Vestibulo-ocular Reflex Gain Values Research Articles

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

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. 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. 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. 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.

An Evaluation of the Vestibular System in Individuals Aged 40-65 Years with Sensorineural Hearing Loss.

Vestibular dysfunction occasionally accompanies sensorineural hearing loss (SNHL) due to anatomical proximity of cochlea and vestibule. The aim of the present study was to evaluate the vestibular system objectively and subjectively in 40-to 65-year-old individuals with and without SNHL. This study included participants of both sexes, between the ages of 40 and 65 years old. There were 31 participants with SNHL and 31 control participants. First of all, participants were grouped in the control and SNHL groups based on the results of their hearing test, which included audiometry and immitance evaluation. Subsequently, for vestibular evaluation, each participant was evaluated subjective with "Dizziness Handicap Inventory" (DHI) as well as with objective tests battery that included positional tests with videonystagmogrophy (VNG) and vestibuloocular reflex (VOR) assessment using the vestibular head impulse test (vHIT). Peripheral nystagmus was found to be significantly higher in patients with SNHL based on the head shake and positional tests (p<0.05). There was a positive correlation between DHI scores and positional test findings of the participants with SNHL (p<0.05). When the VHIT VOR gain values were compared between groups, there was no significant difference (p<0.05). In our study, vestibular involvement was frequently observed in 40- to 65-year-old individuals with SNHL. Therefore, vestibular evaluation should be considered along with the assessment of hearing in individuals with SNHL who are over 40 years old.

Impaired Vestibulo-Ocular Reflex on Video Head Impulse Test in Superior Canal Dehiscence: "Spontaneous Plugging" or Endolymphatic Flow Dissipation?

Surgical plugging of the superior semicircular canal (SSC) represents an effective procedure to treat disabling symptoms in superior canal dehiscence (SCD), despite resulting in an impaired vestibulo-ocular reflex (VOR) gain for the SSC. On the other hand, SSC hypofunction on video head impulse test (vHIT) represents a common finding in patients with SCD exhibiting sound/pressure-induced vertigo, a low-frequency air-bone gap (ABG), and enhanced vestibular-evoked myogenic potentials (VEMPs). "Spontaneous canal plugging" has been assumed as the underlying process. Nevertheless, missing/mitigated symptoms and/or near-normal instrumental findings would be expected. An endolymphatic flow dissipation has been recently proposed as an alternative pathomechanism for SSC VOR gain reduction in SCD. We aimed to shed light on this debate by comparing instrumental findings from 46 ears of 44 patients with SCD exhibiting SSC hypofunction with post-operative data from 10 ears of 10 patients with SCD who underwent surgical plugging. While no difference in SSC VOR gain values was found between the two groups (p = 0.199), operated ears developed a posterior canal hypofunction (p = 0.002). Moreover, both ABG values (p = 0.012) and cervical/ocular VEMP amplitudes (p < 0.001) were significantly higher and VEMP thresholds were significantly lower (p < 0.001) in ears with SCD compared to operated ears. According to our data, canal VOR gain reduction in SCD should be considered as an additional sign of a third window mechanism, likely due to an endolymphatic flow dissipation.

Video head impulse testing: Pitfalls in neurological patients

The video head impulse test (vHIT) assesses the vestibulo-ocular reflex (VOR) during a rapid high-velocity low amplitude (10°–20°) head rotation. Patients with peripheral vestibulopathy have a reduced VOR gain with corrective catch-up saccades during the head turn. There are several pitfalls, mainly technical, which may interfere with interpretation of vHIT data. In addition, intrusive eye movement disorders such as spontaneous nystagmus that affect normal eye position and tracking can affect the vHIT results. To date there has been little study of neurological saccadic eye movements that may interfere with the interpretation of vHIT data. Here, in ten patients with a range of central neurological disorders, we describe oculomotor abnormalities on vHIT in the presence of normal range VOR gain values, recorded at a tertiary vestibular neurology service.

Evaluation of video head impulse test during vertiginous attack in vestibular migraine.

