1. Division of Neurology, Department of Medicine, Faculty of Medicine , 50603 Kuala Lumpur, Federal Territory of Kuala Lumpur , Malaysia
2. Department of Pathology, Faculty of Medicine, University of Malaya , 50603 Kuala Lumpur, Federal Territory of Kuala Lumpur , Malaysia
3. Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia , Jalan Lagoon Selatan, Bandar Sunway, 47500 Subang Jaya, Selangor , Malaysia