Background and Objectives:
@EN Many authors (Simmons, 1973, McGath et al., 1989) described that a small percentage(1-2%) of patients initially complaining of vertigo was found to have bilateral vestibular failure (BLVF). This study evaluates the findings of vestibular
function
test(VFT) including rotating chair test(ROT) and computerized dynamic posturography test (CDP) in the patients with BLVF demonstrated by caloric test and others.
@ES Method:
@EN 400 vertigo patients were given VFT from June, 1994 to October, 1995. In the patients who had absent or reduced responses (total eye speed <10 degrees per second) in cold<17 C) water caloric testing or decreased responses in the range of
lower
frequencies during ROT, we evaluated their VFT results and clinical features.
@ES Results:
@EN There were 38 cases out of total 400 patients (9.5%). Many patients with BLVF had rotational response magnitudes (at 0.04 Hz and above) that were within normal limits. CDP has shown vestibular dysfunction patterns in 32 patients. Hearing
tests
were
normal in 9 cases and mixed hearing loss in 2 cases. Many patients experienced several episodes of acute vertigo with persistent imbalance; Only 4 patients complained of persistent oscillopsia. Viral infection (vestibuloneuronitis), immune
reactions and
toxic factors may play a role in the etiology of this rare BLVF.
@ES Conclusion:
@EN Our incidence of 9.5% is much higher than what was reported in the literature. Herb medications and frequent injections of aminoglycosides may be responsible for this higher incidence of BLVF. ROT is useful in detecting and predicting the
remaining
vestibular function in the BLVF patients.
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