Vagal nerve stimulation as a possible non-invasive treatment for chronic widespread pain in Gulf Veterans with Gulf War Illness

Aims: Widespread pain and headache are common in Gulf War Illness with suboptimal treatments available. We tested the efficacy of non-invasive, transcutaneous vagal nerve stimulation (nVNS) for relief of widespread pain and migraine in Gulf War Veterans with GWI. Main methods: A 10-week double-blind, randomized controlled trial of nVNS used the gammaCore (ElectroCore, Inc.) compared to sham stimulation with the same device followed by a 10-week open-label follow up with active nVNS. The primary outcome was a numerical pain rating at the end of the blinded period. Secondary outcomes included physical function, migraine frequency and severity, and impression of change during the blinded and open-label periods. Two-factor MANOVA models tested for significant differences between groups from baseline to end of the blinded period and during the open-label period. Key findings: Among 27 participants enrolled and issued a nVNS device, there was a slight improvement in pain ratings from baseline to the end of the blinded phase [6.18 (+/- 0.82) vs. 5.05 (+/- 2.3); p = 0.040] which did not differ between active and sham nVNS. Physical function was also slightly improved overall without group differences. There were no significant changes in migraine frequency or severity during the blinded period. Twenty participants started in the open-label phase; no statistically significant changes in pain, physical function, migraine measures, or impression of change were noted during this phase. Significance: Veterans with GWI actively treated with nVNS reported no improvement in either widespread pain or migraine frequency or severity relative to Veterans with GWI who received sham nVNS.