Reduction of Anxiety-Related Symptoms Using Low-Intensity Ultrasound Neuromodulation on the Auricular Branch of the Vagus Nerve: Preliminary Study

Abstract

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 who 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 use in improving and managing moderate to severe symptoms. Objectives 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 of 16 points or greater. Participants completed 5 minutes of treatment daily consisting of LIFU neuromodulation delivered to the auricular branch of the vagus nerve. Participants did this for a period of 4 weeks. Assessments of anxiety symptom severity (Beck Anxiety Inventory), depression symptom severity (Beck Depression Inventory), posttraumatic stress disorder symptom severity (Post Traumatic Stress Disorder Checklist for the Diagnostic and Statistical Manual of Mental Disorders [Fifth Edition]), and sleep quality (Pittsburgh Sleep Quality Index) were taken prior to starting treatment and weekly for 4 weeks of treatment. Usability and safety were also assessed using an exit questionnaire and adverse event logging. Results After completing 4 weeks of LIFU neuromodulation to the auricular branch of the vagus nerve, the average Beck Anxiety Inventory score decreased by 14.9 (SD 10.6) points (Cohen d =1.06; P d =0.81; P Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) score decreased by 20.0 (SD 20.5) points (Cohen d =0.94; P 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 1 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 posttraumatic stress disorder.

Abstract via europepmc.

Flags from extraction

• exposures[0].unspecified_domain.pressure_kpa — Device specification lists 'an average intensity of 1.03 MPa': unit is a pressure but label says intensity; 'average' is undefined. Domain not stated; recorded as 1030 kPa in unspecified_domain.
• exposures[0].timing.pulse_duration_ms — Pulse duration not stated; not computed from PRF and duty cycle.
• exposures[0].timing.sonication_duration_s — 5 minutes per daily session is the instructed duration; device shuts down after 29 minutes; use at home not monitored.
• n_sessions_per_subject — Daily home use for 4 weeks; the number of sessions actually completed is not stated (no objective usage logging).
• exposures[0].timing.waveform — Waveform inferred as pulsed from the stated PRF and 50% duty cycle.
• n_subjects — Text says 22 participants moved into the mild/minimal BAI range while the Figure 5 legend says 20; 28 enrolled and analysed.