The following article has just been accepted for publication in Journal of Neurologic Physical Therapy.
“Increased Sensorimotor Cortex Activation with Decreased Motor Performance during Functional Upper Extremity Tasks Post-Stroke”
By Shannon B Lim, MSc, MPT; Janice J Eng
Background: Current literature has focused on identifying neuroplastic changes associated with stroke through tasks and in positions that are not representative of functional rehabilitation. Emerging technologies such as functional near-infrared spectroscopy (fNIRS) provide new methods of expanding the area of neuroplasticity within rehabilitation.
Purpose: This study determined the differences in sensorimotor cortex activation during unrestrained reaching and gripping after stroke.
Methods: 11 healthy and 11 chronic post-stroke individuals completed reaching and gripping tasks under three conditions using their 1) stronger, 2) weaker, and 3) both arms together. Performance and sensorimotor cortex activation using fNIRS were collected. Group and arm differences were calculated using mixed ANCOVA (covariate: age). Pairwise comparisons were used for post-hoc analyses. Partial Pearson’s correlations between performance and activation were assessed for each task, group, and hemisphere.
Results: Larger sensorimotor activations in the ipsilesional hemisphere were found for the stroke compared to healthy group for reaching and gripping conditions despite poorer performance. Significant correlations were observed between gripping performance (with the weaker arm and both arms simultaneously) and sensorimotor activation for the stroke group only.
Discussion: Stroke leads to significantly larger sensorimotor activation during functional reaching and gripping despite poorer performance. This may indicate an increased sense of effort, decreased efficiency, or increased difficulty after stroke.
Conclusion: fNIRS can be used for assessing differences in brain activation during movements in functional positions after stroke. This can be a promising tool for investigating possible neuroplastic changes associated with functional rehabilitation interventions in the stroke population.
Supplemental Digital Content 1. Video abstract .mp4
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