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World J Psychiatr. Nov 19, 2021; 11(11): 1027-1038
Published online Nov 19, 2021. doi: 10.5498/wjp.v11.i11.1027
How non-rapid eye movement sleep and Alzheimer pathology are linked
Annelies Falter, Maarten J A Van Den Bossche
Annelies Falter, Maarten J A Van Den Bossche, Department of Geriatric Psychiatry, University Psychiatric Center KU Leuven, Leuven 3000, Belgium
Maarten J A Van Den Bossche, Center for Neuropsychiatry, Research Group Psychiatry, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
Author contributions: Falter A performed the literature study; Van Den Bossche MJA planned and coordinated the review and supervised the literature study; Falter A and Van Den Bossche MJA wrote the manuscript; all authors have read and approved the final manuscript.
Supported by the Funds Malou Malou, Perano, Georgette Paulus, JMJS Breugelmans and Gabrielle, François and Christian, Managed by the King Baudouin Foundation of Belgium, No. 2021-J1990130-222081.
Conflict-of-interest statement: The authors declare that there is no conflict of interest for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Maarten J A Van Den Bossche, MD, PhD, Assistant Professor, Staff Physician, Department of Geriatric Psychiatry, University Psychiatric Center KU Leuven, Herestraat 49, Leuven 3000, Belgium. maarten.vandenbossche@upckuleuven.be
Received: February 24, 2021
Peer-review started: February 24, 2021
First decision: July 15, 2021
Revised: July 28, 2021
Accepted: August 17, 2021
Article in press: August 17, 2021
Published online: November 19, 2021
Processing time: 265 Days and 13.7 Hours
Abstract

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder characterized by the presence of senile plaques and neurofibrillary tangles. Research attempts to identify characteristic factors that are associated with the presence of the AD pathology on the one hand and that increase the risk of developing AD on the other. Changes in non-rapid eye movement (NREM) sleep may meet both requirements for various reasons. First, NREM-sleep is important for optimal memory function. In addition, studies report that the presence of AD pathology is associated with NREM-sleep changes. Finally, more and more results appear to suggest that sleep problems are not only a symptom of AD but can also increase the risk of AD. Several of these studies suggest that it is primarily a lack of NREM-sleep that is responsible for this increased risk. However, the majority investigated sleep only through subjective reporting, as a result of which NREM-sleep could not be analyzed separately. The aim of this literature study is therefore to present the results of the studies that relate the AD pathology and NREM-sleep (registered by electroencephalography). Furthermore, we try to evaluate whether NREM-sleep analysis could be used to support the diagnosis of AD and whether NREM-sleep deficiency could be a causal factor in the development of AD.

Keywords: Alzheimer’s disease; Mild cognitive impairment; Sleep; Non-rapid eye movement sleep; Amyloid beta-peptides; Tau proteins; Electroencephalography

Core Tip: Non-rapid eye movement (NREM)-sleep has been shown to be important for memory consolidation. Sleep problems are not only a symptom of Alzheimer's disease (AD) but also seem to increase the risk of developing AD. We herein present the results of studies that investigated the relationship between AD pathology and NREM-sleep (registered by electroencephalography). We discuss whether the presence of AD pathology is associated with specific changes in NREM-sleep on the one hand and whether these changes can serve as an aid in diagnosing the disorder on the other. We also evaluate whether a lack of NREM-sleep may play a causative role in the development of AD.