Vestibular evoked myogenic potentials

Abstract

Intense clicks evoke short-latency myogenic potentials on the sternocleidomastoid (SCM) muscle ipsilaterally. These potentials are named 'vestibular evoked myogenic potentials (VEMP)' because they are lost after vestibular deafferentation, but independent of the cochlear function. To induce VEMP, the subjects need to contract their SCM muscle during the test. The characteristics of the tuning curve of VEMP are a high threshold and low best frequency. They are similar in animal studies, suggesting that the saccule is the most promising candidate for the origin. Some diagnostic merit has been reported in previous papers. First, there is a discrepancy between VEMP and caloric response in patients with both inner ear and retrolabyrinthine disorders. Therefore, the test battery of these two tests is very useful for diagnosing vertiginous patients. Second, the Tullio phenomenon, the phenomenon of vertigo or loss of balance due to intense sound, is also evaluated by using VEMP. The Tullio phenomenon has been found in patients with various disorders, including congenital syphilis, Meniere's disease and perilymphatic fistula. VEMP are expected to be used in a new vestibular function test to evaluate the neural pathway from the saccule to the SCM muscle.