Modification of Cerebellar Afferent Pathway in the Subacute Phase of Stroke

Background: This study aims to identify the relationship between corticopontocerebellar tract (CPCT) and corticospinal tract (CST) integrity as well as motor function after stroke. Materials and Methods: A total of 33 patients with stroke (18 left, 15 right hemispheric lesions) who underwent diffusion tensor imaging within 2 months of stroke onset and 17 age- and sex-matched healthy controls were retrospectively enrolled. Tract volume and the asymmetry index based on tract volume (AI(TV)) of the CST and CPCT were used to identify structural changes in individual tracts and the correlation between those tracts. Motor function was assessed using the Medical Research Council (MRC) muscle scale, manual function test (MFT), functional ambulation category, and modified Barthel index. Results: The volume of the affected CPCT was lower, and that of the unaffected CPCT was higher than the volumes in the control group (P < .001, P = .001, respectively). The CPCT AI(TV), showed a strong positive correlation with the CST AI(TV) in patients with either left or right hemispheric lesions (r, = .779, P < .001; r, = .732, P = .003, respectively). The CPCT AI(TV) negatively correlated with the MRC muscle scale of the shoulder, wrist, and ankle muscles (r = -.490, -.490, -.416; P = .004, .004, .016, respectively). A higher unaffected CPCT volume was indicative of less affected upper extremity function, as assessed by MFT (r(s)=-.546, P = .029). Conclusions: Modification of the CPCT depended on CST integrity and was associated with the severity of hemiplegia and hemiplegic upper extremity function. The CPCT may complement the role of the CST and help to predict the motor function.