[Vibration-induced nystagmus: mechanism and clinical interest]

In 1973 Lücke described nystagmus induced by application of a vibrator on the mastoid process. Since that time, several Authors have applied the vibrator test in normal subjects or patients suffering from various well-characterized conditions.

Recognizing that results obtained with the vibrator test are sometimes in contradiction with those of other vestibular tests, our aim was to formulate an assumption regarding the genesis of induced nystagmus in an attempt to explain such contradictions.

We considered seven very different clinical situations. Each patient underwent a standard protocol including pendular and caloric tests as well as the vibrator test. We sought an assumption allowing, i) an interpretation of the characteristic features of nystagmus induced by the vibrator in any situation, ii) an understanding of the reasons why some vibrator test results do not correlate with those of other vestibular tests.

We assume that the vibrator stimulates phasic cells of the cupula and the vestibular maculae preferentially, if not exclusively. This assumption allows us to retain a very simple protocol for the vibrator test useful for routine clinical practice.