Obstructive sleep apnea (OSA) is characterized by increased resistance to airflow and collapsibility of the upper airway during sleep, resulting in intermittent hypoxia, sleep fragmentation, and excessive daytime sleepiness. OSA is associated with cardiovascular, metabolic, and neurocognitive complications, as well as increased accident risk and reduced quality of life. Additionally, it generates a significant economic burden, with direct and indirect costs related to healthcare, reduced work productivity, and accidents.

The standard treatment includes hygienic-dietary measures and continuous positive airway pressure (CPAP) therapy, which, although effective, has low acceptability and adherence. As a complement or alternative, myofunctional therapy emerges as a promising option. It consists of orofacial exercises that strengthen the musculature of the upper airways. Although evidence suggests benefits in reducing the severity of OSA and daytime sleepiness, its use is not widespread in Spain. This highlights the need to evaluate its effectiveness, safety, cost-effectiveness, and implementation challenges within the Spanish healthcare system.

Objectives

• To evaluate the effectiveness and safety of myofunctional therapy for the treatment of OSA.

• To review the available literature on the cost-effectiveness of myofunctional therapy for the treatment of OSA.

• To assess the costs of this treatment compared to usual clinical practice in Spain from the perspective of the National Health System (SNS).

• To identify ethical, legal, organizational, and social considerations related to myofunctional therapy.

• To identify research needs and standard outcome measures from the perspectives of patients, family members/caregivers, healthcare professionals, and researchers regarding myofunctional therapy.

Methodology

Effectiveness and Safety

A systematic review (SR) was conducted with the objective of evaluating the effectiveness and safety of myofunctional therapy in patients with OSA. First, an initial search was carried out to locate previous SRs or possible health technology assessment (HTA) reports published or in progress by other agencies on the technology to be evaluated, which, due to their scope and methodological rigor, could be updated, adapted, or adopted. Subsequently, identification, evaluation, and synthesis of primary studies were performed. Comprehensive searches were conducted in electronic databases, including MEDLINE, Embase, CINAHL, CENTRAL, PEDro, and other complementary sources such as international clinical trial registries. Search strategies combined terms related to population, intervention, and study design, without language restrictions. Randomized controlled trials (RCTs) in individuals diagnosed with OSA evaluating myofunctional therapy, alone or combined with other techniques, versus no intervention, waitlist, placebo/sham, or other active interventions were selected. Study selection was performed independently by two reviewers, with discrepancies resolved by consensus or involvement of a third reviewer. The methodological quality of identified SRs was assessed using the AMSTAR-2 scale, and the risk of bias of the studies was evaluated with the RoB 2.0 tool. Meta-analysis was conducted when studies were homogeneous in terms of population, intervention, and outcome measures. RevMan software was used to estimate intervention effects via mean differences or standardized mean differences. The quality of evidence assessment and strength of recommendation grading were conducted following the methodology of the international working group Grading of Recommendations Assessment, Development and Evaluation (GRADE).

Cost-effectiveness

A systematic review was conducted of economic evaluations of myofunctional therapy for the treatment of OSA. Economic evaluations (either alongside primary studies or model-based) reporting any of the following outcomes were sought: incremental cost-effectiveness ratio (ICER), costs expressed in monetary units, and benefits expressed as quality-adjusted life years (QALYs), life years gained (LYG), monetary units, or any of the outcome measures included in the effectiveness section. Methodological quality assessment was planned using the Drummond et al. checklist, along with data extraction and a narrative synthesis with tabulation of results.

Cost Study

A cost analysis was conducted to estimate the incremental cost of implementing myofunctional therapy for the treatment of OSA within the National Health System (SNS), considering exclusively direct healthcare costs (cost of sessions). In the base case, a treatment (complementary to usual clinical practice – CPAP) based on one weekly session with a speech therapy specialist over 12 weeks was evaluated. Additionally, a deterministic sensitivity analysis was performed varying the cost per session and treatment characteristics (session frequency and duration).

