1. Otsuka ENT Clinic Yokohama Kanagawa Japan
2. Otorhinolaryngology Shin‐yurigaoka General Hospital Kawasaki Kanagawa Japan
3. Otorhinolaryngology, Nippon Medical School Musashikosugi Hospital Kawasaki Kanagawa Japan
4. Otorhinolaryngology and Head and Neck Surgery Nippon Medical School Tokyo Japan