Nystagmus findings in healthy subjects examined with infrared videonystagmoscopy.

The increased use of video systems for the detection of nystagmus is a new diagnostic tool in the diagnosis of patients with vestibular disorders. Small video cameras mounted in a light sealed mask visualize the eyes which are illuminated with infrared light. Compared to the well-established use of Frenzel glasses the patient has no visual references at all. This new technique requires standards for normal limits. Thirty subjects between 20 and 78 years of age with no history of vestibular disorders were examined with infrared video-oculoscopy with the gaze in primary position, after head-shake and in supine position with head torsion and Dix-Hallpike positions backward and forward according to a standardized procedure at our department. Two subjects had spontaneous nystagmus, but nystagmus after head-shake was not found in any. No subject had torsional nystagmus in the Dix-Hallpike positions. In the elderly subjects horizontal nystagmus in head hanging position was a frequent finding.