Poststroke Ipsilesional Motor Performance: Microstructural Biomarkers and Their Associations With Executive Function.

Background: Unilateral hemispheric stroke can impair the ipsilesional motor performance, which is crucial for attaining optimal functional outcomes poststroke. However, the specific brain structures contributing to ipsilesional motor performance impairment remain unclear.

Objective: To explore the link between ipsilesional motor performance and the microstructural integrity of relevant neural pathways.

Methods: This study enrolled 60 consecutive patients in the early subacute phase of stroke recovery. Ipsilesional motor performance was assessed using the Box and Block Test. Multiple linear regression was used to evaluate the associations between ipsilesional motor performance and the microstructural integrity of relevant white matter tracts (Biomarker models) and cognitive function test scores (Cognition models).

Results: Biomarker models, including the genu of the corpus callosum, ipsilesional cingulum, fornix, uncinate fasciculus, superior longitudinal fasciculus, and contralesional inferior longitudinal fasciculus, showed a significant association with ipsilesional motor performance. Cognition models, including Mini-Mental State Examination and Trail Making Test-B, were significantly associated with ipsilesional motor performance. Final regression models (combined Cognition and Biomarker models) revealed that the performance time of Trail Making Test-B, in combination with biomarkers, including the genu of the corpus callosum, ipsilesional superior longitudinal fasciculus, and ipsilesional cingulum, predicted ipsilesional motor performance with high explanatory power (adjusted R² = .721, .709, and .696, respectively).

Conclusions: This study demonstrated that executive function is associated with poststroke ipsilesional motor performance, as evidenced by the microstructural biomarkers involved in executive function. Our findings highlight that the comprehensive role of cognitive functioning rather than the motor system is closely linked to poststroke ipsilesional motor performance.