Ocular and cervical vestibular evoked myogenic potentials produced by air- and bone-conducted stimuli: Comparative properties and effects of age

Objective: To compare amplitudes, latencies, symmetry and the effects of age for both ocular and cervical vestibular evoked myogenic potentials (oVEMPs and cVEMPs) produced by different types of air- (AC) and bone-conducted (BC) stimuli. Methods: Sixty-one normal subjects aged 18-80 years participated. Both reflexes were recorded in response to AC clicks, AC and BC 500 Hz tone bursts, forehead taps and lateral mastoid accelerations. Results: AC tone bursts, clicks and BC tone bursts evoked oVEMPs in 81%, 59% and 65% of ears, respectively. The AC stimuli had higher thresholds for oVEMPs than for cVEMPs and all three stimuli produced higher asymmetry for the oVEMP than for the cVEMP. Forehead taps and lateral pulses evoked oVEMPs in 96% and 92% of cases. AC click-and BC tone burst-evoked oVEMPs showed a significant decline with age. Conclusions: AC stimulation and BC tone bursts delivered to the mastoid are less effective in evoking oVEMPs than in evoking cVEMPs, have high degrees of asymmetry in normals and appear to decline with age. Forehead taps and lateral accelerations produce more symmetrical effects and showed no significant decline with age. Significance: Stimulus properties need to be considered when deciding the most appropriate way to investigate vestibular function using oVEMPs. (C) 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.