1. From the Department of Neurology, Leiden University Medical Center, Leiden;
2. Department of Clinical Epidemiology, Leiden University Medical Center, Leiden;
3. Department of Neurology, University Hospital Rotterdam, Rotterdam;
4. Department of Pediatric Neurology, University Hospital Rotterdam and Sophia Children's Hospital, Rotterdam;
5. Departments of Neurology, Westeinde Hospital and Juliana Children's Hospital, The Hague;
6. Department of Pediatric Neurology, University Hospital Utrecht and Wilhelmina Children's Hospital, Utrecht; and
7. Department of Pediatric Neurology, St. Elisabeth Hospital, Tilburg, The Netherlands.