1. Department of Otorhinolaryngology Head and Neck Surgery, Faculty of Medicine, Hospital Canselor Tuanku Muhriz, National University of Malaysia, Kuala Lumpur, Malaysia
2. Unit of Otorhinolaryngology, Specialist Children’s Hospital of National University of Malaysia, Kuala Lumpur, Malaysia
3. Department of Otorhinolaryngology Head and Neck Surgery, Faculty of Medicine, Universiti Teknologi MARA, Kuala Lumpur, Malaysia