Video head impulse test: a review of the literature

Computerized Rotational Head Impulse Test: Age-Dependent Normative Data

PURPOSE

The objective of this study was to determine the normative vestibulo-ocular reflex gain output values of the computerized rotational head impulse test (crHIT) with stationary visual targets (earth bound) in healthy participants in each decade age band of life: 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, and 70+ years.

METHOD

Seventy-seven community-dwelling participants (10-85 years of age) with normal lateral semicircular canal (SCC) functioning and no symptoms or history of vestibular dysfunction were recruited through convenience sampling and assessed with the crHIT using stationary targets. These participants were assessed using two standard protocols in a randomized order.

RESULTS

Results from 77 participants (M age = 46 years; 43 women, 34 men) were analyzed. Pearson's correlation coefficient and simple linear regression indicated a statistically significant relationship between crHIT gain output and age (p > .05) for right gain, 1030°/s2, and left gain, 1005°/s2. Although a statistically significant relationship was found, the slope was minor, demonstrating that the clinical effect of age on crHIT gain output was insignificant. Furthermore, no statistically significant relationship exists between crHIT gain output and gender (p > .05). Age-dependent normative data were calculated using the 2.5th and 97.5th confidence interval (CI) percentile method. The responses of angular vestibulo-ocular reflex (aVOR) gain values for crHIT are expected to occur within the range for lower limit reference interval (RI) of 0.85-0.9 and upper limit RI of 1.11-1.18 for 1030°/s2 and lower limit RI of 0.86-0.92 and upper limit RI of 1.13-1.16 for 1005°/s2. It can be expected that 90% CI of the population with normal lateral SCC functioning will have aVOR gain values that fall within this range.

CONCLUSION

Despite a statistically significant relationship that exists with aVOR gain output and age, the changes are minor, declining by 0.0088 units per 10 years, justifying the same normative data for all decade age bands.

Clinical value of auditory nerve enhancement in idiopathic sudden sensorineural hearing loss: a retrospective study

Background

The pathogenesis of idiopathic sudden sensorineural hearing loss remains unclear, and no substantial breakthroughs have been achieved in its treatment. Therefore, we conducted this study with the aim to investigate the clinical features and prognostic factors of patients with idiopathic sudden sensorineural hearing loss and auditory nerve enhancement by using three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) magnetic resonance imaging (MRI) of the inner ear.

Methods

We retrospectively analyzed the clinical data of adult patients, who experienced sudden unilateral deafness and were admitted to the Department of Otolaryngology, Shandong Provincial ENT Hospital, between December 2020 and July 2021. Patients were divided into an auditory nerve enhancement group and a normal inner ear group, according to 3D-FLAIR MRI findings. Differences in sex, age, side, disease course, underlying diseases, dizziness/vertigo, vestibular function, degree of deafness, hearing classification, and treatment efficacy were analyzed.

Results

Of the 112 cases of sudden idiopathic deafness, 16.07% exhibited enhancement of the auditory nerve on inner-ear 3D-FLAIR MRI. Statistically significant differences in the degree and type of hearing loss were detected between the two groups (p < 0.05). The rates of abnormal results in the caloric, vestibular-evoked myogenic potential, and video head impulse tests were higher in the auditory nerve enhancement group. The cure rate (11.1%) in patients with auditory nerve enhancement was lower than that in patients with normal inner ear MRI findings (28.7%); however, the difference was not statistically significant.

Conclusion

Findings from 3D-FLAIR MRI scans of the inner ear indicated that patients with sudden deafness and auditory nerve enhancement experienced severe hearing loss, aggravated vestibular function injury, and a significantly decreased cure rate. Prompt treatment, ideally within 2 weeks of disease onset, can facilitate hearing recovery.

Navigating the vestibular maze: text-mining analysis of publication trends over five decades

Introduction

The field of vestibular science, encompassing the study of the vestibular system and associated disorders, has experienced notable growth and evolving trends over the past five decades. Here, we explore the changing landscape in vestibular science, focusing on epidemiology, peripheral pathologies, diagnosis methods, treatment, and technological advancements.

Methods

Publication data was obtained from the US National Center for Biotechnology Information (NCBI) PubMed database. The analysis included epidemiological, etiological, diagnostic, and treatment-focused studies on peripheral vestibular disorders, with a particular emphasis on changes in topics and trends of publications over time.

Results

Our dataset of 39,238 publications revealed a rising trend in research across all age groups. Etiologically, benign paroxysmal positional vertigo (BPPV) and Meniere's disease were the most researched conditions, but the prevalence of studies on vestibular migraine showed a marked increase in recent years. Electronystagmography (ENG)/ Videonystagmography (VNG) and Vestibular Evoked Myogenic Potential (VEMP) were the most commonly discussed diagnostic tools, while physiotherapy stood out as the primary treatment modality.

Conclusion

Our study presents a unique opportunity and point of view, exploring the evolving landscape of vestibular science publications over the past five decades. The analysis underscored the dynamic nature of the field, highlighting shifts in focus and emerging publication trends in diagnosis and treatment over time.

Video head impulse test in stroke: a review of published studies

Accurate and timely diagnosis of posterior circulation stroke in patients with acute dizziness is a challenge that can lead to misdiagnosis and significant harm. The present review sought to identify and describe published research on the clinical application of vHIT in posterior circulation stroke. vHIT, a portable device, has gained prominence in evaluating peripheral vestibular disorders and offers potential applications in diagnosing neurological disorders, particularly posterior circulation stroke. Several studies have shown that vHIT can differentiate between stroke and vestibular neuritis based on VOR gain values, with high sensitivity and specificity. The manuscript also discusses vHIT's performance in differentiating between types of posterior circulation stroke, such as PICA, AICA, and SCA strokes. While vHIT has demonstrated promise, the review emphasizes the need for further research to validate its use as a tool to rule out stroke in acute dizziness patients in the emergency department. In conclusion, the manuscript underscores the potential of vHIT as a valuable addition to the diagnostic arsenal for acute dizziness, particularly in the context of posterior circulation stroke. It calls for further research and wider adoption of vHIT in clinical settings to improve patient care and reduce unnecessary costs associated with misdiagnoses.

Normalization of the Suppression Head Impulse Test (SHIMP) and its correlation with the Head Impulse Test (HIMP) in healthy adults

OBJECTIVE

In our study, it was aimed to compare vestibulo-ocular reflex (VOR) gain and saccade parameters in HIMP and SHIMP tests between gender, right and left ears, and age groups in healthy adults and to examine the correlation between the tests regarding these parameters.

METHODS

The study included a total of 100 healthy participants aged 18-65 and without complaints of hearing loss, dizziness, lightheadedness, and/or imbalance. Participants underwent HIMP and SHIMP tests, respectively.

RESULTS

No significant difference was found in HIMP and SHIMP VOR gain values according to gender and age groups. SHIMP duration was significantly longer in women. VOR gain values were lower in the right ear. HIMP amplitude values were higher and SHIMP amplitude values were lower with increasing age. In older age groups, SHIMP peak velocity and duration values were significantly decreased, while HIMP duration value increased and latency value was longer. In the 1st saccade, a significant difference was obtained between HIMP and SHIMP tests for all saccade parameters. There was a statistically significant positive correlation between the VOR gain values of HIMP and SHIMP tests.

CONCLUSIONS

The present study showed that VOR gain and saccade parameters obtained in different age groups will be important in determining clinical outcomes in vestibular pathologies.

Comparative utility of vestibular function tests in patients with peripheral and central vestibular dysfunction

Background

Bithermal caloric irrigation, video head impulse test (vHIT), and rotational testing are commonly used to assess peripheral vestibular function, but the relative clinical utility of each test in differentiating patients with peripheral vestibulopathy is debated.

Objectives

To determine whether (1) the combination of two or more vestibular tests enhances diagnostic utility over a single test; (2) abnormal test results on vestibular tests correlate with one another.

Methods

Retrospective analysis of data collected from multidisciplinary vestibular clinics at two academic medical centers from 2016 to 2022.

Results

150 patients (54.10 ± 15.09 years, 88 females) were included. No individual test was significantly better at predicting the presence of peripheral vestibular damage (p > 0.05). vHIT test results improved significantly when combined with either the caloric test (p = 0.007) or rotary chair test (p = 0.039). Caloric and rotational testing had high sensitivity (74.65% and 76.06%, respectively) and specificity (83.54% and 78.48%, respectively). vHIT demonstrated excellent specificity (89.87%) but poor sensitivity (47.89%). Caloric, vHIT, and rotary chair tests results did not correlate with one another (p > 0.05).

