The Clinical And Electrophysiological Study Of Repetitive Transcranial Magnetic Stimulation In Parkinson's Disease

Effects of repetitive transcranial magnetic stimulation on the excitability of the motor cortex in Parkinson's diseaseObjective: 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: 45 PD patients were randomly divided into two groups. 30 patients with PD were performed by rTMS therapy, 15 PD patients were performed sham stimulation, 15 normal volunteers were enrolled as control. In the real-rTMS, the coil of stimulator was positioned over the vertex of the skull(Cz). Stimuli were delivered at an intensity of 110% of resting threshold(RT) and a frequency of 1 Hz. A side of the coil was used for 4 min, then B side was used for 4 min after resting 5 min, once a day for 10 days. In the sham-rTMS, the edge of the coil was positioned horizontally over the Cz, others were sameness with real-rTMS. Excitability of the motor cortex were assessed by RT, central motor conduction time(CMCT), central silent period(CSP) and amplitude of motor evoked potential(MEP). All patients took no dopaminergic drug for at least 12h before each assessment. The data was analysized with SPSS 11.0 statistic software.Results: (1) Before treatmen, the results of RT, CMCTand CSP were significantly decreased or shortened in the PD patients to compare with the normal controls, but MEP amplitudes were not changence. In the real-rTMS, RT increased, CMCT and CSP prolonged, they were closed to normal subjects after treatment. In the sham-rTMS, there was no difference to compare with pre-rTMS. (2) The results of RT, CMCT, MEPamplitudes and CSP were no difference between the patients with marked tremor and marked rigidity. (3) The results of RT, CMCT, MEP amplitudes and CSP were not significant difference in the differcult Unified Parkinson's Disease Rating Scale(UPDRS).Conclusion: In the PD patients, RT were decreased, CMCT and CSP were shortened. It was probable because that the neurons in the motor cortex increased their firing rate and also reduced their rate of deactivation in PD. Excitability of the corticospinal and a -motorneurones were increased in the PD patients. Low frequency rTMS could adjust the nerve loop of the cortex and the subcortex and inhibit the excitability of the nerve cell of the motor cortex to or near to normal state and supply a auxiliary means for treating PD.