広域にわたる各周波数純音刺激にてTullio現象を呈した1症例

Tullio Phenomenon Provoked by Pure Tone Stimulation of a Wide Range

　はじめに

　Tullio現象は，音刺激によりめまい感と限振が誘発される徴候で，1924年にTullioがハトの外側半規管に瘻孔を作成した実験において報告して以来^1），本邦においてもENGに本現象を記録した報告が多くなってきている^2）。一般に，Tullio現象は低音域の刺激により限振が誘発されやすいとされており^3,4），高音域でも誘発されたという報告は少ない。

　今回われわれは，オージオメーターの125Hz〜8,000Hzの低音域より高音域にいたる各純音刺激により眼振を認めたTullio現象を示す1症例を経験したのでENG所見をあわせ報告する。

A 43-year-old man developed vertigo when heheard loud sound 10 years after the onset of the tinnitus and a hearing loss of the right ear due to head trauma. Eye movemens were recorded on ENG when each ear was stimulated with the pure tones of 125, 250, 500, 1,000, 2,000, 4,000, 8,000 Hz at the high intensity level. The nystag-mus was elicited only when the right ear with a high tone sensorineural hearing loss was stimula-ted. The nystagmus was horizontal and directed to the stimulated ear. The nystagmus started with one or few seconds delayed to the onset of the tone stimuli, continued as long as the tone stimuli were provided, and discontinued with the cease of the stimulus. This patient also showed a fistula sign on the affected right car. The nystag-mus during the possitive pressure was directed to the stimulating ear, while during the negative pressure was opposite to the stimulated ear.