Sleep medicine
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The purpose of this study is to examine the factor structure of the Insomnia Severity Index (ISI) across samples recruited from different countries. We tried to identify the most appropriate factor model for the ISI and further examined the measurement invariance property of the ISI across samples from different countries. ⋯ The factorial validity of the ISI is stable in different populations. More importantly, its invariance property across cultures suggests that the ISI is a valid measure of the insomnia severity construct across countries.
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Heartbeat-evoked potentials (HEPs) in electroencephalogram (EEG) provide a quantitative measure of cardiac interoception during sleep. We previously reported reduced HEPs in children with sleep-disordered breathing (SDB), indicative of attenuated cardiac information processing. The objective of this study was to investigate the link between HEP and respiration. ⋯ The expiratory phase of respiration is primarily associated with attenuated cardiac information processing in children with SDB, establishing a pathophysiological link between breathing and HEP attenuation.