Advances in Non-Invasive Neuromodulation: Designing Closed-Loop Devices for Respiratory-Controlled Transcutaneous Vagus Nerve Stimulation

Abstract

Studies suggest non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) as a potential therapeutic option for various pathological conditions, such as epilepsy and depression. Exhalation-controlled taVNS, which synchronizes stimulation with internal body rhythms, holds promise for enhanced neuromodulation, but there is no closed-loop system in the literature capable of performing such integration in real time. In this context, the objective was to develop real-time signal processing techniques and an integrated closed-loop device with sensors to acquire physiological data. After a conditioning stage, the signal is processed and delivers synchronized electrical stimulation during the patient’s expiratory phase. Additional modules were designed for processing, software-controlled selectors, remote and autonomous operation, improved analysis, and graphical visualization. The signal processing method effectively extracted respiratory cycles and successfully attenuated signal noise. Heart rate variability was assessed in real time, using linear statistical evaluation. The prototype feedback stimulator device was physically constructed. Respiratory peak detection achieved an accuracy of 90%, and the real-time processing resulted in a small delay of up to 150 ms in the detection of the expiratory phase. Thus, preliminary results show promising accuracy, indicating the need for additional tests to optimize real-time processing and the application of the prototype in clinical studies.

The Development of a New Vagus Nerve Simulation Electroceutical to Improve the Signal Attenuation in a Living Implant Environment

“…Electroceuticals provide a new and innovative treatment method that can improve the quality of life for patients, especially in cases where traditional drug treatment is either ineffective or impaired with side effects. The electroceutical field continues to grow and is expected to play an important role in the future of medical technology [1][2][3][4].…”

“…The human nerve system includes the central nerve system and the peripheral nerve system, which is derived from the central nerve system. This system distributes branches throughout the human body and transmits nerve signals to organs [1,2]. When the function of the brain's nerve system is damaged, various neurological diseases may occur such as stroke, depression, epilepsy, and Parkinson's disease.…”

“…We developed the prototype to increase the lifespan of the electroceutical to reduce the frequency of reimplantation, thus reducing the medical costs. By using a BLE-based communication app, the communication barrier between patients and doctors can be lowered, facilitating the patient follow-up studies [1][2][3][4][5][6][7][8][9]. The designed VNS prototype incorporates multiple layers of safety features to comply with FDA regulations and safety standards.…”