Abstract
Patients with unilateral vestibular deficits (31 with vestibular neuronitis : 39 with sudden deafness : 19 with Meniere's disease) were examined periodically for positional nystagmus and caloric nystagmus.
1) Vestibular neuronitis : On the first examination, positional nystagmus directed, to the healthy side was observed in all patients. Nystagmus disappeared gradually, but 20% had nystagmus even 1year after onset.
Caloric CP was observed in 76% of the patients who were examined at the time of the first attack, and in 100% of those examined within a week after onset. Caloric CP recovered almost in parallel with the disappearance of positional nystagmus.
2) Sudden deafness : Positional nystagmus disappeared gradually with a tendency to change direction in some cases. In the early period, positional nystagmus in most cases was directed to the healthy side, and that nystagmus disappeared earlier than did the nystagmus of vestibular neuronitis.
Caloric CP was observed in 8% of the patients with sudden deafness.
3) Meniere's disease : The direction of positional nystagmus changed irregularly and did not disappear with time.
None of the 17 patients with Meniere's disease showed caloric CP.
