Longitudinal changes in the inferior cerebellar peduncle and lower limb motor recovery following subcortical infarction.

Background: The cerebellum receives afferent signals from spinocerebellar pathways regulating lower limb movements. However, the longitudinal changes in the spinocerebellar pathway in the early stage of unilateral supratentorial stroke and their potential clinical significance have received little attention.

Methods: Diffusion tensor imaging and Fugl-Meyer assessment of lower limb were performed 1, 4, and 12 weeks after onset in 33 patients with acute subcortical infarction involving the supratentorial areas, and in 33 healthy subjects. We evaluated group differences in diffusion metrics in the bilateral inferior cerebellar peduncle (ICP) and analyzed the correlation between ICP diffusion metrics and changes to the Fugl-Meyer scores of the affected lower limb within 12 weeks after stroke.

Results: Significantly decreased fractional anisotropy and increased mean diffusivity were found in the contralesional ICP at week 12 after stroke compared to controls (all P < 0.01) and those at week 1 (all P < 0.05). There were significant fractional anisotropy decreases in the ipsilesional ICP at week 4 (P = 0.008) and week 12 (P = 0.004) compared to controls. Both fractional anisotropy (r = 0.416, P = 0.025) and mean diffusivity (r = -0.507, P = 0.005) changes in the contralesional ICP correlated with changes in Fugl-Meyer scores of the affected lower limb in all patients.

Conclusions: Bilateral ICP degeneration occurs in the early phase of supratentorial stroke, and diffusion metric values of the contralesional ICP are useful indicators of affected lower limb function after supratentorial stroke.