Objectively measured sleep and beta-amyloid burden in older adults: A pilot study

Background/aims: Although disturbed sleep is associated with cognitive deficits, the association between sleep disturbance and Alzheimer's disease pathology is unclear. In this pilot study, we examined the extent to which sleep duration, sleep quality, and sleep-disordered breathing are associated with beta-amyloid (A beta) deposition in the brains of living humans. Methods: We studied 13 older adults (8 with normal cognition and 5 with mild cognitive impairment). Participants completed neuropsychological testing, polysomnography, and A beta imaging with [C-11]-Pittsburgh compound B. Results: Among participants with mild cognitive impairment, higher apnea-hypopnea index and oxygen desaturation index were associated with greater A beta deposition, globally and regionally in the precuneus. There were no significant associations between sleep-disordered breathing and A beta deposition among cognitively normal participants. There were no significant associations between sleep duration or sleep fragmentation and A beta deposition. Conclusion: These preliminary results suggest that among older adults with mild cognitive impairment, greater sleepdisordered breathing severity is associated with greater A beta deposition.