| Summary: | 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
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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.
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