Does transcranial magnetic stimulation improve the motor symptoms of Parkinson disease?

Repetitive transcranial magnetic stimulation (rTMS) has been used as a potential therapeutic tool in various neurological and psychiatric disorders. We reviewed the effects of rTMS as a treatment of Parkinson disease in this paper. The existing reports have been conflicting regarding the efficacy of the rTMS in PD. The controversy arises from the differences of the stimulation parameters and evaluation methods of the effects in those studies. Furthermore, placebo effects are common in trials of therapy for PD. The Japanese multi-center, double blinded, sham stimulation controlled trial showed an efficacy in both the rTMS-treated and control patients. The stimulation parameters used in this trial showed some efficacy; however, the degree of the effects were not significantly different from randomized, controlled patients. The result does not prove the efficacy of the rTMS; on the other hand, it does not rule out the efficacy. Further trials are necessary to reveal the therapeutic effect of rTMS in PD. Further studies should be performed aiming to reveal the optimal stimulation parameters.