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.
Highlights
Obstructive Sleep Apnea is one of the most common types of sleep-disordered breathing (SDB) [1,2,3]
apnea-hypopnea index (AHI), Apnea Hypopnea Index; TST, total sleep time; NREM, non-rapid eye movement sleep; REM, rapid eye movement sleep; ODI, oxygen desaturation index; minSaO2, minimum oxygen saturation; T90%, percent sleep time below 90% SaO2; arousal index (ArI), Arousal Index. aCompared with Primary snoring group, P < 0.05; bCompared with Mild-moderate OSA group, P < 0.05
We found no significant differences in Pittsburgh Sleep Quality Index (PSQI) score and the prevalence of diabetes, arrhythmia, stroke, coronary artery diseases, and asthma among the three groups
Summary
Obstructive Sleep Apnea is one of the most common types of sleep-disordered breathing (SDB) [1,2,3]. It is characterized by recurrent upper airway collapse during sleep, often leading to repeated awakening, sleep fragmentation, and reduced slowwave sleep [4, 5]. Sleep fragmentation and frequent awakening in OSA patients lead to daytime sleepiness, reduced working and learning efficiency, cognitive dysfunction, as well as increased risks of diseases such as hypertension, stroke, diabetes, and reduced overall quality of life [8]. Current clinical practice calls for better biomarkers that might objectively capture the disease burden faced by patients to better guide therapeutic decisions
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