Comparison of computerized rotational impulse test (crHIT) and video head impulse test (vHIT) in all semicircular canals among normal subjects

Background: The computerized rotational head impulse test (crHIT) employs whole-body impulsive rotations like the angular motion used in the video head impulse test (vHIT) to assess the function of all semicircular canals (SCCs). Objective: This study utilized vertical crHIT and vHIT among healthy subjects to evaluate the effectiveness of these tools in assessing SCC function. Methods: Thirty-five individuals with no history of vestibular disorders or traumatic brain injury were enrolled in this study. Participants underwent vHIT (ICS Impulse Otometrics) and crHIT (Neuro-Otologic Testing Center, Spryson America, Inc.). Results: Mean VOR gain was significantly higher during crHIT compared to vHIT, except for the right horizontal SCC (p < 0.01). Coefficient of variation (CV) for crHIT was smaller than that observed in vHIT across all 6 SCCs, with significant differences in all but the LA and RP SCCs. We also computed lower limits of normal (LLN) for each condition; up to 2.9% of crHIT values fell outside the acceptable LLN compared to up to 37% of vHIT gain values. Average reduced vestibular response (RVR) for crHIT was lower than that observed in vHIT among all semicircular canal pairs and demonstrated less variability for crHIT as compared to vHIT. Conclusions: Overall, these findings support the clinical utility of crHIT for comprehensive SCC function evaluation.