受動回転と能動回転における代償性眼球運動および固視機能の比較

抄録

Compensatory Eye Movement and Gaze Fixation During Active Head Rotation and Passive Head-and-Body Rotation Compensatory eye movement and gaze fixation were compared between passive head-and-body rotations with a rotatory chair and active head rotations (amplitude 40°, frequency 0.2-0.85Hz) using 20 normal subjects. After establishing the control data, passive head rotations were undertaken on patients with unilateral and bilateral loss of labyrinthine function.
The following results were obtained from the control group.
1. At some frequencies, the ratio of the slow-phase eye speed to the corresponding head rotation speed (gain) while doing mental arithmetic in the dark was larger during active than passive rotations. However, there was a large variation among the subjects.
2. Visual fixation on a lamp on the wall was complete under both conditions.
3. Visual fixation on a lamp fixed to the subject's head became poorer by increasing the turning frequency of the head. The fixation was slightly but significantly better during passive than active rotations.
The following results were obtained from five patients with unilateral lesions in the early stage of the disease and six patients with bilateral lesions.
1. Patients with unilateral lesions showed quite different values of gain in the dark when the direction of the head rotation was shifted. The values during rotations to the affected side resembled those in bilateral lesions.
2. Visual fixation on a lamp on the wall was well maintained during rotations to the intact side in patients with unilateral lesions. However, it worsened during rotations to the affected side and in patients with bilateral lesions with increasing frequency.
3. Visual fixation on a lamp fixed to the head worsened with an increase of frequency during rotations to the intact side in unilateral lesions. Rotations to the affected side in unilateral lesions and bilateral lesions showed a good gaze fixation even at 0.85Hz.
4. Pathological findings of compensatory eye movement and gaze fixation during passive rotations resembled those found in active head rotations. Thus, a passive sinusoidal rotation test is a good clinical tool for detecting disorders of the vestibulo-ocular reflex.