1. Headache Centre, Careggi University Hospital, Health Sciences Department, University of Florence, Florence, Italy
2. Headache Centre, Careggi University Hospital, University of Florence, Florence, Italy
3. Medical Toxicology, Headache and Drug Abuse Center, University of Modena and Reggio Emilia, Modena, Italy
4. Regional Referral Headache Centre, Sant’Andrea Hospital, Department of Clinical and Molecular Medicine, Sapienza University of Rome, Rome, Italy