Onabotulinumtoxin A for prophylaxis in chronic migraine: preliminary data from Headache Regional Centre of Aosta Valley.

Chronic migraine (CM) is a complex neurological disorder associated with substantial disability that affects approximately 2 % of general population. Onabotulinumtoxin A is employed for patients suffering from CM refractory to common therapeutic prophylaxis. Since May 2013, we have selected 22 patients referring to our headache centre with a history of CM which meets the diagnostic criteria of ICHD-3 beta (2013).