1. Department of Neurology, University Hospital Essen, Essen, Germany
2. Headache Science Center, IRCCS Mondino Foundation, Pavia, Italy
3. Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
4. Department of Neurology, Mayo Clinic, Phoenix, AZ, USA
5. Jefferson Headache Center, Thomas Jefferson University, Philadelphia, PA, USA
6. Montefiore Headache Center, Department of Neurology and Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY, USA
7. Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
8. Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
9. Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
10. Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
11. National Institute for Health Research Wellcome Trust King's Clinical Research Facility, King's College London, London, England
12. Headache Research Group, Vall d'Hebron Institute of Research, Universitat Autònoma de Barcelona, Barcelona, Spain
13. Headache & Craniofacial Pain Unit, Neurology Department, Hospital Universitari Vall d'Hebron, Barcelona, Spain
14. Neurological Institute, Taipei Veterans General Hospital and Brain Research Center, National Yang-Ming University, Taipei, Taiwan
15. Department of Health Sciences Research, Mayo Clinic Rochester, MN, USA