A study of the relationship between the video head impulse test and air calorics

The video head impulse test (vHIT) has been proposed as an objective approach to detect peripheral vestibular disorder in a clinical setting. Data from several studies indicate that the vHIT is a useful addition to the vestibular test battery and can give complementary information to caloric testing. This study explores the relationship between lateral canal vestibular occular reflex gain measured using the vHIT system and canal paresis indicated using air calorics in a sample of patients attending a clinic for balance disorder. Sensitivity and specificity of the vHIT test relative to calorics was studied for a clinical sample of 51 patients (20 male, 31 female) who attended a private clinic for balance disorders. vHIT gains were compared to the manufacturer's normative range and to data from a normative study using 30 young volunteers. Of 14 patients in the clinical sample that had significant canal paresis indicated by air calorics, only 4 showed a significant abnormality in either canal using a measurement of vHIT gain. vHIT gain does not correlate with canal paresis as indicated by air caloric testing. vHIT gain appears relatively insensitive to peripheral vestibular disorder as indicated by air caloric testing, although patients that had no caloric response on one side showed abnormal vHIT gain. vHIT testing may be a useful addition to the existing vestibular test battery, but it does not appear to be an alternative to it.