歌手にみられた外転型痙攣性発声障害

抄録

Spasmodic dysphonia (SD) is a focal dystonia that affects the larynx. Abductor SD (ABSD) is less common than adductor SD (ADSD). ABSD is typified by breathy breaks in connected speech.
A male professional classic baritone singer, age 46, presented with gradually increasing breathy unphonated breaks in singing over the course of three years. He visited various institutions and was said to have incomplete elevation of the soft palate of unknown origin, myasthenia gravis, etc. His symptoms were remarkable in pronouncing vowels following unphonated consonants. He had been exposed to neither vocal abuse nor heavy singing performances. Our diagnosis was ABSD. An injection of Botulinum toxin (BT) into the posterior cricoarytenoid muscles was done via lateral cervical approach. His voice improved remarkably. His daily conversation became smooth; however, he could not regain his previous brilliant singing voice. He was obliged to discontinue his professional singing performances.