Comparison of the Bedside Head-Impulse Test with the Video Head-Impulse Test in a Clinical Practice Setting: A Prospective Study of 500 Outpatients

Abstract

ObjectivesThe primary aim was to determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the bedside head-impulse test (bHIT) using the video HIT (vHIT) as the gold standard for quantifying the function of the vestibulo-ocular reflex (VOR). Secondary aims were to determine the bHIT inter-rater reliability and sensitivity in detecting unilateral and bilateral vestibulopathy.MethodsIn this prospective study, 500 consecutive outpatients presenting to a tertiary neuro-otology clinic with vertigo or dizziness of various vestibular etiologies who did not have any of the pre-defined exclusion criteria were recruited. Bedside HITs were done by three experienced neuro-otology clinicians masked to the diagnosis, and the results were compared with the vHIT. The patients were likewise blinded to the bHIT and vHIT findings. Patients with VOR deficits were identified on the vHIT by referencing to the pre-selected “pathological” gain of <0.7. The data were then analyzed using standard statistical methods.ResultsFor the primary outcome (vHIT “pathological” VOR gain <0.7), the three-rater mean bHIT sensitivity = 66.0%, PPV = 44.3%, specificity = 86.2%, and NPV = 93.9%. Shifting the “pathological” threshold from 0.6 to 0.9 caused the bHIT sensitivity to decrease while the PPV increased. Specificity and NPV tended to remain stable. Inter-rater agreement was moderate (Krippendorff’s alpha = 0.54). For unilateral vestibulopathy, overall bHIT sensitivity = 69.6%, reaching 86.67% for severely reduced unilateral gain. For VOR asymmetry <40% and >40%, the bHIT sensitivity = 51.7 and 83%, respectively. For bilateral vestibulopathy, overall bHIT sensitivity = 66.3%, reaching 86.84% for severely reduced bidirectional gains.ConclusionFor the primary outcome, the bHIT had moderate sensitivity and low PPV. While the study did not elucidate the best choice for vHIT reference, it demonstrated how the bHIT test properties varied with vHIT thresholds: selecting a lower threshold improved the sensitivity but diminished the PPV, while a higher threshold had the opposite effect. The VOR was most likely normal if the bHIT was negative due to its high NPV. The bHIT was moderately sensitive for detecting unilateral and bilateral vestibulopathy overall, but better for certain subgroups.

Testing of the Semicircular Canal Function in Vertigo and Dizziness

“…It has a moderate sensitivity (35-45%) and a high specificity (90%) [27,28]. To achieve better sensitivity and specificity than the bHIT, the HIT measured with a video system (vHIT) was developed [29][30][31]. The increase in sensitivity and specificity is mainly attributed to the fact that correcting saccades are clearly identified and the VOR gain can be measured.…”

Clinical practice of horizontal video head impulse test in healthy children

“…In addition, the high compliance rate (84%) for vHIT and nonexistence of goggle fitting problems in the present study may be attributed to the presence of a higher lower age limit than the other studies focusing on vHIT in children. [2,9] In the present study, the mean values of gain were significantly different after 40, 60 and 80 ms and the values were significantly decreased from 40 to 80 ms. Similar significant differences were also demonstrated in the study of Hülse et al [13] consisting of 55 children.…”

“…Secondly, the goggles for vHIT have to be fit as much as possible to reduce slippage in order to prevent artifacts. In the literature, it is reported that current goggles allow performing the test as young as three years old [2,9] with sufficient results. In the present study, our lower age limit was six years old because we intended to design a pilot study to explore the practicability of vHIT in children and also to provide normative data for the lateral semicircular canal as an initial goal.…”

“…[1] The adjunct video system provides a technological advancement to the classical clinical head impulse test, which measures vestibulo-ocular reflex (VOR) deficits due to peripheral vestibular disorders by simple observation. [2] In adults, vHIT has been shown to be an effective tool for diagnosing semicircular canal disorders. [3][4][5] The prevalence of vestibular disorders ranges between 0.7% and 15% in children.…”

Economic Testing of Unilateral Vestibular Failure

“…This bed-side test (bHIT) has a moderate sensitivity (35-45%) and high specificity (90%) [4,5]. To improve the sensitivity and specificity than the bHIT, the vHIT was developed [6][7][8]. From this finding I would recommend using the vHIT instead the bHIT if available.…”