SUMMARYObjectiveThe aim of this study is to evaluate vestibular functions with video head impulse test (VHIT) and to understand the value of VHIT in differential diagnosis in patients with vestibular migraine (VM) during dizziness attack.Materials and methodsTwo groups were enrolled in this study. The first consisted of 84 vestibular migraine patients, and second group of 74 healthy subjects. VHIT was applied to patients with VM during vertigo attack and the results were compared with the VHIT values applied to subjects in the control group.ResultsThe mean vestibulo-ocular reflex (VOR) in all semicircular canals in the VM group was lower than healthy individuals, but the results were not statistically significant. Refixation saccades were found in 52.3% of VM patients and in 10.2% of healthy individuals.ConclusionsWhen patients with VM were evaluated with VHIT during vertiginous attack, VOR gain values were not different from healthy individuals, but the number of catch-up saccades were higher in VM patients, which indicates peripheral vestibular involvement. For differential diagnosis in patients with VM, vestibular tests should be performed during the vertigo attack. When evaluating VHIT results, the presence of refixation saccades should also be evaluated.

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

PurposeThis 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 methodsA 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. ResultsThe 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. ConclusionsA 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.

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.

Evaluation of Vestibulo-Ocular Reflex (VOR) in Tinnitus Patients with Normal Hearing.

This study aimed to evaluate the correlation between tinnitus parameters (duration, severity, reaction, handicap levels) and vestibulo-ocular reflex (VOR) gain values in patients with tinnitus with normal hearing without vertigo or any other complaints and to compare the VOR gains with a healthy group. The study group consisted of 30 individuals aged between 18 and 65 years who suffered from tinnitus but not from hearing loss and vertigo. The control group also consisted of 30 individuals who were categorized as healthy adults. The tinnitus handicap inventory, tinnitus reaction questionnaire, and tinnitus handicap questionnaire were applied to each individual in the tinnitus group, and the video head impulse test (VHIT) was conducted in 2 groups. Statistically, a significant difference was found between the 2 groups in terms of VOR gain values in horizontal and vertical semicircular canal planes (p<0.05). However, there was no statistically significant correlation between tinnitus parameters, age, and VOR gain values in the study group (p>0.05). Considering the lower VOR gain values of the study group than the control group, these patients may need to be followed up for vestibular dysfunction associated with tinnitus, which can be a symptom of peripheral vestibular disorder. Moreover, this study will contribute to the literature because we determined a high-frequency component of VOR by VHIT, which was used to evaluate the relationship between tinnitus parameters and peripheral vestibular function.

Normative values for semicircular canal function with the video head impulse test (vHIT) in healthy adolescents

Background The vHIT device, which has a mechanism based on measuring the VOR gain, helps us to quickly evaluate six semicircular canals. Aims/Objectives The aim of this study was to establish normative values for semicircular canal function with the video head impulse test (vHIT) battery in normal adolescents. Material and methods 100 (50 females, 50 males) individuals aged 11–18 years, with a mean age of 14.99 years, were included in the study. Results As a result of the vHIT evaluations performed with vHIT Otometrics ICS Impulse A/S Taastrup, Denmark, the mean lateral canal vestibulo-ocular reflex (VOR) gain value was 0.96, the mean anterior canal VOR gain value was 0.89, and the mean posterior canal VOR gain value was 0.87, all of which were within the normal value range. Conclusion and significance While the VOR gain values and asymmetry values are within the normal value range and are similar to the literature, no statistically significant correlation was observed between these values and age. As a result, the vHIT battery is an easy, fast, and practical test method that can be used in adolescents.

Evaluation of Interexaminer Variability in Video Head Impulse Test Results.

The video head impulse test (vHIT) is a diagnostic tool to assess the function of the semicircular canals and branches of the vestibular nerve. The aim of this study was to analyze the interexaminer variability of vHIT results in healthy subjects. A total of 21 healthy participants were included in the study. vHIT responses were collected by four clinicians. Variability of the vHIT results between examiners was analyzed statistically. The vestibulo-ocular reflex (VOR) velocity regression values were from 0.99 to 1.09 degrees per second for the lateral canals. For the vertical canals, VOR velocity regression values were from 0.87 to 1.21 degrees per second. According to repeated measures analysis of variance, the normality assumptions for the velocity regression of the left lateral canal (p = 0.002) and the right anterior canal (p < 0.01) were met and the differences were statistically significant. The normality assumptions were not met for 40, 60, and 80 ms median gain of the right lateral canal (p = 0.016, p = 0.038, and p = 0.001, respectively); 40 and 60 ms median gain of the left lateral canal (p < 0.001 and p = 0.008, respectively); and the velocity regression of the left posterior canal (p < 0.00). These differences were found to be statistically significant by using the Friedman test. The interexaminer differences of the VOR gain values for the vHIT were statistically significant. Serial vHIT testing should be performed by the same examiner to reduce the effects of interexaminer variability.

