1. Department of Hygiene, Public Health and Preventive Medicine, School of Medicine, Showa University, Tokyo 142-8555, Japan
2. Division of Oral Functional Rehabilitation Medicine, Department of Special Needs Dentistry, School of Dentistry, Showa University, Tokyo 145-8515, Japan
3. Department of Radiology, Division of Radiation Oncology, School of Medicine, Showa University, Tokyo 142-8555, Japan
4. Division of Respiratory Medicine and Allergology, Department of Medicine, School of Medicine, Showa University, Tokyo 142-8555, Japan
5. Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, Showa University, Tokyo 142-8555, Japan