Conclusions

Vestibular function tests have comparable diagnostic utility, yet each offers unique advantages. Caloric and rotational testing may be best suited for screening peripheral damage and vHIT may function ideally as a confirmatory test.

Video head impulse test for the assessment of vestibular function in patients with idiopathic sudden sensorineural hearing loss without vertigo

OBJECTIVE

Idiopathic sudden sensorineural hearing loss may be accompanied by dizziness without true vertigo. This study used the video head impulse test to evaluate vestibular function in idiopathic sudden sensorineural hearing loss patients who described experiencing dizziness and not true vertigo.

METHODS

A prospective study was conducted of 30 consecutive patients diagnosed with idiopathic sudden sensorineural hearing loss with dizziness without true vertigo. A comparison of the video head impulse test results of the patients who complained of dizziness (symptomatic group) with a group of patients with idiopathic sudden sensorineural hearing loss and no dizziness (asymptomatic) was performed.

RESULTS

Nine patients (30 per cent) were symptomatic. Two of those patients had abnormal video head impulse test findings. Seven patients in the asymptomatic group (7 out of 21, 33 per cent) presented with abnormal video head impulse test results. No significant difference in vestibular function between the two groups was detected by the video head impulse test.

CONCLUSION

The site of insult in patients with idiopathic sudden sensorineural hearing loss without true vertigo is usually limited to the cochlea or the cochlear nerve.

Prognosis of vestibular dysfunction in idiopathic sudden sensorineural hearing loss with vertigo: a prospective cohort study

BACKGROUND

Approximately 28%-57% of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) have an acute vertigo attack and probable vestibular dysfunction; however, the prognosis of vestibular function in these patients remains unclear.

METHODS

A prospective cohort study of patients with ISSNHL and vertigo was conducted to evaluate the prognosis of vestibular function, especially the roles of peripheral vestibular restoration and central compensation, in patients with ISSNHL and vertigo. Clinical data were recorded at baseline and at 60 days from onset in participants with unilateral ISSNHL with vertigo. Enrolment occurred from May 1, 2019 to May 1, 2022 in the outpatient clinics and inpatient departments of the Eye and ENT Hospital of Fudan University in Shanghai. The primary outcome measure was the recovery rate of vestibular function 60 days after onset as assessed by vestibular function tests, including caloric tests, cervical and ocular vestibular-evoked myogenic potential tests (cVEMP, oVEMP), video head impulse tests (vHIT), and sensory organization tests (SOT). The secondary outcome measure was the recovery of subjective evaluations in vestibular dysfunction (the dizziness handicap inventory [DHI], and the visual analogue scale for vertigo [VAS-V]) and hearing assessments (pure-tone audiometry [PTA]).

RESULTS

Overall, 86 patients were recruited, with an average duration of disease of 11.7 days and follow-up time of 60.7 days. Vestibular function was significantly improved (p < 0.05) after 60 days. The recovery rates were 100% for anterior semicircular canal (ASC), 56% for posterior semicircular canal (PSC), 41% for horizontal semicircular canal (HSC), 28% for saccule, and 23% for utricle. The recovery of vestibular function was not significantly related to changes in DHI (p = 0.245), VAS-V score (p = 0.509), or hearing outcome (p = 0.390).

CONCLUSIONS

Restoration of peripheral vestibular sensory input and central vestibular compensation can occur during the course of ISSNHL with vertigo. The otolith organs are at a higher risk of being affected and have worse recovery than the semicircular canals. Incomplete and in-process restoration of vestibular dysfunction may perturb and delay the establishment of central compensation for balance. Neither hearing outcomes nor subjective vestibular symptoms are related to recovery from vestibular dysfunction.

TRIAL REGISTRATION

ClinicalTrials.gov (identifier NCT03951584).

Machine Learning Based Diagnosis of Vertigo using Video Head Impulse Test

This work utilises the strength of state space based dynamic modelling and the ability of machine learning based segmentation of SRM standard descriptors to reach superior diagnostic capabilities. Dynamic modelling ensured vHIT input-output characteristics generated SRM standard descriptors, which were consequently used in formation of ML classification models.The best ML model was Linear SVM when built on left and right sided data with the SRM standard descriptors: rise time, settling time, settling minimum, settling maximum, overshoot and undershoot. The model was able to classify individuals to patient or control groups with an accuracy of 100% and a sensitivity and specificity of 1.Clinical Relevance- Dizziness is one of the most common presentations to family physicians and emergency departments. It is associated with significant medical complications such as falls as well as economic costs to both the individual and the community. Vestibular diseases comprise the bulk of dizzy disorders and are often associated with dysfunction of the vestibular or inner ear balance apparatus. This is most commonly the result of hypo-function of the semi-circular canals. Clinically, the most commonly employed objective test of semicircular function is the video Head Impulse Test (vHIT). Here we provide a machine learning approach to a more comprehensible and accurate interpretation of the results obtained by the vHIT to more robustly establish the presence and severity of VOR dysfunction, and ultimately aid in the diagnosis of vestibular disorders.

Dissociation between video head impulse test and caloric test: a marker of menière's disease? - A systematic review and meta-analysis

OBJECTIVE

To analyze, by means of a systematic review and meta-analysis, the proportion of patients with Meniere's disease who have altered caloric test and vHIT, as well as to determine the prevalence of altered caloric test and normal vHIT dissociation in the diagnosis of Meniere's disease.

METHODS

The literature search had no restriction regarding the period of publication on the following indexed data platforms: PubMed, PubMed PMC, BVS-Bireme, Web of Science, Embase and Cochrane Library. Articles that evaluated patients with Meniere's disease who underwent caloric test and vHIT were included. Two researchers independently conducted the analysis of the articles, promoting the selection and capture of data, following the recommendations of the PRISMA method, and complying with the criteria for articles inclusion and exclusion defined in the research protocol. In case of disagreement during the selection process, a third researcher was included for analysis.

RESULTS

From a total of 427 initial studies, the researchers selected 12 articles, published between 2014 and 2021, with a total of 708 patients evaluated, with a mean age of 52.72 years old. The prevalence of patients with Meniere's disease with altered caloric reflex test was 64% (95% CI 57%‒71%), while the prevalence of altered vHIT was only 28% (95% CI 16%-40%). The prevalence of the altered caloric test + normal vHIT dissociation was 47% (95% CI 37%-57%).

CONCLUSION

The video head impulse test and the caloric test are valuable tools for vestibular assessment. The dissociation of findings between these two tests in patients with Meniere's disease was more prevalent in this meta-analysis and may be a result of the tonotopy of specialized hair cells in the ampullary crest. The prevalence of altered caloric test was 64% and anormal vHIT was 28%. The dissociation caloric asymmetry and normal vHIT was observed in 47% of the patients.

LEVEL OF EVIDENCE: 1

Spontaneous Nystagmus in Patients With Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo

OBJECTIVE

This study aimed to investigate the incidence of spontaneous nystagmus (SN) in posterior semicircular canal (PSCC) benign paroxysmal positional vertigo (BPPV) and its effect on treatment outcomes.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

METHODS

This study included 50 patients with idiopathic unilateral PSCC BPPV between July 2021 and May 2022. The presence of SN was investigated, and the results of the bithermal caloric test and video head impulse test (vHIT) were compared.

RESULTS

SN was observed in 13 (26%) of the 50 patients presenting PSCC BPPV. The direction of SN was mainly unidirectional and horizontal in 12 of the 13 patients with a slow-phase velocity ranging from 2 to 4°/s. One patient presented an upbeating torsional SN at the initial evaluation. The mean vHIT gain of the PSCC on the affected side was significantly lower in patients with SN than those without SN (p = .004, Mann-Whitney U test). The proportion of patients who recovered within 2 sessions of the repositioning maneuver was significantly higher in those without SN than that in those with SN (p < .001, Fisher's exact test).

CONCLUSION

This study demonstrated that the treatment outcomes of PSCC BPPV were significantly worse in patients with SN than those without SN. Examining the presence of SN in patients with PSCC BPPV may be helpful in counseling the patients on prognosis, and it is expected that more sessions of canalith repositioning maneuver may be required to treat PSCC BPPV in patients with SN than those without SN.

