VOR gain calculation methods in video head impulse recordings

2020 ◽  
Vol 30 (4) ◽  
pp. 225-234
Author(s):  
Ewa Zamaro ◽  
Ali S. Saber Tehrani ◽  
Jorge C. Kattah ◽  
Karin Eibenberger ◽  
Cynthia I. Guede ◽  
...  
Keyword(s):  
Calculation Method ◽  
Vestibular Function ◽  
Head Impulse Test ◽  
Calculation Methods ◽  
Normal Range ◽  
International Consensus ◽  
Head Impulse ◽  
Acute Vestibular Syndrome ◽  
Vestibulo Ocular Reflex ◽  
The Impact

BACKGROUND: International consensus on best practices for calculating and reporting vestibular function is lacking. Quantitative vestibulo-ocular reflex (VOR) gain using a video head impulse test (HIT) device can be calculated by various methods. OBJECTIVE: To compare different gain calculation methods and to analyze interactions between artifacts and calculation methods. METHODS: We analyzed 1300 horizontal HIT traces from 26 patients with acute vestibular syndrome and calculated the ratio between eye and head velocity at specific time points (40 ms, 60 ms) after HIT onset (‘velocity gain’), ratio of velocity slopes (‘regression gain’), and ratio of area under the curves after de-saccading (‘position gain’). RESULTS: There was no mean difference between gain at 60 ms and position gain, both showing a significant correlation (r2 = 0.77, p < 0.001) for artifact-free recordings. All artifacts reduced high, normal-range gains modestly (range –0.06 to –0.11). The impact on abnormal, low gains was variable (depending on the artifact type) compared to artifact-free recordings. CONCLUSIONS: There is no clear superiority of a single gain calculation method for video HIT testing. Artifacts cause small but significant reductions of measured VOR gains in HITs with higher, normal-range gains, regardless of calculation method. Artifacts in abnormal HITs with low gain increased measurement noise. A larger number of HITs should be performed to confirm abnormal results, regardless of calculation method.

scholarly journals Quantifying the Vestibulo-Ocular Reflex with Video-Oculography: Nature and Frequency of Artifacts

2014 ◽  
Vol 20 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Georgios Mantokoudis ◽  
Ali S. Saber Tehrani ◽  
Jorge C. Kattah ◽  
Karin Eibenberger ◽  
Cynthia I. Guede ◽  
...  
Keyword(s):  
Head Impulse Test ◽  
Head Impulse ◽  
Video Oculography ◽  
Ocular Reflex ◽  
Acute Vestibular Syndrome ◽  
Vestibulo Ocular Reflex ◽  
Corrective Saccades ◽  
Coding Manual ◽  
A Prospective Study ◽  
The Impact

Video-oculography devices are now used to quantify the vestibulo-ocular reflex (VOR) at the bedside using the head impulse test (HIT). Little is known about the impact of disruptive phenomena (e.g. corrective saccades, nystagmus, fixation losses, eye-blink artifacts) on quantitative VOR assessment in acute vertigo. This study systematically characterized the frequency, nature, and impact of artifacts on HIT VOR measures. From a prospective study of 26 patients with acute vestibular syndrome (16 vestibular neuritis, 10 stroke), we classified findings using a structured coding manual. Of 1,358 individual HIT traces, 72% had abnormal disruptive saccades, 44% had at least one artifact, and 42% were uninterpretable. Physicians using quantitative recording devices to measure head impulse VOR responses for clinical diagnosis should be aware of the potential impact of disruptive eye movements and measurement artifacts. i 2014 S. Karger AG, Basel

Vestibular semicircular canal function as detected by video Head Impulse Test (vHIT) is essentially unchanged in people with Parkinson’s disease compared to healthy controls

2021 ◽  
pp. 1-9
Author(s):  
Kim E. Hawkins ◽  
Elodie Chiarovano ◽  
Serene S. Paul ◽  
Ann M Burgess ◽  
Hamish G. MacDougall ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Semicircular Canal ◽  
Neurodegenerative Disorder ◽  
Vestibular Function ◽  
Head Impulse Test ◽  
Healthy Controls ◽  
Video Head Impulse Test ◽  
Head Impulse ◽  
Vestibulo Ocular Reflex

