Augmentation of vestibular evoked myogenic potentials: an indication for distended saccular hydrops.

OBJECTIVE/HYPOTHESIS: Vestibular evoked myogenic potential (VEMP) testing has become a well-established test to explore the sacculo-collic pathways in human. The aim of the present study is to establish a clinical indication for saccular hydrops by VEMP testing.

STUDY DESIGN

Prospective study.

METHODS

Ten patients (three men and seven women) with Meniere's disease and 10 patients (four men and six women) with sudden deafness were admitted and given pure-tone audiometry and VEMP testing daily. Interaural amplitude difference over the sum of amplitudes of both ears was measured, and when the ratio exceeded 0.36, the test result was coined "augmented VEMP."

RESULTS

During admission, three hydropic ears presented with augmented VEMP test results, with increased interaural amplitude difference ratio (mean difference ratio, 0.40+/-0.03). Seven hydropic ears had steady VEMP test results, with a mean interaural amplitude difference ratio of 0.15+/-0.07. Compared with the normal control ears, all had steady VEMP test results, with a mean interaural amplitude difference ratio of 0.14+/-0.11, which is significantly different from the hydropic ears with augmented VEMP test results (P <.05). In another 10 patients with sudden deafness, all had positive steady VEMP test results, with their mean interaural amplitude difference ratio of 0.14+/-0.12, which is similar to that in the control ears.

CONCLUSIONS

Augmented VEMP test results are an indication of distended saccular hydrops, whose distended wall is in contact with the footplate. VEMP testing may be beneficial in differentiating the initial stage of Meniere's disease and sudden deafness.