Measurement of cardio-respiratory dynamics during sleep arousals with a suprasternal pressure sensor

Sleep-disordered breathing disorders, such as ob-structive sleep apnea (OSA), are increasingly prevalent in the general population. Their main characteristic is the recurrence of apneas and hypopneas during sleep, which can cause hypoxia and arousals, degrading overall sleep quality. Fragmented sleep has profound effects on health and quality of life, in both the short (daytime sleepiness, irritability) and long term (increased cardiovascular risk, metabolic distress). The recommended pro-cedure to detect sleep apnea disorders is a polysomnography, with a broad set of sensors covering every aspect of sleep. If polysomnography is unfeasible, home sleep apnea test devices are available for screening purposes and initial diagnoses. However, they employ a reduced set of sensors, which limits the amount of information available, for example misdetecting the time awake, or detecting events through proxy measurements, such as oxygen desaturations instead of apneas. To mitigate the issue, suprasternal notch pressure (SSP) sensors can provide a reliable measure of both respiratory effort and cardiac activity, opening the way to more direct measurements of sleep apnea events and associated heart rate surges. Here, we assess the possibility of characterizing arousals using solely the response of SSP signals to cortical arousals caused by various physiological events. Preliminary results show that distinct patterns of respiratory effort and heart rate are visible in the components of the SSP signal during arousals.

I. Introduction

The measurement of sleep, intended as the combination of physiological changes in the brain, heart, muscles and lungs is a complex task, with healthy and disordered sleep presenting unique characteristics and mechanisms. In clinical practice, a person with suspected sleep disorders will spend a night with multiple sensors placed on their body and receive a diagnosis after a detailed analysis from a trained sleep technician. The technical system that allows this procedure is called polysomnography (PSG).