Role of Video Head-impulse Test in Lateralization of Vestibulopathy: Comparative Study with Caloric Test

Abstract

Introduction: Among diagnostic tests evaluating dizzy patients, caloric test and the head-impulse test (HIT) are important tools in evaluation of unilateral vestibular hypofunction. Since new video head-impulse test (vHIT) is introduced, various studies tried to evaluate the diagnostic value of this system. To evaluate the lateralization value of vHIT in unilateral vestibulopathy, we compared its variables with those of a caloric test.

Methods: In total, 19 healthy volunteers and 92 dizzy patients who underwent both a caloric test and a vHIT were enrolled. Patients were divided into two groups depending on their fluctuating pattern of vertigo. The vestibulo-ocular reflex (VOR) gain and gain asymmetry (GA) of a vHIT, and unilateral weakness (UW) and the sum of the slow-phase velocities (SPVs) of warm and cold irrigation of the same side were compared. A cutoff value of VOR gain of a vHIT was also calculated using a receiver-operating characteristic curve.

Results: A VOR gain in an affected ear and GA of a vHIT showed a statistically significant correlation with UW in a caloric response. There was a significant correlation between vHIT parameters and a caloric test in the patients with fluctuating vestibulopathy. Moreover, the cutoff value of a vHIT was determined to be 0.875, derived under the assumption that UW of a caloric test equal to or less than 25% is normal.

Conclusions: A VOR gain or GA of a vHIT may be a useful parameter in evaluating unilateral vestibulopathy. The vHIT can act as a complementary tool for lateralization of unilateral vestibular hypofunction.