Effects of respiratory muscle therapy on obstructive sleep apnea: a systematic review and meta-analysis

Abstract

Study objectives: The purpose of this study is to conduct a systematic review and meta-analysis evaluating the effects of respiratory muscle therapy (ie, oropharyngeal exercises, speech therapy, breathing exercises, wind musical instruments) compared with control therapy or no treatment in improving apnea-hypopnea index ([AHI] primary outcome), sleepiness, and other polysomnographic outcomes for patients diagnosed with obstructive sleep apnea (OSA).

Methods: Only randomized controlled trials with a placebo therapy or no treatment searched using PubMed, EMBASE, Cochrane, and Web of Science up to November 2018 were included, and assessment of risk of bias was completed using the Cochrane Handbook.

Results: Nine studies with 394 adults and children diagnosed with mild to severe OSA were included, all assessed at high risk of bias. Eight of the 9 studies measured AHI and showed a weighted average overall AHI improvement of 39.5% versus baselines after respiratory muscle therapy. Based on our meta-analyses in adult studies, respiratory muscle therapy yielded an improvement in AHI of -7.6 events/h (95% confidence interval [CI] = -11.7 to -3.5; P ≤ .001), apnea index of -4.2 events/h (95% CI = -7.7 to -0.8; P ≤ .016), Epworth Sleepiness Scale of -2.5 of 24 (95% CI= -5.1 to -0.1; P ≤ .066), Pittsburgh Sleep Quality Index of -1.3 of 21 (95% CI= -2.4 to -0.2; P ≤ .026), snoring frequency (P = .044) in intervention groups compared with controls.

Conclusions: This systematic review highlights respiratory muscle therapy as an adjunct management for OSA but further studies are needed due to limitations including the nature and small number of studies, heterogeneity of the interventions, and high risk of bias with low quality of evidence.

Keywords: apnea-hypopnea index; breathing exercises; myofunctional therapy; obstructive sleep apnea; oropharyngeal exercises; respiratory muscle therapy; speech therapy.

Conflict of interest statement

All authors have reviewed and approved this manuscript. The authors report no conflicts of interest.

© 2020 American Academy of Sleep Medicine.

Figures

Figure 1.. Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flow diagram.

Figure 2.. Summary of risk of bias of eligible randomized controlled trials.

Figure 3.. Overall AHI improved significantly in OSA adults receiving respiratory muscle therapy compared with controls (P < .001).

AHI = apnea-hypopnea index, CI = confidence interval, OSA = obstructive sleep apnea.

Figure 4.. Sleepiness outcomes in adult studies.

(A) Overall ESS index improved but not statistically significantly (P = .062) in OSA adults receiving respiratory muscle therapy (improvement in sleepiness is demonstrated by a lower ESS). (B) Overall PSQI index improved significantly in OSA adults receiving respiratory muscle therapy (P = .026). Improvement in sleep quality was demonstrated by lower PSQI scores. CI = confidence interval, ESS = Epworth Sleepiness Scale, OSA = obstructive sleep apnea, PSQI = Pittsburgh Sleep Quality Index.

Figure 5.. Snoring frequency and intensity outcomes in adult studies.

Overall snoring frequency (A) improved significantly compared with controls (P = .044), but not snoring intensity (B) (P = .068).