUSION: The recovery of UE dexterity is related to the recovery of somatosensation post-stroke. Despite similar improvements in motor impairment from acute hospitalization to 3 months, people with impaired sensation did not improve manual dexterity to the same degree as people with normal sensation. Understanding the impact of somatosensory recovery on dexterity may expand the emphasis of UE rehabilitation after stroke to both motor and sensory retraining. Future work should focus on the use of more precise sensory measures and longitudinal modeling to help predict more robust outcomes associated with sensorimotor relationships.
References
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