1. Department of Neurology, Heinrich-Heine-University, Düsseldorf, Germany hans-peter.hartung@ uni-duesseldorf.de
2. Department of Neurology, Heinrich-Heine-University, Düsseldorf, Germany
3. Department of Neurology, Johns Hopkins Hospital, Baltimore, USA
4. Department of Neurology, HeinrichHeine-University, Düsseldorf, Germany