vHIT Uses and Procedures: A Survey of Audiologists
The vHIT measures semicircular canal function in patients with a suspected vestibular disorder. The clinician creates small but brisk head turns in the directions of the six semicircular canals. Each head turn results in reflexive eye movement to the opposite direction of the head turn, which will allow the subject to maintain focus on a visual target. When the reflex loop between the semicircular canals and the eyes is interrupted, the timing of the eye movements are delayed and measured by the vHIT system. The vHIT has been added to vestibular test batteries in many clinics that provide vestibular services. Because vHIT is a novel assessment tool, the protocols are not solidified. Therefore, modifications to these protocols may be needed depending on the patient population for other factors. In many audiologic assessment tools, a large contributing factor to the need for modification is age. For vHIT, in particular, a client’s age must be taken into account during setup, performance, and data analysis. It would be beneficial to the audiology community to see a comparison of more than two populations in regard to various trends for vHIT procedures and results, since few studies have reported on this. It also is not known whether or not the modifications used in some studies are adopted by the community and how successful they are. This study should provide important data to fellow researchers who utilize this procedure in their vestibular test battery to aid them in maintaining consistency when testing and in choosing which techniques to implement into their practice.