Revised Algorithm for Next Generation DeVilbiss Healthcare AutoAdjust Continuous Positive Airway Pressure (CPAP)

Inclusion Criteria: * Apnea hypopnea index ≥ 15 / hour of sleep on the diagnostic polysomnogram, or diagnostic component of a split night polysomnogram * Sleep efficiency reported on CPAP titration night PSG should be \> 78% * Diagnosis of moderate to severe obstructive sleep apnea (AHI ≥15) or central/complex sleep apnea * On stable CPAP or APAP \[Automatic Positive Airway Pressure\] therapy, with compliant use averaging 4 or more hours nightly * Age 21-75 years * Predominately central sleep apnea for up to 10 subjects only * Willingness to give written informed consent and ability to adhere to visit schedule Exclusion Criteria: Diagnosis of mild sleep apnea * CPAP naïve patients * Co-morbid conditions which render participation to be at risk. These may include patients with congestive heart failure, COPD \[Chronic Obstructive Pulmonary Disease\] or psychiatric illness * Allergies to mask materials * Evidence of another primary sleep disorder * Evidence of arousing periodic limb movements during titration * Contraindications as listed on product labeling * Pregnant * Currently diagnosed with depression if symptomatic * Deemed medically unsuitable by investigator * Evidence of any type of infection or treatment of an infectious condition during the period of research participation * Have a bi-level requirement, or prescribed a bi-level therapy device * CPAP pressure \>15cmH2O * Subjects with tracheotomy * Uncontrolled hypertension * Require supplemental oxygen * Stimulants, major tranquillizers or antipsychotics * Restless Leg Syndrome or Periodic Leg Movement Index of \> 5 per hour