The Effects of Successful OSA Treatment on Memory and AD Biomarkers in Older Adults Study

Inclusion Criteria: * Cognitively normal (TiCS ≥29) * Age 55-85 years * Moderate - severe OSA defined as AHI4 ≥20 events/hour or AHI3A\>40/hr using a hypopnea criterion of a 4% oxygen desaturation (AHI4) or 3% oxygen desaturation and/or EEG arousal (AHI3A), or equivalent based on in-home testing - Testing must have been completed in past 12 months or confirmed by repeat test * Not currently on therapy for OSA and has not received treatment for OSA for at least 6months * Able and willing to be treated for OSA (Treatment group) * Fluency in English or Spanish Exclusion Criteria: * Documented diagnosis of chronic insomnia, or sleep onset insomnia based on Insomnia Severity Index - an answer of severe or very severe in the screening form * Documented diagnosis of circadian rhythm disorder * Any current use of supplemental oxygen * Other sleep-related breathing disorders (central sleep apnea, etc) based on AASM criteria * Current shift work involving night shift (regular work between 12am and 6am or night shift) within the past 6 mo * Anticipated scheduled bariatric surgery within the next 3 months * Chronic regular (\> 2 nights per week) of cannabis for sleep * Chronic regular use (\> 2 nights per week) of sedatives/hypnotics for sleep * Diagnosis of uncontrolled psychiatric disease in the last six months , and/or history of schizophrenia or bipolar disorder. Controlled conditions will include major depressive disorder, panic disorder, generalized anxiety disorder, OCD, substa…