1. Department of Otolaryngology-Head & Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan;
2. Department of Otolaryngology, Kitasato University School of Medicine, Sagamihara, Japan;
3. Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan;
4. Department of Otorhinolaryngology, Saitama School of Medicine, Moroyama, Japan;
5. Department of Otolaryngology, International University of Health and Welfare, Mita Hospital, Tokyo, Japan;
6. Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan;
7. Department of Otorhinolaryngology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan;
8. Department of Otolaryngology, Gunma University Graduate School of Medicine, Maebashi, Japan;
9. Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan;
10. Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan;
11. Department of Otolaryngology, Nagasaki University Faculty of Medicine, Nagasaki, Japan;
12. Department of Otolaryngology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan;
13. Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Japan