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To evaluate pre- and post-operative semicircular canal function in patients with vestibular schwannoma (VS) by the video Head Impulse Test (vHIT). Nineteen patients with VS who underwent surgery were enrolled in this study. The gain in vestibulo-ocular reflex (VOR) and the degree of scatter in catch-up saccades were examined pre- and post-operatively for the semicircular canals in VS patients. Ten of 19 cases (52.6 %) with VS were defined as demonstrating both superior vestibular nerve (SVN) and inferior vestibular nerve (IVN) impairment from the results of pre-operative vHIT. Hearing level and subjective vestibular symptoms showed significant correlations with pre-operative semicircular canal function. Compared to pre-operative vHIT results, VOR gains within 1 month after surgery were significantly reduced in all three canals; however, significant differences had disappeared in the anterior and posterior semicircular canals at 6 months after surgery. Cases of unknown origin had a significantly greater reduction in posterior semicircular canal function after surgery compared with those with disease of IVN origin. As vHIT could evaluate pre-operative vestibular nerve impairment, post-operative VOR gain reduction and the degree of vestibular compensation, semicircular canal function evaluated by vHIT provides a good deal of useful information regarding VS patients undergoing surgery compared to caloric testing, and vHIT should be performed pre- and post-operatively for patients with VS. [ABSTRACT FROM AUTHOR]

The aim was to evaluate the vestibular system of children who had undergone cochlear implant surgery and to compare them with the healthy population by vestibulo-ocular reflex (VOR) gains in unilateral and bilateral implant users, with the implants both on and off. Patients older than 5 years who had undergone cochlear implant surgery between 2012 and 2020 and who were cochlear implant users for at least one year were included. After consent was obtained, a video head impulse test (VHIT) was performed to evaluate the three semicircular canals, with devices on and off, and VOR gains were evaluated. VHIT was also used to assess VOR gains in the control group. The VOR gains of the study and control groups, VOR gains of unilateral and bilateral implant users, and VOR gains with implants on and off were compared. When the VOR gains of 24 unilateral and 13 bilateral cochlear implant users and the control group (n = 30) were compared, a significant difference was found only in the anterior semicircular canal, although the VOR gains were found to be low in all three semicircular canals in the implant users (p < 0.05). There was no significant difference between the VOR gains of unilateral and bilateral implant users. There was no significant difference between the VOR gains when either on or off. There was no correlation between cochlear implant usage time, implant insertion age, patient age and VOR gain. The effects of cochlear implant surgery on the vestibular system continue in the late period, but no correlation was observed between implant usage time and VOR gain after the first year. It was observed that having the cochlear implant on or off had no effect on VOR gain. Furthermore, bilateral implant surgery did not lead to additional vestibular dysfunction compared to unilateral implant surgery. [ABSTRACT FROM AUTHOR]

• In unoperated vestibular schwannoma, ipsilesional canals show decreased vestibulo-ocular reflex (VOR) gain and increased saccade amplitude and frequency. • One week after unilateral vestibular deafferentation lesioned canal gains drop by 0.22–0.35 and first saccade frequency and amplitudes increase by 37% and 2.9°. • The video head-impulse test excitation/dis-facilitation VOR asymmetry is less for the intact posterior canal than for the other canals. To examine the vestibulo-ocular reflex (VOR) and compensatory-saccades before and after complete unilateral vestibular deafferentation (UVD). Forty patients were studied before and after surgery for vestibular or facial schwannoma using the video head-impulse test (vHIT) and multivariable regression. Prior to UVD (median(IQR), 14(58.4) days), the average VOR-gain towards the lesioned -ear was lower than in normal for all semicircular canals (lateral, anterior, posterior: 0.69, 0.72, 0.49). One-week after UVD (5(3.0) days) VOR gains were further reduced (0.22, 0.37, 0.27), however, within one-year after UVD (171(125.0) days) the lesioned- ear VOR gains had slightly increased (+0.08, +0.11, +0.03), maximally for the anterior-canal. After UVD, the VOR gain asymmetry (gain towards minus away from intact-ear) was lower for the intact posterior-canal plane (0.56, 0.56, 0.22). For the lesioned canals, the frequency and amplitude of the first compensatory-saccade increased from 61–93% and 1.9–3.6° pre-surgery, to 98–99% and to 3.1–5.9° one-week post-surgery and remained unchanged over one-year; second saccade frequency and amplitude decreased over the same timespan. After UVD the high-acceleration VOR for the intact posterior-canal plane is more symmetrical than the other canals. First compensatory-saccades adapt within one week and subsequently change only marginally. Saccade compensation from surgical UVD is near complete by one-week. [ABSTRACT FROM AUTHOR]

