Electronystagmography (ENG) is a test used to diagnose the cause of vertigo or dizziness problems. ENG testing utilizes electrodes or goggles that record eye movements, including involuntary eye movements known as nystagmus, allowing measurement of the function of the vestibular/balance system. The ENG test battery has three main parts: oculomotor testing, positioning testing, and caloric testing.
In oculomotor testing, the patient watches or follows glowing lights with their eyes while their eye movements are recorded.
Positioning testing involves recording eye movements while the patient moves into different body positions that may elicit vertigo.
In the final test, caloric irrigation, each ear is irrigated with warm and cool air or water, stimulating the vestibular/balance system in the inner ear. Most patients experience brief vertigo during this test, which allows direct evaluation of vestibular system response to stimuli.
Comparison of the results of each of the subtests assists in determination of the diagnosis and site of lesion for central and peripheral vestibular problems.