Characterisation of Laryngeal Evoked Potentials Induced by Vagus Nerve Stimulation in Refractory Epilepsy Patients

Although VNS has been widely used in clinic for over 30 years, its mechanisms of action remain unclear and there is a lack of individual biomarkers of efficacy. One potential and understudied source of variability on the response to VNS may be related to nerve function and recovery following implantation. VNS co-activates the recurrent laryngeal branch of the vagus nerve, which carries vagal-Aα fibres innervating all the laryngeal muscles except the cricothyroid. VNS-induced effective activation of the recurrent laryngeal nerve generates a so-called LMEP. Despite the fact that the LMEP represents a simple, non-invasive, and feasible technique to employ in clinical routine, it is not yet sufficiently investigated. This study comprises 5 visits (2 weeks, 1 month, 3 months, 6 months, and 12 months after VNS implantation) and consists of the measurement of the laryngeal-motor evoked potentials induced by vagus nerve stimulation (VNS), that will be further compared with the corresponding clinical response to VNS.