• Video Head Impulse tests of the vestibulo-ocular reflex (VOR) provided the best separation of vestibular neuritis (VN) from posterior circulation stroke (PCS). • Refixation saccade-analysis complemented VOR gain measures in differentiating VN from PCS. • Ocular VEMP (oVEMP) asymmetry demonstrated low sensitivity but high specificity as a marker of VN. To separate vestibular neuritis (VN) from posteriorcirculation stroke (PCS) using quantitative tests of canal and otolith function. Video Head-Impulse tests (vHIT) were used to assess all three semicircular canal pairs; vestibulo-ocular reflex (VOR) gain and saccade metrics were examined. Cervical and ocular-Vestibular-Evoked Myogenic Potentials (c- and oVEMP) and Subjective Visual Horizontal (SVH) were used to assess otolith function. For controls (n = 40), PCS (n = 22), and VN (n = 22), mean horizontal-canal VOR-gains were 0.96 ± 0.1, 0.85 ± 0.3 and 0.40 ± 0.2, refixation-saccade prevalence was 71.9 ± 41, 90.7 ± 57, 209.2 ± 62 per 100 impulses and cumulative-saccade amplitudes were 0.9 ± 0.4°, 2.4 ± 2.2°, 8.0 ± 3.5°. Abnormality-rates for cVEMP, oVEMP and SVH were 38%, 9%, 72% for PCS, and 43%, 50%, 91% for VN. A gain ≤0.68, refixation-saccade prevalence of ≥135% and cumulative-saccade amplitudes ≥5.3° separated VN from PCS with sensitivities of 95.5%, 95.5%, and 81.8%, and specificities of 68.2%, 86.4% and 95.5%. VOR-gain and saccade prevalence when combined, separated VN from PCS with a sensitivity and specificity of 90.9%. Abnormal oVEMP asymmetry-ratios were of low sensitivity (50%) but high specificity (90.9%) for separating VN from PCS. vHIT provided the best separation of VN from PCS. VOR-gain, refixation-saccade prevalence and amplitude were effective discriminators of VN from PCS. vHIT and oVEMP could assist early identification of the aetiology of Acute Vestibular Syndrome in the Emergency Room. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the lateralization value of video head-impulse test (vHIT) for the diagnosis of vestibulopathy and to analyze cases showing dissociated results with caloric test.Methods: In total, 19 healthy volunteers and 92 dizzy patients who underwent both a caloric test and a vHIT were enrolled. Patients were divided into two groups depending on their fluctuating pattern of vertigo. The vestibulo-ocular reflex (VOR) gain and gain asymmetry (GA) of a vHIT as well as unilateral weakness (UW) and the sum of the slow-phase velocities (SPVs) of warm and cold irrigation of the same side were compared. A cutoff value of VOR gain of a vHIT was also calculated using a receiver-operating characteristic curve.Results: A VOR gain in an affected ear and GA of a vHIT showed a statistically significant correlation with UW in a caloric test. The cutoff value of a vHIT was determined to be 0.875, derived under the assumption that UW of a caloric test ≤25% is normal. However, the parameters of the two tests were dissociated in 18%.Conclusion: A VOR gain of vHIT is a valuable objective parameter with a lateralization value determining vestibular hypofunction. However, considering substantial dissociation between a vHIT and a caloric test, these tests can be complementary tools for the lateralization of vestibular impairment for the comprehensive evaluation of patients' VOR. [ABSTRACT FROM AUTHOR]

Background Parkinson’s disease (PD) is a common neurodegenerative disease characterized by dopaminergic neuronal loss. The underlying cause of PD is unknown. Objective To assess the clinical relevance of vestibular-ocular reflex (VOR) gain in patients with PD, especially those in the early stages. Methods Sixty-three PD patients and 56 control healthy individuals were enrolled in this study between Mar 2015 and Aug 2015. VOR gains were determined by video head impulse test (vHIT) device. Statistical analysis was performed to assess the difference in VOR gains between PD patients and normal people. The relationship of VOR gain with age, duration and severity of disease was also assessed. Results In the control group, average VOR gain was 0.98 ± 0.09 on the left side and 0.99 ± 0.16 on the right side. No statistically significant difference was observed between the two sides in the control group ( P > 0.05). In the PD group, average VOR gain was 1.20 ± 0.22 on the left side and 1.23 ± 0.23 on the right side. No statistically significant difference was observed between the two sides in the PD group ( P > 0.05). There was a significant difference in VOR gain between the PD (both in early and mid-late stages) and the control group ( P < 0.05). A weak correlation was observed between VOR gain and the motor Unified Parkinson Disease Rating Scale score. No correlation of VOR gain with age, duration of disease or the Hoehn and Yahr Scale score was observed. VOR gains in PD patients were found to be higher than normal, especially in the early stages of the disease. Conclusion vHIT is a potential tool to determine the VOR gain in PD patients and may help detect PD at an early stage. [ABSTRACT FROM AUTHOR]

