[1] Hashima City Hosp, Dept Otolaryngol, Gifu, Japan
[2] Gifu Univ, Grad Sch Med, Dept Physiol, Div Biol Principles, Gifu, Japan
[3] Gifu Univ, Grad Sch Med, Dept Otolaryngol Head & Neck Surg, Gifu, Japan
[4] Osaka Univ, Grad Sch Med, Dept Otorhinolaryngol Head & Neck Surg, Osaka, Japan
[5] Int Univ Hlth & Welf, Tokyo Voice Ctr, Tokyo, Japan
[6] Hashima City Hosp, Dept Radiol, Gifu, Japan
[7] Jichi Med Univ, Sch Med, Dept Otolaryngol Head & Neck Surg, Shimotsuke, Tochigi, Japan
[8] Hashima City Hosp Gifu, Dept Otolaryngol, 3-246 Shinsei Town, Hashima city, Gifu 5016206, Japan