Impact of sleep on the risk of cognitive decline and dementia

Abstract

Purpose of review Trouble falling or staying asleep, poor sleep quality, and short or long sleep duration are gaining attention as potential risk factors for cognitive decline and dementia, including Alzheimer's disease (AD). Sleep-disordered breathing (SDB) has also been linked to these outcomes. Here, we review recent observational and experimental studies investigating the effect of poor sleep on cognitive outcomes and AD and discuss possible mechanisms. Recent findings Observational studies with self-report and objective sleep measures (e.g., wrist actigraphy, polysomnography) support links between disturbed sleep and cognitive decline. Several recently published studies demonstrate associations between sleep variables and measures of AD pathology, including cerebrospinal fluid measures (CSF) of Aβ and positron emission tomography (PET) measures of Aβ deposition. In addition, experimental studies suggest that sleep loss alters CSF Aβ dynamics, that decrements in slow-wave sleep may decrease the clearance of Aβ from the brain, and that hypoxemia characteristic of SDB increases Aβ production. Summary Findings indicate that poor sleep is a risk factor for cognitive decline and AD. Although mechanisms underlying these associations are not yet clear, healthy sleep appears to play an important role in maintaining brain health with age, and may play a key role in AD prevention.

Nocturnal Hypoxemia Is Associated with White Matter Hyperintensities in Patients with a Minor Stroke or Transient Ischemic Attack

“…44 Further, OSA may be a risk factor for progression of mild cognitive impairment to dementia and poor sleep been implicated in the pathogenesis of Alzheimer disease. 45 These findings raise the possibility that WMH may modulate some of the neurological complications of OSA.…”

Sleep, Cognitive impairment, and Alzheimer’s disease: A Systematic Review and Meta-Analysis

“…Previous narrative review articles that have examined this association did so with a focus on different aspects of sleep disturbances/disorders. [16][17][18][19] Palma et al, 16 focusing on sleep deprivation, reviewed how sleep loss constitutes a risk factor for various neurologic diseases including AD. Slats et al, 18 focusing on the role of hypocretin and melatonin, concluded that there is substantial evidence for impairments in both sleep and circadian regulating mechanisms resulting from AD pathology, which may be linked to clinical symptoms.…”

“…If this is true, they could be critical to the goal of preventing this disease because effective interventions exist to improve sleep. 15 Narrative review articles examining this association [16][17][18][19] reflect the opinion and consensus among specialists that there is growing experimental and epidemiologic evidence for a close reciprocal association of cognitive impairment and AD with sleep problems and disorders. However, to date, no review has quantified the effect of having sleep problems and disorders on cognitive impairment and AD.…”

Self-Reported Sleep Disturbance Mediates the Relationship Between PTSD and Cognitive Outcome in Blast-Exposed OEF/OIF Veterans

“…A growing literature suggests that reduced sleep quality and duration may be risk factors for subsequent cognitive decline and dementia. 81,82 Moreover, sleep disruption has been found to contribute to the onset and accumulation of Alzheimer pathology. 83 Given the elevated risk of dementia associated with PTSD 84,85 as well as with TBI, [86][87][88] consideration of sleep as a mediating factor of long-term cognitive outcomes will be of critical importance.…”