Predictive Value of Rectified Vestibular Evoked Myogenic Potential in Determining Lesion Side in Unilateral Vestibulopathy Patients

Son, Hye Ran; Kim, Bong Jik; Rhee, Chung Ku; Jung, Jae Yun

Abstract

BACKGROUND AND OBJECTIVES
Rectified vestibular evoked myogenic potential (rVEMP) is a relatively new method that simultaneously measures the muscle contraction power during VEMP recording and corrects the difference of contraction power afterwards. Several studies showed rVEMP is more reliable than non-rectified VEMP (nVEMP). However, those studies evaluated usefulness of rVEMP in patients with normal vestibular function. Thus, we evaluate the effect of rectification to predict lesion side in unilateral vestibulopathy patients.
MATERIALS AND METHODS
One-hundred nine acute unilateral vestibulopathy patients whom VEMP were performed in were included retrospectively. We regarded hearing loss side as lesion side in sudden hearing loss (n=33), meniere's disease (n=29) and in vestibular neuritis (n=45), the side of positive head thrust test with canal paresis >30% was regarded as a lesion side. We excluded bilateral vestibulopathy. The inter-aural amplitude difference (IAD) ratio was calculated by the nVEMP and rVEMP.
RESULTS
Mismatch rate between nVEMP and rVEMP was 36.61%, match rate was 49.54%, opposition rate was 13.76%. rVEMP predicted lesion side on 15 patients of mismatch group correctly, while nVEMP predicted lesion side on 25 patients of mismatch group. There was no significant difference in IAD ratio between nVEMP and rVEMP in patients who showed lesion side weakness on both nVEMP and rVEMP. But, the younger the patient was, the more chance of mismatch was significantly (p=0.03).
CONCLUSION
There was no more corrective role in determining lesion side by rectification in unilateral vestibulopathy. Thus rVEMP might not be helpful for predicting lesion side in unilateral vestibulopathy.