Role of Video Head-impulse Test in Lateralization of Vestibulopathy: Comparative Study with Caloric Test = 비디오 두부충동검사의 전정기능이상 편측화에 대한 역할: 온도안진검사와의 비교연구

다국어 초록 (Multilingual 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.

목차 (Table of Contents)

• Introduction 1
• Material and Methods 2
• 1. Study papulation 2
• 2. Bithermal caloric test 2
• 3. Video-head-impulse test 3
• 4. Parameters and statistical analysis 3
• Results 5
• Comparison of VOR gain on vHIT with sum of peak SPVs in warm and cold irrigation 5
• Correlation analysis of vHIT parameters (VOR gain and GA) with unilateral caloric weakness in patients 5
• Correlation analysis of vHIT parameters (VOR gain and GA) with unilateral caloric weakness depending on the nature of vertigo 5
• Diagnostic value of vHIT based on the bithermal caloric test 6
• Comparison of UW depending on the pattern of reflexive eye movement on vHIT 6
• Discussion 20
• Clinical correlation 20
• What explains dissociation between a vHIT and a caloric test? 21
• Cutoff value of VOR gain of vHIT 22
• Covert saccade of vHIT 22
• Conclusion 23
• References 24
• Abstract in Korean 27