Assessing residual vestibular function in adults with congenital hearing loss

This study adopted an inner ear test battery in adults with congenital hearing loss to assess residual vestibular function. Thirty patients with non-inherited non-syndromatic congenital hearing loss were assigned to two groups based on their pure tone average (PTA). Subjects in Group A (n = 10) had PTA >90 dB, and those with PTA ≤90 dB were assigned to Group B (n = 20). All patients underwent audiometry, and ocular vestibular-evoked myogenic potential (oVEMP), cervical VEMP (cVEMP) and caloric tests. Percentages of abnormal PTA, and cVEMP, oVEMP, and caloric test results showed a significantly sequential decline in inner ear deficits from the cochlea to the saccule, utricle, and semicircular canals. Group A had significantly higher percentages of absent oVEMP and caloric areflexia than Group B. Via receiver operating characteristic curve analysis, the cutoff value of PTA was 65 dB for discriminating between present and absent oVEMP/caloric responses, with a sensitivity of 71 % and a specificity of 88 %. In conclusion, congenitally deaf patients with PTA ≥65 dB may retain less vestibular function than those with PTA <65 dB, as evidenced by higher percentages of absent oVEMP and caloric areflexia. Hence, comprehensive assessment of the residual vestibular function in congenitally deaf patients may help predict the occurrence of vertigo in the future.