A wearable vital signs monitor at the ear for continuous heart rate and pulse transit time measurements.
A continuous, wearable and wireless vital signs monitor at the ear is demonstrated. The device has the form factor of a hearing aid and is wirelessly connected to a PC for data recording and analysis. The device monitors the electrocardiogram (ECG) in a single lead configuration, the ballistocardiogram (BCG) with a MEMS triaxial accelerometer, and the photoplethysmograms (PPG) with 660 nm and 940 nm LED sources and a static photocurrent subtraction analog front end. Clinical tests are conducted, including Valsalva and head-up tilt maneuvers. Peak timing intervals between the ECG, BCG and PPG are extracted and are shown to relate to pre-ejection period and mean arterial blood pressure (MAP). Pulse Transit Time (PTT) extracted from cross-correlation between the PPG and BCG shows improved results compared to the pulse arrival time (PAT) method for tracking changes in MAP.
Massachusetts Institute of Technology, Cambridge, MA 02139, USA. ewinokur@mit.edu
Eric S
ES
Winokur
David Da
DD
He
Charles G
CG
Sodini
D000465:Algorithms; D001450:Ballistocardiography; D001794:Blood Pressure / Q000502:physiology; D004423:Ear; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008991:Monitoring, Physiologic / Q000379:methods*; D017156:Photoplethysmography