1. Department of Medicine, Yonsei University College of Medicine, Seoul, South Korea
2. Department of Otorhinolaryngology–Head and Neck Surgery, Yonsei University Wonju College of Medicine, Wonju, South Korea
3. Department of Otorhinolaryngology–Head and Neck Surgery, Soonchunhyang University College of Medicine, Seoul, Korea
4. Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, South Korea