Sleep Electroencephalographic Response to Respiratory Events in Patients With Moderate Sleep Apnea–Hypopnea Syndrome

Abstract

Sleep apnea-hypopnea syndrome is a common breathing disorder that can lead to organic brain injury, prevent memory consolidation, and cause other adverse mentalrelated complications. Brain activity while sleeping during respiratory events is related to these dysfunctions. In this study, we analyzed variations in electroencephalography (EEG) signals before, during, and after such events. Absolute and relative powers, as well as symbolic transfer entropy (STE) of scalp EEG signals, were calculated to unveil the activity of brain regions and information interactions between them, respectively. During the respiratory events, only low-frequency power increased during rapid eye movement (REM) stage (δ-band absolute and relative power) and N1 (δ-and θ-band absolute power, δ-band relative power) sleep. But absolute power increased in lowand medium-frequency bands (δ, θ, α, and σ bands), and relative power increased mainly in the medium-frequency band (α and σ bands) during stage N2 sleep. After the respiratory events, absolute power increased in all frequency bands and sleep stages, but relative power increased in medium and high frequencies. Regarding information interactions, the β-band STE decreased during and after events. In the γ band, the intrahemispheric STE increased during events and decreased afterward. Moreover, the interhemisphere STE increased after events during REM and stage N1 sleep. The EEG changes throughout respiratory events are supporting evidence for previous EEG knowledge of the impact of sleep apnea on the brain. These findings may provide insights into the influence of the sleep apnea-hypopnea syndrome on cognitive function and neuropsychiatric defects.

Characterization of specific spatial functional connectivity difference in depression during sleep

“…Previous studies have tried to explore different inter-regional features to exhibit differences in FC distribution, such as left-right asymmetry and anterior-posterior anisotropy (Liao et al, 2019;Pan et al, 2021;Zhou et al, 2020). It has been reported that the FC of the limbic system in the hemisphere of patients with depression is reduced (Cao et al, 2012), whereas Irwin et al found that the FC between the hemispheres of the amygdala was enhanced (Irwin et al, 2004).…”

Sleep-Dependent Anomalous Cortical Information Interaction in Patients With Depression

“…Compared with previous studies ( Zhou et al, 2020 ; Pan et al, 2021 ), our method provided detailed differences in information flow between brain regions, and clearly characterized the role of regions in information transmission (as a receiver or driver). It has been reported that the occipital region and the parietal region are considered to be related to visual information ( Heo et al, 2018 ) and somatosensory information ( Fogassi and Luppino, 2005 ), respectively, while the frontal area has a bearing on senior cognitive functions, emotions, and information integration functions ( Fogassi and Luppino, 2005 ; Alvarez and Emory, 2006 ).…”

“…However, insufficient investigations committed to reveal and characterize the asymmetries of cortical information flow in depressed patients during sleep, the topic of which was considered to provide valuable information for the abnormal cerebral function in patients. Moreover, previous studies have tried to explore different inter-regional features to quantify different patterns of cortical information flow, such as left–right index and anterior–posterior rate ( Zhou et al, 2020 ; Ekhlasi et al, 2021 ; Pan et al, 2021 ). To discover the difference in sleep-dependent information flow patterns in patients, analysis on various EC asymmetry patterns was included in this research.…”

Changes in the cortical network during sleep stage transitions

“…Our previous study indicated that SAHS had a significant effect on the γ cortical network (Pan et al, 2021). Particularly, short‐term changes, significant interhemispheric interactions, and reductions in intrahemispheric processing were observed in the γ band during sleep respiratory events (Zhou et al, 2020). In the central nervous system, non‐benzodiazepine modulators of the key inhibitory neurotransmitter gamma‐aminobutyric acid type A receptors, which is believed to be activated for sleep, have been reported to increase the high‐frequency EEG activity (Faes et al, 2014; Gottesmann, 2002; van Lier et al, 2004).…”

“…Differences in cortical interactions among patients with sleep apnea hypopnea syndrome (SAHS) were investigated according to symbolic transfer entropy. As a result, differences were identified not only during the respiratory events, but also throughout sleep, and spatially distinct results were found in multiple frequency components (Pan et al, 2021;Zhou et al, 2020). It was pointed out that when calculating the symbolic transfer entropy, the amplitudes of the frequency sub-bands were mainly considered.…”