Evaluation of an Algorithm to Detect Sleep and Wake in Continuous Positive Airway Pressure (CPAP)

Inclusion Criteria: * Age 21-70 * Diagnosis of obstructive sleep apnea (OSA) * Current adherent CPAP user (has been using CPAP nightly for at least 2 weeks). * On CPAP pressures of 5-10cm. * Subjects wishing to complete a day or evening appointment need to have significant daytime sleepiness (Epworth Sleepiness Scale score of 8 or above) * Able and willing to provide written informed consent * English speaking Exclusion Criteria: * Participation in another interventional research study within the last 30 days * Major controlled or uncontrolled medical condition such as congestive heart failure, neuromuscular disease, renal failure etc. * Inability to tolerate nasal CPAP mask due to problems breathing solely through their nose. * Chronic respiratory failure or insufficiency with suspected or known neuromuscular disease, moderate or severe chronic obstructive pulmonary disease (COPD), or any condition with an elevation of arterial carbon dioxide levels while awake (PaCo2≥55mmHg) * Severe oxygen desaturation on the polysomnography (PSG), i.e. Sa02 \< 70% for 10% of the study. * Surgery of the upper airway, nose, sinus or middle ear within the past 90 days * Currently using supplemental oxygen * Regular use of sleeping pills or stimulants (\> 3 nights a week) * Currently working night shift or rotating day/night shift * Drowsy Driving or near miss accident in the past 6 months * Inability to tolerate or track to Paced Breathing device during initial habituation session in lab * Chronic insomnia, Restless legs syndrome, or severe periodic limb movement disorder (PLMD - PLMAI\>20/hr).