The Use of Vestibular Test Battery to Identify the Stages of Delayed Endolymphatic Hydrops

Objective. Patients with delayed endolymphatic hydrops (DEH) underwent a vestibular test battery to evaluate the residual function, assess their clinical stage, and predict outcome. Study Design. Case series with chart review. Setting. University hospital. Subjects and Methods. Twenty patients with DEH, 15 with ipsilateral type and 5 with contralateral type, were enrolled. All patients underwent audiometry and caloric, ocular vestibular-evoked myogenic potential (oVEMP), and cervical VEMP (cVEMP) tests. The DEH staging was based on vestibular test results. Stage 0 indicates that all 3 vestibular tests are normal, while stages I through III indicate abnormal results in tests 1 through 3, respectively. Results. Of the 20 DEH patients, 2 patients were stage 0, 12 patients were stage I, 4 patients were stage II, and 2 patients were stage III. The median frequency of vertigo in patients with stages II and III was 4 episodes monthly, significantly less than 15 episodes monthly in those with stages 0 and I. Ipsilateral and contralateral types did not differ significantly in the stage distribution. The percentages of abnormal cVEMP, oVEMP, and caloric test results for patients with ipsilateral type were 80%, 33%, and 13%, not significantly different from those for contralateral type. Conclusions. As a vertiginous attack may subside spontaneously for patients with long-term DEH, one must identify its clinical stage based on cVEMP, oVEMP, and caloric test results. In early stage DEH, most vestibular function remained relatively intact, leading to repeated vertiginous attacks. Conversely, subsidence of vertiginous episode can be anticipated in patients with late stage DEH.