[Benefit of skull vibration-induced nystagmus test in occupational medicine].

Background: Nystagmus induced by vibrations (NIV), has been optimized by the present authors this last decade. The skull vibration-induced nystagmus test (SVINT) can be designated as a high-frequency global "vestibular Weber test" and can be considered as an office-based examination to detect vestibular asymmetry. The aim of this study is to define the tolerance of the SVINT as well as its comparison to the simplified caloric test of Veits (CTV) in normal workers during the pre-employment visit at the occupational medicine center.

Material and methods: The vestibular function has been evaluated by the SVINT and the CTV in 87 healthy workers. The tolerance of the two procedures has been evaluated by a 4-items questionnaire (nausea, vomiting, sweating, asthenia).

Results: The caloric test was normal in each worker. The SVINT was positive in one patient who had a partial unilateral vestibular dysfunction related to trauma. The mean duration of the procedure was 15 min for CTV and 1 min for SVINT. Side effects (nausea, vomiting, sweating, asthenia) were present in 50% of the workers following CTV and in only one patient after SVINT. The SVINT demonstrated significantly less side effects for each item (p < 0.0001).

Conclusions: SVINT is a valid, rapid, low-cost clinical screening test and does not cause patient discomfort. It is suggested that this test which explores vestibular high frequencies and is not modified by vestibular compensation is useful for the diagnostic screening of workers' vestibular dysfunction, when combined with other vestibular tests and complements the CTV.