0063 Age Related Changes in Central Autonomic Couplings During Sleep

Abstract

Abstract Introduction Studies show coupling between central nervous system (CNS) and autonomic nervous system (ANS) activity during sleep. We reported on a novel central/autonomic coupling event (ACE) during non-rapid eye movement (NREM) sleep, in which bursts in heart rate (HRBs) coincide with increased slow-wave activity (SWA) 5 seconds prior to the HRB, followed by a surge in vagal high-frequency activity in the RR signal (HFRR) 5 seconds after the HRB. ACEs predicted sleep-related explicit memory improvement. Aging is characterized with impaired sleep and autonomic loss. We, therefore, investigated ACE activity in older adults. Methods We compared ACEs during a daytime nap between youngers (18-25yrs, N=49) and olders (60-75yrs, N=32). Subjects took an EEG-monitored, 90-minute nap. We measured SWA and HFRR in a 20-sec window around the HRB peak separately for Stage 2 and slow-wave sleep (SWS). EEG were binned into 5-sec intervals around the HRB: -10, -5, +5, +10 bins. For Stage 2 and SWS, repeated-measure ANOVAs with two factors (age and windows) were performed on SWA and HFRR. Corrections used Greenhouse-Geisser and Bonferroni methods. Results For SWA, we found an interaction between age and windows during Stage 2 (p<.001), and SWS (p=.001). SWA during the -5bin was greater in youngers than olders during both Stage 2 and SWS (ps < .001). The ACE profile in youngers showed highest SWA in the -5bin in Stage 2 and SWS (ps < .001) and highest HFRR in the +5bin in Stage 2 (ps < .001) The ACE profile in olders, however, showed no clear pattern for SWA in either sleep stage. Olders showed greater HFRR during the +5bin compared to the -10bin (p=.041) during Stage 2 but no HFRR modulations were found during SWS. Conclusion Our results replicated the ACE profile in daytime naps first reported by Naji et al (2018). In youngers, heart rate bursts were coupled with increased SWA and vagal activity. In contrast, olders demonstrated a lack of boost in SWA and HFRR, which provides implications in cognitive aging. Future research is needed to further understand the impact of decreased coupling between ANS/CNS activity on cognitive decline. Support