Check out our new Ask the Expert article , in which Dr. Helene A. Emsellem, director of the Center for Sleep and Wake Disorders in Chevy Chase, MD, answers common questions about Continuous Positive Airway Pressure. CPAP is the leading therapy for sleep apnea. Patients wear a face or nasal mask during sleep. The mask, connected to a pump, provides a positive flow of air into the nasal passages in order to keep the airway open. Most insurance companies now pay for sleep testing and for CPAP treatment. In the article, Emsellem talks about what to do after you've been diagnosed with sleep apnea and answers questions about CPAP treatment.