Associations of Video Head Impulse Test and Caloric Testing among Patients with Vestibular Schwannoma

Abstract

Objective To determine relationships between caloric testing (CT) and video head impulse testing (vHIT) among patients with unilateral vestibular schwannoma (VS). To describe the distribution of CT and vHIT measurements and assess associations with tumor size and self-perceived handicapping effects. Study Design Retrospective review. Setting Tertiary referral hospital. Subjects and Methods Subjects were adults with presumed unilateral VS between 2014 and 2017. Interventions were CT and vHIT. Primary outcomes were vHIT value (abnormal <0.8) and CT value (abnormal >25%). Secondary outcomes were tumor size and Dizziness Handicap Inventory scores. Results Fifty-one individuals had complete data for CT and vHIT. The odds of abnormal gain increases by 2.18 for every 10% increase in unilateral weakness on CT (range, 1.44-3.34; P < .001). A significant negative correlation between CT and gain exists ( rs = −0.64, P < .001). Odds of observing saccades increased by 2.68 for every 10% increase in unilateral weakness (range, 1.48-4.85; P = .001). This association was larger in magnitude for overt than covert saccades (odds ratios, 2.48 and 1.59, respectively). Tumor size was significantly associated with an increase in caloric weakness (β = 0.135, P < .001). With every 10-mm increase of tumor size, odds of abnormal gain on vHIT increased 4.13 (range, 1.46-11.66; P = .007). Mean Dizziness Handicap Inventory score was 19.7 (σ = 22), without association to caloric weakness, gain, or tumor size. Conclusion CT and vHIT both effectively assess vestibular function for patients with VS and correlate to tumor size. These findings are important as vHIT has a lower overall cost, improved patient tolerance, and demonstrated reliability.

Contralesional High-Acceleration Vestibulo-Ocular Reflex Function in Vestibular Schwannoma

“…The prevalence of abnormal caloric reduction was high across all studies, ranging from 62 to 72%. Two studies (4,5) examined the relationship between vestibular function test results and patient-reported symptoms using the Dizziness Handicap Inventory (DHI) and neither concluded that there was a statistically significant association.…”

“…In the literature, impairment of ipsilesional vestibuloocular reflex (VOR) function is well described in VS, with most studies showing a correlation between gain of the VOR and tumor size (2)(3)(4)(5). A small number of case series also report that bilateral VOR impairment may also occur in VS in 6 to 58% of patients but there is a general paucity of literature regarding this phenomenon.…”

Vestibular Tests Related to Tumor Volume in 137 Patients With Small to Medium‐Sized Vestibular Schwannoma

“…In the literature, the sensitivity of vestibular tests in VS patients has mainly been determined with only some of the vestibular tests in each study, diverse methods, diverse definitions of a pathologic result, and different tumor sizes, thus it is difficult to compare the sensitivities of the tests related to each other. The sensitivities are reported to be 62% to 72% for the caloric test, 4,13,14 27% to 90% for lateral canal vHIT, 9,12-15 50% to 73% for oVEMP, 9,16,17 and 50% to 79% for cVEMP. 9,16,18 Lateral and posterior canal vHIT have been found to be more sensitive than anterior canal vHIT, 9,15,19 with sensitivities ranging from 27% to 57% and 8% to 36%, respectively.…”

Dissociation between Caloric and Video Head Impulse Tests in Dizziness Clinics

“…Interestingly, Brown et al describe abnormal findings on Cal in 63%, and abnormal gains on the ipsilateral side in 31.4% on vHIT testing for 51 patients with VS. They also report that caloric weakness was associated with tumor size, and that there were no cases with abnormal vHIT and normal Cal [ 72 ]. It appears that Cal is more sensitive to detect vestibular abnormalities in patients with VS.…”