Reduction of Anxiety Related Symptoms Using Low Intensity Ultrasound Neuromodulation on the Auricular Branch of the Vagus Nerve; A Preliminary Study (Preprint)

BACKGROUND Neuromodulation of the auricular branch of the vagus nerve using low intensity focused ultrasound (LIFU) is an emerging mode of treatment for anxiety that could provide a complementary or alternative treatment modality for individuals that are refractory to conventional interventions. The proposed benefits of this technology have been largely unexamined with clinical populations. Further research is required to understand its clinical potential and utility in improving and managing moderate to severe symptoms. OBJECTIVE The aim of this study was to do a preliminary investigation into the efficacy, safety, and usability of the wearable headset that delivers LIFU to the auricular branch of the vagus nerve for the purpose of alleviating anxiety disorder symptoms. METHODS This study was a pre-post intervention study design for which we recruited 28 participants with a Beck Anxiety Inventory score greater than or equal to 16 points. Participants completed five minutes of treatment daily consisting of low intensity focused ultrasound neuromodulation delivered to the auricular branch of the vagus nerve. Participants did this for a period of four weeks. Assessments of anxiety symptom severity (Beck Anxiety Inventory), depression symptom severity (Beck Depression Inventory), post-traumatic stress disorder symptom severity (Post Traumatic Stress Disorder Checklist for the DSM-5), and sleep quality (Pittsburgh Sleep Quality Index) were taken prior to starting treatment and weekly for the four weeks of treatment. Usability and safety were also assessed using an exit questionnaire and adverse event logging. RESULTS After completing four weeks of low intensity focused ultrasound neuromodulation to the auricular branch of the vagus nerve the average Beck Anxiety Inventory score decreased 14.9±10.6 points (Cohen d=1.06, p <.001), the average Beck Depression Inventory score decreased 10.3±7.8 points (Cohen d=0.81, p<.001), the average Post Traumatic Stress Disorder Checklist for the DSM-5 score decreased 20.0±20.5 points (Cohen d=0.94, p<.001), and the average Pittsburgh Sleep Quality Index score decreased 2.2±3.1 points (Cohen d=0.65, p=.001). On the exit questionnaire participants rated the treatment highly for ease of use, effectiveness, and worthiness of the time invested. Only one adverse event was reported throughout the entire trial, which was mild and temporary. CONCLUSIONS This preliminary study provided justification for further research into the efficacy, safety, and feasibility of using LIFU to modulate the auricular branch of the vagus nerve and reduce the symptoms of anxiety, depression, and PTSD. CLINICALTRIAL ClinicalTrials.gov [NCT06574971]