Transcutaneous Vagus Nerve Stimulation Through an In-Ear Device For Epilepsy Treatment

Abstract

Several studies have illustrated that Transcutaneous Vagus Nerve Stimulation (t-VNS) is an effective method for epileptic treatment. In contrast to the classical invasive Vagus Nerve Stimulation (VNS) which is already a Food and Drug Administration (FDA) approved therapy for epileptic treatment, t-VNS does not require surgical intervention. However, t-VNS has still not been evolved into an application which can be used in clinical practise due to a lack of power efficiency or size constraints. In this bachelor graduation project, an electrical circuit has been designed and implemented for stimulating the auricular branch of the vagus nerve. This circuit is part of a larger project where an ear piece is developed which is able to process Electroencephalogram (EEG) signals as well. The main design goals of the stimulator were power
efficiency and safety. Furthermore, a design for an integrated circuit has been proposed resulting in an power efficient method for controlling the electrical stimulation circuit. The integrated circuit has, among other things, built in safety features and closed loop stimulation capabilities. Simulations showed that the designed circuit is able to successfully stimulate with current amplitudes up to 8 mA when taking worst case values for an impedance model of the electrode-skin interface. However, the implemented physical design was planned to be tested after the thesis submission. In other words, this thesis only contains the design and simulation phase of the stimulator. The design was found to be safe and power-efficient and could lay the basis for future development in the field of wearable in-ear stimulation devices.