1. Department of Otolaryngology-Head & Neck Surgery, Iwate Medical University, Morioka, Japan;
2. Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan;
3. Department of Otolaryngology-Head and Neck Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan;
4. Department of Otolaryngology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan;
5. Department of Otolaryngology, Ehime University School of Medicine, Toon, Japan;
6. Department of Otorhinolaryngology, Saitama School of Medicine, Moroyama, Japan;
7. Department of Otolaryngology, Hospital, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan;
8. Department of Otolaryngology, International University of Health and Welfare, Mita Hospital, Tokyo, Japan;
9. Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan;
10. Department of Otorhinolaryngology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan;
11. Department of Otolaryngology, Gunma University Graduate School of Medicine, Maebashi, Japan;
12. Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan;
13. Department of Otorhinolaryngology, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan;
14. Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmacy, Okayama, Japan;
15. Department of Otorhinolaryngology Head and Neck Surgery, Keio University School of Medicine, Tokyo, Japan;
16. Department of Otolaryngology, Kitasato University School of Medicine, Sagamihara, Japan;
17. Department of Otorhinolaryngology, Nagoya University, Graduate School of Medicine, Nagoya, Japan;
18. Department of Otorhinolaryngology, Head and Neck Surgery, University of Toyama, Toyama, Japan;
19. Department of Otolaryngology, Nagasaki University Faculty of Medicine, Nagasaki, Japan;
20. Department of Otolaryngology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan;
21. Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan;
22. Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan