[Vestibulo-visual interaction in peripheral lesion of vestibular organ]

Studies were carried out on 32 persons between 38 and 54 years of age (average 45) with unilateral peripheral lesion function of the vestibular organ (among them 8 persons with complete lack of excitability) and 10 healthy persons between 23 and 42 years of age (average 32). All of the patients were examinated for vestibulo-visual interaction. With the help of electronystagmography, the eye movement was registered after visual stimulation, vestibular stimulation and simultaneous vestibulo-visual stimulation, with impulses evoking nystagmus of direction compatible and incompatible. Movement of black stripes on the white optokinetic screen with the velocity of 15 degrees/s, to the left and to the right, was visual stimulus. Vestibular organ was activated by cold water (30 degrees C), according to the Fitzgerald Hallpike's procedure. Nystagmus reaction was evaluated in the highest intensification on the basis of the mean velocity of the slow faze, amount of nystagmus deflexion, sum of amplitudes, as well as gain. We also took into account compatibility or incompatibility of the nystagmus directions which was induced by the simultaneous of the vestibulo-visual stimulation. It has been stated that the vestibulo-visual interaction in the unilateral peripheral lesion of vestibular organ does not differ in comparison with healthy persons. Besides, simultaneous vestibulo-visual stimulation induced by the impulses incompatible in their direction causes the decrease of the parameters value of the nystagmus in healthy persons and in persons with peripheral lesion of labyrinth. In the case of one-sided fall-out function of the vestibular organ an increase was observed of value gain of optokinetic nystagmus directed at the damaged side.