Sleep Apnea Detection Through Respiratory Flow Using a Low-Cost Temperature Sensor

Sleep apnea is a sleep-related breathing disorder marked by repeated episodes of reduced or absent airflow during sleep. It is broadly divided into two main types: obstructive sleep apnea (OSA) and central sleep apnea (CSA). Polysomnography is currently considered the gold standard for sleep apnea diagnosis, providing a comprehensive and non-invasive assessment. However, its high cost, operational complexity, and limited availability often result in long waiting times and delayed diagnosis. These delays are clinically significant, as untreated sleep apnea is associated with reduced quality of life and an increased risk of cardiovascular diseases. To overcome these limitations, recent research has focused on the development of low-cost and portable monitoring systems suitable for home-based screening. In this context, this paper presents a low-cost sleep monitoring approach based on a temperature sensor to capture thermal variations between inhaled and exhaled air and reconstruct respiratory airflow. A piezoelectric chest belt is used as a reference sensor to assess respiratory effort and validate the ability of the temperature sensor to identify apnea events. The combined analysis of these signals enables reliable detection of airflow interruptions and supports the differentiation between OSA and CSA, offering a promising and accessible solution for home-based sleep apnea screening.