Heartbeat and Respiration Detection From Optical Interferometric Signals by Using a Multimethod Approach

• Published in: IEEE transactions on biomedical engineering Vol. 59; no. 10; pp. 2922 - 2929
• Main Authors: Šprager, Sebastijan, Zazula, Damjan
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2012; Institute of Electrical and Electronics Engineers
• Subjects: Adult; Algorithms; Band pass filters; Biological and medical sciences; Female; Fiber Optic Technology - instrumentation; Fiber Optic Technology - methods; Fundamental and applied biological sciences. Psychology; Heart; Heart beat; Heart Rate - physiology; Heart rate variability; Heartbeat detection; Humans; Interferometry - instrumentation; Interferometry - methods; Male; Monitoring, Physiologic - instrumentation; Monitoring, Physiologic - methods; multimethod approach; Optical fiber sensors; Optical fibers; Optical filters; optical interferometer; Optical interferometry; Respiration; respiration detection; Sensitivity and Specificity; Signal Processing, Computer-Assisted; unobtrusive monitoring of vital functions; Vertebrates: cardiovascular system; Human; Optical interferometry; Exploration; multimethod approach; unobtrusive monitoring of vital functions; Heart rate; Optical signal; optical interferometer; Surveillance; Heartbeat detection; respiration detection; Signal processing; Respiration; Monitoring; Biomedical engineering
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/TBME.2012.2213302

In this paper, a multimethod approach for heartbeat and respiration detection from an optical interferometric signal is proposed. Optical interferometer is a sensitive device that detects physical changes of optical-fiber length due to external perturbations. When in direct or indirect contact with human body (e.g., hidden in a bed mattress), mechanical and acoustic activity of cardiac muscle and respiration reflect in the interferometric signal, enabling entirely unobtrusive monitoring of heartbeat and respiration. A novel, two-phased multimethod approach was developed for this purpose. The first phase selects best performing combinations of detection methods on a training set of signals. The second phase applies the selected methods to test set of signals and fuses all the detections of vital signs. The test set consisted of 14 subjects cycling an ergometer until reaching their submaximal heart rate. The following resting periods were analyzed showing high efficiency (98.18 ± 1.40% sensitivity and 97.04 ± 4.95% precision) and accuracy (mean absolute error of beat-to-beat intervals 22±9 ms) for heartbeat detection, and acceptable efficiency (90.06 ± 7.49% sensitivity and 94.21 ± 3.70% precision) and accuracy (mean absolute error of intervals between respiration events 0.33 ± 0.14 s) for respiration detection.