A Phase 1/2 interventional study of High-Resistance Breathing and Drinking Exercises and Low-Resistance Breathing and Drinking Exercises in Obstructive Sleep Apnea (OSA) and Traumatic Brain Injury (TBI), sponsored by Uniformed Services University of the Health Sciences. Recruiting at 1 site in United States. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-09-10.
Sponsored by Uniformed Services University of the Health Sciences · Phase 1/2, Interventional, and Treatment
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.
2,240 studies on the registry are indexed under Sleep Apnea, Obstructive; 475 are open to participants now.
This study's planned enrollment of 60 is above the median of 52 across 1,472 interventional studies indexed under Sleep Apnea, Obstructive.
Browse Sleep Apnea, Obstructive studies →Uniformed Services University of the Health Sciences is the lead sponsor of 45 studies on the registry; 12 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Line of therapy
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Behavioral: High-Resistance Breathing and Drinking Exercises
Behavioral: Low-Resistance Breathing and Drinking Exercises
Three months of drinking at least 32-oz of water daily through a high-resistance nozzle, and inhaling and exhaling 60 times per day through a high-resistance breathing device
Also known as: Device-Assisted Myofunctional Therapy
Three months of drinking 32-oz of water daily through a low-resistance nozzle, and inhaling and exhaling 40 times per day through a low-resistance breathing device
Also known as: Placebo Therapy
Apnea-Hypopnea Index (AHI)
AHI is the number of apneic and hypopneic episodes per hour of sleep. The scores start at zero, meaning no events are taking place. A mild score falls in the range of 5-15; moderate 15-30, and a severe diagnosis is 30 or more events per hour. Pre-intervention AHI is obtained from standard-of-care in-clinic sleep study. Post-intervention AHI is obtained from an in-clinic sleep study conducted as part of this research.
Time frame: From enrollment to end of three-month intervention
SpO2
Oxygen saturation measured during the in-clinic sleep studies. Normal levels range between 95-100%.
Time frame: From enrollment to end of three-month intervention
Snore Index
Number of snoring episodes per hour of sleep
Time frame: From enrollment to end of three-month intervention
Epworth Sleepiness Scale (ESS)
A self-assessment of daytime sleepiness comprising eight questions on a four-point scale (0-3; total range = 0-24). Higher scores indicate greater daytime sleepiness.
Time frame: From enrollment to end of three-month intervention with option for additional three-week follow-up
Functional Outcomes of Sleep Questionnaire-10 (FOSQ-10)
A self-assessment of the impact of daytime sleepiness on daily activities. Of the 10 questions, five are rated 0-4 and five are rated 1-4, for a total score ranging between 5-40. A higher score indicates lower impact.
Time frame: From enrollment to end of three-month intervention with option for additional three-week follow-up
Tongue Strength
The maximum pressure generated during tongue-to-palate compression of an air-filled bulb over three trials.
Time frame: From enrollment to end of three-month intervention with option for additional three-week follow-up
Tongue Endurance
The maximum duration of sustaining tongue-to-palate compression of an air-filled bulb at 50% of maximum pressure.
Time frame: From enrollment to end of three-month intervention with option for additional three-week follow-up
Maximal Inspiratory Pressure (MIP)
The maximum pressures generated during maximal-effort inspiration in cmH2O.
Time frame: From enrollment to end of three-month intervention with option for additional three-week follow-up
Maximal Expiratory Pressure (MEP)
The maximum pressures generated during maximal-effort expiration in cmH2O.
Time frame: From enrollment to end of three-month intervention with option for additional three-week follow-up
Plan to share: Yes — 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.
Supporting information: Study protocol
Time frame: 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).
Access criteria: 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.
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Uniformed Services University of the Health Sciences