Abstract
This paper presents a theoretical study of sensor-artery interaction in arterial pulse signal measurement using a tactile sensor. A measured pulse signal is a combination of the true pulse signal in an artery, the arterial wall, its overlying tissue, and the sensor, under the influence of hold down pressure exerted on the sensor and motion artifact. The engineering essence of sensor-artery interaction is identified as elastic wave propagation in the overlying tissue and pulse signal transmission into the sensor at the skin surface, and different lumped-element models of sensor-artery interaction are utilized to examine how the involved factors affect a measured pulse signal. Achieving ideal sensor-artery conformity is the key for acquiring a measured pulse signal with minimum distortion. Hold-down pressure, sensor design, and overlying tissue collectively contribute to ideal sensor-artery conformity. Under ideal sensor-artery conformity, both the sensor and overlying tissue cause an increase in the measured stiffness of the arterial wall; damping and inertia of the sensor and overlying tissue also affects a measured pulse signal. The theoretical study shows the need to tailor the sensor design for different arteries and individual, and interpret estimated arterial indices with consideration of individual variations as well as instruments used.
