Use of Electronystagmography

Electronystagmography (ENG) is a diagnostic test that measures involuntary eye movements to evaluate balance, hearing, and certain neurological disorders.What ENG IsENG is a test used to assess the function of the vestibular system (inner ear balance organs) and the cranial nerves that control eye movements, hearing, and balance . It detects nystagmus, which is rapid, involuntary eye movement, often triggered by specific stimuli. Abnormal results can indicate problems in the inner ear, the nerves connecting the ear to the brain, or certain brain regions .How ENG Is PerformedDuring an ENG test, electrodes are placed around the eyes—above, below, and on the sides—to record electrical activity of the eye muscles . The test typically includes several components:Calibration Test: You follow a moving light to check for ocular dysmetria, where the eyes overshoot their target .Gaze Nystagmus Test: You fix your gaze on a stationary light to measure involuntary eye movements .Pendulum-Tracking Test: You track a swinging light to evaluate smooth pursuit eye movements .Caloric Test: Warm or cold air (or water) is introduced into the ears to stimulate the vestibular system, and eye movements are recorded . You may also be asked to move your head in specific ways or follow flashing lights to further assess eye and nerve function .What ENG MeasuresENG evaluates the health of several cranial nerves, including:Oculomotor nerve (CN III): Controls most eye movements .Trochlear nerve (CN IV): Assists in eye movement toward or away from the nose .Abducens nerve (CN VI): Controls horizontal eye movement .Vestibular nerve (part of CN VIII): Connects the inner ear to the brain, controlling balance and hearing . It provides an objective assessment of the oculomotor and vestibular systems, helping distinguish between inner ear disorders and neurological causes of dizziness or vertigo .Clinical UsesENG is commonly ordered for patients experiencing:Vertigo or dizzinessBalance problemsUnexplained hearing lossSuspected neurological disorders such as acoustic neuroma Abnormal ENG results can guide further testing or treatment, helping clinicians determine whether symptoms originate from the inner ear, cranial nerves, or brain .AdvancementsA newer version, video nystagmography (VNG), uses infrared cameras instead of electrodes to provide more detailed analysis of eye movements . ENG is a safe, non-invasive test that provides valuable information for diagnosing balance and vestibular disorders, helping clinicians tailor appropriate treatment plans.