The occlusion effect in bone conducted cVEMP

BACKGROUND: Vestibular evoked myogenic potentials (VEMP) are transient alteration in tonic activity of muscles elicited by auditory stimulation of the otolithic organs of the ear. VEMP can be triggered by auditory stimulation via air or bone conduction. Occlusion of the external auditory meatus has long been known to decrease thresholds for sound perception medicated by the cochlea. OBJECTIVE: Proof that the occlusion effect is present for bone conducted (BC) cervical VEMPs (cVEMP). METHODS: Measurement of the thresholds and raw amplitudes of BC-VEMPs in twenty healthy adults with the external auditory canal open and occluded. RESULTS: Thresholds for BC-VEMPs were similar for the open vs. the occluded condition. However, amplitudes were statistically significantly higher in the occluded (average 76.34μV) vs. open group (average 69.9μV). CONCLUSIONS: The occlusion effect is present in cVEMPs. This finding, described herein for the first time, has a number of clinical implications such as the surgically altered ear and the use of occluding hearing aids.