How is the vestibular autorotation test performed in a dizziness evaluation?

Updated: Jun 26, 2018
  • Author: Wayne T Shaia, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Vestibular autorotation testing

  • Because rotational chair testing requires expensive and cumbersome equipment, the vestibular autorotation test (VAT) has been developed to allow evaluation of the VOR. Also, commercially available rotational chairs allow testing at only modest head frequencies, typically less than 1 Hz, whereas VAT allows evaluation of the VOR at higher and more physiologically significant frequencies. The most commonly used system for VAT testing is from Western Systems Research, Inc. (Pasadena, CA).

  • The test is performed by using a computer-generated metronome to which the patient moves his or her head for an 18-second trial period at frequencies from 2-6 Hz. Because high head frequencies are tested, smooth pursuit contributes little to the response, and the test can be conducted in a lighted room while the patient fixates on a stationary target. This test can evaluate both the vertical and horizontal VOR.

  • The best use of the test may be in monitoring the VOR in patients who receive vestibulotoxic agents. The portability of the equipment allows bedside testing of hospitalized patients. The test/retest reliability of the test has been debated in the literature; therefore, it has not been adopted universally as a standard test of VOR function.


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