KPAP vs AirSense 11 With EPR

The KPAP vs AirSense 11 with EPR study is a randomized, crossover study in which treatment efficacy will be compared between SleepRes APAP + KPAP and ResMed APAP + EPR. Participants will be chosen from those with a formal OSA diagnosis (following an in-lab polysomnogram, a split-night study or a home sleep apnea test) within the past 2 years and on PAP therapy. Upon signing an informed consent, participants will be randomized to the order of study and which device will be used first: APAP + KPAP (delivered by a SleepRes device) or APAP + EPR (delivered by a ResMed device). Participants will be blinded to the sequence order. They will then be invited to the laboratory for two overnight sleep studies, one on each treatment device, in the order determined by the randomization. Prior to each overnight, they will have to observe withdrawal of their home PAP treatment for 3 nights. The KPAP drop will be set to the maximum level (i.e., 5 cmH2O), while EPR will be set on 3. APAP from both manufacturers will be set on a 5-20 cmH2O pressure range. The next morning of each sleep study, participants will be administered visual analog scale (VAS) questionnaires to examine subjective sleep quality (1=best sleep quality; 10=worst sleep quality) and, after all studies are completed, a device subjective preference (1=APAP+KPAP was extremely better than APAP+EPR; 10=the opposite). The study will be single blinded with both the participants (the device will be concealed in the laboratory so that participants will not be able to understand what treatment they are on) and the registered technician scoring the polysomnograms (by an independent scoring partner, Sleep Strategies) blinded to treatment allocation.

Inclusion criteria: * BMI above 18 kg/m2, inclusive * Diagnosis of OSA meeting all the following criteria: AHI4 \> 10 on a previous PSG or HST (within the past 2 years), central apneas \< 25% of events, PLM arousal index \< 15 if recorded * Current treatment with PAP of any nightly duration. * Subject is fluent in English and subject understands the study protocol and is willing and able to comply with study requirements and sign informed consent. * Participant voluntarily agrees to participate in this study and signs an Institutional Review Board (IRB)-approved informed consent prior to performing any of the study-related procedures. Exclusion Criteria * A female of child-bearing potential that is pregnant or intends to become pregnant. * Any unstable or severe medical condition of any organ system including congestive heart failure, COPD, renal failure, neuromuscular disease, etc., or at the discretion of the site Principal Investigator (PI). * Taking medication that may affect sleep, sleepiness, or alertness including hypnotics, sedatives, alerting agents, stimulants, anticonvulsants, etc. * The presence of any other sleep disorder (insomnia, periodic limb movement disorder, etc). * The presence of a psychiatric disorder, including attempted suicide within 1 year prior to screening, or current suicidal ideation. * A serious illness or infection in the past 30 days. * Prior/Concomitant Therapy including: chronic nocturnal oxygen therapy, mandibular advancement device, active hypoglossal nerve stimulation implant. * Excessive alcohol consumption (\>21 drinks/week). * The use of any illegal drug(s).