Coupling of within-person changes in sleep quality and subjective cognition in community-dwelling adults

OBJECTIVES: Subjective cognitive decline (SCD) is an early indicator of cognitive impairment and dementia risk. Sleep quality, essential for cognitive health, often deteriorates with age. Intraindividual changes in sleep quality may be linked to concurrent changes in subjective cognition; this dynamic 'coupling effect' could inform strategies for prevention before objective impairments emerge but remains unexamined longitudinally. We investigated this interplay in older adults over multiple years. METHOD: Utilizing the 'nlme' R package, we analyzed nine waves of sleep quality and subjective cognition data from the Transitions in Health and Relationships study (n = 131, ages 59-94 at baseline, 63% female) in hierarchical multilevel models, with random intercepts and slopes. RESULTS: Multilevel models indicated changes in sleep quality were positively associated with concurrent changes in subjective cognition, independent of baseline sleep quality, and sociodemographic covariates. CONCLUSION: Findings highlight the importance of monitoring within-person sleep quality changes as a potential indicator of SCD in older adults. Further studies may help identify pathways to support cognitive health in aging populations.