Transauricular Vagus Nerve Stimulation and Electroencephalographic Assessment in Disorders of Consciousness

The technique of transauricular vagus nerve stimulation (taVNS) is methodologically applied by placing electrodes on the auricular region, specifically on the cymba, cavum, or tragus, to stimulate the vagus nerve non-invasively. Additionally, the earlobe, which is not innervated by the vagus nerve, can serve as a placebo site for control stimulation. The stimulation intensity is adjusted between 0.5-3.0 mA, with session durations ranging from 20-60 min, administered either daily or weekly, depending on the study protocol. The total number of sessions varies according to the protocol, extending from a few weeks to several months. Ethically, research involving taVNS must adhere to regulations set by the local Agency for Medicines and Health Products and European Union guidelines. Approval from an Ethical Committee is required for studies involving healthy participants, while a Medical Ethical Committee is necessary for clinical research, ensuring that written information and informed consent are provided. Additionally, rigorous exclusion criteria must be established to safeguard participant safety, excluding pregnant individuals, those with cardiovascular, pulmonary, or metabolic diseases, psychiatric disorders, epilepsy, hypertension, or those using medications affecting the autonomic nervous system. In terms of clinical outcomes, the current study protocol demonstrated promising results with taVNS in patients with Disorders of Consciousness, showing significant improvement in alertness recovery and response to stimuli. Patients treated with taVNS experienced neurophysiological changes compared to the control group. Moreover, electroencephalographic biomarkers can be utilized to evaluate treatment efficacy, even in the absence of observable behavioral indicators. These findings suggest significant clinical potential for taVNS in managing Disorder of Consciousness, although the lack of specific regulations for taVNS underscores the need to adhere to international scientific best practices and seek consensus on European guidelines for its research application.