The Different Stages of Vestibular Neuritis from the Point of View of the Video Head Impulse Test.

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 study aims to retrospectively evaluate the VOR gain values during the acute and subacute stages of the VN and to correlate these values with the patients’ dizziness-related handicap. 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). VOR 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 (0.54 ± 0.09) in the PAVSg. Patients evaluated within 72 h since the AVS showed anticompensatory saccades (AcS) turning the head toward the contralesional side. Patients with unilateral Superior VN (SVN) 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 unilateral SVN.

Evaluation of Semicircular Canal Functions by the Video Head Impulse Test (vHIT) in Individuals with Motion Sickness

Background: In the occurrence of motion sickness, the functioning of the vestibular system in harmony has an important role. Aim/Objective: To evaluate the effectiveness of the vestibular system in individuals with motion disease with the Video Head Impulse Test (vHIT) device, which evaluates the vestibulo-ocular reflex (VOR). Materials and Methods: Thirty individuals with motion sickness (21 females, 9 males) and 30 healthy individuals (11 females, 19 males) without any vestibular complaints were examined with the vHIT device. All participants were older than 18 years. Results: It was observed that VOR gain values of the individuals with motion disease were significantly lower than those of the healthy individuals. Asymmetry values of the individuals with motion disease in all semicircular canals were higher than those of the healthy individuals; however, this difference was statistically significant only in the anterior semicircular canal. Conclusion and Significance: The observation of low gain values in all semicircular canals in individuals with motion sickness suggested that individuals with motion sickness may experience dysfunction in the sensory organelles in the vestibular system. Studies with larger case series and audiological test batteries will help us better understand motion sickness. Keywords: Motion sickness; vestibular; vHIT DOI: 10.7176/JHMN/79-05 Publication date: August 31 st 2020

Importance of Vestibulo-ocular Reflex Gain and Refixation Saccade Analysis in Individuals with Auditory Neuropathy Spectrum Disorder.

Introduction Auditory neuropathy spectrum disorder (ANSD) features the presence of otoacoustic emissions, poor speech identification score and absent auditory brainstem response. Objective The present study was designed to evaluate the functioning of all six semicircular canals in individuals with ANSD and to compare it with those of normal-hearing individuals. Methods A total of 50 individuals participated in the present study, in which Group I comprised 25 normal-hearing individuals, and Group II comprised 25 individuals with ANSD. All of the participants underwent case history, pure tone audiometry, immittance, otoacoustic emissions, auditory evoked response and video head impulse test (vHIT). Results The independent sample t-test revealed significantly lower vestibulo-ocular reflex gain values in individuals with ANSD. A presence of 100% corrective refixation saccades was observed in the same group. The Pearson correlation test revealed no significant correlation between vestibulo-ocular reflex (VOR) gain with duration of hearing loss and pure tone thresholds for any of the three orthogonal planes. The chi-squared test revealed no association between the VOR gain values and the presence or absence of saccades in any of the semicircular canals ( p > 0.05). Conclusion Huge percentages of individuals with ANSD have been found to have associated vestibular dysfunction as well. Therefore, the vHIT can be used as one of the important tests of the vestibular test battery to evaluate all six semicircular canals in individuals with ANSD.

Perioperative vestibular assessment and testing

Vestibular disorders can be difficult to accurately diagnose and manage. A careful history and focused physical examination are typically adequate to establish a diagnosis and initiate medical treatment. Vestibular testing is an important component of the work-up, but it is particularly essential for patients being considered for surgical intervention for a vestibular disorder, where the testing can be used to more definitively confirm a suspected diagnosis and to determine baseline vestibular organ function. In this article, we will first briefly review key components of the history and physical examination of patients with vestibular complaints. We will then discuss the most commonly used vestibular tests and their role in the preoperative assessment of patients undergoing vestibular surgery, including nystagmography, caloric testing, rotary chair testing, video head impulse testing, and vestibular evoked myogenic potential testing.

Visual Performance and Perception as a Target of Saccadic Strategies in Patients With Unilateral Vestibular Loss.

