1. Department of Otolaryngology-Head & Neck Surgery, Kagawa Rosai Hospital
2. Department of Otorhinolaryngology, the Jikei University School of Medicine
3. Department of Otolaryngology, Kochi Health Sciences Center
4. Department of Otolaryngology-Head & Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
5. Department of Otorhinolaryngology, International University of Health and Welfare, School of Medicine