Sphygmopalpation of Pulse Waves with Variable Applied Fingertip Pressure using a MEMS Flexible Tactile Sensor Array

With the advancement of Digital Chinese Medicine (DCM) using micro/nano sensors and AI technologies, researchers have invested significant efforts in acquiring pulse wave information and relating them to disease symptoms. Many flexible sensors have been developed in the past decade attempting to improve and digitize Traditional Chinese Medicine Pulse Sphygmopalpation (TCMPS) data. Typically, TCM doctors use their fingers to obtain physiological information from the wrist radial artery and determine a patient's physical condition by sensing temporal and spatial information of the pulse waves. However, an important element in the TCMPS method is that the fingertips must apply three different pressure levels onto a patient's wrist in order to properly obtain the wave patterns described by TCM doctors. Unfortunately, past work failed at addressing this fundamental problem for TCMPS – existing flexible sensors have not reported the capability of measuring the truly applied pressure onto a patient's skin while measuring temporal variations of the pulse waves. We present here a method that allows TCM doctors to record a patient's pulse in real-time using a tactile sensor array while the fingertip pressure applied to the skin can also be recorded. We believe our work will significantly advance TCM by providing a repeatable and stable pulse wave collection methodology incorporating the vital concept of sphygmopalpation with variable applied fingertip pressures.