Non-Invasive Blood Pressure Monitoring with Multi-Modal In-Ear Sensing

Continuous blood pressure monitoring is the key to mitigate significant risks for stroke, heart failure and coronary artery disease. Current gold-standard blood pressure devices cause discomfort and interfere with users’ activities. This paper explores an earable system, which continuously monitors users’ blood pressure from the ear. We propose a measurement technique based on the vascular transit time which utilises the time difference between the S1 heart sound and the PPG upstroke in one pulse cycle. We develop a multi-modal sensing hardware and processing pipeline and we evaluate it with 10 participants showing average errors in line with the range recommended by the Association for the Advancement of Medical Instrumentation: 4.07 mmHg for systolic and 5.61 mmHg for diastolic blood pressure.