Repetitive Transcranial Magnetic Stimulation for Fibromyalgia: Systematic Review and Meta-Analysis

BackgroundFibromyalgia (FM) is a prevalent chronic pain syndrome with few effective therapeutic options available. Repetitive transcranial magnetic stimulation (rTMS) is an emerging therapeutic alternative for this condition; however, results have been mixed. ObjectivesTo evaluate the efficacy of rTMS on FM, a comprehensive systematic review and meta-analysis were performed. MethodsRelevant published, English and Portuguese language, randomized clinical trials (RCT) comparing rTMS (irrespective of the stimulation protocol) to sham stimulation for treating FM pain intensity, depression, and/or quality of life (QoL) were identified, considering only those with low risk for bias. Trials available until April 2014 were searched through MEDLINE, EMBASE, the Cochrane Library Databases, and other 26 relevant medical databases covering from every continent. The outcomes for pain, depression, and QoL assessed closest to the 30th day after rTMS treatment were extracted, and changes from baseline were calculated to compare the effects of rTMS vs. placebo. ResultsOne hundred and sixty-three articles were screened, and five with moderate to high quality were included. rTMS improved QoL with a moderate effect size (Pooled SMD=-0.472 95%CI=-0.80 to -0.14); it showed a trend toward reducing pain intensity (SMD=-0.64 95%CI=-0.31 to 0.017), but did not change depressive symptoms. ConclusionIn comparison with sham stimulation, rTMS demonstrated superior effect on the QoL of patients with FM 1month after starting therapy. However, further studies are needed to determine optimal treatment protocols and to elucidate the mechanisms involved with this effect, which does not seem to be mediated by changes in depression, but that may involve pain modulation. Level of evidence 1b.