Sleep electroencephalography-derived brain health and long-term cognitive decline in community-dwelling adults

Sleep electroencephalography (EEG) is linked with cognitive function and dementia risk. Integrated EEG-derived scores, such as the Brain Health Score (BHS), trained to jointly reflect cognitive function and disease risk, and the Brain Age Index (BAI), which estimates brain aging, also correlate with neuropsychological (NP) performance. Yet, it remains unclear whether these sleep scores are associated with the rate of future cognitive decline.

This study included 639 Framingham Heart Study Generation 2 and Omni 1 participants with sleep EEG in mid-to-late life and ≥ 2 NP tests over an average of 14.3 years. Linear mixed effects models estimated associations between BHS and annual changes in memory, executive function, or language. We also evaluated associations between BAI and cognitive decline among 509 Generation 2 participants with BAI values.

Participants were, on average, 58.4 years at sleep assessment, 54 per cent female, and 86 per cent non-Hispanic white. Each 1-SD higher BHS was associated with 0.015 SD/year slower memory decline (95% CI: 0.009-0.021), a 0.009 SD/year slower executive function decline (95% CI: 0.005-0.014), and a 0.011 SD/year slower language decline (95% CI: 0.005-0.017). In contrast, BAI was not associated with changes in any cognitive domain.

Higher sleep EEG-derived brain health in mid-to-late life was associated with a slower decline in multiple cognitive domains over more than a decade of follow-up, whereas an EEG-based measure of brain aging was not. These findings suggest that sleep EEG-derived, data-driven brain health metrics may have value as novel biomarkers for the risk of cognitive decline.