1. Academic Medical Centre, University of Amsterdam; Department of Neurology; Meibergdreef 9 PO Box 22700 Amsterdam Netherlands 1100 DE
2. University Medical Centre Utrecht; Department of Neurology; Rudolf, Magnus Institute of Neuroscience, Heidelberglaan 100 PO Box 85500 Utrecht Netherlands 3508 GA
3. Academic Medical Centre, University of Amsterdam; Clinical Epidemiology and Biostatistics; PO Box 22700 Amsterdam Netherlands 1100 DE
4. University of Amsterdam; Department of Neurology, Academic Medical Centre; Meibergdreef 9 Amsterdam Netherlands 1105 AZ