Abnormal Vestibular Evoked Myogenic Potentials in Medial Medullary Infarction

BACKGROUND The medial vestibulospinal tract (MVST), which descends in the medial longitudinal fasciculus (MLF), may mediate the vestibular evoked myogenic potentials (VEMPs) in the contracting sternocleidomastoid muscle. We report herein abnormal VEMPs in a patient with medial medullary infarction (MMI) that appeared to involve the MLF. CASE REPORT A patient with infarction involving the right medial medulla showed decreased p13-n23 amplitude and increased p13/n23 latencies of the VEMPs on the right side. These abnormal VEMPs recorded in an MMI patient support the theory that VEMPs are mediated by the MVST contained within the MLF. CONCLUSIONS VEMPs may represent a valuable tool for investigating vestibular dysfunction originating from the saccule, even in patients with central vestibulopathies, which is not readily defined by conventional vestibular function tests.