Reduced Vestibulo-Ocular Reflex During Fast Head Rotation in Complete Darkness

The human vestibulo-ocular reflex (VOR) leads to maintenance of the acuity of an image on the retina and contributes to the perception of orientation during high acceleration head movements. Our objective was to determine whether vision affects the horizontal VOR by assessing and comparing the performance at the boundaries of contribution of: (a) unrestricted visual information and (b) no visual information. Understanding how the VOR performs under both lighted and unlighted conditions is of paramount importance to avoiding falls, perhaps particularly among the elderly. We tested 23 participants (M age = 35.3 years, standard error of mean (SEM) = 2.0 years). The participants were tested with the video Head Impulse Test (vHIT), EyeSeeCam from Interacoustics™, which assesses whether VOR is of the expected angular velocity compared to head movement angular velocity. The vHIT tests were performed under two conditions: (a) in a well-lit room and (b) in complete darkness. The VOR was analyzed by evaluating the gain (quotient between eye and head angular velocity) at 40, 60 and 80 ms time stamps after the start of head movement. Additionally, we calculated the approximate linear gain between 0-100 ms through regression. The gain decreased significantly faster across time stamps in complete darkness (p < .001), by 10% in darkness compared with a 2% decrease in light. In complete darkness, the VOR gain gradually declined, reaching a marked reduction at 80 ms by 10% (p < .001), at which the head velocities were 150°/second or faster. The approximate linear gain value was not significantly different in complete darkness and in light. These findings suggest that information from the visual system can modulate the high velocity VOR. Subsequently, fast head turns might cause postural imbalance and momentary disorientation in poor light in people with reduced sensory discrimination or motor control, like the elderly.

Video Head Impulse Test Demonstrates a Residual Function after Plugging of Dehiscent Superior Semicircular Canal

OBJECTIVE

Plugging a symptomatic dehiscent superior semicircular canal (SSCC) often leads to a nonfunctional postoperative canal. However, in some instances, a residual function has been described. This study attempts to describe what factors may lead to such residual function.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral center.

PATIENTS

Thirty-five patients with confirmed SSCC dehiscence.

INTERVENTION

Video head impulse test was conducted pre- and postoperatively to assess any difference in the function of the SSCC.

MAIN OUTCOME MEASURES

Mean gain and pathological saccades were recorded according to well-established thresholds along with dehiscence length and location to evaluate any associations to residual canal function.

RESULTS

When comparing preoperative to postoperative SSCC abnormal gains, a significant increase was observed after plugging ( p = 0.023). This also held true when abnormal gain and pathologic saccades were taken together ( p < 0.001). Interestingly, 55.3% of patients were observed to remain with a residual SSCC function 4 months postoperatively even with a clinical improvement. Of these, 47.6% had normal gain with pathologic saccades, 38.1% had an abnormal gain without pathologic saccades, and 14.3% had normal gain without pathologic saccades (normal function). Preoperatively, SSCC abnormal gain was associated with a larger dehiscence length mean ( p = 0.002). Anterosuperior located dehiscences were also associated with a larger dehiscence length mean ( p = 0.037). A residual SSCC function after plugging was associated with a shorter dehiscence length regardless of location ( p = 0.058).

CONCLUSION

Dehiscence length and location may be useful in predicting disease symptomatology preoperatively and canals function recovery after plugging. These factors could be used as indicators for preoperative counseling and long-term management.

Video Head Impulse Test: A Comparison and Analysis of Three Recording Systems

The present study aimed to compare the efficacy and reproducibility of three existing systems in a group of healthy individuals for vHIT. A prospective randomized study was conducted on 12 healthy individuals. The vHIT tests were carried out. The values of the gains for the 3SCCs of each ear were collected using the three devices. The expected average gain of 1 was the gain standard. The statistical significance in the difference in gains were assessed. There is good reproducibility of the results of the vHIT examination. EyeSeeCam appeared to be the worst performing system with a slightly overstated average gain of 1.15. Otometrics has longest average examination time per patient. Synapsis is the system with the best quality/time invested and easiest to access. Video head impulse system depends on the examiner's preference, reproducible and superimposable depending on the examiner and experience.

Effects of saccade delay, side of deficit, and training on detection of catch-up saccades during head-impulse test in virtual-reality-enhanced mannequin

In this study, a training simulator for the examination of dizzy patients based on a virtual-reality-enhanced mannequin (VREM) was developed to evaluate the detection of catch-up saccades during head impulse test (HIT) and the effect of training in VREM. For novices (n = 35), 2 trials were conducted before and after a training session. Experts (n = 7) were submitted to an evaluation session. In each trial, a left or a right horizontal canal deficit with an overt catch-up saccade (delay between 110 and 320 ms) was randomly presented. Participants scored the difficulty in performing the maneuver, in recognizing the saccades, and the self-confidence in the diagnosis using a visual analogue scale (VAS). Saccade delay significantly influenced the performance. Training significantly improved the sensitivity in the residents (69.1% before to 97.9% after the training, p < 0.001, Fisher's exact test, n = 560 tests), surpassing experts' performances (p < 0.001, versus 87% in experts, Fisher's exact test). The specificity also increased to the expert level (78% before to 95% after the training, and 95% in experts, p < 0.001, Fisher's exact test). The VAS showed a decrease difficulty to execute the HIT, with an increase in the confidence after training. VREM improved the HIT execution performance and the confidence in novice practitioners.

Evaluation of postural stability and vestibulo-ocular reflex in adults with chronic suppurative otitis media

PURPOSE

To evaluate the vestibulospinal reflex and vestibulo-ocular reflex (VOR) in patients with chronic suppurative otitis media (CSOM) using posturography and the video head impulse test (vHIT).

METHODS

Sixty-five patients with CSOM and 65 healthy participants as controls were included. Patients with CSOM were instructed to complete the dizziness handicap inventory (DHI). All participants underwent otoscopy, pure-tone audiometry, posturography sensory organization test (SOT), and vHIT.

RESULTS

Patients with CSOM exhibited a high prevalence of dizziness. The CSOM group had poor SOT vestibular scores compared to the control group. Patients with CSOM had worse sways in the antero-posterior and mediolateral planes. The CSOM group was divided into two subgroups according to the type of hearing loss. SOT vestibular scores were significantly poorer in the mixed hearing loss group than those in the conductive hearing loss group. We found a positive correlation between disease duration and poor SOT vestibular scores. Moreover, poor SOT vestibular scores correlated with high DHI scores. We found abnormalities in the vHIT results in the CSOM group in the form of low VOR gain and corrective saccades.

CONCLUSION

Our study provides clinical evidence of dizziness, poor postural control, and VOR abnormalities in patients with CSOM. The presence of sensory elements of hearing loss in patients with CSOM appears to be positively associated with vestibular dysfunction.

Correlation between nystagmus intensity and vestibular-ocular reflex gain in benign paroxysmal positional vertigo: A prospective, clinical study

BACKGROUND

Video head impulse test (vHIT) and videonystagmography (VNG) provide significant benefits in evaluating benign paroxysmal positional vertigo (BPPV) and determining the semicircular canal localization of the otoconia.

OBJECTIVE

This study aimed to investigate the relationship between vestibular-ocular reflex (VOR) gains measured via vHIT and the slow-phase velocity (SPV) of nystagmus in patients with the posterior semicircular canal (PSCC)-BPPV.

METHODS

Sixty-two patients were included in this study and divided into the study (n = 32, patients with isolated PSCC-BPPV) and control (n = 30, age- and sex-matched healthy individuals) groups. While VOR gains were measured with vHIT in both groups and compared between groups, the SPV values of nystagmus observed during the Dix-Hallpike maneuver in the study group were recorded using VNG and compared with the VOR gains of the study group.

RESULTS

There were significant differences in posterior canal VOR gains between the study and control groups (p < 0.001 and p < 0.01, respectively). Although the affected PSCC had decreased VOR gains versus the control group, it was still within the normal range. However, there was no significant relationship between the VOR gains of the affected PSCC and the SPV of the nystagmus.

CONCLUSIONS

vHIT can help detect semicircular canal dysfunction in patients with PSCC-BPPV. The SPV values of nystagmus on VNG during the Dix-Hallpike maneuver do not correlate with the level of VOR gain.

Head and vestibular kinematics during vertical semicircular canal impulses

BACKGROUND

The video head impulse test (vHIT) is a common assessment of semicircular canal function during high-speed impulses. Reliability of the vHIT for assessing vertical semicircular canals is uncertain. Vertical head impulses require a complex head movement, making it difficult to isolate a single semicircular canal and interpret resulting eye rotations.