Ethical, Legal, Organizational, and Social Aspects

The analysis of these domains was conducted using an algorithm for the assessment of specific ethical, legal, organizational, social, and environmental aspects related to the technology. The algorithm is based on defining the scope considering whether relevant uncertainties exist for decision-making about these aspects and allows exploring and conceptualizing the context of the intervention. Relevant uncertainty is understood as when specific research questions clearly related to the evaluated technology are identified and should be answered to adequately assess the aspects. A preliminary search was carried out in PubMed, CINAHL, and Google Scholar using different combinations of keywords and their derivatives from the search strategy used for the effectiveness section along with terms specific to the assessed aspects. The scope definition did not reveal relevant uncertainties that could be resolved through a systematic review or additional primary study, although uncertainties were detected regarding the applicability of the technique in the SNS concerning equity of access as well as technical and organizational feasibility. To contextualize the use of the technology in the healthcare system, semi-structured consultations were conducted through online meetings with clinical experts.

Identification of Research Needs and Standard Outcome Measures

Areas of uncertainty and necessary outcome measures to evaluate the effectiveness of myofunctional therapy in OSA were identified, considering the perspectives of patients, professionals, researchers, and healthcare managers. For this purpose, the needs identified in the systematic reviews developed for the other report domains were analyzed, and specialized information sources such as the James Lind Alliance (JLA), Core Outcome Measures in Effectiveness Trials (COMET), and International Consortium for Health Outcomes Measurement (ICHOM) were reviewed. Study selection included publications in English and Spanish, excluding conference abstracts and texts in other languages. Data were extracted by one reviewer with validation by a second in case of doubts. Findings were synthesized narratively, highlighting the main research needs and key measures to improve comparison and evaluation of future interventions.

Results

Effectiveness and Safety

In the preliminary search, a high-quality systematic review (SR) was identified that addresses the research question regarding the effectiveness and safety of myofunctional therapy for the treatment of obstructive sleep apnea syndrome (OSA), covering all available evidence up to May 2020. Nine subsequent publications were identified. Finally, a total of 15 randomized controlled trials (RCTs) (18 references) were included in the report, comprising 597 participants. The mean age of participants was 50.53 ± 14.34 years, with only one study focused on a pediatric population, and 67.57% were male.

Myofunctional Therapy versus No Intervention, Waiting List, or Placebo/Sham

Ten RCTs evaluated the effectiveness of myofunctional therapy compared to no intervention, waiting list, or placebo/sham. No significant differences were observed in disease-specific health-related quality of life (HRQoL) (3 studies, N = 56, MD = 1.2, 95% CI: -1.2 to 3.61, very low quality of evidence), sleep efficiency (3 studies, N = 108, MD = 0.78%, 95% CI: -3.13 to 4.68, very low quality of evidence), oxygen desaturation index (3 studies, N = 83, MD = -4.73, 95% CI: -14.11 to 4.65, very low quality of evidence), or average oxygen saturation (2 studies, N = 79, MD = -1.18, 95% CI: -0.68 to 3.04, very low quality of evidence). However, significant improvements were observed in sleep quality (6 studies, N = 164, MD = -2.03, 95% CI: -2.86 to -1.19, very low quality of evidence), daytime sleepiness (8 studies, N = 235, SMD = -0.85, 95% CI: -1.12 to -0.57, low quality of evidence), minimum oxygen saturation (5 studies, N = 174, MD = 2.91%, 95% CI: 1.27 to 4.55, low quality of evidence), and apnea-hypopnea index (AHI) (8 studies, N = 232, MD = -5.55 events/hour, 95% CI: -9.53 to -1.57, low quality of evidence).

Myofunctional Therapy versus CPAP

A single RCT evaluated the effectiveness of myofunctional therapy compared to CPAP. No significant differences were found in disease-specific HRQoL (low quality of evidence), daytime sleepiness (MD = 0.30, 95% CI: -1.65 to 2.25, low quality of evidence), or sleep efficiency (MD = -2.10, 95% CI: -7.85 to 3.65, low quality of evidence). Regarding AHI, the CPAP group showed significantly lower values than the myofunctional therapy group (MD = 9.60, 95% CI: 2.46 to 16.74, low quality of evidence). Likewise, the percentage of minimum and average blood oxygen saturation was significantly lower in patients receiving myofunctional therapy compared to those treated with CPAP (MD = -5.3, 95% CI: -8.89 to -1.71 and MD = -1.4, 95% CI: -2.12 to -0.68, respectively).

