Bilateral Vestibulopathy and Vestibular function test

Lee, Geun Ho; Kim, Jae Il; Jeong, Pil Seob; Jeon, Beom Seok; Lee, Kwang Woo

Abstract

BACKGROUND AND OBJECTIVES: 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. Method : 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 fequencies during ROT, we evaluated their VFT results and clinical features.
RESULTS
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. CBP 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.
CONCLUSION
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.