Objective To evaluate the lateral semicircular canal high frequency vestibulo-oculomotor reflex (LSC HF VOR) in children with cochlear implant. Methods 16 children (10 females and 6 males, age range = 5–17 years) receiving a unilateral (n = 12) or a bilateral (n = 4) cochlear implant were included and compared to a control group of 20 age-matched normal-hearing (NH) children. Both implanted and NH children received a vestibular function test battery, including a Vestibulo-Ocular Reflex (VOR) gain assessment by means of a video-Head Impulse Test (vHIT), which represented the main outcome measure. In implanted subjects, vHIT was measured on both sides in the “CI-ON” and “CI-OFF” conditions. Results Overall, no significant LSC HF VOR gain difference was found between CI users and NH peers. In the unilaterally implanted group, the LSC HF VOR gain measured in the “CI-ON” condition was significantly higher than in the “CI-OFF” condition, both in the implanted and in the non-implanted ear. In the bilaterally implanted group there was no such a difference between the two conditions, on either side. Conclusion This is the first study investigating the LSC HF VOR gain in children with unilateral and bilateral CI. The study demonstrates that the LSC HF VOR of bilaterally implanted children is comparable to normal hearing children. [ABSTRACT FROM AUTHOR]

Globally, there are 3 million people living with multiple sclerosis (PLW-MS). A large proportion of PLW-MS have abnormal vestibular function tests that suggest central vestibular lesions. Yet, data regarding vestibular-ocular control in PLW-MS is limited. Thus, we aimed to further characterize compensatory saccade (CS) behavior in PLW-MS. We analyzed video head impulse data from four groups of six age- and sex-matched adults: people living with mild MS (PLW-mild-MS, people living with moderate MS (PLW-moderate-MS), people living with unilateral vestibular deafferentation (PLW-UVD), and healthy controls (HC). PLW-moderate-MS had lower lateral canal vestibulo-ocular reflex (VOR) gain bilaterally compared to PLW-mild MS (p < 0.001), HC (p < 0.001), and PLW-UVD (p < 0.001). CS frequency was higher for impulses towards the less affected side in PLW-moderate-MS versus the more (p = 0.01) and less (p < 0.001) affected sides in PLW-mild-MS. CS latency was shorter (p < 0.001) and CS peak velocity was lower (p < 0.001) with impulses towards the more affected side versus the less affected side in PLW-moderate-MS. However, CS peak velocity with impulses towards each side was similar in PLW-mild-MS (p = 0.12). Gaze position error (GPE) was larger after impulses towards the more affected side versus the less affected side in PLW-moderate-MS (p < 0.001) and PLW-mild-MS (p < 0.001). MS-related disability was moderately associated with VOR gain (p < 0.001) and GPE (p < 0.001). Additionally, we identified micro-saccades and position correcting saccades that were uniquely employed by PLW-MS as compensatory gaze stabilizing strategies. In PLW-MS, the characteristics of compensatory oculomotor behavior depend on the extent of residual VOR gain. [Display omitted] • People living with moderate multiple sclerosis often fail to generate compensatory saccades. • People living with mild multiple sclerosis tend to over-compensate for gaze position error. • The absence of saccades to compensate for low VOR gain may suggest internuclear ophthalmoplegia. [ABSTRACT FROM AUTHOR]

