Preclinical Alzheimer disease (AD) is associated with rest-activity rhythm fragmentation, independent of age or sex, according to a recent study. The presence of circadian rhythm abnormalities in the preclinical phase of AD suggests that circadian dysfunction could contribute to early disease pathogenesis or serve as a biomarker of preclinical disease. This cross-sectional study was conducted using cognitively normal participants who underwent 7 to 14 days of actigraphy in their home environment between 2010 and 2012, in addition to clinical assessment, amyloid imaging with Pittsburgh Compound B (PiB), and cerebrospinal fluid biomarker collection. Data from 189 participants were included; mean (SD) age was 66.6 (8.3) years, and 121 participants (64%) were women. Researchers found:
- Older age and male sex, in the absence of amyloid pathology, were associated with a significant increase in intradaily variability, a nonparametric measure of rest-activity rhythm fragmentation, as well as decreased amplitude by several measures.
- After correction for age and sex, the presence of preclinical amyloid plaque pathology, assessed by positive PiB imaging or increasing cerebrospinal fluid phosphorylated-tau to amyloid β 42 ratio, was associated with increased intradaily variability, indicating rest-activity rhythm fragmentation.
Musiek ES, Bhimasani M, Zangrilli MA, Morris JC, Holtzman DM, Ju Y-E S. Circadian rest-activity pattern changes in aging and preclinical Alzheimer disease. [Published online ahead of print January 29, 2018]. JAMA Neurology. doi:10.1001/jamaneurol.2017.4719.
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