Videonystagmography (VNG). This test evaluates balance function by assessing eye movement. Balance-related sensors in the inner ear are linked to muscles that control movement of the eye in all directions. This connection is what enables you to move your head around while keeping your eyes focused on a single point.
In a VNG evaluation, warm and cool water or warm and cool air are introduced into the ear canal. Measurements of involuntary eye movements in response to this stimulation are performed using a special pair of video goggles. Abnormalities of this test may indicate an inner ear problem.