Vestibular function in superficial siderosis

BACKGROUND Superficial siderosis (SS) is caused by repeated or continuous bleeding into the subarachnoid space that results in iron from hemoglobin (hemosiderin) being deposited on the surface of the brain. Clinically, the condition is characterized by sensorineural deafness, ataxia, and pyramidal signs. However the mechanism of peripheral vestibular disturbance was not revealed. We show the vestibular function of SS patients, and shed light on saccule-inferior vestibular nerve. METHODS Over the past 9 years, 5 patients were definitively diagnosed with SS by MRI in our department. These patients were subjected to balance testing. RESULTS Vestibular evoked myogenic potential (VEMP) was observed in patients who had suffered from SS for a short period but tended to be diminished or absent in patients who had suffered from the condition for a longer period. CONCLUSIONS These findings in SS patients suggest that saccule-inferior vestibular function is maintained at early stages of the disorder. Our study may help to clarify the mechanism of SS.