1. Faculty of Medicine, Department of Paediatrics and Child Health, University of Khartoum, Khartoum, Sudan
2. Faculty of Mathematical Sciences, Department of Statistics, University of Khartoum, Khartoum, Sudan
3. Faculty of Medicine, Department of Medicine, University of Khartoum, Khartoum, Sudan
4. Faculty of Medicine, Department of Psychiatry, University of Khartoum, Khartoum, Sudan
5. Faculty of Medicine, Department of Physiology, University of Khartoum, Khartoum, Sudan
6. Division of Pediatric Neurology, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia