Effects of Device on Video Head Impulse Test (vHIT) Gain

Area of Science:

• Vestibular system diagnostics
• Ophthalmology
• Neurology

Background:

• Commercial video head impulse test (vHIT) devices calculate gain non-uniformly.
• Standardized evaluation of vHIT devices/algorithms is needed for comparing research using different gain calculations.

Purpose of the Study:

• Compare horizontal canal vHIT gain across three commercial devices/algorithms in healthy adults.
• Assess the impact of age on vHIT gain in healthy adults for each device/algorithm.
• Evaluate the clinical performance of vHIT gain in differentiating normal from abnormal vestibular function across devices.

Main Methods:

• Prospective study involving 61 healthy adults and 11 adults with vestibular loss.
• Administered vHIT using three devices/algorithms (Impulse, EyeSeeCam, VisualEyes) in randomized order on the same day.
• Analyzed gain using different calculation methods (area under the curve, instantaneous, position) and eye recording types (monocular, binocular).

Main Results:

• Significant mean differences in vHIT gain were observed among devices/algorithms for both healthy and vestibular loss groups.
• vHIT gain was larger in the ipsilateral direction of the measured eye, indicating a directional bias.
• Despite device differences and directional bias, vHIT consistently classified normal versus abnormal gain, except for instantaneous gain at 40 msec.
• Age did not significantly affect vHIT gain up to 78 years across all devices/algorithms.

Conclusions:

• vHIT gain values differ significantly between commercial devices/algorithms.
• Direct comparison of absolute vHIT gain values across studies using different devices/algorithms requires caution.
• vHIT remains a reliable tool for distinguishing normal from abnormal vestibular function despite inter-device variability.