Effect of a Multimodal Lifestyle Intervention on Sleep and Cognitive Function in Older Adults with Probable Mild Cognitive Impairment and Poor Sleep: A Randomized Clinical Trial

Background: Poor sleep is common among older adults with mild cognitive impairment (MCI) and may contribute to further cognitive decline. Whether multimodal lifestyle intervention that combines bright light therapy (BLT), physical activity (PA), and good sleep hygiene can improve sleep in older adults with MCI and poor sleep is unknown. Objective: To assess the effect of a multimodal lifestyle intervention on sleep in older adults with probable MCI and poor sleep. Methods: This was a 24-week proof-of-concept randomized trial of 96 community-dwelling older adults aged 65-85 years with probable MCI (<26/30 on the Montreal Cognitive Assessment) and poor sleep (>5 on the Pittsburgh Sleep Quality Index [PSQI]). Participants were allocated to either a multimodal lifestyle intervention (INT); or 2) education + attentional control (CON). INT participants received four once-weekly general sleep hygiene education classes, followed by 20-weeks of: 1) individually-timed BLT; and 2) individually-tailored PA promotion. Our primary outcome was sleep efficiency measured using the MotionWatch8 (c)(MW8). Secondary outcomes were MW8-measured sleep duration, fragmentation index, wake-after-sleep-onset, latency, and PSQI-measured subjective sleep quality. Results: There were no significant between-group differences in MW8 measured sleep efficiency at 24-weeks (estimated mean difference [INT - CON]: 1.18%; 95% CI [-0.99, 3.34]), or any other objective-estimate of sleep. However, INT participants reported significantly better subjective sleep quality at 24-weeks (estimated mean difference: -1.39; 95% CI [-2.72, -0.06]) compared to CON. Conclusion: Among individuals with probable MCI and poor sleep, a multimodal lifestyle intervention improves subjective sleep quality, but not objectively estimated sleep.