Structural remodeling of white matter in the contralesional hemisphere is correlated with early motor recovery in patients with subcortical infarction

PURPOSE: This study aimed to identify brain areas with white matter changes that contribute to motor recovery of affected limbs during acute to sub-acute phases of subcortical infarction. METHODS: Diffusion tensor imaging was performed 1, 4, and 12 weeks after stroke onset in 18 patients with acute subcortical infarct, and in 18 age- and risk factor-matched controls. Fugl-Meyer scale was used to assess levels of motor impairment, and Statistical Parametric Mapping was applied to determine fractional anisotropy (FA) changes for the entire brain in order to identify areas correlated with motor recovery. RESULTS: Fugl-Meyer scores of patients at 4 and 12 weeks were significantly higher than those at 1 week (all p < 0.01). Accompanying with the progressive decreases of FA in the corticospinal tract above and below the stroke lesion, progressive increases of FA in the contralesional medial frontal gyrus, and thalamocortical connections including projections to the somatosensory cortices, primary motor cortex, and premotor areas, were positively correlated with Fugl-Meyer scores (all p < 0.005) within 12 weeks following acute subcortical infarction. CONCLUSIONS: Remodeling of white matter in contralesional brain regions related to motor, cognition, and sensory processing may facilitate early motor recovery in patients with an acute infarct.