Effects of Hand Placement Technique on the Video Head Impulse Test (vHIT) in Younger and Older Adults

Objective To investigate the effects of hand placement techniques on the video head impulse test (vHIT) responses (i.e., gain, velocity) in older and younger adults and to determine intra-rater and inter-rater reliability of the horizontal vHIT. Design Descriptive, reliability study. Setting University research laboratory. Subjects Forty healthy adults grouped by age with negative history of current or previous vestibular diseases between the ages of 20 and 88 years (mean = 46.60, standard deviation 23.20). Main Outcome Measures Three examiners each used two hand placement techniques (chin and head) to elicit the horizontal vHIT responses. Both the examiner and hand placement orders were counterbalanced to account for order and fatigue effects. The outcome measures of interest were vHIT gain and velocity. Results A two-way between-subject factorial analysis of variance revealed a significant main effect for hand placement technique and gain response. Mean values for vHIT gain were higher for head technique. Significant main effects were observed for the velocity response for hand placement technique and age group. Mean velocity values were higher for chin technique and lower velocities were observed in the older age group. Intra- and inter-rater reliability scores were consistent for gain values; however, poor to fair inter-rater reliability scores were observed for velocity values. Conclusion It is suggested that clinical sites select one hand placement technique for the measure to provide consistency of protocol. Establishing clinical norms using the one selected method to verify reliability within and across clinicians is suggested before examination with a disordered population.