中枢性疾患ことに天幕下疾患における眼振の診断的意義—小脳橋角腫瘍を主とする自発眼振（広義）を中心に

　I．はじめに

　前庭系は視器，深部感覚などと共に人の体の平衡を有機的に調節する。したがつてここに何等かの障害が存在すると，自分自身ないしは周囲の異常な運動感・視覚を除いても去らない不快な浮動感・身体の不安定感などが現われる。

　メマイと一般によばれるこのような自覚症状を訴える患者を仔細に検討すると，脳腫瘍・頭部外傷・音響外傷・内耳炎・薬物中毒などの比較的に原因や本体の明らかなものから，他の原因の判然としない不定のものまで種々雑多である。

Vestibular symptoms manifested in 63 cases of infratentorial brain affections were consi-dered in the light of spontaneous nystagmus (broad sense).

There was only 1 cases in which no spont-aneous nystagmus was recognized in the 63.

Nystagmus elicited by change in head-position numbered. 37.

In most of those who showed spontaneous nystagmus in its narrow interpretation the nystagmus was directed to the opposite side of the lesion and horizontal in plane.

On the influence of visual attention that caused nystagmus the cases were divided into 7 general groups according to Kitamura's classification.

Nystagmus caused by change in head-posi-tion is manifested by that in horizontal plane,in alternatingly change in direction and that is fixed in direction ; the largest number bel-onged to the last group. The type that showed alternatingly change the direction of nystag-mus was poined upwards.

Symptoms of cerebello-pontine-angle tumor in thier early stages are manifested, beside the presence of nystagmus, abnormal corneal reflex,nausea and vomiting, disturbed sen-sation of taste and tinnitus. According to the degree of severity these symptoms this disease was divided into V different stages. The aut-hor emphasizes the importance of establishing diagnosis in stage Ⅰ.