1. Department of OtorhinolaryngologyMyunggok Medical Research Institute, Konyang University HospitalKonyang University College of Medicine Daejeon South Korea
2. Department of OtorhinolaryngologySoonchunhyang University College of Medicine Cheonan South Korea
3. Department of OtorhinolaryngologyInstitute of Logopedics and Phoniatrics, Yonsei University College of Medicine Seoul South Korea