Is there a link between sleep changes and memory in Alzheimer's disease?

Abstract

Aging and Alzheimer's disease (AD) are both characterized by memory impairments and sleep changes. We investigated the potential link between these disturbances, focusing on sleep spindles, involved in memory consolidation. Two episodic memory tasks were given to young and old healthy participants, as well as to AD patients. Postlearning sleep was recorded. Sleep spindles were globally reduced in aging and AD. AD patients also exhibited a further decrease in fast spindles. Besides, mean intensity of fast spindles was positively correlated, in AD patients, with immediate recall performance. Our results are the first report of a specific decrease in fast spindles in AD, associated with learning abilities. They also give further hints for a functional differentiation between slow and fast spindles.

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

“…10,12 Sleep disorders may also exacerbate cognitive symptoms through impairment of sleep-dependent memory consolidation processes. 13,14 It is possible that circadian rhythms and sleep disorders have a causal role in the pathophysiology of AD. If this is true, they could be critical to the goal of preventing this disease because effective interventions exist to improve sleep.…”

Sleep spindle alterations in patients with Parkinson's disease

“…In AD, Rauchs et al (2008) found no change in spindle density but found that fast spindles (defined as having frequencies of 13-15 Hz) were significantly reduced when compared to agematched controls. Consistently, Westerberg et al (2012) found that patients with amnestic mild cognitive impairment had fewer N2 spindles compared to age-matched controls, and that the reduction was seen in fast spindles (13-15 Hz) and not in slow spindles (11-13 Hz).…”

“…Further analysis including more PD and iRBD patients, together with a more in-depth investigation of cognitive decline and disease severity would be needed to evaluate the relation of abnormalities in SS development in the disease process, and the use of SS as a prognostic marker. Additionally, SS density has also been reported decreased for other conditions such as Dementia, Alzheimer's disease (AD) and mild cognitive impairment (Rauchs et al, 2008;Westerberg et al, 2012;Latreille et al, 2015), and is also a sign of normal aging (Wauquier, 1993;De Gennaro and Ferrara, 2003;Ktonas et al, 2009). …”

Sleep and Cognition

“…Sleep disorder, in fact, may be one of the earliest signs of neurodegenerative disorders, including early Alzheimer's disease (AD) [6]. This chapter will briefly examine the relationship between sleep (quantity and quality) and cognition throughout the life course, and will consider the evidence which suggests that sleep deprivation and sleep disorders are associated with poor cognitive function.…”