BACKGROUND: Parkinson’s disease (PD) is a common multi-system neurodegenerative disorder with possible vestibular system dysfunction, but prior vestibular function test findings are equivocal. OBJECTIVE: To report and compare vestibulo-ocular reflex (VOR) gain as measured by the video head impulse test (vHIT) in participants with PD, including tremor dominant and postural instability/gait dysfunction phenotypes, with healthy controls (HC). METHODS: Forty participants with PD and 40 age- and gender-matched HC had their vestibular function assessed. Lateral and vertical semicircular canal VOR gains were measured with vHIT. VOR canal gains between PD participants and HC were compared with independent samples t-tests. Two distinct PD phenotypes were compared to HC using Tukey’s ANOVA. The relationship of VOR gain with PD duration, phenotype, severity and age were investigated using logistic regression. RESULTS: There were no significant differences between groups in vHIT VOR gain for lateral or vertical canals. There was no evidence of an effect of PD severity, phenotype or age on VOR gains in the PD group. CONCLUSION: The impulsive angular VOR pathways are not significantly affected by the pathophysiological changes associated with mild to moderate PD.

scholarly journals Prevalence of Vestibular Disorders in Independent People Over 50 That Experience Dizziness

2021 ◽  
Vol 12 ◽  
Author(s):  
William V. C. Figtree ◽  
Jasmine C. Menant ◽  
Allan T. Chau ◽  
Patrick P. Hübner ◽  
Stephen R. Lord ◽  
...  
Keyword(s):  
Time Constant ◽  
High Frequency ◽  
Constant Velocity ◽  
Vestibular Function ◽  
Community Dwelling ◽  
Whole Body ◽  
Head Impulse Test ◽  
Vestibular Loss ◽  
Vestibulo Ocular Reflex ◽  
The Impact

People aged over 50 are the most likely to present to a physician for dizziness. It is important to identify the main cause of dizziness in order to develop the best treatment approach. Our goal was to determine the prevalence of benign paroxysmal positional vertigo (BPPV), and peripheral and central vestibular function in people that had experienced dizziness within the past year aged over 50. One hundred and ninety three community-dwelling participants aged 51–92 (68 ± 8.7 years; 117 females) were tested using the clinical and video head impulse test (cHIT and vHIT) to test high-frequency vestibular organ function; the head thrust dynamic visual acuity (htDVA) test to test high-frequency visual-stability; the dizziness handicap inventory (DHI) to measure the impact of dizziness; as well as sinusoidal and unidirectional rotational chair testing to test low- to mid-frequency peripheral and central vestibular function. From these assessments we computed the following measures: HIT gain; htDVA score; DHI score; sinusoidal (whole-body; 0.1–2 Hz with 30°/s peak-velocity) vestibulo-ocular reflex (VOR) gain and phase; transient (whole-body, 150°/s2 acceleration to 50°/s constant velocity) VOR gain and time constant; optokinetic nystagmus (OKN) gain and time constant (whole-body, 50°/s constant velocity rotation). Our study showed that BPPV, and peripheral or central vestibular hypofunction were present in 34% of participants, suggesting a vestibular cause to their dizziness. Over half (57%) of these with a likely vestibular cause had BPPV, which is more than twice the percentage reported in other dizzy clinic studies. Our findings suggest that the physical DHI score and VOR time constant were best at detecting those with non-BPPV vestibular loss, but should always be used in conjunction with cHIT or vHIT, and that the htDVA score and vHIT gain were best at detecting differences between ipsilesional and contralesional sides.

scholarly journals Prevalence of Peripheral Vestibular Impairment in Adults with Human Immunodeficiency Virus

2021 ◽  
Vol 25 (1) ◽  
pp. 36-42
Author(s):  
Alison Millar ◽  
Karin Joubert ◽  
Alida Naude
Keyword(s):  
Human Immunodeficiency Virus ◽  
Vestibular Function ◽  
Head Impulse Test ◽  
Hiv Positive ◽  
Positive Group ◽  
Head Impulse ◽  
Immunodeficiency Virus ◽  
Central Compensation ◽  
The Impact ◽  
Hiv Negative

