Determination Of Proper Parameters For Selective Electrical Stimulation Of Myelinated Peripheral Nerve Fibers With HFAC Using Computational Simulation

Transcutaneous electrical stimulation of peripheral nerve fibers has always been an important field of research. Many studies indicate the possibility to block the conduction of nerve fibers by using high frequency alternating currents (HFAC). According to the fact that the stimulation of narrower fibers is always accompanied by activation of thicker fibers, in this study, current regions for selective stimulation of different nerve fibers without activating other fibers have been obtained. This success is achieved through the nerve conduction block using HFAC (5-20 KHz). Stimulation current regions is a part of the intensity-frequency diagram which by choosing the excitation parameters in this area, only some target fibers are stimulated according to their diameters. The McIntyre nerve fiber model was used to perform these simulations; The sodium-potassium pump model has also been added to it and its effects have been investigated. A unipolar electrode is considered which acts as a point current source at different distances from the nerve fibers, and selective excitation spaces are obtained for the Aδ and Aβ fibers. the appropriate frequency range for excitation of different fibers is 5 kHz and above, while the desired current for selective excitation of Aδ and Aβ fibers is given by two polynomial equations of order 2 and 3, respectively, which are fitted to the middle of selective parameter space of each nerve fiber. also, the excitation current varies from about 0.8 to 1.8 mA for Aδ fibers and from about 0.55 to 0.95 mA for Aβ fibers. in all of the simulations mentioned in this article, the sinusoidal waveform is used.