抄録
A man, suffering from hypertension, was affected by dizziness and nausea. These symptoms disappeared in a week under medical treatment.
Six or seven years later, the patient again had severe vertigo, nausea and vomiting again. After this attack, he complained of continuous dizziness. Infarction of the inferior left cerebellar hemisphere was detected by MRI, but no abnormal image was found in the medial part of the cerebellum.
We recognized no neurological signs caused by dysfunction in the cerebellar hemisphere, intension tremor, dyssynergy, etc., but severe disequilibrium was confirmed by Romberg's test, Mann's test and in the squatting position.
In the sitting position, the patient did not exhibit gaze nystagmus, but through Frenzel's glasses we recognized downbeat nystagmus in the right and left eye position. In the supine position with his head hanging down, the patient showed spontaneous downbeat nystagmus. This nystagmus increased with gazing, decreased without gazing and included high frequency pendular-saccadic movements. Caloric nystagmus was well developed in both ears, and visual suppression was also good. A horizontal eye tracking test (ETT) showed smooth eye movements and optokinetic nystagmus (OKN) was well developed.
These otoneurologic findings indicated that 1) there was no difference between right and left eye vestibular functions, 2) his brain stem function was not damaged, 3) neurological lesions were present in the medial part of the cerebellum, flocculus, nodules and vermis. These findings disagreed with those of MRI imaging, suggesting that the medical imaging has its limitations in demonstrating lesions of the central nervous system.
This case showed us that diagnosis of disequilibrium should be based not only on results of medical imaging, but also on otoneurological findings.
