Masamitsu Hyodo1, Yasuo Hisa2, Noriko Nishizawa3, Koichi Omori4, Osamu Shiromoto5, Eiji Yumoto6, Tetsuji Sanuki7, Asuka Nagao8, Kahori Hirose8, Taisuke Kobayashi8, Kento Asano9, Masahiko Sakaguchi10. 1. Department of Otolaryngology, Kochi Medical School, Kohasu, Okou-cho, Nankoku, 783-8505 Kochi, Japan. Electronic address: hyodoma@kochi-u.ac.jp. 2. Kyoto University of Advanced Science, Japan. 3. School of Rehabilitation Sciences, Health Sciences University of Hokkaido, Japan. 4. Department of Otolaryngology, Kyoto University, Japan. 5. Department of Communication Sciences and Disorders, Prefectural University of Hiroshima, Japan. 6. Department of Otolaryngology, Kumamoto University, Japan. 7. Department of Otolaryngology, Nagoya City University, Japan. 8. Department of Otolaryngology, Kochi Medical School, Kohasu, Okou-cho, Nankoku, 783-8505 Kochi, Japan. 9. Integrated Center for Advanced Medical Technologies, Kochi Medical School Hospital, Japan; Academic Clinical Research Center, Department of Medical Innovation, Osaka University Hospital, Japan. 10. Integrated Center for Advanced Medical Technologies, Kochi Medical School Hospital, Japan; Department of Engineering Informatics, Osaka Electro-Communication University, Japan.
Abstract
OBJECTIVES: Spasmodic dysphonia (SD) is a rare disease and its epidemiological status is unclear. This review aimed to explore the current prevalence and clinical features of SD in Japan. METHODS: We reviewed Japanese surveys of SD and compared them to surveys reported from other countries. We focused on SD prevalence, clinical features (SD type, sex and age), and treatment modalities. RESULTS: The SD prevalence in Japan was 3.5-7.0/100,000, similar to that in Rochester (NY, USA) and Iceland. Adductor SD predominated (90-95%) and females were four-fold more likely to be affected than males. Mean age at onset was approximately 30 years in Japan. Several years elapsed from onset to diagnosis. The most frequent treatment was botulinum toxin injection, and surgical intervention, particularly type 2 thyroplasty is becoming more popular. CONCLUSIONS: Our review demonstrated some differences of clinical features of SD in Japan compared with other countries, such as a greater female predominance and younger age of onset. Many physicians and patients may be unfamiliar with the clinical features of SD leading to delayed of diagnosis. Therefore, we proposed diagnostic criteria to facilitate early diagnosis and an appropriate choice of treatment modalities.
OBJECTIVES:Spasmodic dysphonia (SD) is a rare disease and its epidemiological status is unclear. This review aimed to explore the current prevalence and clinical features of SD in Japan. METHODS: We reviewed Japanese surveys of SD and compared them to surveys reported from other countries. We focused on SD prevalence, clinical features (SD type, sex and age), and treatment modalities. RESULTS: The SD prevalence in Japan was 3.5-7.0/100,000, similar to that in Rochester (NY, USA) and Iceland. Adductor SD predominated (90-95%) and females were four-fold more likely to be affected than males. Mean age at onset was approximately 30 years in Japan. Several years elapsed from onset to diagnosis. The most frequent treatment was botulinum toxin injection, and surgical intervention, particularly type 2 thyroplasty is becoming more popular. CONCLUSIONS: Our review demonstrated some differences of clinical features of SD in Japan compared with other countries, such as a greater female predominance and younger age of onset. Many physicians and patients may be unfamiliar with the clinical features of SD leading to delayed of diagnosis. Therefore, we proposed diagnostic criteria to facilitate early diagnosis and an appropriate choice of treatment modalities.