The past, present, and future of sleep measurement in mild cognitive impairment and early dementia-towards a core outcome set: a scoping review

Jonathan Blackman; Hamish Duncan Morrison; Katherine Lloyd; Amy Gimson; Luke Vikram Banerjee; Sebastian Green; Rebecca Cousins; Sarah Rudd; Sam Harding; Elizabeth Coulthard

doi:10.1093/sleep/zsac077

The past, present, and future of sleep measurement in mild cognitive impairment and early dementia-towards a core outcome set: a scoping review

Sleep. 2022 Jul 11;45(7):zsac077. doi: 10.1093/sleep/zsac077.

Authors

Jonathan Blackman^{1

2}, Hamish Duncan Morrison^{1

2}, Katherine Lloyd^{1

2}, Amy Gimson², Luke Vikram Banerjee², Sebastian Green^{1

2}, Rebecca Cousins², Sarah Rudd³, Sam Harding⁴, Elizabeth Coulthard^{1

2}

Affiliations

¹ Bristol Medical School, University of Bristol, Bristol, UK.
² Bristol Brain Centre, North Bristol NHS Trust, Bristol, UK.
³ Library and Knowledge Service, North Bristol NHS Trust, Bristol, UK.
⁴ Research and Innovation, North Bristol NHS Trust, Bristol, UK.

Abstract

Study objectives: Sleep abnormalities emerge early in dementia and may accelerate cognitive decline. Their accurate characterization may facilitate earlier clinical identification of dementia and allow for assessment of sleep intervention efficacy. This scoping review determines how sleep is currently measured and reported in Mild Cognitive Impairment (MCI) and early dementia, as a basis for future core outcome alignment.

Methods: This review follows the PRISMA Guidelines for Scoping Reviews. CINAHL, Embase, Medline, Psychinfo, and British Nursing Index databases were searched from inception-March 12, 2021. Included studies had participants diagnosed with MCI and early dementia and reported on sleep as a key objective/ outcome measure.

Results: Nineteen thousand five hundred and ninety-six titles were returned following duplicate removal with 188 studies [N] included in final analysis. Sleep data was reported on 17 139 unique, diagnostically diverse participants (n). "Unspecified MCI" was the most common diagnosis amongst patients with MCI (n = 5003, 60.6%). Despite technological advances, sleep was measured most commonly by validated questionnaires (n = 12 586, N = 131). Fewer participants underwent polysomnography (PSG) (n = 3492, N = 88) and actigraphy (n = 3359, N = 38) with little adoption of non-PSG electroencephalograms (EEG) (n = 74, N = 3). Sleep outcome parameters were reported heterogeneously. 62/165 (37.6%) were described only once in the literature (33/60 (60%) in interventional studies). There was underrepresentation of circadian (n = 725, N = 25) and micro-architectural (n = 360, N = 12) sleep parameters.

Conclusions: Alongside under-researched areas, there is a need for more detailed diagnostic characterization. Due to outcome heterogeneity, we advocate for international consensus on core sleep outcome parameters to support causal inference and comparison of therapeutic sleep interventions.

Keywords: AD; Alzheimer’s disease; MCI; mild cognitive impairment; sleep.

Publication types

Review
Research Support, Non-U.S. Gov't

MeSH terms

Alzheimer Disease*
Cognitive Dysfunction* / diagnosis
Disease Progression
Humans
Outcome Assessment, Health Care
Polysomnography
Sensitivity and Specificity
Sleep