迷路性障害にみられた一過性交代性眼振

ALTERNATING NYSTAGMUS OF LABYRINTHINE ORIGIN WITH THE EYES CLOSED

　I．はじめに

　交代性眼振（nystagmus altcrnans）は報告でみる限りいわゆる先天性眼振などの非迷路性疾患に多く，迷路性のものは稀とされているが，われわれは瘻孔症状を伴つた中耳真珠腫症例に正中眼位で自発性にその方向が交代する眼振を認めたのでここに報告し，その成因や非迷路性交代性眼振との差異につき考察を加えたので諸賢のご批判をいただきたい。

　A case of alternating nystagmus found in a body, aged 17, with his eyes closed, is reported.

　This nystagmus was discovered incidently during nystagmography test, since no such a sign was noted with Frenzel's spectacle.

　The period of alternation varied from 40 to 60 sec. The pursuit of the eye movements was smooth and the optokinetic nystagmus fell within normal limits. No other neurological sign was noted.

　Fistula sign was present. And after the radical mastoidectomy, the alternating nystagmus disappeared.

　The principle lesion causing this nystagmus appeared to be located in the lateral semicircular canal and it seemed that the fistula covered by granulation tissues was the causative factor manifesting the alternating nystagmus.

　Other types of alternating nystagmus such as the congenital or those of the cerebellar origin were compared with this nystagmus.