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Purpose: The video Head Impulse Test is routinely used to assess semicircular canal function in adults, but to date, pediatric reference values are scarce. This study aimed to explore the vestibulo-ocular reflex (VOR) in healthy children at different development stages and to compare the obtained gain values with reference to those in an adult population. Methods: This prospective, single-center study recruited 187 children from among patients without otoneurological diseases, healthy relatives of these patients, and staff families from a tertiary hospital. Patients were divided into three groups by age: 3–6 years, 7–10 years, and 11–16 years. The vestibulo-ocular reflex was assessed by video Head Impulse Test, using a device with a high-speed infrared camera and accelerometer (EyeSeeCam®; Interacoustics, Denmark). Results: We found a lower vestibulo-ocular reflex gain of both horizontal canals in the 3–6-year-old group when compared with the other age groups. No increasing trend was found in the horizontal canals from age 7–10 years to age 11–16 years, and no differences were found by sex. Conclusion: Gain values in the horizontal canals increased with age until children reached age 7–10 years and matched the normal values for adults. [ABSTRACT FROM AUTHOR]

Caloric irrigation (CI) is the gold standard to investigate peripheral vestibular dysfunction. The video head impulse test (vHIT) is faster and more accessible and may be useful during acute vertigo stroke risk differentiation. Comparative studies between the two methods are needed. The objective of this study was to compare vestibular function data derived from caloric irrigation with that from vHIT. This study included 80 patients with acute onset vertigo who underwent caloric irrigation and vHIT. CI derived sum of slow phase velocities (SPVs) and unilateral weakness (UW) were compared with vHIT vestibulo-ocular reflex (VOR) gain and gain asymmetry (GA) using correlation analyses. Optimal cut offs for vHIT VOR gain and GA were calculated using Youden indexes. There was a strong positive correlation between the asymmetry measures UW and GA whereas the correlation between the sum of SPVs and VOR gain was weaker. The optimal cut offs to diagnose unilateral vestibular weakness were 0.80 for VOR gain and 28% for GA; with specificities for predicting normal caloric irrigation results of 55% and 93%, respectively. In one third of cases the results from caloric irrigation and vHIT dissociated. The results from vHIT correlated with those from CI, still neither test seem to have the accuracy to replace the other. GA appears as an attractive measure in acute vertigo as the high specificity can be used to identify those with a substantial probability of normal vestibular function in need of more comprehensive work-up for central causes. To diagnose vestibular dysfunction, CI remains gold standard. [ABSTRACT FROM AUTHOR]

This study aimed to determine the incidence, pattern, and etiology of dissociated vestibulo-ocular reflex (VOR) function according to the stimulus frequency in dizzy patients. We retrospectively evaluated the results of bithermal caloric tests and video-head impulse tests (vHITs) in 1022 patients with dizziness or vertigo between July 2016 and April 2021. Patients were classified into concordant group (normal or abnormal results on both tests) and discordant group (dissociated results between two tests). Of 1022 patients, discordant group had 159 (16%), comprising abnormal horizontal vHITs with normal caloric responses (n = 36, 23%) and abnormal caloric tests with normal horizontal vHITs (n = 123, 77%). The former group showed similar frequency of peripheral (44%) and central (42%) causes, and more common involvement of bilateral horizontal semicircular canals in central than peripheral causes (86.7 vs 37.5%, p = 0.005). The most common peripheral causes were Meniere's disease and chronic vestibular neuritis, while central causes were variable, but mainly affecting the cerebellum. In the latter group, peripheral causes were common (67%), with the main etiologies being Meniere's disease and vestibular neuritis, whereas central causes were found in only 5%. The degree of canal paresis did not differ significantly between patients with central and peripheral causes. Discordant VOR function according to the stimulus frequency was not uncommon in dizzy patients. Specific patterns of VOR dissociation according to the disease etiologies may offer insight into underlying pathophysiology. [ABSTRACT FROM AUTHOR]