OBJECTIVE

The purpose of this study was to provide descriptive head kinematics and vestibular stimuli during vertical plane impulses to ultimately improve impulse delivery and interpretation of vHIT results for vertical semicircular canals.

METHODS

Six participants received right anterior (RA) and left posterior (LP) semicircular canal impulses. Linear displacements, rotational displacements, and rotational velocities of the head were measured. Peak velocities in semicircular canal planes and peak-to-peak gravitoinertial accelerations at the otolith organs were derived from head kinematics.

RESULTS

The largest rotational velocities occurred in the target semicircular canal plane, with non-negligible velocities occurring in non-target planes. Larger vertical displacements and accelerations occurred on the right side of the head compared to the left for RA and LP impulses.

CONCLUSIONS

These results provide a foundation for designing protocols to optimize stimulation applied to a singular vertical semicircular canal and for interpreting results from the vHIT for vertical semicircular canals.

Characteristics of vestibular migraine, probable vestibular migraine, and recurrent vertigo of childhood in caloric and video head impulse tests

Objective

Vertigo is very common in children, but the specific diagnosis and characteristics are not clear. The main objective of this study was to analyze the characteristics of caloric test (CT) and video head impulse test (vHIT) in vestibular migraine of childhood (VMC), probable vestibular migraine of childhood (PVMC), and recurrent vertigo of childhood (RVC), which can provide a reference value for their clinical diagnosis.

Methods

We selected VMC, PVMC and RVC patients under 18 years of age from the outpatient Department of Otolaryngology–Head and Neck Surgery between May 2021 and August 2022. All patients underwent vestibular function examinations, including eye movement recording CT and vHIT. CT results depended on whether both canal paresis and directional preponderance were under normal limits, and vHIT results depended on the gain values of vestibulo-ocular reflex. The results of both tests were analyzed according to the disease type.

Results

Among the 81 pediatric vertigo patients aged 5–17 years, 44 were females and 37 were males. According to the type of vertigo, 29 patients (25.80%) were diagnosed with VMC, 11 (13.58%) with PVMC, and 41 (50.62%) with RVC. The abnormal rates of the CT in VMC, PVMC, and RVC patients were 24.14%, 36.36%, and 17.07%, respectively. There was no significant difference in the abnormal rates among the three groups (P &gt; 0.05). None of the patients showed abnormal vHIT results (all abnormal rates 0.00%). The abnormal CT rates were significantly higher than those of abnormal vHIT rates (P &lt; 0.05).

Conclusions

VMC, PVMC, and RVC are more likely to be diagnosed by symptoms, as neither CT nor vHIT are specific to any conditions. Due to different clinical presentations of vertigo in pediatric patients, it is critical to further clarify the diagnosis with medical history and clinical characteristics.

Reliability of Monothermal Caloric Test as Screening Test of Vestibular System

This retrospective study completed at a tertiary care center aimed to assess the monothermal caloric test (MCT) as a screening test, using the bithermal caloric test (BCT) as a reference. Additionally, it attempts to measure the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of a fixed inter-auricular difference (IAD) value for both cold and warm stimuli using water irrigation. Medical records of 259 patients referred for vestibular symptoms who underwent BCT with water irrigation were reviewed. Patients with bilateral vestibular weakness and caloric tests using air irrigation were excluded. BCT showed 40.9% unilateral weakness. Two formulas were used to determine the monothermal caloric asymmetry (MCA-1 and MCA-2). The measurement of agreement Kappa between the two formulas in comparison with BCT revealed moderate agreement at 0.54 and 0.53 for hot and cold stimulation, respectively. The monothermal warm stimulating test (MWST) using MCA-2 showed better results, with a sensitivity of 80%, specificity of 91%, PPV of 83.1%, and NPV of 89.2%. Thirty-four patients had horizontal spontaneous nystagmus (HSN) with a mean velocity of 2.25°/s. These patients showed better sensitivity but lower specificity after adjustment of HSN using the MCA-2 formula at warm temperatures. Therefore, they should complete the caloric test with cold irrigation to perform the BCT. MCT is efficient as a screening test if the warm stimulus is used with the MCA-2 formula fixed at 25%. If present, HSNs should be adjusted. Negative IAD (normal) in the absence or presence of adjusted HSN or slow-phase eye velocity ≤ 6°/s at each right and left warm stimulation should be accomplished by the BCT.

What does the video head impulse test tell us about post-caloric vestibular recruitment?

OBJECTIVE

The vestibular recruitment observed in caloric testing is a new tool in the study of the vestibulo-ocular reflex. This study aimed to determine the sensitivity and specificity of the video head impulse test to detect post-caloric vestibular recruitment.

METHOD

In this cross-sectional study, all participants underwent the standard otoneurological assessment of the service, caloric test, and video head impulse test. A non-linear mixed model was used to test for associations.

RESULTS

The study group consisted of 250 (89 male and 161 female) patients, with a mean age of 54.84 years. The control group comprised 35 participants, 18 men and 17 women, with a mean age of 40.42 years. Sex and age had no effect on group responses. There was no difference between the study and control groups regarding the interaction between recruitment and gain (p = 0.7487); recruitment and overt (p = 0.7002) and covert saccades (p = 1.0000); and recruitment and anti-compensatory saccades in the contralateral ear (p = 0.3050). The video head impulse test had a sensitivity of 51% and a specificity of 50% as a predictor of post-caloric recruitment.

CONCLUSION

The video head impulse test results showed no relevance in predicting post-caloric vestibular recruitment.

Diagnostic Value of the Vestibular Autorotation Test in Menière's Disease, Vestibular Migraine and Menière's Disease with Migraine

(1) Background: Vestibular migraine (VM) and Menière's disease (MD) share multiple features in terms of clinical presentations and auditory-vestibular functions, and, therefore, more accurate diagnostic tools to distinguish between the two disorders are needed. (2) Methods: The study was of retrospective design and examined the data of 69 MD patients, 79 VM patients and 72 MD with migraine patients. Five vestibular autorotation test (VAT) parameters, i.e., horizontal gain/phase, vertical gain/phase and asymmetry were subjected to logistic regression. The receiver operating characteristic (ROC) curves were generated to determine the accuracy of the different parameters in the differential diagnosis of MD and VM. (3) Results: Our results showed that the horizontal gain of VAT significantly outperformed other parameters in distinguishing MD and VM. In addition, the sensitivity, specificity and accuracy of the horizontal gain were 95.7%, 50.6% and 71.6%, respectively, for the differentiation between VM and MD. In most MD patients, the horizontal gain decreased in the range of 3-4 Hz, while in most VM patients, horizontal gain increased in the range between 2-3 Hz. More MD with migraine patients had an increased horizontal gain when the frequency was less than 5.0 Hz and had a decreased horizontal gain when the frequency was greater than 5.0 Hz. (4) Conclusion: Our study suggested the VAT, especially the horizontal gain, as an indicator, may serve as a sensitive and objective indicator that helps distinguish between MD and VM. Moreover, VAT, due to its non-invasive and all-frequency nature, might be an important part of a test battery.

Age-related High-frequency Hearing Loss Is Not Associated With Horizontal Semicircular Canal Function

OBJECTIVE

Investigate the association between age-related hearing loss and reduced peripheral vestibular function using paired assessments of high-frequency hearing and horizontal semicircular canal (HSC) function. We hypothesized that age-related high-frequency hearing loss would be correlated with reduced HSC function and, therefore, useful to predict age-related vestibular hypofunction.

DESIGN

We conducted a single center, retrospective cross-sectional study in a tertiary/academic referral hospital. This study included 185 patients who were diagnosed with a cerebellopontine angle (CPA) tumor and referred to the academic hospital to evaluate treatment options. Data collected included pure-tone audiometry, caloric reflex test, video head-impulse test (vHIT), and medical history. High-frequency hearing loss was quantified by the high Fletcher index (hFI), and horizontal semicircular canal (HSC) function were quantified by the caloric reflex test and vHIT.

RESULTS

We observed a significant association between age and high-frequency hearing loss that was significantly worse in men compared with women. In contrast, we observed no significant association between age and HSC function assessed by either the caloric reflex test or vHIT. We observed associations between HSC function and sex, with male sex predicting reduced HSC function by caloric reflex testing but enhanced HSC function by vHIT. High-frequency hearing loss did not predict HSC hypofunction.

CONCLUSIONS

We found no evidence indicating age-related decline in HSC function or an association between age-related high-frequency hearing loss and age-related decline in HSC function. We did observe sex-specific differences in HSC function. Our study highlights the need for sex-specific normative values for identifying age-related reduced peripheral vestibular function and for future work linking comprehensive assessments of inner ear function with tests of balance and stability to understand the complex interactions underlying hearing loss and imbalance, especially in the elderly.

