Vibration induced nystagmus in normal subjects and in patients with dizziness. A videonystagmography study

To analyze the incidence and characteristics of vibration-induced nystagmus in normal subjects and in patients with vertigo.

This is a prospective analysis of the effect of vibration on several points of the skull in 38 normal subjects, 10 patients who had undergone labyrinthectomy and 125 consecutive patients with dizziness referred to a tertiary care center. Nystagmus was documented and its corresponding slow phase velocity measured with a videonystagmography system.

In 81.6% of normal subjects and 80.8% of all patients, nystagmus could be provoked by stimulation of at least one of the points on the skull to which the vibrator was applied. In normals, however, no subject had nystagmus greater than 2.8 degrees s-1 whereas 35.2% of patients did.

The value of the slow-phase velocity of vibration-induced nystagmus can be used to identify a sizeable proportion of patients with a vestibular disorders. Vibration-induced nystagmus is a frequent sign in patients with dizziness and can provide complimentary information about vestibular system function.