Electronystagmography (ENG) is a diagnostic test to record involuntary movements of the eye caused by a condition known as nystagmus. It can also be used to diagnose the cause of vertigo, dizziness or balance dysfunction by testing the vestibular system.
The test is performed by attaching electrodes around the nose and measuring the movements of the eye in relation to the ground electrode. 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). ENG provides an objective assessment of the oculomotor and vestibular systems. A newer standard for the recording is the use of infrared video systems which allow for a more detailed observation and analysis of these eye movements, called video nystagmography (VNG). A similar test is performed for testing vertigo by using the caloric reflex test, which can be induced by air or water of specific temperatures, typically ± 7 degrees Celsius from body temperature.
The standard ENG test battery consists of three parts:
oculomotor evaluation positioning and positional testing caloric stimulation of the vestibular system