Equilibrium and vertigo exam
VNG (Videonystagmography)
vHIT (video Head Impulse Test)
VEMP (Vestibular Evoked Myogenic Potential)
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VEMP (Vestibular Evoked Myogenic Potential)
The great feature of VEMP is its ability to test the function of the saccule and utricle. These two otolithics structures detect linear movements. If the VNG and vHIT give us information about the function of the semicircular canals, the VEMP is the only test to date that is capable of testing the function of these two structures (saccule and utricle).
The test principle is based on the fact that these structures of balance organ (saccule and utricle) react to sound stimuli.
The VEMP is divided into two parts:
cVEMP or cervical VEMP for testing the function of the saccule.
oVEMP or ocular VEMP for testing the function of the utricle.
cVEMP: During this test, electrodes are pasted at the sterno-cleido-mastoid (SCM) on the same side of the ear to be tested. A sound is sent to the ear. The patient is placed on his back and raised his head so that his SCM muscle is in contraction. The software analyzes the relaxations of SCM. According to the auditory stimulation threshold (lower than normal, normal or absent), the differential diagnosis is considered.
oVEMP: It is now possible to specifically test the function of the utricle. Electrodes are adhered to the skin of the eye muscles on the opposite side to the tested ear, so we can record their contractions. The software analyzes the contractions of the contralateral extraocular muscles. According to the auditory stimulation threshold (lower than normal, normal or absent), the differential diagnosis is considered.
The VEMP is essential in cases of superior semicircular canal dehiscence, where the threshold value is less than the normal level.
Polyclinic Centre-Ville is known for its expertise in vertigo and dizziness. She is proud to be one of the out of the hospital centers in Canada to work in this field. The VEMP is an easy test, does not last longtime, well tolerated by children and adults too; also it enables you and your ENT to detect the abnormalities in the saccule and / or the utricle.