1. Institute for Medical Informatics, Biometry and Epidemiology (IMIBE), Department of Neuroepidemiology, University Duisburg-Essen, Essen, Germany
2. Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
3. Headache Science & Neurorehabilitation Centre, IRCCS C., Mondino Foundation, Pavia, Italy
4. Department of Neurology, Mayo Clinic, Phoenix, Arizona
5. Atria Institute, New York, New York