Wearable Neural Interfacing System for REM Sleep Restoration and Enhancement

This study evaluates a wearable system (NEUSleeP) that combines overnight EEG recording with transcranial focused ultrasound (tFUS) targeted to deep brain structures involved in REM sleep regulation (e.g., subthalamic nucleus). The primary objective is to assess safety and estimate effects on REM sleep quantity and architecture; secondary objectives include changes in stress-related measures. Healthy adults aged 18-50, with or without subclinical sleep or stress complaints, will complete two consecutive overnight recordings: Night 1 (baseline, no stimulation) and Night 2 (tFUS, EEG-guided and timed to REM). Participants will complete stress questionnaires. fMRI is conducted using two paradigms: in an imaging-validation subset, pre- and post-stimulation scans are acquired in the same MRI-FUS session; in the two-night cohorts, scans are acquired the morning before and the morning after the FUS night to assess BOLD responses. Outcomes include REM time, REM percentage, number of REM periods, REM latency, safety/tolerability, and exploratory neuroimaging and self-reported stress measures. Findings will inform the feasibility of a wearable EEG-tFUS approach to modulate REM sleep and stress adaptation.