To evaluate the ability of saccadic strategies developed during vestibular compensation to reduce the effect of an impaired vestibulo-ocular reflex (VOR) on a retinal smear and image motion sensation. Twenty patients with unilateral vestibular loss were examined with a video head impulse test before and after vestibular rehabilitation (VR) with the use of gaze stabilization and refixation saccades training. Head and eye velocity functions were processed to infer the retinal eccentricity, and through its correlation with visual acuity (VA), several measurements are proposed to evaluate the influence of VR on saccades behavior and visual performance. To isolate the effect of saccades on the findings and avoid bias because of gain differences, only patients whose VOR gain values remained unchanged after VR were included. Improved contribution of covert saccades and reduction of overt saccades latency were measured after VR. We found significant differences when assessing both the interval less than 70% VA (50.25 ms), which is considered the limit of a moderate low vision, and less than 50% VA (39.515 ms), which is the limit for severe low vision. Time to recover a VA of 75% (near normal) was reduced in all the patients (median: 56.472 ms). Despite the absence of VOR gain improvement, patients with unilateral vestibular loss are able to develop saccadic strategies that allow the shortening of the interval of retinal smear and image motion. The proposed measurements might be of use to evaluate VR outcomes and visually induced impairment.

Range of Peak Head Velocity in Video Head Impulse Testing for Pediatric Patients.

To examine peak head velocity in video head impulse testing of pediatric patients and its effect on vestibulo-ocular reflex (VOR) gain. Retrospective case review. Tertiary referral center. Pediatric patients ages 3 to 18 years old who underwent video head impulse testing during clinical evaluation of dizziness and/or imbalance. Conducted video head impulse test (vHIT) in horizontal, left anterior-right posterior (LARP), and right anterior-left posterior (RALP) planes. Peak head velocity and mean VOR gain for individual semicircular canals in different age groups. For the horizontal plane, vHIT peak head velocity greater than 150 degrees/s was achieved in 43 to 63% of 219 patients. In contrast, vHIT peak head velocity greater than 150 degrees/s was achieved in only 3 to 14% for the LARP and RALP planes. Analyses of differences in mean VOR gains among three ranges of peak head velocity (100-125 degrees/s, 126-150 degrees/s, and >150 degrees/s) by paired-t tests were not significant (p > 0.05) within individual patients. Mean VOR gains of three vertical canals in younger patients were significantly lower with higher peak head velocities compared with older children (p < 0.05). Peak head velocities of greater than 150 degrees/s may not be feasible in a large proportion of children and adolescents, especially in LARP and RALP planes. However, such high velocities may not be necessary in the pediatric population since VOR gain values obtained at lower peak head velocities of 100 to 150 degrees/s were found to be comparable to those observed at higher velocities.

Vestibulo-ocular reflex gain values in the suppression head impulse test of healthy subjects.

To assess whether there are differences in vestibulo-ocular reflex (VOR) gain for suppression head impulse (SHIMP) and head impulse (HIMP) video head impulse test paradigms, and if so, what are their causes. Prospective multicenter observational double-blind nonrandomized clinical study was performed by collecting 80 healthy subjects from four reference hospitals. SHIMP data was postprocessed to eliminate impulses in which early SHIMP saccades were detected. Differences between HIMP and SHIMP VOR gain values were statistically evaluated. Head impulse maximum velocity, gender, age, direction of impulse, and hospital center were considered as possible influential factors. A small significant statistical difference between HIMP and SHIMP VOR gain values was found on repeated measures analysis of variance (-0.05 ± 0.006, P < 0.001). Optimized linear model showed a significant influence of age variable on the observed differences for HIMP and SHIMP gain values and did not find influence between gain values differences and maximum head impulse velocity. Both HIMP and SHIMP VOR gain values were significant lower (-0.09, P < 0.001) when the impulses were performed to the left side. We had observed a difference in SHIMP and HIMP gain values not adequately explained by known gain modification factors. The persistence of this slight but significant difference indicates that there are more factors causing lower SHIMP VOR gain values. This difference must to be considered in further studies as well as in the clinical SHIMP testing protocols. We hypothesized that VOR phasic response inhibition could be the underlying cause of this difference. 2b. Laryngoscope, 128:2383-2389, 2018.

Higher Asymmetry Ratio and Refixation Saccades in Individuals with Motion Sickness.

