Effects of Repetitive Transcranial Magnetic Stimulation on the Excitability of the Motor Cortex in Parkinson′s Disease

Aim:To investigate the effects of low frequency repetitive transcranial magnetic stimulation (rTMS) on the excitability of the motor cortex in Parkinson′s disease (PD) and to study mechanism of PD from the eletrophysiology. Methods:30 patients with PD were performed by 1Hz rTMS therapy to 10 days, 15 patients were performed sham stimulation, 15 normal volunteers were enrolled as control. Excitability of the motor cortex were assessed by rest threshold (RT), central motor conduction time (CMCT), central silent period (CSP) and amplitude of motor evoked potential(MEP). Results:①Patients with PD were treated by rTMS, the results of RT, CMCT and CSP decreased or shortened significantly compared with control, but MEP amplitudes were not changed. In the treatment group, RT increased, CMCT and CSP prolonged, they were closed to normal subjects after treatment, but these changes were not observed in sham group. ②The four indexes were not different in patients with marked tremor or marked rigidity. ③ Patients were divided into mild, moderate and grievous groups by Unified Parkinson′s Disease Rating Scale (UPDRS). The results of the three groups were not significant different by comparing the four indexes. Conclusion An increased motor cortical excitability in PD was observed in our study. Low frequency rTMS may to some extent inhibit the enhanced cortical excitability. But rTMS is not so sensible to detect the excitability of early PD,and more work needs to be done.