Association between slow-wave activity from multi-night at-home wireless EEG records and cognitive performance in...

Evidence for the association between slow-wave sleep and cognitive function in older adults has been inconsistent. We measured the variability in-home electroencephalography (EEG) recordings over multiple nights to determine its impact on the association between sleep slow wave measures and cognition.

Participants were 49 (26 females) community-dwelling older adults (median age 75.3 years) who were functionally independent and without cognitive impairment or self-reported sleep disorders. Each contributed eight nights of at-home EEG headband sleep recordings (Dreem Headband, Beacon Biosignals, Boston, USA). Night-to-night variability in sleep stage percentage and spectral power in SWA (0.8-4.5 Hz), Theta (4.5-7.5 Hz), Alpha (8-12 Hz), and Sigma (11-15 Hz) was determined using the coefficient of variation (CV). CV of <20% was considered stable. Correlation between stable sleep metrics and multi-domain cognitive performance was assessed.

Most older adults independently operated the Dreem band with good acceptability. Night-to-night variability in the current sample (n = 49; 302 nights) was high for N3% (CV = 47%), moderate for rapid eye movement (REM)% (CV = 22%), and low for N2% and relative power from all frequency bands (CV = 3%-17%). Only relative slow-wave activity (SWA) (0.8-4.5 Hz) was significantly associated with global cognition, when considering both averaged (r = 0.55, p < .001) and single-night (r = 0.2-0.5) assessments.

Wearable EEG can reliably collect at-home, multi-night sleep data in older adults. SWA but not N3 duration showed high night-to-night stability within each participant and was the only measure significantly and robustly associated with cognitive function.