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Vestibular testing of Congenital Nystagmus Patients

For more about CN follow this link.

Timothy C. Hain, MD Page last modified: August 11, 2013

ENG and rotatory testing of patients with Congenital Nystagmus generally just shows that they have CN. On the other hand, tests that don't use eye movements such as evoked potentials (i.e. VEMP) and posturography, can potentially provide useful information about vestibular function.

Movie of this patient's Congenital nystagmus during fixation and then in dark (listen for click for dark, 53 meg).

SNHere the CN is brisker in the light than in the dark. It slower in the dark. This is typical of CN, and opposite of the pattern of vestibular nystagmus. Sometimes the ENG technician/audiologist will say that there is "poor fixation suppression". This is not just poor -- it is opposite. See the movie above that illustrates this again.

 

Saccades

There is a CN nystagmus after saccades.

 

Pursuit

The eye is in constant motion. It does not show the usual "backup saccades" seen in a CN variant, LN.

Dix-Hallpike

This Dix-Hallpike test is dominated by CN. It would be very difficult to determine if this person has BPPV.

OKN

OKN follows the drum somewhat, but with oscillation superimposed.

R-chairRotatory chair test results are distorted by the nystagmus.

Copyright August 3, 2016 , Timothy C. Hain, M.D. All rights reserved. Last saved on August 3, 2016