1. From the Department of Neurology, Northwestern University Medical School and Children's Memorial Hospital, Chicago, Illinois, U.S.A.
2. From the King Faisal University, Dammam, Department of Pediatrics, Northwestern University Medical School and Children's Memorial Hospital, Chicago, Illinois, U.S.A.
3. From the King Faisal Specialist Hospital and Research Centre, Riyadh, and Department of Pediatrics and Neurology, Northwestern University Medical School and Children's Memorial Hospital, Chicago, Illinois, U.S.A.