Videonystagmography (VNG) is a study used to clinically evaluate patients with dizziness, vertigo, or balance dysfunction. The vestibular system monitors the position and movements of the head to stabilize retinal images. This information is integrated with the visual system and spinal afferents in the brain stem to produce the vestibulo-ocular reflex (VOR). VNG provides an objective assessment of the oculomotor and vestibular systems.

Essentially, the standard VNG test battery consists of 3 parts: oculomotor evaluation, positioning/positional testing, and caloric stimulation of the vestibular system. The comparison of results obtained from various subtests of VNG assists in determining whether a disorder is central or peripheral. In peripheral vestibular disorders, the side of lesion can be inferred from the results of caloric stimulation and, to some degree, from positional findings.