Applicability of method of image for simulation of myoelectric potentials detected by surface electrodes

Surface myoelectric potentials are detected through the geometrical structures which lie between the active motor units and recording surface electrode, such as inhomogeneous muscle tissue, subcutaneous tissue and skin surface. The method of image is simple simulation method for myoelectric potentials. This method, however, has limitations in application to surface myoelectric potentials, because of its assumption that the region considered is homogeneous and infinite. The authors investigate applicability of the method of image to the simulation for surface myoelectric potentials by comparison with simulation by the finite element method. The results reveal that the applicability lower as the muscle is small, the curvature of the muscle surface is large or subcutaneous tissue is thick.