1083 SLOW WAVE ACTIVITY AND SIGMA AS NON-RAPID EYE MOVEMENT SLEEP FEATURES CHARACTERIZING POSTTRAUMATIC STRESS DISORDER SYMPTOM SEVERITY AND COGNITIVE FUNCTIONING IN MILITARY VETERANS

Inadequate sleep is a hallmark of posttraumatic stress disorder (PTSD), and may contribute to poor cognitive functioning. Non-rapid eye movement (NREM) sleep, specifically slow wave activity (SWA; 0.5-4Hz) and sigma (12-16Hz), have been linked to cognition in clinical and healthy populations, but remain understudied in PTSD. This study explored relationships between PTSD, SWA, sigma, and cognitive symptoms in military veterans. 129 previously-deployed veterans with (PTSD+; n=100) and without (PTSD-; n=29) PTSD, completed the Clinician Administered PTSD Scale (CAPS) and two consecutive sleep laboratory nights with full polysomnography, where relative delta (a marker of SWA) and sigma power were extracted from C4 channel for whole, second night NREM sleep. Analysis of covariance and partial correlations assessed group differences and magnitude of relationships. The PTSD+ group demonstrated less SWA [F1, 113=5.11, p=.03] than the PTSD- group, but no group differences were observed in sigma. In the PTSD+ group, SWA positively correlated with overall PTSD severity determined by the CAPS (r=.21, p=.05) and sigma negatively correlated with CAPS cognitive items (r=-.21, p=.05). Adjusting for age did not impact the significance of relationships tested. However, age correlated with overall PTSD severity (r=-.50, p< .001) CAPS cognitive items (r=-.26, p=.01) and SWA (r=-.48, p< .001), but not with sigma. SWA is associated with overall PTSD severity and age, while sigma is related to CAPS cognitive items. Although sigma did not differ between groups, other related features, such as sleep spindles, may be related to cognitive functioning in PTSD, and age may uniquely contribute to relationships involving SWA. More precise and objective measures are necessary to fully assess the relationships between SWA, sigma, PTSD, and cognitive functioning in military veterans. Department of Defense Congressionally Directed Medical Research Programs (Germain-W81XWH-06-1-0257, W81XWH-08-1-0637, W81XWH-12-2-0024; Reifman-W81XWH- 14-2-0145) National Institutes of Health (Germain-MH083035; PI: Buysse- 4T32HL082610-10). Disclaimer: The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the US Army or of the US Department of Defense. This abstract has been approved for public release with unlimited distribution.