About 1000 CEFALY users, having the device since more than one year and having reordered electrodes in the last year, will be invited to participate to an Internet survey. This survey contains at most 8 questions, and data will be collected completely anonymously. Questions concern the use or not of the CEFALY during migraine attacks, the number of treated attacks and the number and type of acute anti-migraine drugs that were avoided thanks to the use of the CEFALY.
