Influence of different stimulation parameters on the somatosensory evoked potentials of the nervus vagus--how varied stimulation parameters affect VSEP.

Vagus somatosensory evoked potentials are a method for assessing the function of the vagus nerve, which were shown to be altered in neurodegenerative diseases like Alzheimer's and Parkinson's disease. Various parameters of the stimulation such as the electrode position and the stimulus intensity have already been investigated. In this study, the focus is on the systematic examination of the other parameters of the stimulation of the vagus somatosensory evoked potentials: stimulus duration, interstimulus interval, and, again, the stimulation intensity. Thirty young and healthy subjects were examined using five different sets of stimulation parameters, and 24 were included in the further analysis. The results show that a reduction of the stimulus duration and a decrease in stimulus intensity have a significant effect on the amplitudes. A shortening of the interstimulus interval does not seem to have such an effect, but this stimulation is rated more painful and unpleasant than the standard stimulation. Overall, the standard stimulation used so far seems to be the most preferable condition.