Poor sleep linked to cortical amyloid burden

The researchers plan to investigate the observed association using objective measures of sleep and obstructive sleep apnea (OSA), according to Ms. Sprecher. "And we’ll do some longitudinal follow-up as well in our cohort to see how sleep changes might relate to actual progression of the disease."

Study participants completed the Medical Outcomes Study (MOS) Sleep Scale and the Epworth Sleepiness Scale (ESS). Amyloid deposition in the brain was measured by positron-emission tomography performed with Pittsburgh Compound B.

The participants were 63 years old, on average, and two-thirds were female. Overall, 76% had a family history of Alzheimer’s, and 34% were positive for the APOE4 allele, which is associated with risk of this disease.

‘It’s kind of tantalizing that sleep may be a tool that we can use to prevent or delay Alzheimer’s pathology.’

Analyses adjusted for these and other confounders showed a correlation (P less than or equal to .05) between somnolence on the MOS Sleep Scale – the average of scores for drowsiness, trouble staying awake, and napping – and the burden of amyloid in the left supramarginal gyrus (correlation [r] = 0.22), the left frontal medial orbital cortex (r = 0.21), and the left frontal inferior orbital cortex (r = 0.21).

Poorer quality of sleep was significantly correlated with amyloid burden in the cortex overall (r = 0.25) as well as in the left and right precuneus (r = 0.23 and 0.25), the right supramarginal gyrus (r = 0.23), the left and right frontal medial orbital cortex (r = 0.29 and 0.29), and the left and right frontal inferior orbital cortex (r = 0.26 and 0.25). Scores on the Sleep Problem Index were also linked to greater burden in some of these cortical areas.

Although ESS scores were significantly correlated with MOS scores, they were not directly correlated with amyloid burden in any of the regions studied. "This could be because the two questionnaires probe slightly different aspects of sleepiness," Ms. Sprecher said in an interview. "The ESS asks how likely you are to fall asleep in several common situations such as while watching TV or driving a car. The MOS asks whether you take naps, feel sleepy during the day, or feel that you get enough sleep at night. Therefore, the MOS may be better at probing how adequate your sleep is, even if you are managing to stay awake during the day."

Ms. Sprecher had no disclosures.