[1] Univ Newcastle Upon Tyne, Sch Med, Dept Neurol, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England
[2] Univ Halle Wittenberg, Dept Neurol, Halle Saale, Germany
[3] Univ Halle Wittenberg, Teaching Hosp, Berufsgenossenschaftlichen Kliniken Bergmannstros, D-4010 Halle Saale, Germany