1. Headache Center, San Lazzaro Hospital, Azienda Sanitaria Locale CN2, Alba, CN, Italy.
2. Clinical Epidemiology Unit, Liver Research Center, Basovizza, TS, Italy.
3. Laboratory, San Lazzaro Hospital, Azienda Sanitaria Locale CN2, Alba, CN, Italy.
4. Neurology Department, San Giacomo Hospital, ASL Alessandria, Novi Ligure, AL, Italy.
5. Direction, San Lazzaro Hospital, Azienda Sanitaria Locale CN2, Alba, CN, Italy.