Continuous theta burst stimulation combined with skilled motor practice after stroke : effects on implicit learning and electroneurophysiology

After stroke, cortical excitability is decreased in the ipsilesional primary motor cortex and increased in the contralesional primary motor cortex. This abnormal pattern of excitability detrimentally affects performance with the hemiparetic arm. Short lasting improvements in motor performance occur following repetitive transcranial magnetic stimulation (rTMS) over the contralesional hemisphere after stroke; however, no work has considered the impact of pairing rTMS with skilled motor practice over multiple days on motor learning, hemiparetic arm function, or electroneurophysiology in the brain. The aim of this thesis was to determine the impact of 3 days of continuous theta burst stimulation (cTBS) over contralesional primary motor cortex paired with skilled motor practice on 1) learning of a novel motor task and hemiparetic arm motor function and 2) levels of intracortical inhibition, intracortical facilitation, and transcallosal inhibition following stroke. In a cross-over design, participants with chronic stroke were randomized to first receive either active or sham cTBS over the contralesional primary motor cortex. Functional measures, motor task performance, and electroneurophysiology were assessed at baseline. 3 days of cTBS paired with skilled motor practice were completed; functional measures, motor learning, and electroneurophysiology were re-evaluated at posttesting. After a 2-week washout period participants underwent the second half of the study with the other form of cTBS. Participants showed larger motor learning related change following active cTBS than sham cTBS. The magnitude of this improvement correlated with enhanced performance on standardized measures of arm function after stroke. Active cTBS also decreased levels of facilitation in the contralesional hemisphere and decreased the amount of inhibition being sent from the contralesional hemisphere to the ipsilesional hemisphere. No adverse effects were reported. Results of this thesis suggest that cTBS over the contralesional motor cortex iii paired with skilled motor practice facilitates both improved hemiparetic arm function and motor learning beyond that seen with skilled motor practice alone. The results of this thesis contribute to research relevant to rehabilitation of individuals with stroke and may facilitate the development of new rehabilitation strategies to improve functional recovery after stroke.Medicine, Faculty ofGraduat