Background and Objectives: Globally, the human immunodeficiency virus (HIV) is responsible for one of the most serious pandemics to date. The vulnerability of the vestibular system in individuals with HIV has been confirmed, and central vestibular impairments have been frequently reported. However, there are disagreements on the impact of HIV on peripheral vestibular function. Thus, the current study aimed to determine the prevalence of peripheral vestibular impairment, specifically related to the semi-circular canals (SCCs), in HIV-positive individuals receiving antiretroviral (ARV) treatment.Subjects and Methods: A total of 92 adults between the ages of 18 and 50 years (divided into two groups) participated in the study. The first group comprised HIV-positive individuals receiving ARV treatment (n1=60), and the second group comprised HIV-negative participants (n2=32). The video head impulse test was used to conduct the head impulse paradigm (HIMP).Results: Bilateral normal HIMP results were obtained in 95% of the HIV-positive participants and all HIV-negative participants. The gain of the left posterior SCCs was significantly lower in the HIV-positive group, while the gains of all other canals between the two groups were comparable.Conclusions: The prevalence of peripheral vestibular impairment in the HIV-positive group was not significantly different from that of the HIV-negative group. The reduced prevalence in the current study may be attributed to participant characteristics, the test battery employed, and the central compensation of the vestibular dysfunctions at the later stages of infection.

The Effects of Cochlear Implantation on Vestibular Function

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P60-P60
Author(s):  
Thuy-Anh N. Melvin ◽  
Americo Migliaccio ◽  
John P Carey ◽  
Charles Coleman Della Santina
Keyword(s):  
Cochlear Implantation ◽  
Full Range ◽  
Vestibular Function ◽  
Head Movements ◽  
Vestibular Evoked Myogenic Potentials ◽  
Head Impulse Test ◽  
Head Impulse ◽  
Vestibular Hypofunction ◽  
Before And After ◽  
Vestibulo Ocular Reflex

Objective 1) Measure vestibular function before and after cochlear implantation (CI) using a battery of tests covering the full range of stimulus frequencies over which the normal angular vestibulo-ocular reflex (VOR) stabilizes gaze. Methods Semicircular canal (SCC) function was assayed using head impulse test during 3-dimensional scleral search coil eye movement recordings (HIT), dynamic visual acuity during rapid head movements (DVA), head-shake nystagmus (HSN), and caloric electronystagmography (ENG). Saccular function was determined using vestibular-evoked myogenic potentials (VEMP). Patient self-assessment via the dizziness handicap inventory (DHI) and clinical head impulse testing (cHIT) were also measured. Results One of 28 post-implanted ears (4%) suffered severe loss of vestibular function in all 3 SCCs. HSN revealed no change in 11 subjects. ENG revealed new hypofunction in 1 of 16 ears (6%). Passive DVA revealed no significant change for 16 implanted ears. VEMP revealed significant increase or disappearance in threshold in 5 of 16 ears (31%). DHI scores were variable and correlated poorly with objective tests. The cHIT performed by one otolaryngologist in 14 subjects exhibited 44% sensitivity and 94% specificity for detection of severe hypofunction confirmed via quantitative HIT. Conclusions CI carries a small but nontrivial risk of iatrogenic vestibular hypofunction in the implanted ear. For bilateral simultaneous-CI, the risk of bilateral vestibular hypofunction is ∼0.16%, comparable to the likelihood of meningitis. The cHIT was highly specific for vestibular hypofunction in this study, but likely depends heavily on the examiner's threshold for abnormal.

scholarly journals The clinical course of vestibular neuritis from the point of view of the video Head Impulse Test

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Leonardo Manzari ◽  
Domenico Graziano ◽  
Marco Tramontano
Keyword(s):  
Clinical Course ◽  
Cranial Nerves ◽  
Point Of View ◽  
Vestibular Neuritis ◽  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Head Impulse ◽  
Acute Vestibular Syndrome ◽  
Vestibulo Ocular Reflex ◽  
Contralesional Side

