SleepFlex head and neck exercise program for the treatment of mild to moderate obstructive sleep apnea - We propose to optimize a simple, non-invasive treatment for obstructive sleep apnea (OSA) that uses head and neck exercises to increase oral, pharyngeal, and cervical muscle strength and endurance. As current therapies have substantial limitations and are not acceptable to many patients, there is an enormous unmet need for effective, well-tolerated, safe, and non-invasive OSA treatments. Head and neck exercises for OSA treatment have received attention over the past decade, with multiple placebo-controlled, randomized studies showing improvement but incomplete resolution of OSA. Previous approaches have important limitations. Our strategy is a focused, effective, safe, and non-invasive head and neck exercise program delivered with the aid of a smartphone app user interface to provide instruction for proper exercise performance with simple devices. SleepFlex® will increase strength and endurance of key muscles to increase dilator muscle force during sleep. Our program includes head and neck exercises selected to target the muscles of the tongue, soft palate, and lateral pharyngeal walls. This Fast Track SBIR proposal builds on our initial work to optimize then evaluate the program. Phase I Aim 1: Optimize the SleepFlex® program, including achieving reliable, accurate device performance. The exercises will require two sets of devices that ensure correct performance with appropriate levels of resistance. The smartphone app user interface (iOS and Android) incorporates instructional videos as well as other visual and written information on proper exercise performance. Phase I Aim 2: Perform pilot safety and feasibility study of the optimized SleepFlex® program. We will enroll 20 adults with mild to moderate OSA unable to tolerate positive airway pressure. All study participants will undergo SleepFlex® treatment, 3 days/wk for 12 weeks. Participants will complete study assessments (including 2-night home sleep apnea tests) at baseline and at 4, 8, and 12 weeks of active treatment. We will assess effectiveness (apnea- hypopnea index/AHI, sleepiness, quality of life, muscle strength and endurance). Adverse events (pain, dysphagia), usability, and adherence will be measured. Phase II Aims: (1) evaluate the effectiveness of the SleepFlex® program in reducing OSA severity with a multicenter randomized, placebo-controlled trial; and (2) evaluate the long-term benefits and the need for maintenance treatment with a multicenter randomized trial. We will enroll 100 study participants with previously-diagnosed mild to moderate obstructive sleep apnea who have been unable to tolerate positive airway pressure therapy. All study participants will undergo randomization 2:1 to active treatment with the SleepFlex® program vs. placebo for 12 weeks. The primary outcome will be change in the apnea-hypopnea index from baseline to 12 weeks. Study participants who complete 12 weeks of active treatment will undergo randomization 1:1 to maintenance treatment vs. observation for 12 additional weeks. The primary outcome will be change in the apnea-hypopnea index from 12 weeks to 24 weeks. Adverse events (pain, dysphagia), usability, and adherence will be measured.