0461 Parietal EEG Slow Activity During NREM Is Associated with Overnight Spatial Memory Performance in CPAP-treated OSA

Abstract Introduction Sleep disturbance from obstructive sleep apnea (OSA) impairs overnight memory processing which may be mediated by changes to slow wave sleep. Indeed, reduced region-specific EEG slow activity during non-REM sleep has been associated with worse overnight declarative, motor and spatial memory. Using a polysomnologically (PSG)-verified model of SWS-specific CPAP-withdrawal to create three conditions of 1) stable-SWS on CPAP, 2) SWS-fragmentation with intermittent hypoxemia (OSAsws), and 3) SWS-fragmentation with reduced hypoxemia (OSAsws+O2), we investigated whether CPAP withdrawal during SWS induces acute changes in EEG slow wave activity that is associated with overnight spatial navigational memory performance. Methods 19 channel EEG, re-referenced to average mastoids from 72 PSGs in 24 CPAP-adherent patients (7 female, average age 56yrs) with moderate-to-severe OSA was inspected visually for artifact removal prior to analysis using an automatic algorithm (DETOKS) for detection of relative slow wave (0.5-4Hz, SWA) and slow oscillation (0.6-1Hz, SOA) activity. During each PSG visit, participants explored one of three 3D maze environments, performing 3 timed trials before and after each of 3 randomized and counterbalanced SWS disruption conditions, 1)CPAP, 2)OSASWS & 3)OSASWS+O2. Frontal (Fz), central (Cz) and parietal (Pz) relative SWA, SOA and overnight change in maze completion times were compared according to PSG condition using Friedman Rank Sum and Conover’s tests. The relationship between SWA and maze performance was tested using Pearson’s correlation coefficient. Results No significant differences were observed between the three conditions for non-REM EEG slow activities or overnight change in maze completion times. In the CPAP condition only, greater EEG slow activity at Pz (SWA, r=0.57, p=0.01 and SOA, r=0.67, p=0.002) was associated with larger improvements in overnight maze completion times. Conclusion EEG slow wave activity and maze performance were not influenced by the recapitulation of OSA during SWS in CPAP-treated individuals. There was, however, a positive relationship between parietal-specific EEG slow oscillation activity and overnight maze performance during stable CPAP-treated slow wave sleep. These observations suggest that OSA of sufficient severity to impact SWA or SOA may negatively impact spatial navigational memory, but the selective withdrawal of CPAP in SWS only was not sufficient to do so. Support (if any) R01AG056682,R21OH012623,K24HL109156