Vestibular neuritis (VN) is one  of the most common causes of acute vestibular syndrome (AVS). Quantifying the vestibulo-ocular reflex (VOR) gain by the video Head Impulse Test (vHIT) could provide useful information to diagnose VN. This retrospective study is aimed to investigate the clinical course of VN evaluating the horizontal VOR gain (hVOR) values in acute and subacute stages and to correlate these values with the patients’ quality of life. Medical record of 28 patients with VN were reviewed. Patients were assigned to two groups according to the time since the acute vestibular syndrome (AVS). One group with patients assessed within seventy-two hours since the AVS (AVSg) and one group with patients evaluated from four days to six weeks since the AVS (PAVSg). hVOR gain was evaluated in all selected patients and correlated to Dizziness Handicap Inventory (DHI). Significant differences were found in the between-subjects analysis in DHI score (p=0.000) and in the ipsilesional hVOR gain values (p=0.001). The correlation analysis showed significant results (p=0.017) between DHI score ( 40±16.08) and ipsilesional VOR gain (0.65±0.22) in the PAVSg. Patients evaluated within 72 hours since the AVS showed anticompensatory saccades (AcS) turning the head toward the contralesional side. Patients with VN could have dissimilar hVOR gain values and DHI score according to the damage of the VIII pair of cranial nerves. AcS in the contralesional side is a sign of acute phase in patients with VN.

scholarly journals Vestibular Function Measured Using the Video Head Impulse Test in Congenital Nystagmus and Vertigo: A Case Report

2021 ◽  
Vol 12 ◽  
Author(s):  
Antonio Denia-Lafuente ◽  
Belén Lombardero
Keyword(s):  
Vestibular Function ◽  
Semicircular Canals ◽  
Head Impulse Test ◽  
Congenital Nystagmus ◽  
Video Head Impulse Test ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Vertical Semicircular Canals

In patients with congenital nystagmus (CN), the study of vestibular function is complicated by many factors related to the measurement of the vestibulo-ocular reflex (VOR) by means of caloric testing and the video head impulse test (vHIT), and to date no such studies have successfully employed the vHIT to evaluate vestibular function in these patients. We present a case with CN and vertigo in which peripheral vestibular function was evaluated using the vHIT system, including head impulse testing and the suppression head impulse protocol. We show that it is possible (a) to identify lateral VOR changes such as abnormalities resembling those produced by bilateral vestibular lesions, though not necessarily related to the same mechanism; (b) to identify peripheral VOR lesions of the vertical semicircular canals (SCC); and (c) to document compensation and recovery subsequent to these peripheral lesions during follow-up of patients with CN. vHIT is a useful tool that should be used to study vestibular function in patients with CN and vertigo, which could constitute a new clinical application of this technique.

Vestibular function assessment of Susac syndrome patients by the video head impulse test and cervical vestibular-evoked myogenic potentials

2020 ◽  
Vol 30 (6) ◽  
pp. 393-399
Author(s):  
Yahav Oron ◽  
Ophir Handzel ◽  
Zohar Habot-Wilner ◽  
Keren Regev ◽  
Arnon Karni ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Vestibular Function ◽  
Pure Tone Audiometry ◽  
Sensorineural Hearing ◽  
Vestibular Evoked Myogenic Potentials ◽  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Head Impulse ◽  
Susac Syndrome

BACKGROUND: Susac syndrome (retino-cochleo-cerebral vasculopathy, SuS) is an autoimmune endotheliopathy characterized by the clinical triad of encephalopathy, branch retinal artery occlusions and sensorineural hearing loss. In contrast to data regarding auditory function, data measuring vestibular function is sparse and the cervical vestibular-evoked myogenic potentials (cVEMPs). OBJECTIVE: To determine whether the video head impulse test (vHIT) can serve as a confirmatory assessment of vestibulocochlear dysfunction in cases of suspected SuS. METHODS: Seven patients diagnosed with SuS underwent pure tone audiometry, a word recognition test, cVEMPs and the vHIT. RESULTS: Five patients were diagnosed with definite SuS, and two with probable SuS. Two patients were asymptomatic for hearing loss or tinnitus, and no sensorineural hearing loss was detected by audiograms. Four patients complained of tinnitus, and three patients reported experiencing vertigo. Three patients had abnormal cVEMPs results. All seven patients’ vHIT results were normal, except for patient #2, who was one of the three who complained of vertigo. The calculated gain of her left anterior semicircular canal was 0.5, without saccades. CONCLUSIONS: This is the first study to describe the results of the vHIT and cVEMPs among a group of patients with SuS. The results suggest that the vHIT should not be the only exam used to assess the function of the vestibular system of SuS patients.

