1. Department of Neurology, Heilig Geist-Hospital, Cologne, Germany.
2. Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
3. Department of Neurology, Cologne City Hospitals, Cologne, Germany.
4. Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, Jülich, Germany.