Myofunctional Therapy plus CPAP versus CPAP Alone

Three RCTs assessed the effectiveness of adding myofunctional therapy to CPAP treatment compared to CPAP alone. The results show that combining both interventions significantly improves CPAP adherence, increasing usage time per night (2 studies, N = 119, MD = 0.87 hours, 95% CI: 0.33 to 1.41, low quality of evidence). However, no significant differences were found in critical variables such as sleep quality (1 study, MD = -0.30, 95% CI: -2.81 to 2.21, low quality of evidence) or daytime sleepiness (3 studies, N = 119, MD = -1.10, 95% CI: -3.52 to 1.32, low quality of evidence). Regarding HRQoL, results were mixed. Additionally, no differences were observed in AHI (2 studies, N = 119, MD = -1.06, 95% CI: -2.86 to 0.75, low quality of evidence) or minimum oxygen saturation (2 studies, N = 119, MD = -0.82, 95% CI: -2.78 to 1.14, low quality of evidence).

Safety of Myofunctional Therapy

Only four studies reported data on adverse events, according to the definitions provided by the studies themselves. No serious adverse events were reported.

Cost-effectiveness

The systematic review of economic evaluations did not identify any study meeting the established selection criteria.

Cost analysis showed that the inclusion of myofunctional therapy in the National Health System (NHS) would imply a cost of €279.08 per patient. Sensitivity analysis determined a range of incremental cost variation between €60.6 and €717.96 per patient when varying the unit cost per session, and between €46.51 and €1395.38 per patient when modifying treatment characteristics.

Ethical, Legal, Organizational, and Social Aspects

In the scope definition, no relevant studies were identified regarding ethical, legal, social, and organizational aspects related to the evaluated technology. Consultation with three experts in speech therapy and pulmonology helped identify key barriers to the implementation of myofunctional therapy for the treatment of OSA. The main challenges include lack of awareness of the technique, insufficient specialized training, and scarcity of trained professionals. However, the experts consider that, with adequate resources, implementation would be feasible due to the technical simplicity of the therapy and its low cost, which facilitates its integration into the NHS. Equity in access to myofunctional therapy could be affected by the uneven distribution of professionals and specialized care centers, highlighting the need to invest in training and accessible healthcare infrastructure. Regarding acceptability, the therapy is well received for being non-invasive, simple, and easy to integrate clinically, with high receptivity from both patients and healthcare professionals. Despite its potential, implementation faces challenges related to the shortage of speech therapists in the NHS, limiting its current feasibility. To maximize its positive impact, it will be crucial to promote professional training, generate more scientific evidence, and support specific educational programs.

Identification of Research Needs and Standard Outcome Measures

The main research needs identified in the report focus on improving the design of future studies on myofunctional therapy for OSA, including randomized controlled trials (RCTs) with adequate sample sizes, long-term follow-up, and subgroup analyses by severity, gender, and age. Also highlighted are the need for cost-effectiveness studies, qualitative research on experiences and barriers, and organizational assessments to integrate this therapy into the NHS. Additionally, it is crucial to develop standardized protocols for myofunctional therapy, explore its combination with other interventions such as CPAP, and personalize exercises according to individual patient characteristics.

Through the JLA initiative, research priorities were identified related to improving access, service quality, and the use of complementary therapies for OSA. However, no specific publications on relevant standard outcome measures were found in sources such as COMET or ICHOM.

