Microstructural white matter changes following gait training with Hybrid Assistive Limb initiated within 1 week of stroke onset.

The early initiation of robot-assisted gait training in patients with acute stroke could promote neuroplasticity. The aim of this study was to clarify the microstructural changes of white matter associated with gait training using Hybrid Assistive Limb (HAL) by diffusion tensor imaging (DTI). Patients with first-ever stroke and requiring a walking aid started gait training within 1 week of stroke onset. The patients were quasi-randomly assigned either to the conventional physical therapy (CPT) group or gait training using HAL (HAL) group. Motor function and DTI were examined at baseline and after 3-5 months. Voxel-based statistical analyses of fractional anisotropy (FA) images were performed using diffusion metric voxel-wise analyses. Volume of interest (VOI)-based analyses were used to assess changes in FA (ΔFA). Twenty-seven patients (17 in the CPT group and 10 in the HAL group) completed the study. There were improvements in motor function and independency in the CPT and HAL groups (p < .001). Compared to baseline, there were decreases in FA in the ipsi-lesional cerebral peduncle in the CPT group (p < .001) and increases in the contra-lesional rostrum of the corpus callosum in the HAL group (p < .001) at the second assessment, consistent with the mean ΔFA in each group from VOI analysis (CPT/HAL: cerebral peduncle, -0.066/-0.027, p = .027; corpus callosum, 0.002/0.042, p < .001). Gait training using HAL initiated within 1 week after stroke onset facilitated the recovery of inter-hemispheric communication and prevented the progression of Wallerian degeneration of the affected pyramidal tract.