New onset episodic vertigo as a presentation of vestibular neuritis

Objective

Vestibular neuritis (VN) is a common peripheral cause of acute vestibular syndrome, characterized by sustained vertigo and gait instability, persisting from 1 day to several weeks. With the widespread use of comprehensive vestibular function tests, patients with VN and non-sustained vertigo have drawn attention. In this study, we retrospectively analyzed the clinical presentation of patients with VN and episodic vertigo, aiming to expand the atypical clinical features of VN.

Methods

This retrospective study enrolled 58 patients with VN. Among them, 11 patients with more than 3 remissions per day, each lasting over 1 h were assigned to the episodic vertigo (EV) group, and 47 subjects without significant relief into the sustained vertigo (SV) group. Demographic information, clinical manifestations and data of supplementary examinations were collected and statistically analyzed. These patients were followed up 1 year after discharge to gather prognostic information.

Results

The incidence of spontaneous nystagmus (SN) and proportion of severe vertigo (Dizziness Handicap Inventory questionnaire score >60) in the SV group were significantly higher than those in the EV group. Spearman correlation showed that with a longer disease course, the velocity of overt saccade was smaller (p < 0.05, Rs = −0.263) in all patients with VN.

Conclusion

The non-sustained manifestations in VN overlap with a wider spectrum of other vestibular disorders and stroke-related vertigo, which add an additional layer of complexity to the differential diagnosis of new onset episodic vertigo. By retrospectively analyzing the clinical characteristics and vHIT parameters, our study has expounded on the atypical features and potential pathophysiological mechanism of episodic syndromes in VN. VOR gain and saccades measured by vHIT could be reliable indicators for vestibular rehabilitation process.

A Prospective Study on the Vestibular Toxicity of Gentamicin in a Clinical Setting

OBJECTIVE

Gentamicin is a widely used aminoglycoside with ototoxicity as a known adverse effect. Because of the difficulty in clinical recognition, the prevalence of gentamicin ototoxicity in practice is thought to be higher than reported. This study aimed to prospectively assess the effect of gentamicin on vestibular function and whether ototoxicity is underrecognized.

STUDY DESIGN

Single-center, prospective, nonblinded trial.

SETTING

Inpatient tertiary hospital setting followed by vestibular outpatient clinic review.

PATIENTS

Forty-eight patients undergoing a urologic procedure were recruited, with 24 and 17 patients having one or two follow-up tests, respectively, after initial gentamicin administration.

INTERVENTIONS

Single dose of gentamicin during a urologic procedure.

MAIN OUTCOME MEASURES

Gains for the vestibuloocular reflex (VOR) were measured using the video head impulse test before receiving gentamicin and at two other timepoints after gentamicin. The gains in VOR were then compared with previous testing sessions to determine if there was a deterioration after gentamicin use.

RESULTS

Before receiving gentamicin, the gains for horizontal VOR were measured for 48 patients. The gains were measured a second time for 24 patients at varying durations postgentamicin (1-56 d) and a third time for 17 patients (14-152 d) postgentamicin. The mean VOR gain for Timepoints 1, 2, and 3 were 0.72 ± 0.13, 0.75 ± 0.16, and 0.79 ± 0.18, respectively. Linear-mixed model with repeated-measure analysis revealed no significant difference in VOR gain between Timepoints 1 and 2 ( p = 0.19).

CONCLUSION

There was no significant effect observed on mean VOR gain decrement after a single dose of gentamicin.

Comparison of EOG and VOG obtained eye movements during horizontal head impulse testing

Introduction

Video head impulse testing is frequently used to evaluate the vestibular function. During this test, eye movement responses are recorded with video-oculography (VOG). However, the use of VOG can sometimes be challenging, especially due to pupil detection problems (e.g., blinking, droopy eyelids, etc.). Therefore, this study investigated whether electro-oculography (EOG), a technique that does not depend on pupil tracking but on the orientation of the corneoretinal potential, might be an alternative to VOG for quantifying eye movement responses during head impulse testing.

Subjects and methods

Head impulse testing was performed in 19 healthy subjects without a prior history of vestibular symptoms. Horizontal eye movements were recorded simultaneously with EOG (using an EOG system) and VOG (using a VHIT system: ICS Impulse). The eye movement responses to each side of both techniques were compared using a concordance correlation coefficient (r_c), t-testing, and Bayes Factor (BF) paired t-testing.

Results

EOG and VOG obtained eye movement traces that correlated well with each other during head impulse testing (average r_c = 0.89). Average VOR gains obtained with EOG and VOG were not significantly different from each other for all subjects during left head impulses. However, VOG gains differed between both techniques regarding right head impulses. VOG showed significant VOR gain asymmetry (5% to the right), whereas EOG showed no significant asymmetry (1% to the right).

Conclusion

This study demonstrated the use of EOG to record eye movements during head impulse testing for the first time. EOG and VOG obtained eye movement traces that correlated well with each other during horizontal head impulse testing. In addition, EOG showed smaller VOR gain asymmetry in healthy individuals, in contrast to VOG. These findings indicate that EOG might potentially be applicable as an alternative to VOG for collecting eye movement responses during head impulse testing.

Trial registration number

10192021-38 dated 19.10.21.

The Narrowed Internal Auditory Canal: A Distinct Etiology of Pediatric Vestibular Paroxysmia

Vestibular paroxysmia (VP) is a disorder encountered in the pediatric population that etiology has been attributed to neurovascular cross-compression syndrome (NVCC). The purpose of this study was to report a new probable pathological condition, the narrowed internal auditory canal (IAC), which appears to be involved in the development of a clinical picture of VP in the pediatric population. A retrospective descriptive comparative study was conducted to compare clinical, electrophysiological, radiological, and therapeutic outcomes in both etiologies. Overall, 16 pediatric patients suffering from VP were included and divided into two groups: patients with narrowed internal auditory (Group 1) were compared to those with NVCC syndrome (Group 2). Patients in both groups were similar in terms of auditory complaints, as well as hearing, vestibular, and electrophysiological status. A narrowed IAC was encountered in the adolescent age category and females, especially those with rapid growth. The diagnosis requires a careful analysis of the shape and diameters of the IAC. Radiologic measurements in the axial plane do not seem to be sufficient to confirm the diagnosis, and, therefore, an analysis of diameters in the coronal plane is required. Treatment with sodium-channel blockers drugs showed promising results not only by relieving vertigo but also by normalizing the electrophysiological findings. In conclusion, a narrowed IAC can be considered in patients suffering from VP.

Agreement Between Caloric and Horizontal Video Head Impulse Testing in School-Aged Children Presenting With Dizziness

OBJECTIVE

The purpose of this investigation was to determine the relationship between the horizontal semicircular canal video head impulse test (hvHIT) and the caloric test in a sample of school-age children evaluated due to complaints of dizziness or imbalance. In adults, these two tests provide different but complementary information regarding vestibular function and/or pathology. However, the most common causes of vestibular loss in children are different than those in adults, and it is not clear how these two tests of horizontal semicircular canal function are related in a pediatric population.

METHOD

This is a retrospective study of electronic records of pediatric patients (< 18 years old) who were referred for vestibular function testing and completed both hvHIT and caloric testing. Agreement between both test results was evaluated by examining measures of sensitivity, specificity, and calculating Cohen's kappa.

RESULTS

Results from 117 patients (mean age = 13.7 years, age range: 8-17 years, 37 males) were analyzed. Most patients (97/115 [84.3%]) demonstrated both normal hvHIT and caloric test results. Compared to caloric testing, the hvHIT had poor sensitivity (38.9%) and excellent specificity (98.0%). Cohen's kappa analysis revealed moderate agreement between the methods (coefficient = 0.49 [0.24, 0.73]). Where disagreement between the two tests occurred, the final diagnosis was not contingent on either test result.

CONCLUSIONS

There is a moderate agreement between the hvHIT and the caloric test in pediatric patients presenting to a tertiary care medical center for a vestibular evaluation. Most patients in this cohort presented with normal findings. The specificity of hvHIT was excellent, although the sensitivity was low. This may be related to the low prevalence of peripheral vestibular system disease in this study cohort, and these results do not generalize to centers that serve populations of children where vestibular disorders are more prevalent (e.g., children with sensorineural hearing loss).