• Placement of a hanger diagonally on the head rotates the head towards the hanger. • The mechanism underlying the hanger reflex (HR) is unknown. • We found an asymmetric reduction in the vestibular response during HR. • This inhibitory somatosensory-vestibular interaction may be a mechanism of HR. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the effects of acquired esotropia on vestibulo-ocular reflex (VOR) gain in children using video (vHIT) and functional head impulse (fHIT) tests. A total of 62 children aged 6–18 years, with acquired esotropia and normal vision, were evaluated in the study. The patients were divided into two sub-groups: accommodative and non-accommodative. VOR gains were analyzed by performing lateral canal vHIT and fHIT with monocular and binocular recordings by a single examiner. Seventeen (10 male, 7 female) children with accommodative esotropia, 24 (14 male, 10 female) children with non-accommodative esotropia, and 21 (8 male and 12 female) healthy controls were included in this study. The vHIT findings did not differ between the groups (p ˃.05). In the non-accommodative esotropia group, the location of the camera in both binocular and monocular vHIT recordings made a significant difference in the left VOR gain (p =.025, z = −2.243, p =.032, and z = −2.143, respectively), but no difference was observed in the right VOR gain. In the accommodative esotropia group, while the camera was on the left there was a significant difference in the right VOR gain between binocular and monocular recordings (p =.016, z = −2.413) but no difference was observed in the left VOR gain. No overt or covert saccade was detected in any group. The statistical differences found in vHIT and fHIT in acquired esotropia patients are thought to be sporadic and based on the results of this study no correction or change in recording technique is required for vHIT or fHIT in children with acquired esotropia. • Video and functional head impulse tests can be performed with standard methods in children with acquired esotropia. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The function of the semicircular canal receptors and the pathway of the vestibulo-ocular-reflex (VOR) can be diagnosed with the clinical head impulse test (cHIT). Recently, the video head impulse test (vHIT) has been introduced but so far there is little clinical experience with the vHIT in patients with peripheral vestibular disorders. The aim of the study was to investigate the horizontal VOR (hVOR) by means of vHIT in peripheral vestibular disorders. Methods: Using the vHIT, we examined the hVOR in a group of 117 patients and a control group of 20 healthy subjects. The group of patients included vestibular neuritis (VN) (n =52), vestibular schwannoma (VS) (n =31), Ménière''s disease (MD) (n =22) and bilateral vestibulopathy (BV) (n =12). Results: Normal hVOR gain was at 0.96±0.08, while abnormal hVOR gain was at 0.44±0.20 (79.1% of all cases). An abnormal vHIT was found in VN (94.2%), VS (61.3%), MD (54.5%) and BV (91.7%). Three conditions of refixation saccades occurred frequently in cases with abnormal hVOR: isolated covert saccades (13.7%), isolated overt saccades (34.3%) and the combination of overt and covert saccades (52.0%). Conclusions: The vHIT detects abnormal hVOR changes in the combination of gain assessment and refixation saccades. Since isolated covert saccades in hVOR changes can only be seen with vHIT, peripheral vestibular disorders are likely to be diagnosed incorrectly with the cHIT to a certain amount. [Copyright &y& Elsevier]

The video head impulse test (vHIT) is a diagnostic tool to examine patients experiencing dizziness by assessing the function of the semicircular canals. vHIT has been widely studied in adults but relatively less so in children. The aim of this study was to evaluate the causes of dizziness and the results of vHIT in children. We also identified factors that affect the vHIT results such as artifacts and technical errors. Retrospective review; Tertiary care center. A total of 39 patients who visited our clinic for dizziness from 2014 to 2017. The gain of vestibulo-ocular reflex, refixation saccades, and artifacts were analyzed using vHIT. We analyzed 691 individual vHIT traces and categorized the artifacts into 8 categories. Twenty-three males and 16 females were included. The mean age was 13.84 ± 2.60 years (range, 7–18). Common causes of dizziness were benign paroxysmal vertigo of childhood (25.6%), vestibular neuritis (20.5%), and vestibular migraine (17.9%). The sensitivity and specificity of vHIT based on the bithermal caloric test results were 40% and 94%, respectively. The analysis of vHIT traces revealed that the children had higher artifact ratios of vHIT than the adults. The main artifacts were high gain and blinking eyes. The vHIT results showed a higher percentage of artifacts in children than in the adults. More careful efforts are required to obtain more accurate results during the test, and it is necessary to check for technical errors while interpreting the results. [ABSTRACT FROM AUTHOR]

Vestibular Migraine in children can mimic other disorders, especially at presentation. Outcome is hard to predict and management may be challenging due to the fact that many of the patients are too young to describe their symptoms and these are not always accompanied by headache. To assess vestibulo-ocular reflex (VOR) in pediatric patients who meet criteria for defined Vestibular Migraine and to compare results to healthy controls. Twenty-one patients aged 11–16 years were included in this prospective multicentric study. VOR was assessed using the video Head Impulse Test by EyeSeeCam®(Interacoustics, Denmark). Patients with Vestibular Migraine (VM) have higher values of gain compared to asymptomatic patients. Video Head Impulse Test (vHIT) is a useful and relatively fast-to-perform examination in children compared to other vestibular tests. Patients with VM seem to have higher values of gain at vHIT. • Gain values in video Head Impulse Test are higher in pediatric patients with VestibularMigraine. [ABSTRACT FROM AUTHOR]

Acute vestibular syndrome is most often caused by vestibular neuritis or stroke, although demyelinating diseases may be responsible for 4% of all AVS episodes. The authors present the case of a previously healthy 17-year-old female patient complaining of spontaneous vertigo and right-sided hearing loss. Otoneurological examination suggested a peripheral vestibular cause and video head impulse test revealed a reduced vestibulo-ocular reflex gain. The presence of sensorineural hearing loss raised the suspicion of a central cause and prompted imaging evaluation. A brain MRI evidenced demyelinating lesions in the right middle cerebellar peduncle and the patient was ultimately diagnosed with Multiple Sclerosis. [ABSTRACT FROM AUTHOR]