Sleep 2019 Apr 20. Epub 2019 Apr 20.
The Health Observatory, Adelaide Medical School, University of Adelaide, The Queen Elizabeth Hospital Campus, Woodville, South Australia, Australia.
Study Objectives: Quantitative EEG measures of sleep may identify vulnerability to obstructive sleep apnea (OSA) sequelae, however, small clinical studies of sleep microarchitecture in OSA show inconsistent alterations. We examined relationships between quantitative EEG measures during rapid eye movement (REM) and non-REM (NREM) sleep and OSA severity among a large population-based sample of men while accounting for insomnia.
Methods: All-night EEG (F4-M1) recordings from full in-home polysomnography (Embletta X100) in 664 men with no prior OSA diagnosis (age ≥40) were processed following exclusion of artefacts. Power spectral analysis included non-REM and REM sleep computed absolute EEG power for delta, theta, alpha, sigma and beta frequency ranges, total power (0.5-32 Hz) and EEG slowing ratio.
Results: Apnea hypopnea index (AHI) ≥10/h was present in 51.2% (severe OSA [AHI ≥30/h] 11.6%). In mixed effects regressions, AHI was positively associated with EEG slowing ratio and EEG power across all frequency bands in REM sleep (all p<0.05); and with beta power during NREM sleep (p=0.04). Similar associations were observed with oxygen desaturation index (3%). Percentage total sleep time with oxygen saturation <90% was only significantly associated with increased delta, theta and alpha EEG power in REM sleep. No associations with subjective sleepiness were observed.
Conclusions: In a large sample of community-dwelling men, OSA was significantly associated with increased EEG power and EEG slowing predominantly in REM sleep, independent of insomnia. Further study is required to assess if REM EEG slowing related to nocturnal hypoxemia is more sensitive than standard PSG indices or sleepiness in predicting cognitive decline.