Disturbed Sleep and Alzheimer’s

A new Alzheimer’s & Dementia study has found that prolonged rapid eye movement sleep latency (REML) – the time it takes to enter REM after falling asleep – could be associated with key biomarkers of Alzheimer’s disease (AD). The study highlights REM sleep disruptions as a potential early indicator of AD pathology, even in individuals with mild cognitive impairment (MCI) or normal cognition.

The multinational group of researchers analyzed 128 participants (64 with AD, 41 with MCI, and 23 with normal cognition) using polysomnography (PSG) to measure REM latency and biomarker analysis. This analysis included taking amyloid β (Aβ) PET scans and plasma biomarker analysis of the patients, with results revealing that individuals with longer REM latency had a higher Aβ burden, increased p-tau181 levels, and lower BDNF (brain-derived neurotrophic factor) concentrations. These associations remained significant after adjusting for demographics, APOE ε4 status, and cognitive function.

The authors suggest that prolonged REML could serve as an early warning sign of neurodegeneration, particularly for individuals at risk of AD. The findings also align with prior research suggesting that cholinergic dysfunction and orexin system dysregulation – both implicated in AD – may also play a role in REM sleep disturbances. They authors add that future studies could investigate whether targeting REM sleep with sleep-promoting medications, such as orexin receptor antagonists, might help to slow AD progression.