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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]

• The data of spontaneous nystagmus and vHIT in 169 neurotologic patients were analysed. • Positive predictive value of nystagmus for vestibular loss on vHIT was 44.4%. • Negative predictive value of nystagmus for vestibular loss on vHIT was 93.5%. • Older adults were more likely to show discrepancies between nystagmus and vHIT. • The data provide guidance for screening vestibular functions by nystagmus and vHIT. The vestibulo-ocular reflex (VOR) in neurotologic patients can be evaluated most quickly by spontaneous nystagmus examinations, and the video Head Impulse Test (vHIT) quantitatively evaluates the VOR of the semicircular canals. We aimed to clarify the concordance and discrepancies between spontaneous nystagmus and vHIT findings, to provide guidance on screening vestibular functions by initial spontaneous nystagmus examination then vHIT. We evaluated 169 outpatients by spontaneous nystagmus examination in the dark using a charge-coupled device camera, then by horizontal vHIT the same day. Vestibular loss on vHIT was defined if both reduced VOR gain (<0.8) and corrective saccade were observed. Adjusted logistic regression modelling revealed that differences in right and left VOR gain positively impacted the presence of nystagmus, which suggests lateralised vestibular dysfunction (P <0.05; odds ratio 1.39 [95% confidence interval, 1.1–1.8] per 0.1 increment). When vHIT is regarded as the standard clinical test, the positive predictive value of nystagmus for vestibular loss on vHIT was 44.4%, and the negative predictive value was 93.5%. The adjusted odds ratio of adults ≥65 years old compared to younger patients associated with a discrepancy of nystagmus and vHIT was significant (2.4 [1.1–5.3]). In conclusion, if spontaneous nystagmus is initially observed in patients, further assessment by vHIT could confirm vestibular dysfunction in 40–50% of cases. If no nystagmus is observed, vHIT might also result in a negative finding in >90% of cases. Older adults appear more likely to show discrepancies between nystagmus and vHIT. [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]