Vagus nerve stimulation (VNS) with an electrode implanted in the neck is an FDA-approved treatment for depression and epilepsy, when these conditions do not respond to medications. Since antidepressant and anti-epilepsy medications help migraines, I had six patients (four with migraines and two with cluster headaches) treated with VNS. Two of the four chronic migraine patients and both cluster patients had good relief – results that were published in the journal Cephalagia in 2005. This publication led to the development of gammaCore, a device to stimulate the vagus nerve through the skin, without the need for surgical implantation of an electrode. The New York Headache Center participated in one of the earliest studies of this device and the results were encouraging.
An article published in the current issue of Neurology presents the results of another study of gammaCore. In this first double-blind study 59 adults with chronic migraines (15 or more headache days each month) were given either real VNS or sham treatment for two months. After two months they were all given the real treatment for 6 months. The main goal of the study was to examine the safety and tolerability of this treatment, but the researchers also looked at the efficacy by measuring the change in the number of headache days per 28 days and acute medication use.
Both sham and real treatment were well tolerated with most adverse events being mild or moderate and transient. The number of headache days were reduced by 1.4 days in the real and 0.2 days in the sham group. Twenty-seven participants completed the open-label 6-month phase, which suggests that this treatment might work for half of the patients. However, larger sham-controlled studies are needed to prove that this treatment really works. GammaCore is also being tested for the treatment of cluster headaches. Although it has not been definitively proven to be effective, it is already being sold in some European countries.
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