Otoneurophysiologic diagnosis of vascular disturbances in the central nervous system

103 consecutive patients attending the Visby County Hospital due to vertiginous symptoms were included in the present study. All patients underwent conventional audiometric investigation, brainstem audiometry (ABR), electronystagmography including spontaneous, -gaze-, and positional nystagmus in darkness and under fixation, caloric tests with and without ocular fixation, pendular smooth pursuit test and saccade analyses. Optokinetic nystagmus-test and visual evoked potential recording were performed in some of the patients. Half of the patients underwent CT brain-scan. Abnormal otoneurophysiologic findings suggesting a central origin (pons, mesencephalon, cerebellum) was noted in 55% of the cases. CT brainscan displayed acoustic neuromas in three patients and a cerebellar affection in three patients. Otherwise the CT-scan was normal in the examined patients. In the present investigation the most sensitive tests for diagnosing disorders of central origin resulting in vertiginous symptoms were found to be the brainstem audiometry and smooth pursuit testing. In only two patients the results of the otoneurophysiologic examinations was found to be normal despite a convincing history suggesting a central nervous system disorder.