Equilibrium and Vestibular Safety of Modafinil in Healthy Volunteers

BACKGROUND: Modafinil, as a wake-promoting agent, is commonly used to relieve fatigue during military operations. However, there is a lack of clarity regarding the effects of modafinil on the equilibrium and vestibular organs, especially when prescribing this drug to flight crewmembers. The objective of this study was to evaluate the equilibrium- and vestibular-related safety effects of modafinil.METHODS: In a randomized, double-blind, placebo-controlled, crossover study, 10 healthy male volunteers received a single 200-mg oral dose of modafinil or placebo. Equilibrium and vestibular functions were assessed 2 h after oral administration by the sensory organization test (SOT), adaptation test (ADT), and video head impulse test (v-HIT).RESULTS: There was no change in the equilibrium scores of the six SOT conditions or the composite scores between the modafinil and placebo groups. Statistically significant differences were not observed for the sway energy score (SES) in the toe-down test. In the toe-up test, the SES decreased by 16.7% in the modafinil group relative to the placebo group in trial 2, while the differences in other trials were not statistically significant. In the v-HIT, there was no significant difference in the gain of each semicircular canal between the two groups.DISCUSSION: A single 200-mg dose of modafinil did not cause any impairment to vestibular function, equilibrium ability, or adaptive balance response; in fact, modafinil might have a positive effect on adaptation function in healthy volunteers. These findings preliminarily suggest that there is no hidden risk of vestibular dysfunction among aviation employees using modafinil.Liu F, Zhang M, Chen T, Zhai L, Zhang Z, Xue J. Equilibrium and vestibular safety of modafinil in healthy volunteers. Aerosp Med Hum Perform. 2022; 93(6):487–492.

Instantaneous Gain in Video Head Impulse Test: A Reliability Study

Objective:

Methods:

Results:

Conclusion:

Clinician's perspectives in using head impulse-nystagmus-test of skew (HINTS) for acute vestibular syndrome: UK experience

BACKGROUND

Acute vestibular syndrome (AVS) features continuous dizziness and may result from a benign inner ear disorder or stroke. The head impulse-nystagmus-test of skew (HINTS) bedside assessment is more sensitive than brain MRI in identifying stroke as the cause of AVS within the first 24 hours. Clinicians' perspectives of the test in UK secondary care remains unknown. Here, we explore front-line clinicians' perspectives of use of the HINTS for the diagnosis of AVS.

METHODS

Clinicians from two large UK hospitals who assess AVS patients completed a short online survey, newly designed with closed and open questions.

RESULTS

Almost half of 73 total responders reported limited (n=33), or no experience (n=19), reflected in low rates of use of HINTS (n=31). While recognising the potential utility of HINTS, many reported concerns about subjectivity, need for specialist skills and poor patient compliance. No clinicians reported high levels of confidence in performing HINTS, with 98% identifying training needs. A lack of formalised training was associated with onward specialist referrals and neuroimaging (p=0.044).

CONCLUSIONS

Although the low sample size in this study limits the generalisability of findings to wider sites, our preliminary data identified barriers to the application of the HINTS in AVS patients and training needs to improve rapid, cost-effective and accurate clinical diagnosis of stroke presenting with vertigo.

Eye and Head Movement Recordings Using Smartphones for Telemedicine Applications: Measurements of Accuracy and Precision

Objective

Smartphones have shown promise in the assessment of neuro-ophthalmologic and vestibular disorders. We have shown that the head impulse test results recorded using our application are comparable with measurements from clinical video-oculography (VOG) goggles. The smartphone uses ARKit's capability to acquire eye and head movement positions without the need of performing a calibration as in most eye-tracking devices. Here, we measure the accuracy and precision of the eye and head position recorded using our application.

Methods

We enrolled healthy volunteers and asked them to direct their eyes, their heads, or both to targets on a wall at known eccentricities while recording their head and eye movements with our smartphone application. We measured the accuracy as the error between the eye or head movement measurement and the location of each target and the precision as the standard deviation of the eye or head position for each of the target positions.

Results

The accuracy of head recordings (15% error) was overall better than the accuracy of eye recordings (23% error). We also found that the accuracy for horizontal eye movements (17% error) was better than for vertical (27% error). Precision was also better for head movement (0.8 degrees) recordings than eye movement recordings (1.3 degrees) and variability tended to increase with eccentricity.

Conclusion

Our results provide basic metrics evaluating the utility of smartphone applications in the quantitative assessment of head and eye movements. While the new method may not replace the more accurate dedicated VOG devices, they provide a more accessible quantitative option. It may be advisable to include a calibration recording together with any planned clinical test to improve the accuracy.

Uneven Effects of Sleep Apnea on Semicircular Canals and Otolithic Organs

OBJECTIVE

This study aimed to explore how obstructive sleep apnea (OSA) affects the function of each vestibular organ and to identify the correlations among them.

METHODS

A prospective study was conducted involving 32 healthy controls and 64 patients with OSA. The objective detection methods of the utricle and saccule are vestibular-evoked myogenic potentials (VEMPs). A combination of the caloric test and video head impulse test (vHIT) was used to comprehensively evaluate the objective function of semicircular canals.

RESULTS

Elevated thresholds (p < 0.001), decreased waveform amplitudes (p < 0.001), prolonged first wave latencies (p < 0.001), and shortened first interpeak latencies (p < 0.001) were observed in both ocular VEMP (oVEMP) and cervical VEMP (cVEMP). A significant difference was found in the caloric test comparison (χ² = 4.030, p = 0.045) but not in the vHIT. The intergroup comparison of normal rates among the VEMPs, caloric test, and vHIT groups showed a significant difference (p < 0.001).

CONCLUSION

The impairment of vestibular function in patients with OSA was uneven and biased. More attention should be given to vestibular dysfunction in the diagnosis and treatment of OSA.

Effects of primary Sjögren's syndrome on hearing and vestibular systems

Objective

This study aimed to evaluate primary Sjögren's syndrome patients in terms of hearing and vestibular functions.

Methods

The patient group consisted of 35 individuals diagnosed with primary Sjögren's syndrome and a control group of 35 healthy individuals similar in terms of age and gender.

Results

The rate of hearing loss in the patient group was significantly higher than in the control group (p = 0.021). The N1 latency value for the ocular vestibular-evoked myogenic potentials test was significantly longer in the patient group than in the control group (p = 0.037). Additionally, the posterior semicircular canal and lateral semicircular canal vestibulo-ocular reflex gain values were significantly lower than in the control group (p = 0.022 and p < 0.001, respectively).

Conclusion

These results indicate subclinical vestibular involvement and hearing loss in primary Sjögren's syndrome patients. Vestibular-evoked myogenic potentials and video head impulse tests can be used to detect vestibular involvement in primary Sjögren's syndrome patients.

Prevention of Severe Vestibular Hypofunction after Systemic Gentamicin

The importance of early evaluation by a neurotologist in patients with infective endocarditis treated with systemic gentamicin and its impact on the patients’ quality of life was evaluated. This is a longitudinal retrospective cohort study of 29 patients who received intravenous gentamicin for the treatment of infective endocarditis. Patients were classified into two groups: group A, before a neurotologist was included in the treatment protocol, and group B, after the inclusion of a neurotologist. The frequency of the different symptoms in each group was measured, and the gain of the vestibulo-ocular reflex (VOR) and its relationship with the presence of oscillopsia. In total, 13 and 16 patients were assigned to groups A and B, respectively. The mean gain of the VOR measured using the video head impulse test in group A was 0.44 in the best side and 0.39 in the worst side. In group B, the mean gain was 0.71 (best side) and 0.64 (worst side) (p < 0.0001). The patients who complained about oscillopsia had a main gain of 0.41 in the best side and 0.35 in the worst side. Evaluation of vestibular function should be included in the infective endocarditis treatment protocol, including the adverse effects of systemic gentamicin.

Age adjusted normative data for Video Head Impulse Test in healthy subjects

PURPOSE

This study aims to assess the effect of age in vestibulo-ocular reflex (VOR) gain measured by Video Head Impulse Test (VHIT) and to present normative data of VOR gain, median gain at 40, 60, 80 and 0-100 ms, and gain asymmetry according to decades of life in healthy subjects.

MATERIAL AND METHODS

A total of 132 subjects with no previous history of vestibular disorders were enrolled to assess VOR gain by employing VHIT. The test was performed in the X-axis evaluating both horizontal semicircular canals (HSC). The same right-handed operator performed the test in all subjects.

