The effects of TaVNS on GAD, CP and IBS. Participants were investigated during a 4-week period and a 2-month follow-up. Groups (GAD, CP, IBS) were assessed using questionnaires: Anxiety (Generalized Anxiety Disorder GAD-7); CP (Brief Pain Inventory Short Form Questionnaire) and IBS (Irritable Bowel Syndrome Severity Scoring System). TaVNS was performed using a standard transcutaneous electrical nerve stimulation (TENS) device and ear clip electrodes plugged into the concha area of the left ear. All participants received a bi-weekly 30 minutes stimulation (8 sessions). We defined three different TaVNS parameters for each group in hertz (Hz) and microsecond (µs), (GAD: 20Hz-80µs), (CP: 5Hz-200 µs), (IBS: 3Hz-250µs).
