Comparison of Breathing Event Detection by a Continuous Positive Airway Pressure Device to Clinical Polysomnography

Inclusion Criteria: 1. Age 21-75 2. Diagnosis of OSAHS with a baseline AHI ≥ 15 events/hr of sleep assessed January 01, 2007 or later 3. CPAP prescription of 8cm of H20 or higher 4. Able and willing to provide written informed consent 5. Native English speaker Exclusion Criteria: 1. Participation in another interventional research study within the last 30 days 2. Major medical or psychiatric condition that would interfere with the demands of the study and adherence to PAP. Examples include unstable cardiovascular disease (Class III / IV CHF), neuromuscular disease, cancer, and renal failure. 3. Chronic respiratory failure or insufficiency with suspected or known neuromuscular disease, moderate or severe continuous positive airway pressure (COPD) or other pulmonary disorders, or any condition with an elevation of arterial carbon dioxide levels (\> 45 mmHg) while awake, or subjects requiring continuous oxygen therapy. 4. Surgery of the upper airway, nose, sinus, or middle ear within the previous 90 days 5. Surgery at any time for the treatment of OSAHS such as uvulopalatopharyngoplasty (UPPP) 6. Presence of untreated or poorly managed,non-OSAHS related sleep disorders: 1. moderate to severe periodic limb movements(≥ 30/hr with symptoms or arousals) 2. arousals associated with periodic limb movements \> 10 per hour or 3. anyone experiencing chronic and severe insomnia. 7. Consumption of ethanol immediately prior to the research PSG