[The phenomenon of the fixation suppression of caloric nystagmus in the diagnosis of vestibular disorders].

Fixation nystagmus suppression in caloric tests was used in examination of 56 patients suffering from chronic remittent labyrinthopathy, acute labyrinthopathy, vestibular neuronitis, otosclerosis, adhesive otitis media, vertebrobasilar insufficiency, motor disease, chronic remittent vestibulopathy and neurinoma of the VIII nerve. The bithermal test (BT) with electronystagmography was made to calculate the fixation suppression index (FSI). Complete suppression of the caloric nystagmus in at least one BT test appeared to be the most frequent variant of the response (24 cases). This was not dependent on the severity of the vestibular analyzer lesion. In 3 cases FSI of the caloric nystagmus was rather high (> 0.50). Introduction of the period of glance fixation in performance of all the 4 BT tests may serve an additional method in differential diagnosis of the vestibular disorders. The fixation test results should be compared to findings obtained in the other vestibulometric tests.