Abstract
Background:
Numerous video head impulse test (vHIT) devices are available commercially; however,
gain is not calculated uniformly. An evaluation of these devices/algorithms in healthy
controls and patients with vestibular loss is necessary for comparing and synthesizing
work that utilizes different devices and gain calculations.
Purpose:
Using three commercially available vHIT devices/algorithms, the purpose of the present
study was to compare: (1) horizontal canal vHIT gain among devices/algorithms in normal
control subjects; (2) the effects of age on vHIT gain for each device/algorithm in
normal control subjects; and (3) the clinical performance of horizontal canal vHIT
gain between devices/algorithms for differentiating normal versus abnormal vestibular
function.
Research Design:
Prospective.
Study Sample:
Sixty-one normal control adult subjects (range 20–78) and eleven adults with unilateral
or bilateral vestibular loss (range 32–79).
Data Collection and Analysis:
vHIT was administered using three different devices/algorithms, randomized in order,
for each subject on the same day: (1) Impulse (Otometrics, Schaumberg, IL; monocular
eye recording, right eye only; using area under the curve gain), (2) EyeSeeCam (Interacoustics,
Denmark; monocular eye recording, left eye only; using instantaneous gain), and (3)
VisualEyes (MicroMedical, Chatham, IL, binocular eye recording; using position gain).
Results:
There was a significant mean difference in vHIT gain among devices/algorithms for
both the normal control and vestibular loss groups. vHIT gain was significantly larger
in the ipsilateral direction of the eye used to measure gain; however, in spite of
the significant mean differences in vHIT gain among devices/algorithms and the significant
directional bias, classification of “normal” versus “abnormal” gain is consistent
across all compared devices/algorithms, with the exception of instantaneous gain at
40 msec. There was not an effect of age on vHIT gain up to 78 years regardless of
the device/algorithm.
Conclusions:
These findings support that vHIT gain is significantly different between devices/algorithms,
suggesting that care should be taken when making direct comparisons of absolute gain
values between devices/algorithms.
Key Words
aging - vestibular - video head impulse test
