ENG/VNG testing is used to determine if a vestibular (inner ear) disorder is causing problems with balance or dizziness. The test is performed by measuring eye movements through the use of electrodes or goggles which contain a video camera. This eye movement is called nystagmus and occurs during certain kinds of visual and vestibular stimulation. Nystagmus can help to distinguish between a peripheral vestibular disorder and one that is located within the central nervous system.