Platform development for adaptive auricular vagus nerve stimulation based on cardiac activity

Abstract

Vagal nerve stimulation is a medical act which has been studied since the 2nd half of the 20th century, as a cure for various diseases like epilepsy, though invasive stimulation. Currently, a new site of stimulation though the auricular branch of the nerve offers new perspectives for various positive effects on the patient through non invasive stimulation. In that optic, we designed a software on Matlab associated with a Biopac station, to detect in real time diverse biosignal characteristic from the cardiovascular system, like ECG, PPG, or respiration, and to perform with a microcontroller an adaptative stimulation though a triphasic signal at simultaneously 3 different places of the ear. The aim is to align stimulation events with the temporal activity of the cardiovascular and respiratory system and thus to synchronize artificial stimulus with the intrinsic physiological activity for therapy individualization. The specificity of this platform is the ability to provide a robust detection algorithm of the cardiovascular events, with over 90% detection rate of the R peaks in a noisefree ECG signal with a delay less than 100ms, to perform the stimulation at a specific time point of the cardiovascular system in real time. The accuracy of the stimulation was tested in open loop with no direct stimulation of the patient and gave satisfying results in term of timing of the stimulation. In the future, it must be tested on real patient to see what kind of impact it will have on the stimulation parameters and on the resulting cardiovascular function in general. The goal would then to integrate this process in an embedded device as a medical cure for various chronic diseases.