Low-frequency repetitive transcranial magnetic stimulation on Parkinson motor function: a meta-analysis of randomised controlled trials

Objectives: Previous studies have demonstrated inconsistent findings regarding the efficacy of low-frequency repetitive transcranial magnetic stimulation (rTMS) in treating motor symptoms of Parkinson's disease (PD). Therefore, this meta-analysis was conducted to assess the efficacy of low-frequency rTMS. Methods: A comprehensive literature search (including PubMed, CCTR, Embase, Web of Science, CNKI, CBM-disc, NTIS, EAGLE, Clinical Trials, Current Controlled Trials, International Clinical Trials Registry) was conducted dating until June 2014. The key search terms ('Parkinson', 'PD', 'transcranial magnetic stimulation', 'TMS', 'RTMS' and 'noninvasive brain stimulation') produced eight high-quality randomised controlled trials (RCT) of low-frequency rTMS versus sham stimulation. Results: These eight studies, composed of 319 patients, were meta-analysed through assessment of the decreased Unified Parkinson's Disease Rating Scale (UPDRS part III) score. Pooling of the results from these RCTs yielded an effect size of -0.40 (95% CI = -0.73 to -0.06, p<0.05) in UPDRS part III, which indicated that low-frequency rTMS could have 5.05 (95% CI = -1.73 to -8.37) point decrease in UPDRS part III score than sham stimulation. Discussion: Low-frequency rTMS had a significant effect on motor signs in PD. As the number of RCTs and PD patients included here was limited, further large-scale multi-center RCTs were required to validate our conclusions.