A novel approach for precise simulation of the EMG signal detected by surface electrodes

We propose a new electromyogram generation and detection model. The volume conductor is described as a nonhomogeneous (layered) and anisotropic medium constituted by muscle, fat and skin tissues. The surface potential detecte d in space domain is obtained from the application of a two-dimensional spa tial filter to the input current density source. The effects of electrode c onfiguration, electrode size and inclination of the fibers with respect to the detection system are included in the transfer function of the filter. C omputation of the signal in space domain is performed by applying the Radon transform; this permits to draw considerations about spectral dips and cle ar misunderstandings in previous theoretical derivations. The effects of ge neration and extinction of the action potentials at the fiber end plate and at the tendons are included by modeling the source current, without any ap proximation of its shape, as a function of space and time and by using agai n the Radon transform. The approach, based on the separation of the tempora l and spatial properties of the muscle fiber action potential and of the vo lume conductor, includes the capacitive tissue properties.