Videonystagmography (VNG) is a test that measures a type of involuntary eye movement called nystagmus. ElectroNystagmoGraphy (ENG) and VideoNystagmoGraphy (VNG) tests are part of a comprehensive evaluation conducted to detect pathologies within the. The ENG test is the gold-standard for diagnosis of ear disorders affecting one ear at a time. Electronystagmography, or ENG, is a test that measures how well the nerves inside. The Electronystagmography (ENG) or Videonystagmography (VNG) examination is a test of certain components of the balance system. What Do VNG/ENG Testing Involve? To measure your visual responses, VNG tests involve the use of video goggles while ENG tests use electrodes.