PENDULAR ROTATORY PATTERN TEST

Abstract

Pendular rotation test was performed on four different visual conditions, a) the subject was directed to; gaze at a fixed target b) to watch stripes instructed as he was rotated c) to close the eyes, and d) to open the eyes behind an eye- patch. In the course of c), the subject was asked to do calculations (c'). The amplitude of pendular rotation was approximately 90°. The period of pendular rotation was _??_5 sec. Ocular deviation was recorded electronystagmo-graphically with a time constant of 6 sec. The speed of eye deviation was simultaneously regis-teredwith a time constant of 0.015 sec. As shown in Fig. I, normal test-subjects showed smooth wave ocular deviations when rotated while gazing at a fixed target. The eye deviation in a) was largest and decreased in the following order, b), c), (c') and d). In b), eye deviation was also large. A nystagmus of a large amplitude was always superim-posed upon the sine wave. In c), eye deviation was less than in b), and about the half of that seen in a). The deviation curve showed a sine-wave configuration when no nystagmus was provoked, which was the case for the majority of the observations. When calculation was imposed (c'), nystagmus was induced. In d), eye deviation was the smallest of all Cases which had peripheral labyrinthine lesions showed generally no different pattern from those of normal recording. Cases with central lesions showed some parti-cular patterns on pendular rotation test which va-ried depending on the cases. In a), some showed nystagmus and saccadic eye tracking. They had a kind of disturbance in oculomotor system. In b), disturbances were not so clearly shown as by optokinetic pattern (OKP) test, probably because the vestibular input assists the reaction. In c), some cases with central lesions showed irregularities in deviation curves. In some cases with central lesions the ocular deviation and total amplitude in c), c) and d) were significantly large. These two characteristics in c) and d), that is, the distortion and the large amplitude of ocular deviation were among the important findings to be looked for in central lesions.