1. Department of Otorhinolaryngology and Head & Neck Surgery, Dankook University Hospital, Cheonan, Chungnam, Republic of Korea
2. Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
3. Brain Research Institute, College of Medicine, Chungnam National University, Daejeon, Republic of Korea