Poor Sleep May Presage Alzheimer's Disease

 A cross-sectional study involving cognitively normal people suggests that disturbed sleep quality may be an early sign of Alzheimer's Disease.  David Holtzman, from Washington University School of Medicine (Missouri, USA), and colleagues studied 142 men and women, ages 45 and older, who were free of cognitive impairment at the study’s start. For a two-week period, the team measured sleep via actigraphy, to obtain a measurement of sleep efficiency as the primary measure of sleep quality. The team also measured levels of beta-amyloid 42 in the cerebrospinal fluid of the subjects, to determine whether amyloid deposition was taking place. Of the subjects, 32 had elevated levels of beta-amyloid 42 in the brain; as well, the subjects had a worse sleep quality (measured as sleep deficiency) as compared to other subjects. A second measure sleep quality, wait time after sleep onset, was also higher in these 32 subjects.  The study authors report that: "Amyloid deposition in the preclinical stage of [Alzheimer's Disease] appears to be associated with worse sleep quality but not with changes in sleep quantity.”