Assessment of nerve cathodal block for the percutaneous auricular vagus nerve stimulation

Nerve cathodal block mechanism for the percutaneous auricular vagus nerve stimulation is investigated. The response of individual axons to stimulation will be assessed in terms of excitation, blocking and propagation of action potentials in order to optimize stimulation patterns. It was seen that the response obeyed the activating function remarkably well. The found sensitivity indices of the blocking threshold for variations in diameter and temperature (61 % and 15 % respectively) are significantly higher than for the excitation threshold. Finally, the threshold needed for cathodal block (around -5 V) is far from the amplitudes used to stimulate the nerves (around -1 V). More investigations by performing an uncertainty analysis varying axonal trajectories and electrode placement can lead to the conclusion that cathodal block is less likely to occur when stimulating with clinically used amplitudes in pVNS.