Equilibrium and vertigo exam
VNG (Videonystagmography)
vHIT (video Head Impulse Test)
VEMP (Vestibular Evoked Myogenic Potential)
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VNG (Videonystagmography)
Videonystagmography is a test, which allows precise exploration of the vestibular function.
It can detect low amplitude nystagmus that would remain unnoticed during physical examination. Nystagmus is an involuntary movement of the eyes, low oscillation amplitude, and rotation of the eyeball. Nystagmus reflects the presence of dizziness and imbalance. VNG allows recording the nystagmus and quantifying with high spontaneous resolution and induced eye movements resulting from a unilateral or bilateral vestibular dysfunction.
This test is carried out in the dark and lasts approximately one hour.
During the test, the patient wears a mask over his eyes and has only one eye open. On the mask there is a small camera with an infrared light. The camera records all eye movement and transmits them to a software. The system provides highly accurate results.
The videonystagmography is an exam including a set of tests.
The tests include automated calibration and search of spontaneous nystagmus, gaze, pursuit, saccade, optokinetic, positional, the Dix-Hallpike test, and bithermic caloric test (at 30 ° C and 44 ° C). The caloric test is either done with water, or with air when the eardrum is perforated. The caloric test reports the percentage of vestibular deficit of the horizontal semicircular canal on one side compared to the one on the contralateral side.
It is essential to follow these instructions before coming for a VNG at the Polyclinique Centre-Ville:
- No solid foods 4 hours before the examination,
- Stop using drugs against dizziness or nausea 24 hours before the test,
- Remove any makeup and products on the face.