1. Department of Otolaryngology-Head and Neck Surgery, Asahikawa Medical University, Asahikawa, Hokkaido, Japan,
2. Department of Otolaryngology, Oita University Faculty of Medicine, Oita, Japan,
3. Department of Otolaryngology, Niigata University Faculty of Medicine, Niigata, Japan,
4. Department of Otolaryngology, Jichi Medical University Saitama Medical Center, Omiya, Japan,
5. Department of Otolaryngology-Head and Neck Surgery, Tottori University Faculty of Medicine, Tottori, Japan,
6. Department of Otolaryngology, Fukushima Medical University, Fukushima, Japan,
7. Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan,
8. Department of Otolaryngology, Ehime University Faculty of Medicine, Tonoo, Japan,
9. Department of Otolaryngology, Nagasaki University Faculty of Medicine, Nagasaki, Japan,
10. Department of Neuro-otolaryngology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan,
11. Department of Internal Medicine, Juntendo University Koshigaya Hospital, Koshigaya, Japan, and
12. Department of Otolaryngology, Miyazaki University Faculty of Medicine, Miyazaki, Japan