Effects of Neuromuscular Electrical Stimulation on Swallowing Function for Post-Stroke Dysphagia: A Systematic Review and Meta-Analysis.

OBJECTIVE

In this study, our aim is to compare the effects of neuromuscular electrical stimulation (NMES) and other treatment methods for treating dysphagia after a stroke.

METHODS

A systematic search in Web of Science, PubMed, Scopus, Clinical Trials was conducted from their earliest record to 5 September 2024. The study included a randomised controlled trial design. The experimental group received NMES alone, while the control group received NMES and/or conventional dysphagia therapy. The Physiotherapy Evidence Database rating scale was utilized to evaluate the quality of the studies that were included in this analysis. We obtained the post-treatment mean differences (MD) and standard deviations (SD) for the selected outcomes recorded in both the experimental and control groups to facilitate subsequent meta-analyses.

RESULTS

A total of sixteen studies were identified. In the comparison of swallow treatment that incorporates NMES versus swallow treatment that does not include neuromuscular electrical stimulation, the meta-analysis found a significant MD of -7.23, with a 95% confidence interval (CI) ranging from -13.62 to -0.84 (P = 0.03) in the functional dysphagia scale (FDS). In Functional Oral Intake Scale, the MD = 0.66, 95%CI ranging from -0.31 to 1.62 (P = 0.18). In Penetration Aspiration Scale, the MD = -1.05, 95%CI ranging from -1.50 to -0.60 (P < 0.00001).

CONCLUSION

The application of NMES in swallow therapy appears to demonstrate greater efficacy in the management of post-stroke dysphagia compared to approaches that do not incorporate such stimulation, albeit the existing body of research is limited. Furthermore, the evidence currently available is inadequate to substantiate the assertion that NMES, when employed in isolation, surpasses swallow therapy.

WHAT THIS PAPER ADDS: What is already known on this subject Post-stroke dysphagia is a common and debilitating condition, significantly impairing the quality of life for stroke survivors. Neuromuscular electrical stimulation (NMES) has gained attention as an adjunct to conventional dysphagia therapy, with prior studies indicating potential benefits. However, the clinical efficacy of NMES for improving swallowing functions specifically in stroke-induced dysphagia remains unclear due to inconsistent findings and methodological limitations in existing research. What this study adds to existing knowledge This study provides a comprehensive meta-analysis, confirming that NMES significantly improves functional swallowing outcomes, particularly on the Functional Oral Intake Scale (FOIS). Additionally, it highlights that NMES may enhance neuroplasticity and muscle coordination when used alongside traditional therapies. The study identifies specific benefits, such as improved oral intake and reduced aspiration risks, offering new evidence to guide therapeutic approaches. What are the potential or actual clinical implications of this work? NMES can be an effective component of dysphagia rehabilitation protocols, improving swallowing safety and efficiency for post-stroke patients. The findings support the integration of NMES into clinical practice, emphasizing its role in enhancing swallowing function and reducing the risks of complications like aspiration pneumonia. Future research should focus on optimising stimulation parameters and evaluating long-term effects to maximize patient outcomes.