Audiovestibular function in patients with otosclerosis and balance disorders

The aim of this study was to investigate the clinical aspects of balance disorders and to assess the audiovestibular functions of patients with otosclerosis.

Among 13,800 patients examined for balance disorders between 2002 and 2006, 98 (0.7%) presented with otosclerosis. Seventy-three patients (28 treated nonoperatively, 27 operated on unilaterally, and 18 operated on bilaterally for otosclerosis) with an audiovestibular assessment were included in this retrospective study.

Complaints were dizziness in 42 patients (56%), benign paroxysmal positional vertigo in 37 patients (51%), and rotatory vertigo in 21 patients (29%), with no difference between patients operated on and those treated nonoperatively. In patients treated nonoperatively, despite the absence of correlation for hearing loss between the right and left ears, a strong correlation was observed for the bithermic caloric response (BCR; Y = 2.54 + 0.73X, Y = left, X = right, R2 = 0.71, n = 26, p < 0.0001, analysis of variance). In contrast, the correlation between the ipsilateral and contralateral ears in BCR was weak in patients operated on 1 side (Y = 15.1 + 0.66X, Y = contralateral, X = ipsilateral, n = 27, R2 = 0.20, p < 0.05), and this was associated to a caloric paresis suggesting a surgery-induced deficit. There was no correlation between hearing thresholds and the BCR.

The proportion of patients with otosclerosis among those with balance disorders was similar to the estimated prevalence of otosclerosis in the general population. Despite the asymmetric hearing loss, BCR was symmetrical in patients treated nonoperatively. In contrast, the loss of vestibular function symmetry in patients suggested a surgery-induced vestibular trauma.