1. Academic Medical Centre, University of Amsterdam; Department of Neurology; Meibergdreef 9 PO Box 22700 Amsterdam Netherlands 1100 DE
2. Queen Elizabeth Hospital; Department of Neurology; Edgbaston Birmingham UK B15 2TH
3. University of Amsterdam; Department of Neurology, Academic Medical Centre; Meibergdreef 9 Amsterdam Netherlands 1105 AZ
4. Academic Medical Centre, University of Amsterdam; Clinical Epidemiology and Biostatistics; PO Box 22700 Amsterdam Netherlands 1100 DE