1. Multiple Sclerosis Center, Second Department of Neurology, School of Medicine, Aristotle University of Thessaloniki, 54621 Thessaloniki, Greece
2. First Department of Neurology, Aeginition Hospital, National and Kapodistrian University of Athens, 11528 Athens, Greece
3. Department of Neuropsychiatry, Faculty of Medicine, Alexandria University, Alexandria 21311, Egypt