This CPB is revised to state that attended full-channel nocturnal polysomnography (Type I device) performed in a healthcare facility is considered medically necessary for diagnosis of obstructive sleep apnea in members with obesity hypoventilation syndrome. This CPB is revised to state that the following tests are considered experimental and investigational: daytime nap polysomnography, maintenance of wakefulness test (MW), and diagnostic audio recording with or without pulse oximetry. This CPB is revised to state that replacement of positive airway pressure devices or oral appliances is considered medically necessary prior to the end of the 5-year reasonable useful lifetime due to a change in the member's condition; replacement needed due to misuse or abuse are not covered.