Quantitative Spectral Analysis of Waking Electroencephalography in Patients With Moderate to Severe Obstructive Sleep Apnea and Excessive Daytime Sleepiness: A Case–Control Matched Pilot Study

Objectives: This study aims to examine the differences in spectral analysis of waking electroencephalography (EEG) patterns between patients with moderate to severe obstructive sleep apnea (OSA) experiencing excessive daytime sleepiness (EDS) and matched healthy participants, to gain insights into the neurophysiological underpinnings of daytime impairments.Methods: A cross-sectional analysis was conducted involving 17 patients with moderate to severe OSA confirmed by overnight polysomnography (PSG). These patients had ≥15 per hour apnea–hypopnea index (AHI) and ≥11 Epworth Sleepiness Scale (ESS). EEG recordings were captured within 30 minutes of awakening. A corresponding group of the equal number of age and sex-matched healthy participants was also analyzed for comparative purposes. Spectral analysis of quantitative EEG (qEEG) of patients with OSA compared with that of an equal number of age- and sex-matched healthy participants.Results: The analysis included 17 patients (16 males, average age 57.2 years) with moderate to severe OSA experiencing EDS (mean AHI 38.1±20.5; ESS 14.4±3.2). The patients with OSA exhibited altered sleep architecture during diagnostic PSG, significantly higher EEG delta band power in the frontal regions upon awakening after night sleep, and decreased connection of delta band in frontal area than normal participants (3.78±5.53 vs. 3.22±0.98 μV2, p=0.03).Conclusions: The study demonstrated difference in delta activity and connectivity in the frontal area between patients with OSA experiencing EDS and the control group. These findings suggest awakening qEEG in OSA may helpful to guide or enhance understanding of daytime functional impairment and EDS.