1. Clinical Research Centre, Ministry of Health Malaysia, Hospital Seberang Jaya, Seberang Jaya, Penang, Malaysia
2. Department of Neurology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
3. Department of Family Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
4. Department of Medicine, Hospital Canselor Tuanku Muhriz, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
5. Department of Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
6. Department of Medicine, Ministry of Health Malaysia, Hospital Seberang Jaya, Seberang Jaya, Penang, Malaysia