White matter changes follow low-frequency repetitive transcranial magnetic stimulation plus intensive occupational therapy for motor paralysis after stroke: a DTI study using TBSS

Intervention that combines low-frequency repetitive transcranial magnetic stimulation (rTMS) and intensive occupational therapy (OT) may improve brain function in post-stroke patients with motor paralysis. We aimed to clarify the brain region involved in motor function improvement following chronic stroke. We recruited 25 patients hospitalized for 15 days with post-stroke upper extremity paralysis to receive 12 sessions of low-frequency rTMS over the non-lesioned hemisphere and occupational therapy. In this study, 72% of the patients had suffered from intracranial haemorrhage. Imaging analysis was performed using diffusion tensor imaging (DTI) to assess changes in white matter after intervention. We investigated white matter change before and after intervention and the relationship between white matter structure and motor function recovery using tract-based spatial statistics. The intra-voxel directional coherence was significantly increased in the anterior limb of the internal capsule and anterior thalamic radiation on the lesional side following intervention. Mean diffusivity and radial diffusivity values of clusters in the superior corona radiata on the lesional side were negatively correlated with motor function recovery. White matter nerve fibre structures are involved in motor function improvement following rTMS and OT interventions. Our results show novel findings regarding the relationship between stroke neurorehabilitation and cerebral nerve structure.