1. Department of Neurology, Aarhus University Hospital, 8200 Aarhus, Denmark
2. Department of Clinical Medicine, Aarhus University, 8200 Aarhus, Denmark
3. Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
4. Harvard Medical School, Boston, MA 02115, USA
5. Research Unit for Neurology, Odense University Hospital, University of Southern Denmark, 5000 Odense, Denmark