LAUSR

Differences between subjective and objective sleep [subjective-objective sleep discrepancy (SOSD)] is prevalent in insomnia and older adults. Despite associations between cognition and sleep parameters, the impact of cognitive functioning on SOSD is unclear. We examined associations between various cognitive domains and SOSD in older adults and whether insomnia status moderates these associations. Older adults with (N=47, Mage=68.85, 66% women) and without (N=32, Mage=67.41, 78% women) insomnia [met DSM-5 criteria plus reported >30 mins sleep onset latency (SOL) and/or wake time after sleep onset (WASO) on 3+nights/7] completed measures of subjective sleep (7-days of sleep diaries), objective sleep (one-night polysomnography, PSG), and objective cognitive tasks: Dimensional Change Card Sort (executive functioning, EF), List Sorting (working memory, WM), Auditory Verbal Learning Test (episodic memory), Flanker (inhibitory control), Pattern Comparison (processing speed). SOSD direction (average sleep diary variable – PSG variable) was computed. Moderated regressions determined independent and interactive (with insomnia status) associations between cognitive performance and SOSD for SOL, WASO, total sleep time (TST) and sleep efficiency, controlling for age, sex, apnea-hypopnea index, and sleep medication usage. For insomnia, longer self-reported than PSG TST was associated with better WM (b=27.90, SE=9.05, p=.003, episodic memory (b=12.83, SE=2.77, p=.01), processing speed (b=9.50, SE=2.00, p<.01), and inhibitory control (b=118.40, SE=54.09, p=.03). Similarly for insomnia, better self-reported than PSG sleep efficiency was associated with better WM (b=5.58, SE=2.12, p=.01), episodic memory (b=2.66, SE=1.08, p=.02), and processing speed (b=2.11, SE=0.47, p<.01). For non-insomnia, reports of SOSD were not associated with cognitive functioning (ps>.05). Better diffuse cognitive functioning may be a contributing SOSD mechanism in older adults with insomnia. We speculate that better cognitive functioning may suppress cognitive arousal symptoms that are prevalent in insomnia patients, leading to better self-reported sleep relative to what is objectively measured. Prospective studies examining independent and interactive associations between cognition functioning and arousal, and insomnia on SOSD may inform underlying mechanisms of poor sleep health and the temporal impact on cognition. This research project was made possible by awards (PI: Curtis) from the American Academy of Sleep Medicine Foundation, a foundation of the American Academy of Sleep Medicine.