Which findings from electronystagmography (ENG) are characteristics of rotary nystagmus?

Updated: Aug 06, 2019
  • Author: Angela G Shoup, PhD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Answer

If rotary nystagmus is observed, the results must have the following 4 characteristics to be considered classically positive:

  • Delayed onset, in which nystagmus begins a few seconds after the patient is positioned

  • Transient burst of nystagmus, in which nystagmus lasts less than a minute

  • Subjective report of vertigo

  • Fatigability, in which the response decreases with repetition

In addition to these 4 characteristics, the clinician may observe a reversal of the nystagmus. When the patient resumes the sitting position, the nystagmus may begin beating in the opposite direction.

When a classically positive response is observed during the Dix-Hallpike maneuver, a peripheral lesion on the side that is down when the nystagmus occurs may be indicated.


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