Electrical modeling of nerve fibers infected by multiple sclerosis disease

Multiple sclerosis (MS) is a disease that causes the immune system to attack the nervous system, and damages the myelin sheaths that surrounds the nerve fiber. As a result, the nerves loss their ability to send and receive messages. The electrical models of the nerve fiber have been studied extensively for the normal case. However, there are no many studies on modeling a nerve fiber infected by MS disease. In this study, we aim to quantify the distortion in the neural signal transmitted through the infected fiber. We derived a mathematical expression to the signal propagated through the disordered part. The derived expression revealed that the distortion is caused by a change in the input impedance at the disease location. Furthermore, we compute the mean square error between the samples of the signal transmitted through the infected fiber and those of the signal propagated through the normal fiber. Our results show that the signal is totally distorted when the disease covers only one internode of the fiber