Sleep disturbances in people with mild cognitive impairment

Mild cognitive impairment represents an early stage of memory loss or declining cognitive abilities, including language and spatial perception. This deterioration exceeds what is typical for a person's age and education level, yet they can still independently manage most daily activities. Mild cognitive impairment serves as a transitional phase between normal functioning and dementia. 

A systematic review and meta-analysis of 25 studies found that mild cognitive impairment affects 16% of the global population. According to the hypothetical Alzheimer's disease staging model, those with mild cognitive impairment may stabilise, revert to normal cognitive function, or progress to dementia, with over half transitioning to dementia within five years. As there are limited treatments for dementia, mild cognitive impairment is seen as a critical "window of opportunity" for timely intervention to prevent further cognitive decline and enhance cognitive function.

Recent research underscores the connection between sleep disturbances and mild cognitive impairment. Individuals with mild cognitive impairment often suffer more pronounced sleep problems, such as longer sleep latency, reduced total sleep time, and less efficient sleep, compared to typical older adults. Sleep disturbances are also linked to various adverse health outcomes, including diabetes and depression. Furthermore, there appears to be a bidirectional relationship between sleep quality and mild cognitive impairment / Alzheimer's disease onset, with deteriorating sleep quality serving as an early indicator. This underscores the importance of monitoring sleep in individuals with mild cognitive impairment as a non-invasive means of screening for dementia risk.

The community and clinics play vital roles in recruiting participants for studies on mild cognitive impairment. The prevalence of obstructive sleep apnea in mild cognitive impairment varies based on the recruitment site, with clinic-based studies showing different results compared to community-based ones. Assessments of sleep quality include subjective measures such as the Pittsburgh Sleep Quality Index and objective methods such as polysomnography. The inconsistency between subjective and objective measures highlights the importance of using both when assessing sleep in individuals with mild cognitive impairment or cognitive impairment.
 

While several studies have explored sleep disturbances in different populations, a comprehensive review of the prevalence of sleep disturbances specifically in individuals with mild cognitive impairment, utilising both subjective and objective measurements, is lacking. Understanding the evolution of sleep disturbances in mild cognitive impairment over time is crucial for resource allocation, research funding, and public health education to enhance awareness of sleep health and its implications for cognitive well-being. A systematic review is currently underway to determine the prevalence of sleep disturbances in individuals with mild cognitive impairment.

The protocol is available in the November issue of JBI Evidence Synthesis.

Prevalence of sleep disturbances in people with mild cognitive impairment: a systematic review protocol

Mo, Wenping; Liu, Xiaoji; Yamakawa, Miyae
 

JBI Evidence Synthesis 21(11):p 2211-2217, November 2023. | DOI: 10.11124/JBIES-22-00438