0116 Autonomic And Sleep Interaction During Acoustic Enhancement Of Sleep

Abstract Introduction Acoustic stimulation applied during sleep can enhance slow wave activity (SWA). Given the relationship between sleep and the autonomic nervous system (ANS), we aimed to explore how these two systems interacted in healthy young adults receiving acoustic stimulation. Methods Twenty subjects (25 ± 4 years, 75% female) participated in a randomized cross-over study with two 2-night visits. After one night of adaptation, participants were randomized to either receive stimulation or sham stimulation on the following night. During NREM sleep, a phase locked auditory stimulation procedure using single input from the midline frontopolar channel, was used to deliver 50ms pulses of pink noise in blocks of 5 (ON intervals) followed by a pause of approximately 6 seconds (OFF intervals). Changes in EEG spectral power across multiple frequency bands were calculated during ON and OFF intervals for both conditions. ANS function was assessed using heart rate variability (HRV) that was quantified before “lights off” over a 5-minute period in supine position and during 5-minute periods of slow wave sleep (SWS) in the first three cycles of sleep. The following HRV measures, representative of cardiac vagal regulation, were calculated: RMSSD (square root of the mean squared differences of successive NN-intervals) and HF% (high frequency, relative power). Results Acoustic stimulation increased SWA (0.5-4Hz) by 40% and sigma activity (11-15Hz) by 14% during ON vs OFF intervals compared to sham (p