Transcranial magnetic stimulation for monitoring the rehabilitation of upper-extremity function after stroke

Abstract

Objective To evaluate the effect of the transcranial magnetic stimulation on upper-extremity function rehabilitation and changes in the excitability of cerebral cortex, and to evaluate from the viewpoint of electrophysiology the prognosis so as to guide the rehabilitation treatment of patients after stroke. Methods Forty-six patients in the early stage after a stroke were given TMS examinations of the ipsilateral brain region. Those with the motor evoked potentials (MEPs) amplitudes lower than 50 μV were classified into a motion-induced experimental negative group (the negative group), while those whose MEP amplitude reached 50 μV or more were classified as movement-induced positive (the positive group). Both groups were given the same treatment. Before and after 2, 4 and 8 weeks of treatment the Fugl-Meyer movement function rating scale was used to assess their bilateral upper limb movement function. TMS technology was used to detect any change in the resting motor threshold (RMT) and the amplitude (Amp) of MEPs in the motor cortex. The incubation period of the cortex (CL) and the central motor conduction time (CMCT) in the contralateral motor cerebral cortex were also observed. Results After 4 weeks of treatment, the average score of the positive group on Fugl-Meyer upper movement function rating scale reached (54.99±2.76), significantly higher than before treatment and significantly higher than the negative group's average (P 0.05). After the treatment the CL and CMCT had shortened significantly in the negative group compared to before the treatment (P 0.05). Conclusions The excitability of the contralateral motor cortex changes after a stroke. TMS can be used to characterize the MEP to monitor and predict recovery. This should help clinicians prepare more scientific rehabilitation plans. Key words: Transcranial magnetic stimulation; Stroke; Upper limb movement function; Cortical excitability