1. Division of Otorhinolaryngology, Sendai Municipal Hospital, Sendai, Japan.
2. Department of Anatomy and Embryology II, Faculty of Medicine, Complutense University, Madrid, Spain.
3. Division of Internal Medicine, Iwamizawa Kojin-kai Hospital, Iwamizawa, Japan.
4. Laboratory of Rehabilitative Auditory Science, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan.
5. Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan.