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

Abstract

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.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.Prospective.Sixty-one normal control adult subjects (range 20–78) and eleven adults with unilateral or bilateral vestibular loss (range 32–79).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).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.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.

Avaliação do efeito da idade sobre a função vestibular por meio do Teste do Impulso Cefálico (v-HIT)

“…Saccades were not present in the study groups, a fact that agrees with the literature since the saccades reveal labyrinth hypofunction and are considered signs of pathology (1,2,4,5,13,(17)(18)(19)27,28,29) .…”

“…The gains of all the semicircular canals presented means close to 1, thus confirming the findings of other studies where healthy individuals were evaluated (7,11,13,(18)(19)(20) . Mossman et al (21) also reported gain values near 1 in 60 individuals without otoneurological alterations.…”

“…In the present study, the mean age of the sample was 46.4 years, with females being the most prevalent. Although it was a convenience sample, the characteristics of the assessed group may favor future comparative studies, since, according to the literature, dizziness is more frequent in women over 40 years of age (3)(4)(5)(6)13,18,19) .…”

Bilateral Vestibular Weakness

“…There is a modest literature ( 73 , 75 , 115 , 117 ) suggesting that vHIT can play a valuable role in the identification of BVW, but its sensitivity and specificity (compared with the gold standard of RCT) has yet to be established. Comparison of vHIT with RCT is complicated by several factors that can introduce variability into calculation of VOR gain on vHIT; the first reason is physiologic, and has to do with the fact that target viewing distance (which may not be carefully controlled) can have a significant effect on gain both in healthy individuals ( 118 – 120 ) and in patients with peripheral vestibular disease ( 121 ); the second reason is technological, as it has been demonstrated that different devices and different algorithms can render different results in gain ( 122 ).…”

Reflexo vestíbulo-ocular em crianças hígidas: aplicabilidade do >i<video Head Impulse Test>/i<

“…Salienta-se que, apesar do uso do vHIT ser comprovadamente útil para a avaliação da população infantil, observou-se falta de consenso entre os pesquisadores em relação aos resultados e à aplicabilidade do exame (HÜLSE et al, 2015;MATIÑO-SOLER et al, 2015;ROSS;HELMINSKI, 2016;ALIZADEH et al, 2017;LEHNEN et al, 2017;WIENER, 2017;BACHMANN et al, 2018;JANKY;RODRIGUES, 2018 ).…”