Visual-vestibulo-ocular interactions in patients with peripheral vestibular disorders.

In order to evalute the interation of visual with vestibular systems in 131 patients with peripheral vestibular disorders, the vestibulo-ocular reflex (VOR) gain and the visual-vestibuloocular reflex (VVOR) gain were analyzed by a mini-computer (PDP 11/34). Pendular harmonic sinusoidal rotation and optokinetic stationary stimuli were used. The patients were rotated sinusoidally in an illuminated OK drum at an amplitude of 120°and a frequency of 0.1Hz (maximum velocity 75.4°/s), both with eyes closed (VOR) and open (VVOR).The results obtained were as follows.1. VVOR responses in peripheral patients were usually normal, whereas a VOR-DP with normal VVOR gain was more frequently observed in patients with definite Meniere's disease and in those with sudden deafness accompanied by vertigo or dizziness.2. VOR-DP was highly correlated with caloric CP and DP, and tended to be associated with the intact vestibular side.3. In most peripheral patients, spontaneous nystagmus and VOR-DP showed the same direction and this fact can be useful in differential diagnosis with reference to CNS disorders.4. The rate of decreased VOR-gain paralleled the decline of the patient's condition. The VOR and VVOR test battery constitutes an effective method in the evaluation of vestibular compensation.