1Headache Unit Neurology Department, Hospital Clínico Universitario Valladolid, Avda. Ramón y Cajal 3, 47005 Valladolid, Spain
2Danish Headache Centre and Department of Neurology, University of Copenhagen, Rigshospitalet Glostrup, Copenhagen, Denmark
3Headache Department, Iranian Center of Neurological Research Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
4Child Neuropsychiatry School, University of Palermo, Palermo, Italy
5U.O. Neuropsychiatry - ARNAS Civico, PO Di Cristina, Palermo, Italy
6Neurology Department, University Hospital of Brussels, Brussels, Belgium
7Headache Center, Bambino Gesù Children Hospital IRCCS, Rome, Italy
8Pavlov First Saint Petersburg State Medical University, Saint Petesburg, Russia
9Almazov National Medical Research Centre, Saint Petesburg, Russia
10Internal Medicine Department, Sant’Andrea Hospital, Rome, Italy
11Regional Referral Headache Centre, Department of Clinical and Molecular Medicine, Sant’Andrea Hospital, Sapienza University, Rome, Italy
12Headache Centre, Careggi University Hospital, University of Florence, Florence, Italy
13Danish Headache Center, Department of Neurology, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
14Department of Clinical Physiology and Nuclear Medicine, Center for Functional and Diagnostic Imaging, Hvidovre Hospital, Copenhagen, Denmark