Repetitive transcranial magnetic stimulation as an alternative therapy for dysphagia after stroke: a systematic review and meta-analysis

Objectives: A meta-analysis and systematic review was conducted to investigate the potential effects of repetitive transcranial magnetic stimulation on dysphagia in patients with stroke, including different parameters of frequency and stimulation site. Methods: PubMed, Embase, MEDLINE databases and the Cochrane Library, were searched for randomized controlled studies of repetitive transcranial magnetic stimulation treatment of dysphagia published before March 2016. Results: Six clinical randomized controlled studies of a total of 163 stroke patients were included in this meta-analysis. A significant effect size of 1.24 was found for dysphagic outcome (mean effect size, 1.24; 95% confidence interval (CI), 0.67-1.81). A subgroup analysis based on frequency showed that the clinical scores were significantly improved in dysphagic patients with low frequency repetitive transcranial magnetic stimulation treatment (P<0.05) as well as high frequency repetitive transcranial magnetic stimulation treatment (P<0.05). A stimulation site stratified subgroup analysis implied significant changes in stroke patients with dysphagia for the unaffected hemisphere (P<0.05) and the bilateral hemisphere stimulation (P<0.05), but not for the affected hemisphere (P>0.05). The analysis of the follow-up data shows that patients in the repetitive transcranial magnetic stimulation groups still maintained the therapeutic benefit of repetitive transcranial magnetic stimulation four weeks after the last session of repetitive transcranial magnetic stimulation therapy (P<0.05). Conclusion: This meta-analysis indicates that repetitive transcranial magnetic stimulation has a positive effect on dysphagia after stroke. Compared with low-frequency repetitive transcranial magnetic stimulation, high-frequency repetitive transcranial magnetic stimulation may be more beneficial to the patients. This meta-analysis also supports that repetitive transcranial magnetic stimulation on an unaffected - or bilateral - hemisphere has a significant therapeutic effect on dysphagia.