1. Hospital Clinico Universitario de Valladolid, Headache Unit, Department of Neurology, Valladolid, Spain
2. Department of Neurology, Hospital General de Albacete, Albacete, Spain
3. Headache Unit, Department of Neurology, Hospital San Carlos, Madrid, Spain
4. Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
5. Universidad Complutense de Madrid, Madrid, Spain
6. Neurology Department, University Hospital “La Paz”, Madrid, Spain
7. La Paz Institute for Health Research (IdiPAZ), Madrid, Spain, Madrid, Spain
8. Headache Unit, Neurology Department, Hospital Universitari Vall d’Hebron, Barcelona, Spain
9. Headache Research Group, Vall d’Hebron Research Institute, Universitat Autónoma de Barcelona, Barcelona, Spain
10. Hospital Universitario de la Princesa, Department of Neurology, Madrid, Spain
11. Valladolid East Primary Care Basic Health Area, Valladolid, Spain
12. Department of Medicine, University of Valladolid, Valladolid, Spain