1. Department of Neurology University Hospital Zurich Zurich Switzerland
2. The Danish Headache Center Rigshospitalet‐Glostrup Faculty of Health Sciences University of Copenhagen Glostrup Denmark
3. Headache Unit Department of Neurology Hospital Clínico Universitario de Valladolid Valladolid Spain
4. Department of Neurology Akershus University Hospital Oslo Norway
5. Department of General Practice University of Oslo Oslo Norway
6. Department of Neurology Johns Hopkins University Baltimore MD USA
7. Department of Anesthesiology and Critical Care Medicine Johns Hopkins University Baltimore MD USA
8. Center for Neurology Asklepios Hospitals Schildautal Seesen Germany
9. Department of Neurology University of Duisburg‐Essen Essen Germany
10. Departement of Neurology and Neurorehabilitation RehaClinic Group Bad Zurzach Switzerland
11. Department of Neurology Inselspital Bern University Hospital University of Bern Bern Switzerland
12. Metabolic Neurology Institute of Metabolism and Systems Research College of Medical and Dental Sciences University of Birmingham Birmingham UK
13. Department of Neurology University Hospitals Birmingham NHS Foundation Trust Birmingham UK
14. Department of Neurology Elisabeth‐TweeSteden Hospital Tilburg the Netherlands