Personalized heart-controlled stimulator for auricular vagus nerve stimulation with closed-loop control (VagusVibe)

Abstract

Neurological and psychological conditions such as epilepsy, depression, chronic stress, and cardiovascular diseases are challenging conditions that interrupt day-to-day life. Vagus nerve stimulation is a promising therapy for these conditions due to the vagus nerve’s influence on autonomic functions. Particularly, auricular vagus nerve stimulation (aVNS), a non-invasive method, show therapeutic benefits by modulating vagal activity using miniature needles without surgical intervention.This thesis explores the development of a personalized, heart-controlled stimulator for aVNS with a closed-loop control system, called VagusVibe. VagusVibe aims to be able to provide personalized treatment by dynamically adjusting its stimulation parameters based on real-time physiological feedback. It is able to use connected sensors for electrocardiography (ECG) and photoplethysmography to monitor the patient’s heart rate.The primary goal of this research was to create a portable, user-friendly device capable of providing personalized aVNS therapy. To achieve this, a compact device was developed, incorporating a microcontroller, power management, stimulation circuits, and connectivity options via Bluetooth, SPI, I2C and USB.Preliminary testing involved hardware commissioning and laboratory tests as well as animal experiments to evaluate the device’s functionality. VagusVibe was able to start the stimulation with a delay of 550 μs after the conditions were fulfilled and a threshold of the ECG signal was overstepped. Thus showing that the closed-loop stimulation could be executed relatively fast.The laboratory experiments and hardware commissioning have shown VagusVibe’s potential for aVNS. Additional clinical trials should be done in order to validate its efficacy and safety. The long-term vision for VagusVibe includes expanding its therapeutic applications, enhancing its technological capabilities, and refining its design based on ongoing research. VagusVibe is a forward-orientated step into delivering a promising therapeutic tool for improving life quality for people with conditions influenced by vagal activity.