Usefulness of galvanically induced nystagmus as a diagnostic test of peripheral vestibular hypofunction.

BACKGROUND

Galvanic Vestibular Stimulation (GVS) has long been used as a vestibular stimulus. A major issue observed in GVS research was the high variability of the responses, which has led some researchers to question its diagnostic utility.

OBJECTIVES

Determine the diagnostic accuracy of galvanically induced nystagmus for the diagnosis of subjects with unilateral peripheral vestibular hypofunction.

METHODS

A total of 195 dizzy patients were prospectively enrolled, forming a consecutive series as they were received. Individuals with spontaneous nystagmus or using vestibular sedatives were excluded. Nystagmus induced by a 4 mA galvanic stimulus was compared with the caloric test as a reference standard.

RESULTS

Of the 195 subjects tested with GVS, 115 were subjects with a unilateral peripheral vestibular hypofunction. The presence of nystagmus showed an AUC of only 0.529 (0.478 to 0.580, p = 0.125), and the maximum slow phase velocity of nystagmus showed an AUC of only 0.523 (0.472 to 0.573, p = 0.439).

CONCLUSIONS

Since neither AUC is better than random discrimination, this study concludes that GVS-induced nystagmus is not useful as a diagnostic tool for unilateral peripheral vestibular hypofunction. These findings discourage the use of GVS-induced nystagmus in the clinical setting.