Conclusion: Patients with sudden deafness who had abnormal ocular vestibular-evoked myogenic potential (oVEMP)/cervical VEMP (cVEMP) responses but retained caloric function may subsequently develop secondary hydrops with a mean interval of 8 years.
Objective: This study applied the inner ear test battery in patients who had sudden deafness previously to elucidate how secondary endolymphatic hydrops occurs years after sudden deafness.
Methods: Twenty patients who had experienced recent vertiginous attacks several years after sudden deafness (group A) and 20 patients without rotational vertiginous episode for at least 5 years following sudden deafness (group B) were enrolled. All patients underwent an inner ear test battery comprising audiometry, caloric test, and oVEMP and cVEMP tests.
Results: The mean interval from initial sudden deafness to vertiginous attack in group A was 8 years, with a mean hearing level of 66 ± 20 dB, which did not significantly differ from 61 ± 20 dB in group B. For the vestibular test results, the percentages of abnormal cVEMP, oVEMP, and caloric tests in group A were 65%, 70%, and 25%, respectively. Compared to the respective 70%, 60%, and 75% abnormalities in group B, only the caloric test differed significantly.