Conclusions

• Myofunctional therapy in patients with OSA, compared to no intervention, waitlist, or placebo/sham, showed benefits in outcomes such as sleep quality, daytime sleepiness, reduction of the apnea-hypopnea index (AHI), and minimum blood oxygen saturation percentage. However, no significant improvements were observed in other critical outcomes, such as sleep efficiency, oxygen desaturation index (ODI), or sleep-specific quality of life. The quality of evidence for most outcomes was rated very low, mainly due to high risk of bias, heterogeneity among studies, and imprecision in confidence intervals.
• Compared to CPAP, myofunctional therapy was not superior in any of the evaluated outcomes. CPAP was significantly more effective in reducing the AHI. Nevertheless, myofunctional therapy showed significant improvement in the physical dimension of health-related quality of life (HRQoL) in a single study. The quality of evidence for this comparison was also considered very low.
• The combination of myofunctional therapy and CPAP, compared to CPAP alone, showed a significant improvement in adherence to CPAP treatment, increasing the average usage time per night. However, no additional benefits were observed in other key outcomes such as AHI or HRQoL. The quality of evidence for this comparison was very low.
• Myofunctional therapy was considered a safe intervention. None of the included studies reported serious adverse events associated with its use, except for a single case of epithelial abrasion of the intraoral mucosa, which resolved after temporary discontinuation of treatment.
• Myofunctional therapy can be considered a complementary option for patients with mild to moderate OSA who do not tolerate CPAP or seek non-invasive strategies. However, its effectiveness is limited compared to CPAP, and therefore it is not recommended as a standard standalone treatment.
• No published economic evaluations were identified that assessed myofunctional therapy in patients with OSA and met the inclusion criteria established in the systematic review.
• The cost analysis in this report showed that including myofunctional therapy as a complementary treatment to usual clinical practice (CPAP) would entail an incremental cost of €279.08 per patient from the perspective of the NHS. This cost may vary considerably depending on session frequency and treatment duration, highlighting the need to standardize protocols to optimize implementation.
• No relevant studies were identified regarding ethical, legal, social, and organizational aspects related to the evaluated technology. However, expert consultation highlighted key barriers such as lack of knowledge of the technique, insufficient specialized training, and scarcity of adequately trained professionals. Despite these challenges, experts consider implementation feasible with appropriate resources, given the therapy’s low cost and technical simplicity, although unequal distribution of professionals and centers could affect equity of access. The therapy is well accepted due to its non-invasive nature and ease of clinical integration, with high receptivity among patients and professionals.
• More studies with robust methodology, large samples, and long-term follow-up are required to evaluate the effectiveness and safety of myofunctional therapy in people with OSA, as well as to collect data on resource use and costs to inform its cost-effectiveness. Additionally, qualitative studies exploring perceptions and experiences of patients and professionals, as well as barriers and facilitators encountered during implementation, are needed. Future research should also address issues such as improving accessibility, coordination, and quality of public services for people with OSA, combining interventions with CPAP, and seeking alternative methods to effectively treat OSA.

Recommendations

Myofunctional therapy versus no intervention

Based on the results of this report, a conditional recommendation is made in favor of myofunctional therapy for individuals with OSA who do not tolerate CPAP or seek less invasive alternatives. This recommendation is based on the low certainty associated with the effectiveness of the technology, as well as the absence of evidence regarding costs derived from its implementation.

Myofunctional therapy versus CPAP

Based on the results of this report, a conditional recommendation is made against the full inclusion of myofunctional therapy as a substitute for CPAP in adults with OSA within the healthcare system. This recommendation is based on the lack of evidence showing superiority of myofunctional therapy compared to CPAP for key outcome measures. Although the evaluated technology may be an alternative for individuals who reject CPAP treatment, it is not recommended as first-line therapy for all people with OSA.

Myofunctional therapy combined with CPAP versus CPAP alone

Based on the results of this report, a conditional recommendation is made in favor of including myofunctional therapy in combination with CPAP for adults with OSA within the healthcare system. This recommendation is based on the limited and low certainty evidence regarding the effectiveness of the technology, as well as increased costs associated with its implementation compared to usual clinical practice. While the evaluated technology appears to be a promising alternative that improves CPAP adherence, further high-quality research with low risk of bias is required to increase certainty about the effectiveness and safety of the technology, as well as to assess its economic impact in real-world settings.