The overall purpose of this study is to compare changes in sleep outcomes in people with obstructive sleep apnea (OSA) depending on their participation in one of two behavioral interventions; both involve drinking water and breathing. A second purpose is to compare outcomes between people who have sustained a traumatic brain injury (TBI) and those with no history of TBI. The main questions it aims to answer are whether sleep quality improves after 3-months of high-resistance versus low-resistance exercises, and whether people have different outcomes depending on their history of TBI.

Background

A nonintrusive, inexpensive behavioral approach is emerging as a promising alternative to the management of obstructive sleep apnea (OSA). Generally referred to as myofunctional therapy (MFT), the approach involves exercising the muscles of the oropharynx and respiratory system.The exercises are intended to improve muscle strength and tone so that the muscular structures of the upper airway improve their neuromuscular responsiveness to breathing and resist collapsing into the airway during sleep. They are relatively simple to implement and train, but the regimen requires high-dosage practice and strict dedication to habituate. There is a need for an MFT protocol to be delivered in a consistent manner that is simple, sustainable, and motivating. This study takes advantage of recent low-tech tools that appear to elicit the desired muscle actions achieved with MFT.

Participant Recruitment

Participants are recruited from the Sleep Clinic at Walter Reed National Military Medical Center if they receive a new diagnosis of obstructive sleep apnea (AHI >5) based on standard-of-care polysomnography (PSG) or if they do not successfully use a standard first-line treatment. After providing informed consent and passing screening tests, they are randomized into one of two behavioral interventions.

Interviews will determine whether participants have a history of TBI. Participants in the two intervention arms will be block stratified based on +/- TBI and TBI severity. The groups will also be stratified based on OSA severity.

Interventions

The interventions involving drinking water through a study-provided water bottle with a specially designed nozzle and breathing in and out through a study-provided handheld breathing device multiple times daily for 3 months. Therefore, this novel intervention is called "HydroBreathe Therapy." The intervention arms are named for the color of the breathing device. Participants will be informed that the Green option involves exercises intended to relax airway structures and promote better airway patency, and that the Black option involves high-resistance exercises intended to increase airway muscle strength to resist structural collapse. Participants are not informed which of the options is expected to be more therapeutic, but they are informed that both may help and neither will worsen their OSA.

Participants will enter their daily practice into electronic adherence logs, which will be monitored by the study team. A study team member will contacted participants every 2 weeks throughout the intervention period to offer encouragement and answer questions.

Assessments

Pre- and post-intervention measures are obtained from PSG results, self-assessment questionnaires, and measures of tongue and respiratory muscle function. Participants in the experimental group will be given the option to participate in a 3-week follow-up assessment including the questionnaires and muscle-function testing if they are willing to delay first-line treatment for OSA. All participants will be referred back to the Sleep Clinic for standard treatment at the conclusion of the study.

Inclusion Criteria:

• New diagnosis of OSA (AHI, ≥ 5) or failure of first-line OSA treatment;
• Willingness to forego first-line OSA treatment or stop current OSA treatment for 3 months;
• Ability to follow directions and perform the required exercises;
• Age between 18-65 yr.

Exclusion Criteria:

• Current use of OSA treatment;
• Medical comorbidities that require restricting fluid intake (e.g., dysphagia, renal disease, liver disease, hyponatremia);
• Severe nasal obstruction; 4) severe ankyloglossia; 4) craniofacial abnormality; 5) severe pulmonary disease; 6) severe post-traumatic stress disorder; 7) very severe insomnia; 8) body mass index (BMI) ≥30 kg/m2

Per a Data Sharing Agreement, de-identified primary and secondary outcome data from Walter Reed National Military Medical Center will be shared with investigators at Uniformed Services University of the Health Sciences, contractors with the Geneva Foundation, and colleagues at University of Minnesota (UMN). UMN colleagues are conducting a concurrent study using the same procedures as the experimental arm; both sites plan to pool data for a larger sample size.

The study protocol was developed during grant-proposal preparation. Investigators communicate regularly to share updates and coordinate procedures for study implementation. IPD will be made available periodically throughtout data-collection and during data analysis and dissemination (anticipated Jan 2026 -- Dec 2028).

The WRNMMC/USUHS research team will share coded data with project-related Geneva Foundation contractors and UMN collaborators.

The coded data will be stored on REDCap, housed on an encrypted password- and firewall-protected server. Authorized project personnel may request IPD through the PIs.