Ocular and cervical vestibular-evoked myogenic potentials to bone conducted vibration in Meniere's disease during quiescence vs during acute attacks

Objective: Two indicators of otolithic function were used to measure dynamic otolith function in the same patients both during an acute attack of Meniere's disease (MD) and in the quiescent period between attacks. Methods: The early negative component (n10) of the ocular vestibular-evoked myogenic potential (the oVEMP) to brief 500 Hz bone conducted vibration (BCV) stimulation of the forehead, in the midline at the hairline (Fz) was recorded by surface EMG electrodes just beneath both eyes while the patient looked up. It has been proposed that the n10 component of the oVEMP to 500 Hz Fz BCV indicates utricular function. It has been proposed that the early positive component (p13) of the cervical vestibular-evoked myogenic potential (the cVEMP) recorded by surface electrodes on both tensed SCM neck muscles to 500 Hz Fz BCV indicates saccular function. Results: Sixteen healthy control subjects tested on two occasions showed no detectable change in the symmetry of oVEMPs or cVEMPs to 500 Hz Fz BCV. In response to 500 Hz Fz BCV 15 early MD patients tested at both attack and quiescent phases showed a dissociation: there was a significant increase in contralesional of n10 of the oVEMP during the attack compared to quiescence but a significant decrease in the ipsilesional p13 of the cVEMP during the attack compared to quiescence. Conclusions: During an MD attack, dynamic utricular function in the affected ear as measured by the n10 of the oVEMP to 500 Hz Fz BCV is enhanced, whereas dynamic saccular function in the affected ear as measured by the p13 of the cVEMP to 500 Hz Fz BCV is not similarly affected. Significance: The MD attack appears to affect different otolithic regions differentially. (C) 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.