Vagal Nucleus Connectivity Predicts Percutaneous Electrical Nerve Field Stimulation Treatment Response in Veterans with Fibromyalgia

Abstract

Percutaneous electrical nerve field stimulation (PENFS) is a minimally invasive therapy that involves electrodes placed on the ear through needle arrays to stimulate the auricular branches of the cranial nerves. We hypothesize that PENFS can decrease pain in fibromyalgia through stimulation of the auricular branch of the vagus nerve. We previously published data suggesting a neuromodulatory effect of PENFS in fibromyalgia1, and here we seek to further explore the potential vagal mechanisms. This was a randomized, controlled, open label investigation conducted in a government hospital. Twenty-one veterans with fibromyalgia were randomized to receive either standard therapy or ST with auricular PENFS (ST+PENFS). Seed-based connectivity using a vagal nucleus seed was assessed and correlated to pain scores using the CONN toolbox. Functional connectivity between the vagal nucleus and several clusters in the cuneus and lingual gyri predicted greater decreases in pain for the PENFS treatment group, relative to the standard-care control group. Our results further suggest that connectivity to the vagal nucleus may be predictive of treatment response in fibromyalgia. Future directions include extracting heart rate variability data to further assess the potential effects of PENFS on vagal nerve modulation for pain treatment.