Videonystagmography (VNG) refers to a comprehensive vestibular test battery using goggles with video cameras to monitor the eyes. The video cameras measure eye movements to evaluate signs of vestibular dysfunction or neurological problems. Generally, this evaluation is performed in a room that is dark or with low lighting. The audiologist will ask random questions that are meant to occupy the person being tested and keep them alert.
VNG tests are the most common set of tests administered to people with dizziness, vertigo, and/or imbalance. Parts of the VNG test battery evaluate the movement of the eyes as they follow different visual targets. Other parts of the VNG observe eye movements as the head and body are placed in different positions. A third component of the VNG is called the caloric test, which uses changes in temperature within the ear canal to stimulate part of the vestibular system. Air or water may be used to modulate the ear canal temperature, which may be warmer or cooler than body temperature. This test should provoke jerking eye movements (nystagmus) for a short time.
The Balance System
The body maintains balance by receiving information from three systems:
- Ears (Vestibular System)
- Proprioception (sensory information from spine, legs, and feet).
The information from these systems is regulated in the cerebellum. If there is a miscommunication in any of the systems, dizziness may occur.
Dizziness can be caused by:
- Outer/middle ear dysfunction
- Inner Ear Dysfunction
- Neurological Dysfunction
- Medication side effects or interactions between medications
- Low blood pressure
- Cardiovascular dysfunction
Treatment of Dizziness
After obtaining a full case history and completing the vestibular test battery, the audiologist will provide her comments and recommendations regarding the balance disorder and possible treatment options. Some disorders can be treated by a repositioning maneuver done in the office or vestibular rehabilitation done with a physical therapist, while other disorders require further testing to provide more information for the diagnosis. The audiologist will discuss these recommendations with the patient as well as provide a comprehensive report to the referring physician.