Effects of repetitive transcranial magnetic stimulation on motor functions in patients with stroke: A meta-analysis

Background and Purpose-The purpose of this study was to perform a meta-analysis of studies that investigated the effects of repetitive transcranial magnetic stimulation (rTMS) on upper limb motor function in patients with stroke. Methods-We searched for randomized controlled trials published between January 1990 and October 2011 in PubMed, Medline, Cochrane, and CINAHL using the following key words: stroke, cerebrovascular accident, and repetitive transcranial magnetic stimulation. The mean effect size and a 95% CI were estimated for the motor outcome and motor threshold using fixed and random effect models. Results-Eighteen of the 34 candidate articles were included in this analysis. The selected studies involved a total of 392 patients. A significant effect size of 0.55 was found for motor outcome (95% CI, 0.37-0.72). Further subgroup analyses demonstrated more prominent effects for subcortical stroke (mean effect size, 0.73; 95% CI, 0.44-1.02) or studies applying low-frequency rTMS (mean effect size, 0.69; 95% CI, 0.42-0.95). Only 4 patients of the 18 articles included in this analysis reported adverse effects from rTMS. Conclusions-rTMS has a positive effect on motor recovery in patients with stroke, especially for those with subcortical stroke. Low-frequency rTMS over the unaffected hemisphere may be more beneficial than high-frequency rTMS over the affected hemisphere. Recent limited data suggest that intermittent theta-burst stimulation over the affected hemisphere might be a useful intervention. Further well-designed studies in a larger population are required to better elucidate the differential roles of various rTMS protocols in stroke treatment.