1. Department of Neurology, University Hospital Schleswig-Holstein, Kiel
2. Department of Neurosurgery, University Hospital Schleswig-Holstein, Kiel
3. Department of Neurosurgery, University Hospital Schleswig-Holstein, Lübeck
4. Department of Neurosurgery, Medical School Hannover, Hannover, Germany
5. Department of Neurosurgery, SHG-Klinik, Idar-Oberstein
6. Department of Neurology, University of Essen, Essen