RESULTS

The mean VOR gain was higher in the right ear (0.99 ± 0.09) compared to the left ear (0.97 ± 0.08) (p = 0.001). Median gain at 60 ms was 0.92 ± 0.12 in the right HSC and 0.93 ± 0.10 for the left HSC, without significant difference (p = 0.94). A significant decrease of VOR gain occurred with increasing age in the right ear (r = -0.21, p = 0.01). Median gain at 60 ms decreased significantly as age increased in both HSC (right r = -0.17, p = 0.04; left r = -0.23, p = 0.006). No significant differences in VOR gain values were observed when the sample was stratified by age according to the analysis of variance.

CONCLUSIONS

A slight but significant decrease in VOR function was observed as age increased for gain and median gain at 60 ms. Larger studies, including patients with central and peripheral vestibular disorders, are needed to assess the clinical implication of this effect when evaluating patients with vestibular disorders.

Evaluating the Vestibulo-Ocular Reflex Following Traumatic Brain Injury: A Scoping Review

Purpose:To identify the tests and tools used to evaluate vestibulo-ocular reflex (VOR) function after traumatic brain injury (TBI) in all age groups and across TBI severity.Methods: An electronic search was conducted to include relevant peer-reviewed literature published up to November 2019. Studies included those done with humans, of all ages, and had assessments of oculomotor and/or vestibulo-ocular function in TBI.Results: Of the articles selected (N = 48), 50% were published in 2018/2019. A majority targeted mild TBI, with equal focus on non-computerized versus computerized measures of VOR. Computerized assessment tools used were videonystagmography, dynamic visual acuity/gaze stability, rotary chair, and caloric irrigation. Non-computerized tests included the head thrust, dynamic visual acuity, gaze stability, head shaking nystagmus, rotary chair tests and the vestibular/oculomotor screening tool. High variability in administration protocols were identified. Namely: testing environment, distances/positioning/equipment used, active/passive state, procedures, rotation frequencies, and variables observed.Conclusions: There is a rapid growth of literature incorporating VOR tests in mild TBI but moderate and severe TBI continues to be under-represented. Determining how to pair a clinical test with a computerized tool and developing standardized protocols when administering tests will help in developing an optimal battery assessing the VOR in TBI.

Assessment of balance after recovery from Covid-19 disease

Objective

To answer the question whether balance related systems have been affected in adults who recovered from Covid-19 disease. This is the first case-control study to assess balance objectively and quantitatively in Covid-19 disease.

Methods

Thirty-seven patients who recovered from Covid-19 disease and 30 healthy controls were compared using Dizziness Handicap Inventory (DHI), Computerized Dynamic Posturography (CDP), Vestibular Evoked Myogenic Potentials(VEMP) and Video Head Impulse Test (v-HIT).

Results

On CDP, the composite and visual general scores of the patients were significantly lower than controls (p<0.01). The v-HIT gains of the patients significantly decreased in the vertical semicircular canals compared to controls (p<0.01).There was a significant difference between the patients and controls regarding the absence of o-VEMPs (p<0.01) while the amplitudes and latencies were similar between the groups (p>0.05). Decreased P1/N1 amplitudes and elongated N1 latencies were found on c-VEMP testing (p<0.05). Anosmia, taste disorder and gender were not associated with subjective and objective test results (p>0.05).

Conclusion

The Covid-19 disease can cause dizziness rather that incapacitating vertigo. Dizziness can be seen in almost one-fifth of the adult covid19 out-patients, which may be due to involvement of vestibular and visual systems,ortheir central connections. The squeals created in the balance related systems may be irreversible as they have persisted after the recovery of the patients. It is also plausible to anticipate more severe condition in the older patients who were treated in the intensive care units. In the long term follow up of the survivors, the need for balance rehabilitation programs should be remembered in order to minimize risks of falling down.

Evaluation on Effectiveness of a New System as well as Analysis on Optimal Horizontal Eye Position for Vertical Video Head Impulse Test

OBJECTIVE

To compare the performances among three different systems for video head impulse test (vHIT), and to identify an optimal target angle for precisely evaluating the function of vertical semicircular canals in vHIT.

METHODS

A two-center prospective study was done. Participants were sit 1.2 m away from the wall in a noise-proved room that dedicated for vHIT experiments. During the comparison experiments, similar settings were ensured in both hospitals, with the same distance to wall and angle of staring. For each equipment, the procedures followed the developers' recommendations. The same examiner performed the comparison between two systems in one location. For the eye-position projects, targets were placed on the wall sequentially at the pre-marked lines for different angles. For the comparison projects, 9 and 13 participants were recruited, respectively. Any participant with otologic or vestibular disorders was excluded. A total of 26 healthy participants were recruited in the eye-position experiments, 16 of which were further involved in inter-examiner tests.

RESULTS

Our evaluations of three different systems showed that a new vHIT system, VertiGoggles® ZT-VNG-I (VG) performed as good as the long-tested Otometrics® ICS impulse (Oto) and EyeSeeCam® (ESC). During the comparison, we validated 25-degree, instead of right ahead at 0 degree, is a better place to set the targets when torsion was applied at vertical semicircular canal planes.

CONCLUSION

The new VG system is good for clinical practices. Furthermore, we proposed a new protocol to set the targets 25 degrees from right ahead after tilting head 45 degrees to evaluate vertical canals during vHIT.

Effect of different head impulse procedures on vestibulo-ocular reflex gain

OBJECTIVE

to study the effects on vestibulo-ocular reflex (VOR) gain using both video head impulse test (vHIT) and Suppression Head impulse test (SHIMP) either using the outward or the inwards head impulse.

METHODS

Twenty healthy subjects were enrolled in the study. They were examined using otometric vHIT and SHIMP test lateral plane using the lateral outwards head impulse ten impulses for each side and the inwards head impulse ten impulses for each side. The VOR gain resulting from the outwards versus inwards head impulse during the vHIT and SHIMP were statistically compared.

RESULTS

Twenty healthy subjects, 10 Males and 10 females with a mean age 35±11.7. Paired t- test showed no statistical significance difference in the mean VOR gain of right lateral semicircular canal (1.1±.12) using outwards versus (1.03 ± .22) inwards head impulses, nor for the left lateral semicircular canal mean VOR gain (1.1 ± .22) using outwards head impulse (1.1 ± .3) for inwards head impulse in vHIT. Paired t- test showed no statistical significance difference in the mean VOR gain of right lateral semicircular canal (0.96 ± 0.2)using outwards versus (1.04 ± 0.2) inwards head impulses, nor for the left lateral semicircular canal mean VOR gain (0.98 ± 0.25) using outwards head impulse (1.1 ± 0.28) for inwards head impulse in SHIMP test. No statistical significant difference was found between the VOR gain resulting from the right versus the left semicircular canal.

CONCLUSION

The starting head position does not affect the VOR gain using both vHIT and SHIMP tests.

Vestibulo ocular reflex in multiple sclerosis patients without any optic neuritis

PURPOSE

To investigate vestibulo ocular reflex (VOR) in MS patients without any history of optic neuritis.

METHODS

26 MS patients without any previous history of optic neuritis and 13 age- matched control subjects were included in this study. Their age ranged from 22 to 50 years old. We evaluated monocular visual evoked potential (VEP), monocular and binocular best corrected static and dynamic visual acuity, near and distance phoria and VOR gain.

RESULTS

Mean spherical equivalent (SE) was - 0.40 ± 0.93 D and - 0.04 ± 0.14 D for study and control group, respectively (P = 0.060). There was a significant difference in dynamic visual acuity (DVA) between two groups (P = 0.029). VOR gain was not significantly different in both groups through vHIT measurements (P = 0.338). Duration of MS had a mean of 78.38 ± 75.94 months (ranged from 6 to 336 months). We found no significant correlation between disease duration and VOR (Rho 0.277, P = 0.171) or DVA (Rho 0.782, P = 0.057).

CONCLUSION

Our study showed that although vHIT results decreased in MS patients, there was no significant differences between two groups.

Paradigm shift in acute dizziness: is caloric testing obsolete?

Objective

Cold and warm water ear irrigation, also known as bithermal caloric testing, has been considered for over 100 years the ‘Gold Standard’ for the detection of peripheral vestibular hypofunction. Its discovery was awarded a Nobel Prize. We aimed to investigate the diagnostic accuracy of Caloric Testing when compared to the video head impulse test (vHIT) in differentiating between vestibular neuritis and vestibular strokes in acute dizziness.

Design

Prospective cross-sectional study (convenience sample).

