The effects of surface neuromuscular electrical stimulation on post-stroke dysphagia: a systemic review and meta-analysis

Objective: In this study, we intended to evaluate whether swallow treatment with neuromuscular electrical stimulation is superior to that without neuromuscular electrical stimulation, and whether neuromuscular electrical stimulation alone is superior to swallow therapy. Methods: We searched the PubMed and Scopus databases from their earliest record to 31 December 2014 for randomized and quasi-randomized controlled trials that used neuromuscular electrical stimulation to treat post-stroke dysphagia. The Jadad scale was used to assess the quality of the included studies. We extracted the mean differences and standard deviation (SD) between baseline and posttreatment or posttreatment mean and SD for selected outcomes measured in the experimental and control groups for subsequent meta-analyses. Results: Eight studies were identified. For the comparison swallow treatment with neuromuscular electrical stimulation vs. swallow treatment without neuromuscular electrical stimulation, we found a significant standardized mean difference (SMD) of 1.27 (95% confidence interval (CI)=0.51-2.02, P=0.001) with significant heterogeneity (I-2=85%). The meta-analysis for the comparison of neuromuscular electrical stimulation alone and swallow therapy demonstrated a non-significant SMD of 0.25 (95% CI=-0.16-0.65, P=0.23) without significant heterogeneity (I-2=16%). Conclusion: Swallow treatment with neuromuscular electrical stimulation seems to be more effective than that without neuromuscular electrical stimulation for post-stroke dysphagia in the short term considering the limited number of studies available. Evidence was insufficient to indicate that neuromuscular electrical stimulation alone was superior to swallow therapy.