頭位変化時にみられる眼振（頭位変化眼振）に関する研究—眼振のうち方を中心にみた鑑別診断的意義

　はじめに

　前庭系の障害を他覚的に示す所見のひとつに眼振がある。このなかで，頭位変化眼振は末梢前庭性疾患はもちろん，いろいろの中枢性疾患にともなつて観察されることも多い。また本年はBaselにおけるActa otolaryngologicaの主催するGremiumでもこの問題はEwaldの第二法則と共にとりあげられ欧州の諸家が討論をかさねているところである。

　われわれはさきに頭位変化眼振の検査法と分類について提案し^1），さらに興味深い個々の症例をあげてこれを考察すると共にこの眼振検査の重要性を強調した^2）。

One hundred and thirty eight cases of diagnostically positive nystagmus due to po-sitional change of head were analysed for the relation between the character of the nystagmus and the seat of the lesion.

1 Generally when the nystagmus is slight and the attack is noted by absence of spon-taneous one the lesion may be located in the labyrinthine system, which is provoked by phenomenon of stress such as a sudden cha-nge in the position of the head or body.

2 Whenever a vertical nystagmus or that of deep oscillation is elicited by dynamic test particularly by those advanced by Strenger or by Dix-Hallpike the lesion would be pointed to be located in either the cerebellum or the brain-stem. Moreover, when such symptoms are unaccompanied by either spo-ntaneous nystagmus or other symptoms of cerebral irratations, the results of this test is highly significant in reaching an early diagnosis.

3 When rotatory or mixed nystagmus is shown by dynamic test labyrinthine disturb-ance should he considered as a prime factor.

4 The concept that labyrinthine nystagm-us elicited below level of the lesion is direc-ted below is not always true ; depending upon the stage of development its direction may be indefinite.