P038. Effects of non-invasive vagus nerve stimulation on cerebral vasomotor reactivity in patients with chronic migraine during intercritical phase: a pilot study

Abstract

We enrolled 20 patients aged between 18 and 65 years, suffering from chronic migraine and 20 healthy non- migraineur subjects matched for demographic character- istics. None of them assumed vaso-reactive drugs for at least 30 days before registration. Subjects enrolled underwent registration of blood flow velocity in the middle cerebral artery bilaterally through transcranial Doppler (TCD), in the morning and fasting from food and caffeine. The monitoring was performed at baseline, during and after apnea lasting 30 seconds. After the recording, the subjects underwent external sti- mulation of the vagus nerve with “Gammacore” device for 90 seconds, and 20 minutes after we once again registered VMR through apnea test. VMR was calculated by means of Breath holding index according to the fol- lowing formula [4]: VMR/apnea duration in seconds. Preliminary results No statistically significant differences emerged comparing VMR before and after VNS in our population, irrespective of groups. No patient suffered from adverse event during or after VNS. Conclusions Non-invasive VNS resulted safe and did not seem to influ- ence VMR, neither in migraineurs nor in healthy volun- teers. However, the small sample of our study population does not allow to draw definitive conclusions, hence the study will be further continued to extend sample size. Written informed consent to publication was obtained from the patient(s).