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.