Setting

All patients presenting with signs of an acute vestibular syndrome at the emergency department of a tertiary referral center.

Participants

One thousand, six hundred seventy-seven patients were screened between February 2015 and May 2020 for Acute Vestibular Syndrome (AVS), of which 152 met the inclusion criteria and were enrolled. Inclusion criteria consisted of a state of continuous dizziness, associated with nausea or vomiting, head-motion intolerance, new gait or balance disturbance and nystagmus. Patients were excluded if they were younger than 18 years, if symptoms lasted < 24 h or if the index ED visit was > 72 h after symptom onset. Of the 152 included patients 85 completed testing. We assessed 58 vestibular neuritis and 27 stroke patients.

Main outcome measures

All patients underwent calorics and vHIT followed by a delayed MRI which served as a gold standard for vestibular stroke confirmation.

Results

The overall sensitivity and specificity for detecting stroke with a caloric asymmetry cut-off of 30.9% was 75% and 86.8%, respectively [negative likelihood ratio (NLR) 0.29] compared to 91.7% and 88.7% for vHIT (NLR 0.094). Best VOR gain cut-off was 0.685. Twenty-five percent of vestibular strokes were misclassified by calorics, 8% by vHIT.

Conclusions

Caloric testing proved to be less accurate than vHIT in discriminating stroke from vestibular neuritis in acute dizziness. Contrary to classic teaching, asymmetric caloric responses can also occur with vestibular strokes and might put the patient at risk for misdiagnosis. We, therefore, recommend to abandon caloric testing in current practice and to replace it with vHIT in the acute setting. Caloric testing has still its place as a diagnostic tool in an outpatient setting.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10667-7.

The Impact of Optical Illusions on the Vestibular System

Background and Objectives

Balance control is maintained in stationary and dynamic conditions, with coordinated muscle responses generated by somatosensory, vestibular, and visual inputs. This study aimed to investigate how the vestibular system is affected in the presence of an optical illusion to better understand the interconnected pathways of the visual and vestibular systems.

Subjects and Methods

The study involved 54 young adults (27 males and 27 females) aged 18-25 years. The recruited participants were subjected to the cervical vestibular evoked myogenic potentials (cVEMP) test and video head impulse test (vHIT). The cVEMP and vHIT tests were performed once each in the absence and presence of an optical illusion. In addition, after each test, whether the individuals felt balanced was determined using a questionnaire.

Results

cVEMP results in the presence of the optical illusion showed shortened latencies and increased amplitudes for the left side in comparison to the results in the absence of the optical illusion (p≤0.05). When vHIT results were compared, it was seen that the right lateral and bilateral anterior canal gains were increased, almost to 1.0 (p<0.05).

Conclusions

It is thought that when the visual-vestibular inputs are incompatible with each other, the sensory reweighting mechanism is activated, and this mechanism strengthens the more reliable (vestibular) inputs, while suppressing the less reliable (visual) inputs. As long as the incompatible condition persists, the sensory reweighting mechanism will continue to operate, thanks to the feedback loop from the efferent vestibular system.

Sport as a Factor in Improving Visual Spatial Cognitive Deficits in Patients with Hearing Loss and Chronic Vestibular Deficit

Hearing loss and chronic vestibular pathologies require brain adaptive mechanisms supported by a cross-modal cortical plasticity. They are often accompanied by cognitive deficits. Spatial memory is a cognitive process responsible for recording information about the spatial environment and spatial orientation. Visual-spatial working memory (VSWM) is a kind of short-term working memory that allows spatial information to be temporarily stored and manipulated. It can be conditioned by hearing loss and also well-compensated chronic vestibular deficit. Vestibular rehabilitation and hearing aid devices or training are able to improve the VSWM. We studied 119 subjects suffering from perinatal or congenital hearing loss, compared with 532 healthy subjects and 404 patients with well-compensated chronic vestibular deficit (CVF). VSWM was evaluated by the eCorsi test. The subjects suffering from chronic hearing loss and/or unilateral or bilateral vestibular deficit showed a VSWM less efficient than healthy people, but much better than those with CVF, suggesting a better multimodal adaptive strategy, probably favored by a cross-modal plasticity which also provides habitual use of lip reading. The sport activity cancels the difference with healthy subjects. It is therefore evident that patients with this type of deficit since childhood should be supported and advised on a sport activity or repeated vestibular stimulation.

Feasibility of Preoperative Video Head Impulse Test to Predict the Nerve of Origin in Patients with Vestibular Schwannomas

Vestibular schwannoma (VS) originates from Schwann cells in the superior or inferior vestibular nerve. Identifying the precise origin will help in determining the optimal surgical approach. We retrospectively analyzed the preoperative vestibular function test according to VS origin to determine whether the test is a valuable indicator of tumor origin. Forty-seven patients with VS (male:female = 18:29, mean age: 54.06 ± 13.50 years) underwent the cochleovestibular function test (pure-tone audiometry, caloric test, video head impulse test (vHIT), cervical and ocular vestibular-evoked myogenic potential, and posturography). All patients then underwent surgical removal of VS, and the schwannoma origin was confirmed. The tumor originated from the superior vestibular nerve (SVN group) in 21 patients, the inferior vestibular nerve (IVN group) in 26 patients, and an undetermined site in eight patients. The only value that differed significantly among the groups was the gain of the vestibular-ocular reflex (VOR) in the ipsilesional posterior canal (iPC) during the vHIT. Our results indicate that VOR gain in the iPC may be used to predict the nerve origin in patients with VS. Other cochleovestibular function tests have limited value to discriminate nerve origins, especially in cases of medium to large VS.

Risk of Sensorineural Hearing Loss in Patulous Eustachian Tube

OBJECTIVE

To investigate whether the long-term presence of a patulous Eustachian tube (PET) is associated with sensorineural hearing loss (SNHL).

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

Ears (n = 100) were classified into two groups based on duration of PET symptom(s), i.e., Short (≤3 mo; n = 47 ears) and Long (≥48 mo; n = 53 ears). Contralateral ears without PET (n = 28 ears) were classified as the Contralateral group.

MAIN OUTCOME MEASURES

We used ISO 7029 to calculate the hearing thresholds of an age- and sex-matched population at a given frequency. Hearing loss was defined as >25% of these calculated values.

RESULTS

At 4 kHz, the Long PET group showed a higher prevalence of hearing loss (47%) at 4 kHz than did the Contralateral (21%) and Short PET (19%) groups (p = 0.0280 and 0.0043, respectively). Ears with breathing autophony or a sonotubometric low probe tone level showed a higher prevalence of hearing loss at 4 kHz than those without this symptom or with a high probe tone level (p = 0.0329 or 0.0103, respectively). At low frequencies, ≥89% of the ears in all groups showed mild hearing loss.

CONCLUSION

Chronic PET was associated with SNHL at 4 kHz. PET patients showed low-frequency hearing loss regardless of disease duration. Further studies are needed to better understand the pathophysiology of SNHL in patients with PET.

Evaluation of the vestibular system in individuals with presbycusis using video head impulse test and videonystagmography

BACKGROUND

Vestibulo-ocular reflex (VOR) function is expected to be normal in patients with presbycusis during sudden head rotations.

AIM

This study aimed to determine whether presbycusis was accompanied by vestibular system pathologies. In addition, it was examined whether there was a difference existed between the patients with and without presbycusis in terms of normative data.

MATERIALS AND METHODS

A total of 40 individuals were included in the study: 20 in the presbycusis group and 20 in the control group. The vestibular systems of both groups were evaluated using the video head impulse test and videonystagmography.

RESULTS

The right and left lateral VOR gain values were decreased in the group with presbycusis compared to the control group. The difference between the two groups in the mean VOR gains in the right lateral canal and left lateral canal were statistically significant (p = .040 and p = .050, respectively). The air caloric tests of all individuals were found to be normal.

CONCLUSIONS

This result suggests that the loss of vestibular hair cells and vestibular nerve degeneration in the lateral semicircular canal may be more severe in presbycusis than in the same age group with normal hearing.

Perspectives: Evaluation of Older Adult Cochlear Implant Candidates for Fall Risk in a Developing Country Setting

Dizziness, vertigo, and falls are common in older adults. Data suggest that cochlear implant candidates are no different and could be argued to be at elevated risk due to the presence of hearing loss and likely vestibular involvement. Perspectives contextualizes current testing and screening paradigms for vestibular deficits and fall risk and suggests a protocol suitable for use in developing country settings.