0454 In Cognitively Normal Elderly, Obstructive Sleep Apnea Worsens Spatial Navigational Memory Performance

Introduction Normal sleep has a favorable effect on the consolidation of spatial navigational memory. Previous work suggests normal overnight sleep enhances spatial navigation performance in a hippocampus-dependent manner. Our group has previously demonstrated post-sleep spatial navigational performance may be affected by obstructive sleep apnea (OSA). Here we aim to replicate these findings in a much larger sample size. Methods Using a virtual 3D Maze, 162 subjects (66.8 ± 6.5 years, 88 female) completed spatial navigational encoding and recall across their nocturnal polysomnography visit. Participants were instructed to find the maze exit within a ten-minute period and were given three trials pre- and post-sleep. We compared overnight changes and trial-by trial completion times between participants with and without OSA (AHI4% > 5) using Wilcoxon signed-rank test. Results Of the 162 participants, 76 had OSA (10.5± 16.12 AHI4). There was no statistically significant difference in overnight change in completion time (%) between OSA/non-OSA groups (OSA: 2.5 ± 58.3, non-OSA: 9.9 ± 52.1). However, the average completion time worsened with each successive trial during encoding (pre-sleep) in OSA [T1: 305 ± 18, T2: 328 ± 21, T3: 345 ± 23 seconds] as compared to non-OSA [T1: 369 ± 20, T2: 324 ± 19, T3: 320 ± 20 seconds]. Further, we observed that the average completion time worsened with each successive trial during recall (post-sleep) in the OSA group [T4: 306 ± 20, T5: 296 ± 20, T6: 332 ± 20 seconds] as compared to the non-OSA group [T4: 331 ± 19, T5: 312 ± 20, T6: 277 ± 18 seconds], such that, in the final post-sleep trial (T6), OSA patients had significantly slower completion times than the those without OSA (p = 0.034). Conclusion Despite no difference in overnight change in completion time between non-OSA and OSA, the pattern of performance during encoding and recall was different; These observations suggest OSA may be creating a working memory deficiency more strongly than an offline processing deficiency. Future analyses evaluating PVT performance in the OSA and non-OSA groups may be instructive to probe whether a different domain of executive is also impacted and its relationship to subjective sleepiness. Support (if any)