Accurate and timely diagnosis of sleep apnea is crucial for effective treatment. Current gold standard is polysomnography (PSG) in the sleep laboratory, which measures EEG, EOG, EMG, oronasal airflow, nasal pressure, respiratory effort, SpO2, body position, and snoring sound. The sleep study is scored manually to produce study outcomes such as the apnea-hypopnea index (AHI) – the average number of apnea and hypopnea events per hour of sleep. This labor-intensive diagnosis requiring an overnight hospitalization makes in-lab sleep study expensive and inconvenient. Some patients have trouble falling asleep due to discomfort from many attached sensors and the first-night effect.
Home sleep test (HST) is a cost-effective alternative to diagnose patients with moderate to severe sleep apnea. Limited signals are measured in HST to estimate the AHI: nasal pressure, SpO2, respiratory effort, and snoring. Though more HSTs are prescribed than PSG now, the reduced measurements often fail to accurately stratify the severity of the breathing disorder.