Abstract

Introduction Sleep-dependent memory consolidation differs by sex and maybe disrupted by Alzheimer’s disease (AD) risk. Whether sex moderates associations between apolipoprotein E ε4 (APOE ε4) status, non-rapid eye movement (NREM) sleep, and memory remains unclear.

Methods Eighty cognitively unimpaired older adults completed a word-pair memory task with encoding and immediate testing occurring prior to overnight polysomnography with high-density electroencephalography (hdEEG) and delayed recall occurring after sleep. Sleep-memory associations were examined as a function of sex and APOE ε4 status.

Results In this sample, a sex×APOE ε4 interaction was associated with overnight memory retention, with female carriers exhibiting less overnight forgetting than female non-carriers and male ε4 carriers. NREM sleep differed by sex and APOE ε4 status and was associated with memory retention in ε4 carriers.

Discussion These findings indicate sex-specific, sleep-dependent memory mechanisms associated with genetic AD risk, highlighting sleep as a potential early target for intervention, pending replication in larger samples.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study was funded bygrants R56 AG052698, R01 AG027161, R01 AG021155, ADRC P50 AG033514, R01 AG037639, K01 AG068353 from the National Institute on Aging, as well as by the Clinical and Translational Science Award (CTSA) program through the NIH National Center for Advancing Translational Sciences (NCATS) under grant UL1TR000427 and T32AG000096 (Principal Investigator: Negin Sattari).

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All participants provided written informed consent prior to participation. Study procedures were approved by the Institutional Review Board at the University of Wisconsin-Madison.

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Data Availability

All data produced in the present study are available upon reasonable request to the authors

1 AbbreviationsADAlzheimer’s diseaseAPOE ε4apolipoprotein E epsilon 4EEGelectroencephalographyhdEEGhigh-density electroencephalographyNREMnon-rapid eye movementREMrapid eye movementN2stage 2 NREM sleepN3stage 3 NREM sleep.