Sleep changes without medial temporal lobe or brain cortical changes in community-dwelling individuals with subjective cognitive decline

INTRODUCTION: Subjective cognitive decline (SCD) is a risk factor for mild cognitive impairment (MCI) and Alzheimer's disease (AD). Although sleep has been shown to be altered in MCI and AD, little is known about sleep in SCD. METHODS: Seventy cognitively normal community-dwelling participants were classified as SCD (32) or controls (38) using the Subjective Cognitive Decline Questionnaire. Sleep was assessed using actigraphy and diaries. FreeSurfer was used for performing medial temporal lobes (MTLs) and brain cortical parcellation of 3T magnetic resonance images. Multiple regression models were used to assess the presence of sleep, MTL, or regional cortical differences between groups. RESULTS: Objective sleep was disrupted in SCD participants, which showed increased nighttime wakefulness and reduced sleep efficiency. No group differences emerged in subjective sleep or magnetic resonance imaging outcomes. DISCUSSION: Objective sleep resulted disrupted in community-dwelling SCD, without any subjective sleep or cortical change. Sleep assessment/intervention in SCD might help prevent/delay AD onset.