1. Center for Pain and Neuroplasticity, School of Medicine , Aalborg University , Aalborg , Denmark
2. Department of Neuroscience , Rehabilitation, Ophthalmology, Genetics and Maternal Child Health , Genoa , Italy
3. Department of Health Sciences (DISSAL), Section of Biostatistics , University of Genoa , Genoa , Italy
4. Headache Centre, Department of Medicine and Surgery , University of Parma , Parma , Italy
5. Headache Centre , IRCCS, Ospedale Policlinico San Martino , Genoa , Italy