0098 Improving Sleep-Dependent Memory in Individuals with Mild Cognitive Impairment via a Tailored Lighting Intervention

Abstract Introduction Tailored Lighting Interventions (TLI) that target the circadian system can improve sleep in individuals with mild cognitive impairment (MCI). Yet, whether these sleep benefits translate to improved cognitive function is not known. To address this gap, we examined how at-home TLI impacted longitudinal trajectories of sleep-dependent episodic and working memory in older adults with MCI. Methods We conducted a randomized, placebo-controlled, longitudinal at-home TLI trial in adults with MCI. Participants (n=61; 69.7±8.0 years; 29F) were randomly assigned to the active TLI or placebo condition, with all participants completing four at-home visits at weeks 1 (baseline), 13, 25, and 37 (follow-up). At each visit, participants completed episodic and working memory tasks before and after a full night of sleep at-home monitored by actigraphy. Episodic memory was assessed via the Word Pair Association task, while working memory was assessed via the operation span (OSPAN) task. Sleep-dependent memory for each task was defined as the over-night change in performance. Linear mixed effects models evaluated main and interaction effects of group (TLI vs. placebo) and time (visit) on sleep-dependent memory. Significant interaction effects were further examined using post-hoc t-tests. Results The TLI group showed significantly greater sleep-dependent memory at the follow-up visit compared with placebo (p < .05). For both tasks, mixed linear models yielded a significant interaction of visit x group (WPA: p = .02, t = -2.33; OSPAN: p = .03, t = -2.19), with post-hoc t-tests identifying significant differences between groups at visit 4, with greater sleep-dependent memory in the TLI group (WPA: p = .003, t = 3.16; OSPAN: p = .04, t = 2.17). No significant main effects of visit or group were observed (p > .05), suggesting that the TLI specifically contributed to long-term benefits in sleep-dependent memory. Conclusion Our findings demonstrate that circadian entrainment can be done at-home to improve sleep-dependent memory in individuals with MCI. This approach holds translational relevance for developing accessible, sleep-focused, at-home strategies to mitigate age-related cognitive decline. Support (if any) The NIA provided funding under grant number R01AG062288 and R01AG034157.