Analysis of the Effects of Point Electrode and Variation of Muscle Thickness in the Assesment of the Electrical Impedance Myography Through Finite Element Method

Electrical impedance myography (EIM), an electrophysiological technique, is recently proposed as a painless, non-invasive technique for assessing neurological disease status. In EIM, bio impedances such as resistance, reactance, and phase are measured over the muscle or muscle group of interest. However, this EIM data depends on several anatomic and nonanatomic factors, such as muscle grith, subcutaneous fat thickness, and electrode configuration. This study has been conducted to explore the effect of variation of muscle thickness on EIM data by applying point electrodes' placement. To our best knowledge, this is the first time we have developed a point electrode configuration placed over the muscle or muscle group of interest to better understand the EIM's ability to access muscle health. In this study, a finite element model (FEM) of the human arm is developed based on the anatomic data. The result shows that of the three major EIM parameters-resistance, reactance, and phase, resistance is least sensitive to the alternation of the muscle thickness in point electrode configuration placement on the FEM model. For example, a 66% increase in muscle thickness resulted in a 50% change in reactance at 50 kHz but only a 13% change in resistance. These exciting findings are a significant augmentation for further study in EIM research.