DELAYS in rapid eye movement (REM) sleep may serve as an early indicator of Alzheimer’s disease, as longer REM sleep latency is associated with higher levels of toxic proteins linked to the condition and reduced neuroprotective factors.
Sleep disturbances are increasingly recognised as a potential early marker of Alzheimer’s disease (AD) and related dementias (ADRD), but the link between specific sleep patterns and AD pathology remains unclear. This study aimed to investigate whether REM sleep latency (REML)—the time taken to enter REM sleep—correlates with established AD biomarkers. Researchers enrolled 128 participants from a tertiary hospital in China, comprising individuals with AD, mild cognitive impairment (MCI), and normal cognition. The study cohort had a mean age of 70.8 years, with 56.9% being female. All participants underwent overnight polysomnography (PSG), amyloid beta (Aβ) positron emission tomography (PET), and blood biomarker analysis, including phosphorylated tau-181 (p-tau181), neurofilament light (NfL), and brain-derived neurotrophic factor (BDNF).
After adjusting for demographic factors, APOE ε4 status, cognitive ability, and comorbidities, findings revealed that prolonged REML was significantly associated with increased Aβ burden (β = 0.08, 95% confidence interval [CI]: 0.03 to 0.13, p = 0.002), elevated p-tau181 levels (β = 0.19, 95% CI: 0.02 to 0.13, p = 0.002), and decreased BDNF concentrations (β = -0.47, 95% CI: -0.68 to -0.13, p = 0.013). These results indicate that delayed REM sleep may reflect underlying AD-related neurodegeneration.
These findings highlight the potential of REML as an early biomarker for Alzheimer’s disease, reinforcing the growing recognition of sleep disturbances as a contributor to neurodegenerative processes. The clinical implications are significant, as interventions targeting REM sleep—such as optimising sleep hygiene, managing sleep disorders, and exploring pharmacological approaches—could potentially alter disease progression. Future studies should examine whether treatments aimed at reducing REML delay can modify AD risk or slow cognitive decline. Given the increasing accessibility of sleep-tracking technology, REML measurement may also offer a non-invasive tool for early AD detection and risk stratification in clinical practice.
Katrina Thornber, EMJ
Reference
Jin J et al. Association of rapid eye movement sleep latency with multimodal biomarkers of Alzheimer’s disease. Alzheimer’s & Dementia. 2025;e14495.
