Day‐to‐day sleep and circadian variability in association with Alzheimer’s Disease biomarkers

Background Increasing evidence shows that Alzheimer’s Disease (AD) pathology, i.e., the Aß peptide, tau tangles and APOEε4 allele, have all been associated with disrupted sleep change in circadian rhythms. However, objective measurements are often assessed over a single night. Measures of day-to-day variability might reveal unstable rhythms may reflect neurodegenerative processes. We sought to evaluate association between AD biomarkers measured week actigraphy. Method 203 dementia-free participants (age: 68.5±5.4 years, 151 women) from PREVENT-AD cohort known carrier status were tested Overlapping subsamples for determination cerebrospinal fluid (CSF) Aß1-42, total t-tau p(181)-tau (n = 100); CSF apoE protein 69); plasma Aß1-42 144). Day-to-day actigraphy measures using standard deviation individual results. was compared carriers non-carriers t-tests. Linear regressions performed plasma, adjusted age, sex, time interval measurements. An interaction term additionally regression models. Result did not differ meaningfully regarding variability. Lower higher morning awakening nighttime duration (ß -0.263, p 0.009; b -0.206, 0.041). Higher also bed, activity counts, onset latency, efficiency, 0.160 0.242; 0.010 0.002). increased awakening, -0.243 -0.420; 0.042 <0.001). t-tau, trend inε4 only (interaction p<0.001;ß 0.330, 0.047; 0.281, 0.094). Conclusion Sleep pathology metabolism. These results suggest promotes neurodegeneration or, conversely, neuropathology disrupts function.