Myofunctional therapy has a growing evidence base, with the strongest support for treating obstructive sleep apnea and preventing orthodontic relapse. Multiple meta-analyses show measurable improvements in airway function, and professional organizations like the American Speech-Language-Hearing Association recognize it within their scope of practice. That said, the research has real limitations: most studies are small, few use rigorous blinding, and there’s no standardized treatment protocol across practitioners.
Strongest Evidence: Sleep Apnea
The most robust data for myofunctional therapy comes from its use in obstructive sleep apnea. A meta-analysis of 15 studies covering 237 patients found that the average number of breathing disruptions per hour (the apnea-hypopnea index, or AHI) dropped from 28.0 to 18.6, a statistically large effect. Lowest oxygen saturation during sleep also improved modestly, rising about 2 percentage points. An earlier systematic review in the journal Sleep reported even more striking numbers: roughly a 50% reduction in AHI for adults and 62% for children.
To put those numbers in context, an AHI of 28 qualifies as moderate-to-severe sleep apnea, while 18.6 still falls in the moderate range. So the therapy meaningfully reduces severity but typically doesn’t eliminate the condition. Lowest oxygen levels improved by about 3 to 4 percentage points across studies, which matters because even small gains in overnight oxygen can reduce strain on the heart and brain.
The underlying mechanism makes physiological sense. People with sleep apnea tend to have weaker or less coordinated muscles in the tongue, soft palate, and throat walls. Research using electromyography (sensors that measure muscle electrical activity) shows that the main tongue muscle’s activation during wakefulness directly correlates with how collapsible the airway is during sleep. Strengthening these muscles through targeted exercises increases their resting tone, which helps keep the airway open at night.
Orthodontic Relapse Prevention
The second area with solid clinical evidence is preventing relapse after orthodontic treatment, particularly for open bites. When front teeth don’t fully close after braces, the culprit is often a tongue-thrust swallowing pattern that pushes teeth apart again over time. One clinical study compared patients who received myofunctional therapy alongside orthodontics to those who had orthodontics alone. The therapy group relapsed an average of just 0.5 mm, while the control group relapsed 3.4 mm. That difference was both statistically and clinically significant, meaning the therapy group kept their bite correction while the control group lost much of it.
Speech and Swallowing Patterns
For speech sound errors, the picture is more nuanced. ASHA notes that clinicians should exercise caution before using myofunctional therapy as a standalone approach for speech problems and may need to combine it with traditional articulation therapy. One randomized controlled trial found that speech therapy alone was not effective for correcting atypical swallowing patterns, while myofunctional therapy alone was. But for lisps and other sound distortions linked to tongue posture, the evidence suggests the exercises work best as a complement to speech therapy rather than a replacement.
What Treatment Actually Looks Like
There’s no single standardized protocol, which is one of the field’s biggest weaknesses. Across clinical trials, treatment typically involves 15 to 20 minutes of daily home exercises over at least three to six months. Exercises target the tongue, lips, and soft palate through a combination of strength-building (isometric) and movement-based (isotonic) repetitions. Examples from published studies include pressing the tongue firmly against the roof of the mouth, lip-sealing exercises using resistance trainers, and specific swallowing drills.
Most protocols require in-person sessions with a therapist once or twice a month, with the bulk of the work happening at home. In pediatric studies, parents were asked to supervise and sometimes record training sessions on video. Some studies also incorporated passive devices like oral appliances worn at night for up to a year. Early improvements can appear within two months, but most successful trials ran for six months or longer.
Compliance is a major variable. The therapy only works if patients actually do the exercises consistently, and adherence is difficult to measure or enforce in research settings. ASHA has specifically called for more studies evaluating compliance and long-term outcomes.
How Practitioners Assess the Problem
Diagnosis typically involves a structured clinical examination. The most widely used tool across the literature is the Orofacial Myofunctional Evaluation with Scores (OMES), a protocol that assigns numerical scores to different aspects of facial and oral function. The assessment generally includes observation of resting posture (where the tongue sits, whether the lips are sealed), evaluation of swallowing patterns, speech production, and a comprehensive oral-motor exam. Some clinicians also use instruments that measure tongue strength or range of motion, and imaging techniques can assess airway dimensions when sleep apnea is involved.
ASHA recognizes orofacial myofunctional disorders as within the scope of practice for speech-language pathologists, with the caveat that practitioners should be specifically educated and trained in this area. Diagnosing related conditions like jaw joint disorders or bite problems falls outside the SLP’s scope and requires collaboration with dentists or orthodontists.
Where the Evidence Falls Short
The biggest limitation across the myofunctional therapy literature is study quality. Sample sizes are small, often under 50 participants. True blinding is nearly impossible since patients know whether they’re doing exercises. Many studies lack control groups entirely, comparing patients only to their own pre-treatment baselines. This design can’t account for placebo effects or natural changes over time.
There’s also no consensus on which exercises work best, how long treatment should last, or how to measure success consistently across studies. Protocols vary widely: some studies used 10 minutes of exercises three times daily, others required 20 minutes once a day, and still others combined exercises with oral appliances. This inconsistency makes it hard to compare results or write clear treatment guidelines.
Long-term follow-up data is particularly sparse. Most studies measure outcomes immediately after the treatment period ends, leaving open the question of whether gains persist for months or years afterward. For sleep apnea specifically, it’s unclear whether patients need to continue exercises indefinitely to maintain their improvements.
Insurance Coverage
Myofunctional therapy can be billed under existing medical codes for speech-language services. TRICARE, for example, lists myofunctional therapy under CPT codes used for speech treatment services. Coverage varies widely by insurer, though. Some plans cover it when prescribed for a diagnosed condition like sleep apnea or an orofacial myofunctional disorder, while others classify it as experimental. If you’re considering treatment, checking your specific plan’s policy before starting is worth the phone call.