The association between sleep spindles and cognitive function in middle-aged and older men from a community-based cohort study

Jesse L Parker; Sarah L Appleton; Robert J Adams; Yohannes Adama Melaku; Angela L D'Rozario; Gary A Wittert; Sean A Martin; Peter G Catcheside; Bastien Lechat; Alison J Teare; Barbara Toson; Andrew Vakulin

doi:10.1016/j.sleh.2023.03.007

The association between sleep spindles and cognitive function in middle-aged and older men from a community-based cohort study

Sleep Health. 2023 Oct;9(5):774-785. doi: 10.1016/j.sleh.2023.03.007. Epub 2023 Jun 1.

Authors

Affiliations

¹ Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia. Electronic address: park0769@flinders.edu.au.
² Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia. Electronic address: sarah.appleton@flinders.edu.au.
³ Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia; Respiratory and Sleep Services, Southern Adelaide Local Health Network, Adelaide, South Australia, Australia. Electronic address: robert.adams@flinders.edu.au.
⁴ Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia. Electronic address: yohannes.melaku@flinders.edu.au.
⁵ CIRUS, Centre for Sleep and Chronobiology, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia; The University of Sydney, Faculty of Science, School of Psychology, Sydney, New South Wales, Australia. Electronic address: angela.dorzario@sydney.edu.au.
⁶ Australian Institute of Family Studies, Melbourne, Victoria, Australia; Freemasons Centre for Male Health and Wellbeing, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia. Electronic address: gary.wittert@adelaide.edu.au.
⁷ Australian Institute of Family Studies, Melbourne, Victoria, Australia; Freemasons Centre for Male Health and Wellbeing, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia. Electronic address: sean.martin@aifs.gov.au.
⁸ Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia. Electronic address: peter.catcheside@flinders.edu.au.
⁹ Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia. Electronic address: bastien.lechat@flinders.edu.au.
¹⁰ Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia. Electronic address: alison.teare@flinders.edu.au.
¹¹ Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia. Electronic address: barbara.toson@flinders.edu.au.
¹² Flinders Health and Medical Research Institute, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia; CIRUS, Centre for Sleep and Chronobiology, Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia. Electronic address: andrew.vakulin@flinders.edu.au.

PMID: 37268483
DOI: 10.1016/j.sleh.2023.03.007

Abstract

Objectives: Previous studies examining associations between sleep spindles and cognitive function attempted to account for obstructive sleep apnea without consideration for potential moderating effects. To elucidate associations between sleep spindles, cognitive function, and obstructive sleep apnea, this study of community-dwelling men examined cross-sectional associations between sleep spindle metrics and daytime cognitive function outcomes following adjustment for obstructive sleep apnea and potential obstructive sleep apnea moderating effects.

Methods: Florey Adelaide Male Ageing Study participants (n = 477, 41-87 years) reporting no previous obstructive sleep apnea diagnosis underwent home-based polysomnography (2010-2011). Cognitive testing (2007-2010) included the inspection time task (processing speed), trail-making tests A (TMT-A) (visual attention) and B (trail-making test-B) (executive function), and Fuld object memory evaluation (episodic memory). Frontal spindle metrics (F4-M1) included occurrence (count), average frequency (Hz), amplitude (µV), and overall (11-16 Hz), slow (11-13 Hz), and fast (13-16 Hz) spindle density (number/minute during N2 and N3 sleep).

Results: In fully adjusted linear regression models, lower N2 sleep spindle occurrence was associated with longer inspection times (milliseconds) (B = -0.43, 95% confidence interval [-0.74, -0.12], p = .006), whereas higher N3 sleep fast spindle density was associated with worse TMT-B performance (seconds) (B = 18.4, 95% confidence interval [1.62, 35.2], p = .032). Effect moderator analysis revealed that in men with severe obstructive sleep apnea (apnea-hypopnea index ≥30/hour), slower N2 sleep spindle frequency was associated with worse TMT-A performance (χ² = 12.5, p = .006).

Conclusions: Specific sleep spindle metrics were associated with cognitive function, and obstructive sleep apnea severity moderated these associations. These observations support the utility of sleep spindles as useful cognitive function markers in obstructive sleep apnea, which warrants further longitudinal investigation.

Keywords: Cohort; Impairment; Microarchitecture; Quantitative EEG.