Introduction to electronystagmography for END technologists.

Electronystagmography (ENG) is a procedure used to evaluate patients with vertigo. Electrodes applied around the patient's eyes use the corneoretinal potential to record eye movements in response to numerous test maneuvers. Some of the portions of the ENG measure a patient's ability to track moving stimuli. Others monitor for the presence of nystagmus. Lastly, the lateral semicircular canals of the ear can be stimulated with warm and cool water or with air producing nystagmus. A comparison of the responses to stimulations of the left and right ears can demonstrate the relative sensitivities of the peripheral vestibular systems. Videonystamography (VNG) is similar to ENG in the data obtained. VNG uses infrared cameras to monitor eye position.