Direction-fixed positional nystagmus; spontaneous nystagmus.
In the tracings above, the nystagmus does not vary more than 1[degrees]/sec from one position to the next. This finding defines spontaneous nystagmus. No matter which position the head is in, the direction and velocity of the nystagmus remain unchanged. This concept avoids defining the "spontaneous" position.
This is an abnormal positional study result, which indicates a vestibular system abnormality of no localizing value as to site (i.e., peripheral or central) or side. This type of abnormality is usually seen in a patient who has a peripheral vestibular disorder of an irritative variety in the left ear. The side is best further deduced from additional ENG information, audiology, history, and neurotologic examination. Turning the neck does not have any effect on the nystagmus in any position.
From Neurotologic Associates, P.C., New York City.
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|Author:||Brookler, Kenneth H.|
|Publication:||Ear, Nose and Throat Journal|
|Date:||Oct 1, 1999|
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