A study published in the Journal of Headache and Pain, carried out by Dr. Thomas Kinfe of the University of Bonn, found that twice daily stimulation of the vagus nerve with the hand-held gammaCore nVNS device reduced the number of headache days per month from 14.7 to 8.9 (p<0.001) and the number of monthly migraine attacks from 7.3 to 4.5 (p<0.001).
All patients in this study were identified as treatment-refractory, with 50% falling into the class of chronic migraineurs (migraines on 15 or more days per month), with the remaining being episodic (<15 days per month). Among the chronic patients, the number of headache days dropped by a third (18.1 days to 12.1 days, p<0.001), while the episodic patients experienced a 50% reduction (11.3 days to 5.7 days).
Thomas Kinfe, MD the lead author, who is a member of the Division of Functional Neurosurgery and Neuromodulation at the University Hospital Bonn commented:
We found a clinically meaningful response to the three months of prophylactic non-invasive vagus nerve stimulation with significant reductions both in pain intensity and the number of headache days.
The open label trial enrolled twenty refractory patients, defined by a failure to respond to at least four other classes of preventative medication, and treated them for three months. Treatment consisted of self-administration of nVNS using the gammaCore device, which was placed on the neck, over the vagus nerve, and activated for two minutes twice per day.
In this study, patients were also asked to report the intensity of their migraine attacks before and after treatment with nVNS. The median pain intensity, measured using the validated VAS scoring system, dropped from baseline by 50% (8.0 to 4.0, p<0.001) at the end of the study.
The study also examined other important migraine-related symptoms, including sleep disturbance and depression. The results showed that there were clinically meaningful improvements in migraine-associated disability, depression and sleep quality.