This study presents a novel technique to develop an equivalent circuit model (ECM) for analyzing the responses of the layered body structure to transcutaneous electrical nerve stimulation (TENS) by parameterizing electrical and geometrical properties. Many classical ECMs use custom meta-parameters instead of the physically driven parameters because of the difficulty in projecting physical properties directly into ECM. However, the difference in what parameters are customized hampers general agreement in modeling the responses to TENS. To overcome this limitation, we propose a tissue property-based (TPB) approach for the direct parameterization of the layered body structure.
The proposed method was first validated through in vitro phantom studies and then was applied in-vivo to analyze the TENS on the forearm. The TPB-ECM calculated the impedance network in the forearm and corresponding the responses to TENS. In addition, the modeled impedance was in good agreement with well-known impedance properties that have been achieved empirically.
The TPB approach uses the physical parameters instead of meta-parameters, thus overcoming the disagreement problem of conventional ECMs. Therefore, the TPB-ECM has a potential for widely-applicable TENS analysis and could provide impactful guidance in the TENS parameter design.