[1] Kyushu Univ, Grad Sch Med Sci, Dept Otorhinolaryngol, Fukuoka, Japan
[2] Univ Teacher Educ Fukuoka, Dept Special Needs Educ, Fukuoka, Japan
[3] Univ Nagasaki, Fac Nursing & Nutr, Nagasaki, Japan
[4] Fussa Dai Nana Elementary Sch, Tokyo, Japan
[5] Fukuoka Sanno Hosp, Voice & Swallowing Ctr, Fukuoka, Japan
[6] Adachi Otorhinolaryngol Clin, Fukuoka, Japan
[7] Fukuoka Univ Hosp, Dept Otorhinolaryngol, Fukuoka, Japan
[8] Int Univ Hlth & Welf, Fukuoka, Japan
[9] Kyushu Univ, Grad Sch Med Sci, Dept Otorhinolaryngol, 3 1 1 Maidashi, Higashi ku, Fukuoka 8128582, Japan