1. Headache Outpatient Clinic, Department of Neurology, ‘Agios Andreas’ State General Hospital of Patras, Patras, Greece
2. Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
3. 1st Department of Neurology, Aeginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
4. Headache Clinic, Mediterraneo Hospital, Glyfada, Greece