Sensorimotor Cortical Activity during Respiratory Arousals in Obstructive Sleep Apnea

Area of Science:

• Neuroscience
• Sleep Medicine
• Biomedical Engineering

Background:

• Respiratory cortical arousals (RCAs) are a key pathophysiological feature in obstructive sleep apnea (OSA).
• Understanding brain oscillatory differences during RCAs can help differentiate OSA severity.

Purpose of the Study:

• To investigate brain oscillatory features associated with respiratory arousals in moderate versus severe OSA patients.
• To identify EEG signal characteristics that can distinguish between moderate and severe OSA.

Main Methods:

• Retrospective analysis of raw electroencephalography (EEG) data from 102 OSA patients undergoing polysomnography (PSG).
• Analysis of EEG signals during, before, and after respiratory cortical arousals (RCAs) across sleep stages (N1, N2, REM).
• Computation of approximate entropy (ApEn), spectral entropy (SpEn), and area under the curve (AUC) of EEG signals during RCAs.

Main Results:

• Severe OSA patients showed significantly decreased EEG signal AUC during RCAs compared to moderate OSA patients (p < 0.0001).
• Spectral entropy (SpEn) was significantly decreased before and after RCAs in severe OSA patients relative to moderate OSA.
• Approximate entropy (ApEn) exhibited an inverse pattern, with the highest increase observed in sleep stage N1 for severe OSA.

Conclusions:

• The dynamic range of sensorimotor cortical activity during RCAs is sleep-stage specific and depends on respiratory event frequency.
• Brain oscillatory patterns during RCAs are uncoupled from autonomic activation.
• These EEG-based findings may aid in the differential diagnosis of severe OSA from moderate OSA.