Low-Frequency rTMS and intensive occupational therapy improve upper limb motor function and cortical reorganization assessed by functional near-infrared spectroscopy in a subacute stroke patient

Abstract

There is still no agreement on the most suitable time and modality for application of repetitive transcranial magnetic stimulation (rTMS) to improve motor recovery in subacute stroke patients. The underlying mechanism of motor recovery following low-frequency rTMS is considered to be modulation of the interhemispheric asymmetry. On the other hand, the cortical balance of brain activity during the acute to chronic phase of stroke is reported to be unstable. Therefore, we conducted this study to clarify the time course of the interhemispheric asymmetry and the effect of application of low-frequency rTMS combined with occupational therapy on motor recovery and cortical imbalance of brain activity in a subacute stroke patient. The interhemispheric asymmetry in this patient with new-onset subcortical cerebral infarction and upper limb hemiparesis was evaluated longitudinally using functional near-infrared spectroscopy with finger tasks. A nonlesional hemisphere-dominant activation pattern was observed on day 28 after onset. On day 56 after onset, a bilaterally eminent activation pattern was observed. Low-frequency rTMS was applied on day 109 after stroke onset when the cortical activity shifted to the nonlesional hemisphere. The treatment resulted in improvement in motor function of the affected upper limb and a shift in brain activation to the lesional hemisphere. Our report is the first to describe the therapeutic benefits of low-frequency rTMS as assessed by longitudinal neuroimaging for functional recovery and interhemispheric asymmetry in a subacute stroke patient.