1. Neurology Department, Hospital Obispo Polanco, Teruel, Spain
2. Aragon Institute for Health Research (IIS Aragón), Zaragoza, Spain
3. Neurology Department, Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain
4. Danish Headache Center, Department of Neurology, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark