Frequency of EEG arousals from nocturnal sleep in normal subjects.
Level 4 - case-series / case-control
Cross-sectional normative study in healthy volunteers (incorrectly tagged as RCT in indexing).
PubMed 7676165 · doi:10.1093/sleep/18.5.330
What was done
Overnight polysomnography was performed on 55 healthy control subjects (recruited from 59 approached on a family practice list, ranging from late teens to early 70s). Awakenings were scored using Rechtschaffen and Kales criteria, and brief arousals were evaluated using three criteria, including the American Sleep Disorders Association (ASDA) definition.
What was found
Participants had a mean of 4 (95% CI, 1-15) Rechtschaffen and Kales awakenings per hour and a mean of 21 (95% CI, 7-56) ASDA brief arousals per hour slept. Arousal frequencies increased significantly with age (p < 0.001). Excluding subjects who snored, had witnessed apneas, or experienced daytime sleepiness did not alter the high upper limit of arousal frequency.
Why it matters
This study provides normative reference ranges showing that brief EEG arousals are frequent in healthy individuals during single-night polysomnography, helping prevent overinterpretation of high arousal counts as sleep pathology.
Limits
The study is limited by a modest sample size (n = 55) and relying on a single night of polysomnography, which may be affected by first-night effect. Confidence intervals were wide, and quantitative results for two of the three arousal criteria mentioned were omitted from the abstract.
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