1. Headache Centre, Careggi University Hospital, Department of Health Sciences, University of Florence, Florence, Italy
2. Regional Headache Referral Center, Department of Neurology, University of L’Aquila, L’Aquila, Italy
3. IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
4. Department of Medical, Technological and Translational Sciences, Headache Centre, University of Trieste, Trieste, Italy
5. Regional Referral Headache Centre, Sant’Andrea Hospital, Department of Clinical and Molecular Medicine, Sapienza University, Rome, Italy
6. Headache and Drug Abuse Research Centre, Policlinico Hospital, Department of Diagnostic Medicine, Clinical and Public Health, University of Modena e Reggio Emilia, Modena, Italy
7. Headache Centre, Department of Medical, Surgical, Neurological, Metabolic and Ageing Sciences, University of Campania “Luigi Vanvitelli”, Naples, Italy