Impaired Vagal Efficiency Predicts Auricular Neurostimulation Response in Adolescent Functional Abdominal Pain Disorders.

To determine whether pretreatment vagal efficiency (VE), respiratory sinus arrhythmia, and heart period can predict pain improvement with auricular neurostimulation in pediatric functional abdominal pain disorders. A total of 92 adolescents with functional abdominal pain disorders underwent a 4-week randomized, double-blinded, sham-controlled auricular neurostimulation trial. Electrocardiogram-derived variables at baseline were used to predict pain using mixed effects modeling. A 3-way interaction (95% confidence intervals: 0.004-0.494) showed that the treatment group subjects with low baseline VE had lower pain scores at week 3. There was no substantial change in the placebo or high VE treatment group subjects. This effect was supported by a significant correlation between baseline VE and degree of pain reduction only in the treatment group. Impaired cardiac vagal regulation measured by VE predicts pain improvement with auricular neurostimulation.