EEG Power Spectral Analysis of Abnormal Cortical Activations During REM/NREM Sleep in Obstructive Sleep Apnea

Abstract

Objective: To characterize electroencephalogram (EEG) power in different frequency bands during rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep in patients with obstructive sleep apnea (OSA).Methods: Retrospective data on 151 patients were collected and divided into three groups: primary snoring group (AHI < 5/h), mild-moderate OSA group (6 ≤ AHI < 30/h), and severe OSA group (AHI ≥ 30/h). EEG recordings in the frontal, central, and occipital regions were extracted from both REM and NREM sleep, to compute the normalized spectral power densities in the delta, theta, alpha, sigma, beta, and gamma frequency bands, using Fast Fourier Transform. Correlations between the computed EEG power and PSG parameters were analyzed.Results: In NREM sleep, elevated normalized power spectral density (PSD) in the delta band was observed in the severe OSA group compared to the other two groups. In contrast, the PSD of the other frequency bands showed a corresponding decrease in the severe OSA group. In REM sleep, similar changes were observed in the frontal region. Delta band PSD was positively correlated with Apnea Hypopnea Index (AHI) (r = 0.33), longest time of apnea, oxygen desaturation index (ODI) (r = 0.34), percent sleep time below 90% SaO2 (T90%) (r = 0.30), Arousal Index (ArI) (r = 0.29), and negatively correlated with N3%, minimum oxygen saturation (minSaO2).Conclusion: Our findings provide neurophysiological evidence for pathological cortical activation during REM/NREM sleep, which may be associated with the arousals and cognitive impairments in OSA. The technique of power spectral analysis could prove a potentially useful tool in complementing traditional PSG parameters in assessing disease burden to guide therapeutic decisions.

Electroencephalography Theta/Beta Ratio Decreases in Patients with Severe Obstructive Sleep Apnea

“…This is supported by previous studies, which demonstrated an increase in delta power and a decrease in theta power in the severe OSA group compared to primary snoring and mild-moderate groups. 10 One study including 76 patients with OSA found that higher delta power in REM sleep and higher beta power in NREM sleep were predictors of worse steering deviation on a 30-minute driving simulator task. 36 Inconsistent findings have also been reported, that is, higher delta activity during NREM sleep in OSA patients than in controls 37 or simple snoring participants.…”

“…Previous quantitative EEG (qEEG) studies in OSA patients demonstrated a significantly slow brain activity during wakefulness over all cortical regions, suggesting lower levels of vigilance or a general brain dysfunction. 2 Several studies exploring sleep EEG focused on specific EEG attributes of OSA patients, such as spindles, 8 theta 9 , 10 or delta 9 , 11 activity, but the results were inconsistent. Consequently, how OSA alters the overnight electrical behavior of the brain remains unclear.…”

Getting More from the Sleep Recording

“…14 Specialized computer-based analysis of the EEG by techniques such as spectral analysis provides additional insight into sleep physiology and pathology beyond traditional sleep staging, but these are research-oriented and have little application in the clinical setting of respiratory sleep disorders. 15,16…”

Polysomnography Analysis of Electroencephalography in Patients Expending Benzodiazepine Drugs

“…The group of BDZ users was divided Based on whether they had taken BDZs for ≥365 days or ＜365 days, the BDZ group were divided into long-term-use or short-term-use groups [3]; 13 patients were included in the long-term-use group (4 male, 9 female, mean age: somnography readings were excluded [13][14][15]. This study was approved by the Institutional Review Board of Dankook University and was performed in accordance with the principles stated in the Declaration of Helsinki (IRB number: DKU202103014).…”