1. Department of Neurology, Mayo Clinic, Phoenix, Arizona, USA
2. Headache Science & Neurorehabilitation Unit, National Neurological Institute C. Mondino Foundation, Pavia, Italy
3. Deptartment of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
4. Jefferson Headache Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
5. Division of Neurology, Children’s Hospital of Philadelphia & Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
6. Institute of Public Health, Charité – Universitätsmedizin Berlin, Berlin, Germany
7. Headache Unit, Neurology Department, Vall d’Hebron University Hospital & Headache Research Group, Vall d’Hebron Research Institute, Universitat Autonoma de Barcelona, Barcelona, Spain
8. Danish Headache Center, Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
9. Department of Neurorehabilitation/Traumatic Brain Injury, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
10. Department of Neurology, Department of Epidemiology and Population Health, Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
11. Institute for Medical Informatics, Biometry and Epidemiology, University Duisburg-Essen, Essen, Germany
12. Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands