Accurate Noncontact Sleep Apnea-Hypopnea Detection using a K-band Biomedical Radar

The golden standard of nocturnal respiratory function assessment is polysomnography (PSG) especially for diagnosis of sleep apnea-hypopnea syndrome (SAHS). However, the use of PSG sensors usually obstructs the patients' breathing, causing discomfort. One of the most important signals in PSG to assess respiratory function is airflow, especially for sleep apnea detection. Radar-based contactless detection technique provides a non-contact monitor way to overcome such limitation. Aiming at developing an alternative of airflow, a 24-GHz biomedical radar sensor combined with airflow reconstruction algorithm is developed to provide accurate continuous measurement of respiratory waveform during sleep. Simultaneously with PSG, the radar data of SAS patients were recorded to validate the monitoring feasibility of the sleep apnea-hypopnea events, which consists of obstructive sleep apnea (OSA), central sleep apnea (CSA) and hypopnea. The overnight experimental results show that all the apnea and hypopnea events can be accurately detected, which makes the at-home monitoring possible in the future.