Acoustic Stimulation During Sleep: Effects on Memory and p-tau217 in MCI

The goal of this clinical trial is to determine whether acoustic stimulation during sleep can enhance slow-wave sleep (SWS), improve cognitive function, and reduce AD-related pathology in individuals with mild cognitive impairment (MCI), compared with cognitively healthy participants. The main questions it aims to answer are: 1. Does acoustic stimulation increase SWS (e.g., slow oscillation and sleep spindle activity) in individuals with MCI? 2. Does enhancing SWS lead to improvements in memory and cognitive performance? 3. Does acoustic stimulation influence plasma p-tau217 levels as a marker of underlying Alzheimer's disease pathology? Researchers will compare participants receiving acoustic stimulation during sleep with those not receiving stimulation to evaluate its effects on sleep architecture, cognition, and plasma biomarkers. Participants will: * Undergo sleep recordings to assess sleep architecture, including SWS, slow oscillations, and sleep spindles * Receive acoustic stimulation during sleep across multiple nights * Complete cognitive assessments, particularly memory-related tasks * Provide blood samples to measure plasma p-tau217 levels * Provide clinical and demographic information for analysis