Effect of Elevated Intracranial Pressure on Amplitudes and Frequency Tuning of Ocular Vestibular Evoked Myogenic Potentials Elicited by Bone-Conducted Vibration.

OBJECTIVE: Recently, it could be demonstrated that an increased intracranial pressure causes a modulation of the air conducted sound evoked ocular vestibular evoked myogenic potential (oVEMP). The mechanism for this modulation is not resolved and may depend on a change of either receptor excitability or sound energy transmission.

DESIGN: oVEMPs were elicited in 18 healthy subjects with a minishaker delivering 500 and 1000 Hz tone bursts, in supine and tilted positions.

RESULTS: The study could confirm the frequency tuning of oVEMP. However, at neither stimulus frequency could a modulating effect of increased intracranial pressure be observed.

CONCLUSION: These data suggest that the observed modulation of the oVEMP response by an increased intracranial pressure is primarily due to the effect of an increased intralabyrinthine pressure onto the stiffness of the inner ear contents and the middle ear-inner ear junction. Future studies on the effect of intracranial pressure on oVEMP should use air-conducted sound and not bone-conducted vibration.