Nonintrusive Vital Signs Monitoring for Sleep Apnea Patients: A Preliminary Study

Sleep is a fundamental and vital physiological function. Getting enough quality sleep is necessary to a person's mental health, physiological well-being, quality of life, and safety. Sleep-disordered breathing, specifically obstructive sleep apnea can result in serious health issues, including hypertension and stroke. The current approaches for diagnosing sleep disorders are burdensome, intrusive, and can affect the patient's sleep quality. As a result, there is a crucial need for less cumbersome systems to diagnose sleep-related problems. In this paper, we evaluated the capacity of the microbend fiber optic sensor to monitor heart rate and respiration in a nonintrusive manner. In addition, we tested the capacity of the sensor in discriminating between shallow breathing and no breathing. The proposed sensor was compared with the three-channel portable monitoring device (ApneaLink) in a clinical setting during a drug-induced sleep endoscopy. Across all ten patients recruited for our study, the system achieved satisfactory results in the mean heart rate and the mean respiratory rate with an error of 0.55 ± 0.59 beats/minute and 0.38 ± 0.32 breaths/minute, respectively. Besides, the Pearson correlation coefficient between the proposed sensor and the reference device was 0.96 and 0.78 for heart rate and respiration, respectively. On the contrary, the proposed sensor provided a very low sensitivity (24.24 ± 12.81%) and a relatively high specificity (85.88 ± 6.01%) for sleep apnea detection. It is expected that this preliminary research will pave the way toward unobtrusive detection of vital signs in real time.