Motion sickness is a complex autonomic phenomenon caused by the intersensory conflict among the balancing systems, resulting in a mismatch of signals between static physical conditions of the susceptible individual exposed to dynamic environment. The present study was done to assess the sacculocollic reflex pathway and six semicircular canals in individuals susceptible to motion sickness. Standard group comparison was used. A total of 60 participants with an age range of 17-25 yr were included, where group I comprised 30 participants with motion sickness and group II comprised 30 participants without motion sickness. The Motion Sickness Susceptibility Questionnaire-Short was administered to classify the participants into groups with or without motion sickness. The cervical vestibular-evoked myogenic potential (cVEMP) test and video head impulse test (vHIT) were administered to all participants. The Shapiro-Wilk test revealed normal distribution of the data (p > 0.05). Hence a parametric independent sample t test was done to check significant difference in cVEMP and vHIT parameters between the two groups. The present study revealed no significant difference for cVEMP latencies and amplitude in individuals with motion sickness. However, significantly higher cVEMP asymmetry ratio was observed in individuals with motion sickness. Though the vestibulo-ocular reflex (VOR) gain values showed no significant difference between the two groups except for the right anterior left posterior plane, the asymmetry in VOR gain values revealed significant difference between the groups, suggesting asymmetry as a better parameter than absolute VOR gain values. Also, the presence of refixation saccades in 100% of the individuals with motion sickness accorded with various studies reported earlier with vestibular-related pathologies. Presence of higher asymmetry ratio in cVEMP and vHIT test results plus refixation saccades to stabilize the gaze in vHIT can suggest some amount of vestibular anomalies in individuals with motion sickness.

Rotational and Collic Vestibular-Evoked Myogenic Potential Testing in Normal Developing Children and Children With Combined Attention Deficit/Hyperactivity Disorder.

Vestibular dysfunction in childhood can have a major effect on a child's developmental process. Balance function has been reported to be poorer in children with attention deficit and hyperactivity disorder (ADHD) than in their typically developing peers. Due to contradictory available evidence and the paucity of research on vestibular function specifically in children with combined ADHD (cADHD), we designed this aged-matched study to assess vestibular function in children with cADHD. We enrolled 30 typically developing children (15 boys and 15 girls; mean age, 9 years 6 months; range, 7 to 12 years) and 33 children (19 boys and 14 girls; mean age, 9 years 0 months; range, 7 to 12 years) with cADHD diagnosed by our research psychiatrist. Typically developing controls were used to obtain normative data on vestibular testing and to examine the impact of age on the vestibular response parameters, and these results were compared with those of the cADHD group. All children underwent the sinusoidal harmonic acceleration subtype of the rotary chair test (0.01, 0.02, 0.08, 0.16, and 0.32 Hz) and the cervical vestibular-evoked myogenic potential (cVEMP) test. At all five frequencies in the sinusoidal harmonic acceleration test, there was no significant correlation between age and any of the following rotary chair response parameters in typically developing children: vestibulo-ocular reflex (VOR) gain, phase, asymmetry, and fixation index. Furthermore, there was no significant correlation between age and any of the following cVEMP parameters for the right and left ears of control group: p1 and n1 latency, amplitude, threshold, and amplitude ratio. Significantly higher VOR gains were observed for children with cADHD at frequencies of 0.01 (p = 0.001), 0.08 (p < 0.001), 0.16 (p = 0.001), and 0.32 (p = 0.003) Hz, when compared with the control group. Furthermore, fixation abilities were significantly lower in the cADHD group than in the control group at 0.16 (p < 0.001) and 0.32 (p < 0.001) Hz. cVEMP parameters showed no significant differences between the two groups. Our results showed higher VOR gains and poorer fixation abilities in children with cADHD compared with typically developing children. Cerebellar dysfunction in patients with ADHD has been well documented in the literature, and our findings of cVEMP and rotary chair tests for these children showed impaired vestibular function in these children, based on increased VOR gain values and decreased fixation capabilities. Because VOR gain is mediated through the inferior olive and controlled by the cerebellum, our results suggest that central inhibition of vestibular function may be deficient in children with cADHD, resulting in higher VOR gains. Also, there is general agreement that failure of fixation suppression indicates a central lesion. The lesion can originate from the parietal-occipital cortex, the pons, or the cerebellum. However, failure of fixation suppression is most prominent in lesions involving the midline cerebellum that could be counted for children with cADHD. We believe that this contribution is theoretically and practically relevant as high VOR gains and decreased suppression capabilities may result in symptoms of reading and writing difficulties, learning disabilities, vertigo, and motion sickness in these children. Therefore, assessment of vestibular function in children with cADHD at a young age must be considered when developing rehabilitation protocols for these children.