This study is a randomized controlled trial with two phases: pre-trial and formal trial. The pre-trial will include 5 participants to observe the 4-week adherence (≥4 hours/night) and safety (adverse event rate) of the iNAP device. For the formal trial, 60 patients with MCI and moderate-to-severe OSA will be stratified and block randomized (by baseline AHI levels: 15-30 events/h vs \>30 events/h) into either the iNAP intervention group (using the device nightly for 24 weeks) or the control group (receiving only sleep hygiene guidance). The primary outcome is the change in MoCA scores from baseline at week 24. Secondary outcomes include AHI reduction rate, sleep efficiency, plasma Aβ42/Aβ40 ratio, cognitive assessments, and brain imaging indicators. Follow-up visits will occur at baseline, week 12, and week 24 to monitor cognitive function, sleep parameters, and safety.