Short Average Duration of NREM/REM Cycle Is Related to Cognitive Decline in an Elderly Cohort: An Exploratory Investigation

Article type: Research Article

Authors: Suh, Seung Wan^a | Han, Ji Won^a | Lee, Ju Ri^a | Byun, Seonjeong^a | Kwak, Kyung Phil^b | Kim, Bong Jo^c | Kim, Shin Gyeom^d | Kim, Jeong Lan^e | Kim, Tae Hui^f | Ryu, Seung-Ho^g | Moon, Seok Woo^h | Park, Joon Hyukⁱ | Seo, Jiyeong^j | Youn, Jong Chul^k | Lee, Dong Young^{l; m} | Lee, Dong Wooⁿ | Lee, Seok Bum^o | Lee, Jung Jae^o | Jhoo, Jin Hyeong^p | Yoon, In Young^{a; m} | Kim, Ki Woong^{a; m; q; r; *}

Affiliations: [a] Department of Neuropsychiatry, Seoul National University Bundang Hospital, Seongnam, Korea | [b] Department of Psychiatry, Dongguk University Gyeongju Hospital, Gyeongju, Korea | [c] Department of Psychiatry, Gyeongsang National University School of Medicine, Jinju, Korea | [d] Department of Neuropsychiatry, Soonchunhyang University Bucheon Hospital, Bucheon, Korea | [e] Department of Psychiatry, School of Medicine, Chungnam National University, Daejeon, Korea | [f] Department of Psychiatry, Yonsei University Wonju Severance Christian Hospital, Wonju, Korea | [g] Department of Psychiatry, School of Medicine, Konkuk University, Konkuk University Medical Center, Seoul, Korea | [h] Department of Psychiatry, School of Medicine, Konkuk University, Konkuk University Chungju Hospital, Chungju, Korea | [i] Department of Neuropsychiatry, Jeju National University Hospital, Jeju, Korea | [j] Department of Psychiatry, Gyeongsang National University Changwon Hospital, Changwon, Korea | [k] Department of Neuropsychiatry, Kyunggi Provincial Hospital for the Elderly, Yongin, Korea | [l] Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea | [m] Department of Psychiatry, Seoul National University, College of Medicine, Seoul, Korea | [n] Department of Neuropsychiatry, Inje University Sanggye Paik Hospital, Seoul, Korea | [o] Department of Psychiatry, Dankook University Hospital, Cheonan, Korea | [p] Department of Psychiatry, Kangwon National University, School of Medicine, Chuncheon, Korea | [q] Department of Brain and Cognitive Sciences, Seoul National University, College of Natural Sciences, Seoul, Korea | [r] National Institute of Dementia, Seongnam, Korea

Correspondence: [*] Correspondence to: Ki Woong Kim, MD, PhD, Department of Neuropsychiatry, Seoul National University, College of Medicine, and Seoul National University Bundang Hospital, 82, Gumi-ro 173beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea. Tel.: +82 31 787 7432; Fax: +82 31 787 4058; E-mails: kwkimmd@snu.ac.kr, kwkimmd@gmail.com.

Abstract: Prospective studies concerning sleep architecture and cognitive function have focused on individual sleep measures per se, without considering the complementary role of non-REM (NREM) and REM sleep. We explored the association between NREM/REM cycle-related sleep architecture and cognitive decline. Community-dwelling elderly people in Korea from the Korean Longitudinal Study on Cognitive Aging and Dementia were enrolled. They were cognitively normal and underwent overnight polysomnography at baseline. A NREM/REM cycle is a sequence of NREM and REM sleep, uninterrupted by a waking period of >2 min. After 4 years, the development of mild cognitive impairment (MCI) or dementia was related to the measures of sleep architecture, including NREM/REM cycle parameters by logistic regression analyses. Of 235 participants (mean [SD] age 68 [5] years; 60% female) at baseline, 14 (5.9%) developed MCI/dementia at follow-up. A short average cycle length (OR, 0.97 [95% CI, 0.94–0.99]; p = 0.02) was significantly associated with cognitive decline. When its substructure and NREM and REM sleep outside of cycles were considered simultaneously, the average REM sleep duration per cycle (OR, 0.87 [95% CI, 0.76–0.98]; p = 0.03) was significantly related to the outcome. In conclusion, short average duration of NREM/REM cycles, especially average REM sleep duration in each cycle, in cognitively normal elderly might be used as an early marker of cognitive decline.

Keywords: Dementia, mild cognitive impairment, sequential hypothesis, sleep

DOI: 10.3233/JAD-190399

Journal: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1123-1132, 2019