EEG slowing during REM sleep in older adults with subjective cognitive impairment and mild cognitive impairment

Aaron Kin Fu Lam; James Carrick; Chien-Hui Kao; Craig L Phillips; Yi Zhong Zheng; Brendon J Yee; Jong Won Kim; Ronald R Grunstein; Sharon L Naismith; Angela L D'Rozario

doi:10.1093/sleep/zsae051

EEG slowing during REM sleep in older adults with subjective cognitive impairment and mild cognitive impairment

Sleep. 2024 Feb 23:zsae051. doi: 10.1093/sleep/zsae051. Online ahead of print.

Authors

Aaron Kin Fu Lam^{1

2

3}, James Carrick¹, Chien-Hui Kao^{2

3}, Craig L Phillips^{2

3}, Yi Zhong Zheng², Brendon J Yee^{2

4

5}, Jong Won Kim⁶, Ronald R Grunstein^{2

4}, Sharon L Naismith^{1

7}, Angela L D'Rozario^{2

3}

Affiliations

¹ The University of Sydney, School of Psychology, Camperdown, NSW, AU.
² Woolcock Institute of Medical Research, Centre for Sleep and Chronobiology, Glebe, NSW, AU.
³ Macquarie University, School of Psychological Sciences, Faculty of Medicine, Sydney, NSW, AU.
⁴ Royal Prince Alfred Hospital, Sydney Medical School, Faculty of Medicine and Health Camperdown, AU.
⁵ Central Clinical School, University of Sydney, NSW, AU.
⁶ Inje University, Department of Healthcare IT, Gimhae, Gyeongsangnam-do, KR.
⁷ The University of Sydney, Charles Perkins Centre, Sydney, NSW, AU.

PMID: 38394454
DOI: 10.1093/sleep/zsae051

Abstract

Study objectives: In older adults with Alzheimer's disease, slowing of electroencephalographic (EEG) activity during REM sleep has been observed. Few studies have examined EEG slowing during REM in those with mild cognitive impairment (MCI) and none have examined its relationship with cognition in this at-risk population.

Methods: 210 older adults (mean age = 67.0, sd = 8.2 years) underwent comprehensive neuropsychological, medical, and psychiatric assessment and overnight polysomnography. Participants were classified as subjective cognitive impairment (SCI; n=75), non-amnestic MCI (naMCI, n=85), and amnestic MCI (aMCI, n=50). REM EEG slowing was defined as (delta + theta) / (alpha + sigma + beta) power and calculated for frontal, central, parietal, and occipital regions. Analysis of variance compared REM EEG slowing between groups. Correlations between REM EEG slowing and cognition, including learning and memory, visuospatial and executive functions, were examined within each subgroup.

Results: The aMCI group had significantly greater REM EEG slowing in the parietal and occipital regions compared to the naMCI and SCI groups (partial η2 = 0.06, p<0.05 and 0.06, p<0.05, respectively), and greater EEG slowing in the central region compared to SCI group (partial η2 = 0.03, p<0.05). Greater REM EEG slowing in parietal (r = -0.49) and occipital regions (r = -0.38 (O1/M2) and -0.33 (O2/M1) were associated with poorer visuospatial performance in naMCI.

Conclusion: REM EEG slowing may differentiate older adults with memory impairment from those without. Longitudinal studies are now warranted to examine the prognostic utility of REM EEG slowing for cognitive and dementia trajectories.

Keywords: ageing; cognition; dementia; executive function; memory; microarchitecture; polysomnography; power spectral analysis; visuospatial.