Chia-Chun Chen1,2, Chin-Kuo Chen3. 1. Department of Otolaryngology, Chi Mei Medical Center, Tainan, Taiwan. 2. Department of Medical Education, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan. 3. Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan.