Sleep-wake behavior, perceived fatigability, and cognitive reserve in older adults.

Introduction: The effects of sleep-wake behavior on perceived fatigability and cognitive abilities when performing daily activities have not been investigated across levels of cognitive reserve (CR).

Methods: CR Index Questionnaire (CRIq) data were collected and subjected to moderated mediation analysis.

Results: In amnestic mild cognitive impairment (aMCI; n = 41), CR moderated sleep-related impairments (SRIs), and fatigability at low CR (CRIq < 105.