Viewing Target Distance Influences the Vestibulo-Ocular Reflex Gain when Assessed Using the Video Head Impulse Test

2018 ◽  
Vol 23 (5) ◽  
pp. 285-289 ◽  
Author(s):  
Patricia Castro ◽  
Sara Sena Esteves ◽  
Florencia Lerchundi ◽  
David Buckwell ◽  
Michael A. Gresty ◽  
...  
Keyword(s):  
Head Movements ◽  
Target Distance ◽  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Gaze Stabilization ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Significant Difference ◽  
Vestibulo Ocular Reflex ◽  
Reflex Gain

Gaze stabilization during head movements is provided by the vestibulo-ocular reflex (VOR). Clinical assessment of this reflex is performed using the video Head Impulse Test (vHIT). To date, the influence of different fixation distances on VOR gain using the vHIT has not been explored. We assessed the effect of target proximity on the horizontal VOR using the vHIT. Firstly, we assessed the VOR gain in 18 healthy subjects with 5 viewing target distances (150, 40, 30, 20, and 10 cm). The gain increased significantly as the viewing target distance decreased. A second experiment on 10 subjects was performed in darkness whilst the subjects were imagining targets at different distances. There were significant inverse relationships between gain and distance for both the real and the imaginary targets. There was a statistically significant difference between light and dark gains for the 20- and 40-cm distances, but not for the 150-cm distance. Theoretical VOR gains for different target distances were calculated and compared with those found in light and darkness. The increase in gain observed for near targets was lower than predicted by geometrical calculations, implying a physiological ceiling effect on the VOR. The VOR gain in the dark, as assessed with the vHIT, demonstrates an enhancement associated with a reduced target distance.

Acute vertigo in the ENT emergency

2021 ◽  
Vol 70 (3) ◽  
pp. 146-155
Author(s):  
Václav Albrecht ◽  
Lukáš Školoudík ◽  
Peter Sila ◽  
Jan Mejzlík ◽  
Michal Janouch ◽  
...  
Keyword(s):  
Emergency Department ◽  
Vestibular Function ◽  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Head Impulse ◽  
Video Assisted ◽  
Vestibular Testing ◽  
Group A ◽  
The Difference ◽  
Group B

Summary Introduction: Acute vertigo ranks among the common reasons for visiting the emergency department. The aim of this study was to evaluate the rate of peripheral vestibular syndrome (PVS) in patients with acute vertigo examined at the ENT emergency department and to compare the agreement of physical ENT examination with video-assisted vestibular testing. Methods: Patients eamined at the ENT emergency department from January to December 2019 were evaluated retrospectively. The patients who underwent basic ENT examination without video-assisted vestibular testing form group A. The patients who underwent basic ENT examination which was followed by video head impulse test (vHIT) and videonystagmography in the next four days form group B. Results: A total of 117 patients with acute vertigo were included in group A, PVS was found in 31 patients (27%). In total, 50 patients were included in group B; PVS was found in 15 patients (30%), vestibular neuronitis was dia­gnosed most often (10 patients). The difference in the dia­gnosis of PVS by basic ENT examination (27 patients, 54%) and by video-assisted vestibular testing (15 patients, 30%) was statistically significant (P = 0.0030). The gain of the lateral (P = 0.0101) and superior (P = 0.0043) semicircular canal proved to be statistically significant, while vHIT was lower in PVS in comparison to other causes of vertigo. Conclusion: After basic ENT examination, PVS as a cause of acute vertigo was dia­gnosed in 27%. Video-assisted vestibular testing proved a statistically significant lower incidence of PVS in comparison to basic ENT examination. Accessibility of video- -assisted vestibular testing in the emergency department might allow for higher accuracy in the dia­gnosis of acute vertigo. Key words acute vertigo – vestibular function tests – video head impulse test – videonystagmography

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