Simple and Autonomous Sleep Signal Processing System for the Detection of Obstructive Sleep Apneas

Abstract

Obstructive sleep apnea (OSA) is a common sleep disorder characterized by repetitive upper airway obstruction, intermittent hypoxemia, and recurrent awakenings during sleep. The most used treatment for this syndrome is a device that generates a positive airway pressure—Continuous Positive Airway Pressure (CPAP), but it works continuously, whether or not there is apnea. An alternative consists on systems that detect apnea episodes and produce a stimulus that eliminates them. Article focuses on the development of a simple and autonomous processing system for the detection of obstructive sleep apneas, using polysomnography (PSG) signals: electroencephalography (EEG), electromyography (EMG), respiratory effort (RE), respiratory flow (RF), and oxygen saturation (SO2). The system is evaluated using, as a gold standard, 20 PSG tests labeled by sleep experts and it performs two analyses. A first analysis detects awake/sleep stages and is based on the accumulated amplitude in a channel-dependent frequency range, according to the criteria of the American Academy of Sleep Medicine (AASM). The second analysis detects hypopneas and apneas, based on analysis of the breathing cycle and oxygen saturation. The results show a good estimation of sleep events, where for 75% of the cases of patients analyzed it is possible to determine the awake/asleep states with an effectiveness of >92% and apneas and hypopneas with an effectiveness of >55%, through a simple processing system that could be implemented in an electronic device to be used in possible OSA treatments.

Diseño e implementación de dos dispositivos biomédicos para pacientes con Síndrome de Apnea Obstructiva del Sueño (SAOS) basados en la detección de apneas e hipopneas y rehabilitación por medio de estimulación eléctrica

“…Se escogieron 20 exámenes de PSG realizadas en una noche, desarrollando dos algoritmos en el software Matlab: Algoritmo de detección de estados de sueño, el cual distingue los estados despierto o dormido y Algoritmo de detección de apneas e hipopneas del sueño, filtrando en el caso de las apneas solo las de tipo obstructivo. Los resultados de este algoritmo fueron publicados como uno de los resultados de esta investigación [94].…”