1. Neurology Service, Barzilai Medical Center, Ashkelon, Israel
2. Epidemiology and Genetics Unit, Departnent of Neurology, University of Minnesota, Minneapolis 55455
3. Department of Neurology, Chaim Sheba Medical Center. Tel Hashomer, Israel
4. Departm1ent of Neurology, Hadassah-Hebrew University Hospital. Jerusalem, Israel