Videonystagmogram (VNG)



The videonystagmogram (VNG) is a diagnostic evaluation composed of multiple parts that measures the function of the inner ear and it's connection with your brainstem, brain and eyes.  The VNG is composed of the following:
  • Evaluation of the vestibulo-ocular reflex (VOR)
  • Caloric testing (measuring the inner ear nerve function using cool and warm air or water)
  • Positional testing (a minimum of five and sometimes seven head/body positions are evaluated)
  • Central (brain) tests, including measurement of slow (tracking) and fast (saccades) eye movements and optokinetic nystagmus (OPK)


Below is a recording made on an infrared camera, which sits inside the goggles (see above).  The "cross hairs" lock on to the center of the pupil.  All eye movements are recorded, broken down into a horizontal and vertical component.  The computer recording consists of a vertical and horizontal channel and the data is displayed graphically.

Electrical signals from the data obtained from the infrared camera are fed into the computer to create a digital readout.  On the horizontal channel, movement up indicates an eye movement to the right and movement down indicates an eye movement to the left.  On the vertical channel, movement up indicates an eye movement up and movement down indicates an eye movement down.



To learn more about the different parts of the VNG, follow the links below:
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