Altered structural connectivity associated with motor improvement in chronic supratentorial ischemic stroke

This study aimed to identify brain structural changes associated with motor recovery, after neurorehabilitation in patients with chronic supratentorial ischemic stroke. Twenty-one chronic stroke patients with an improved Fugl-Meyer motor assessment score were retrospectively included in the study. All participants underwent diffusion tensor imaging twice: before and after the outpatient neurorehabilitation program. A fractional anisotropy map, derived from diffusion tensor imaging, was used to identify changes in brain structural connectivity. A paired t-test of the fractional anisotropy maps was performed to calculate statistical significance. Structural connectivity was significantly increased along the corticospinal tract pathway in the ipsilesional hemisphere (uncorrected P<0.005 with cluster size>10 voxels). The posterior corpus callosum, which connects the bilateral hemispheres, and the bilateral middle cerebellar peduncle, which is the main pathway of the afferent fibers from the cerebrum to cerebellum, also showed significantly increased structural connectivity (uncorrected P<0.005 with cluster size>10 voxels). Motor-associated brain regions, mainly in the ipsilesional hemisphere, were involved in motor improvements in patients with chronic supratentorial ischemic stroke. These findings could be incorporated into the neurorehabilitation of chronic stroke patients for improved motor recovery.