Objective: To evaluate the treatment efficacy of transcutaneous electrical nerve stimulation (TENS) in patients with obstructive sleep apnea (OSA).
Data sources: Primary studies were identified though PubMed, Scopus, OVID, and Cochrane Library.
Review methods: Systematic review was conducted by querying databases for articles published through July 2019. The search identified randomized controlled trial, randomized comparison, or observational studies pertaining to TENS treatment for OSA. Meta-analysis was performed on pre- and posttreatment apnea-hypopnea index (AHI), mean oxygen saturation (SaO2), lowest oxygen saturation (LSAT), and arousal index (AI).
Results: Literature search identified 10 studies that reported sufficient outcome measures to be considered for analysis. A total of 198 patients were identified with a mean age of 50.9 years with a male to female ratio of 1.6:1. Average body mass index (BMI) of the cohort was 29.8 kg/m2. Treatment with TENS demonstrated reduction in AHI by 12.9 points (95% confidence interval, -22.3 to -3.43; P = .008). The mean differences in SaO2, LSAT, and AI did not reach statistical significance.
Conclusion: The TENS treatment of upper airway dilator muscles resulted in reduction of AHI in patients with OSA. However, its effects on SaO2, LSAT, and AI were equivocal. Its impact on patients' quality of life could not be assessed due to heterogeneity in outcome measures. Future randomized controlled trials with generalizable standardized outcome measures are needed to assess the efficacy and compliance of TENS.
Keywords: apnea-hypopnea index; electrical nerve stimulation; noninvasive management; obstructive sleep apnea; quality of life; transcutaneous electrical stimulation.