Expiratory-Gated Transcutaneous Auricular Vagus Nerve Stimulation Combined With Slow Breathing in War-Related Traumatic Stress: A Pilot Study

Objectives This pragmatic pilot study explored the potential effectiveness of a hybrid intervention combining transcutaneous auricular vagus nerve stimulation (taVNS) with slow breathing and assessed its feasibility, adherence, and acceptability among individuals with post-traumatic stress disorder (PTSD) symptoms related to the war in Ukraine. Materials and Methods A delayed treatment within-subject design was used with five monthly assessments: one month before the intervention, pre- and postintervention (including physiologicdata), and two follow-ups with self-reported outcomes only. A total of 20 Ukrainian women (aged 18–49 years) with PTSD symptoms (PTSD checklist for DSM-5 [PCL-5] ≥31) practiced slow breathing paced by taVNS at 0.1 Hz (4-s inspiration and 6-s expiration with stimulation), twice daily for four weeks. Self-reported outcomes included PTSD symptoms (PCL-5), psychologic distress (Hopkins Symptom Checklist-25), well-being (World Health Organization-Five Well-Being Index), insomnia (Insomnia Severity Index), and somatic symptoms (Patient Health Questionnaire-15). Physiologic measures: heart rate, respiratory heart rate variability (respHRV), end-tidal CO₂, and respiratory rate were collected at rest and during paced breathing to standardize respHRV measurement. Results Compared with the preintervention waiting period, improvements were observed during the intervention in most self-reported outcomes. The strongest effects were observed for insomnia ( d _z = 1.01) and somatic symptoms ( d _z = 0.84). PTSD improvement did not reach significance ( p = 0.08, d _z = 0.44). Follow-up data suggested partial persistence of benefits. No significant changes were found in physiologic outcomes. The intervention was well tolerated and positively evaluated, with mostly mild side effects. Conclusions This study suggests that taVNS combined with slow breathing is feasible and potentially effective, with the most promising effects on insomnia and somatic symptoms. Further investigation in randomized controlled trials is warranted.