BILATERAL MONDINI DYSPLASIA WITH NORMAL-HEARING

A 37-year-old man with both Mondini dysplasia and normal hearing is re ported. The patient visited our clinic with a complaint of unsteadines s. Pure-tone audiometry showed a normal hearing level in both ears. Po lytomography and computed tomography (CT) revealed enlargement of the vestibules and lateral semicircular canals in both ears but a normal s hape of the cochlea and other semicircular canals. The caloric test in dicated severe canal paresis (CP) in the left ear and moderate CP in t he right ear, whereas the active head rotation test demonstrated that head-eye coordination was preserved at frequencies of 0.33 and 0.67 Hz but slightly deteriorated at 1.0 Hz. The patient's unsteadiness seeme d to be attributable to a hypofuncion of the bilateral semicircular ca nals, which may be due to insidious, repeated cerebrospinal fluid otor rhea caused by judo wrestling. Although Mondini dysplasia with normal hearing has been believed to be rare, phylogenetic consideration sugge sts that more such patients exist than has been assumed.