Emerging therapies for obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a prevalent disorder often associated with daytime sleepiness, cognitive dysfunction, and adverse cardiovascular consequences. Available therapies are limited by either lack of long-term adherence or low response rates. Two emerging therapies hold promise in providing alternatives to patients with OSA. The first stems from the importance of the upper-airway dilator muscles in maintaining pharyngeal stability. Electrical stimulation of the genioglossus muscle improves both upper-airway diameter and ameliorates pharyngeal obstruction. The results of phase I and II clinical trials hold promise, but the reported improvements in the apnea-hypopnea index vary between subjects and concerns about long-term safety await long-term studies. The second technology relies on creating an increased expiratory nasal resistance via a bidirectional valve designed to be worn just inside the nostrils. Initial findings of clinical trials suggest reduction in severity of sleep apnea and subjective daytime sleepiness. Considerable heterogeneity in response to the nasal device was noted despite the high adherence rates. It remains unclear which patients will likely benefit a priori from these devices.