Optimization of the electrode configuration of electrical impedance myography for wearable application

Abstract

Electrical Impedance Myography (EIM) based on the four-electrode method is a novel method for assessing muscle state in the fields of sports, fitness, and medical rehabilitation. However, commonly used configuration of electrodes is not suitable for the wearable field, because of its large total area and low sensitivity. An optimized electrode configuration for wearable application is proposed as Mode B. Equivalent circuit model B of the four-electrode method is established by using the equivalent circuit of biological tissues, and in-vivo measurements of the electrical impedance of the biceps muscle are carried out on six volunteers using bioimpedance spectroscopy device ImpTM SFB7. The experimental results show that equivalent circuit model B of the four-electrode method is reliable. Moreover, the variation in muscle electrical impedance measured using the optimal configuration of model B is twice that measured using the optimal configuration of model A. The optimized electrode configuration of EIM based on this approach is model B (i.e. square electrodes in parallel array; size, 20 mm × 20 mm; spacing, 5–24 mm).