Deep Sleep Time Measured by Wearable Device Associated with Amyloid Burden in the Elderly with Subjective Cognitive Decline.

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AbstractBackgroundFactors other than age and genetics may influence the development of Alzheimer’s disease. In particularly, there is growing evidence that sleep disturbances are associated with increased β‐amyloid burden. We investigated the association between sleep characteristics measured with a wearable device and β‐amyloid burden in the elderly diagnosed with subjective cognitive decline.MethodWe conducted a cross‐sectional study in 76 elderly people over 60 years of age with subjective cognitive decline determined by detailed neuropsychological tests. β‐amyloid burden was determined by F18‐florbetaben positron emission(PET) using two methods. Firstly, visual rating of BAPL (Brain amyloid plaque load) score was used to determine β‐amyloid positivity. Secondly, the SUVR (standardized uptake value ratio) values were used for the quantitative evaluation of β‐amyloid deposition. Sleep characteristics including total sleep time, number of awakenings during sleep, REM sleep time, deep sleep time, and light sleep time were measured using a wearable device. In addition, we investigated the association between β‐amyloid burden and age, ApoE4 genotype, MMSE, and PSQI.ResultOf the 76 subjects included in the analyses, 64.5% were women. The subjects were 70.7 (±6.09) years of age at the beginning of the study. Fifteen subjects were positive and 61 were negative on F18‐florbetaben PET. The average SUVR value was 1.27 (±0.220). In particular, we found that deep sleep time was significantly higher in the β‐amyloid‐negative group (49.5±13.1 minutes) than in the positive group (39.4±13.1 minutes). (p‐value 0.009)ConclusionAccording to our analysis, a decrease in deep sleep time appears to be associated with amyloid deposition. This is consistent with recent evidence that sleep disturbances may be associated with increased β‐amyloid burden. A large‐scale prospective study is needed to clarify the causal relationships between deep sleep and amyloid deposition.