Goggle Versus Remote-Camera Video Head Impulse Test Device Comparison.

OBJECTIVES: This study compared remote versus goggle video head impulse testing (vHIT) outcomes to validate remote-camera vHIT, which is gaining popularity in difficult to test populations. DESIGN: Seventeen controls and 10 individuals with vestibular dysfunction participated. Each participant completed remote-camera and goggle vHIT. The main outcome parameters were canal gain, frequency of corrective saccades, and a normal versus abnormal rating. RESULTS: Horizontal and vertical canal vHIT gain was significantly lower in the vestibular compared with the control group; remote-camera gains were significantly lower compared with goggle gain for the vestibular group only. The devices categorized control versus vestibular canals identically except for one vertical canal. In the vestibular group, there was not a significant difference in the percentage of compensatory saccades between devices. CONCLUSION: These data provide validation that results obtained with a remote-camera device are similar to those obtained using a standard goggle device.

Effect of Real-Ear Adjusted Stimuli on Vestibular Evoked Myogenic Potential Variability in Children and Young Adults.

OBJECTIVES: There is large variability in cervical and ocular vestibular evoked myogenic potential (c- and oVEMP) amplitudes. One potential source of variability is differences in ear canal shape and size. Real ear-to-coupler difference (RECD) values are used to measure the acoustic environment of an individual's ear canal. RECD may be a useful measure to calibrate air conducted VEMP stimuli, which are elicited at high intensities and may put patients at risk of unsafe sound exposure. A recommendation for avoiding unsafe exposure is to use a 125 dB SPL stimulus for individuals with an equivalent ear canal volume (ECV) ≥ 0.9 mL and a 120 dB SPL stimulus for individuals with a smaller ECV. The purpose of this project was to determine if using a stimulus calibrated in the ear using RECD values significantly reduces intra-subject and inter-subject VEMP amplitude variability. We hypothesized that using a RECD-calibrated stimulus would significantly reduce inter-subject amplitude variability but not significantly reduce intra-subject variability. We further hypothesized that an RECD-adjusted VEMP stimulus would better protect against delivering unsafe sound exposure compared to the method of using ECV alone. DESIGN: Eleven children (4 to 9 years), 10 adolescents (10 to 18 years), and 10 young adults (20 to 40 years) with normal hearing, tympanometry, vestibular and neurological function participated. On all subjects, RECD was measured twice per ear to account for test-retest reliability. cVEMP and oVEMP were then recorded bilaterally with a 500 Hz tone burst at a traditional and an adjusted VEMP intensity level. The traditional intensity level was 125 dB SPL for individuals with ≥ 0.9 mL ECV and 120 dB SPL for individuals with ≤ 0.8 mL ECV. The adjusted intensity level was calculated by subtracting the average 500 Hz RECD measured values from the 500 Hz normative RECD value. This value was applied as a correction factor to a 125 dB SPL stimulus. Peak to peak amplitudes were recorded and used to calculate asymmetry ratios. RESULTS: Young children had significantly smaller ECVs compared to adolescents and young adults. Young children had larger RECDs; however, this was not significant in post hoc analyses. The method of calibration had no significant effect on intra-subject variability for cVEMP [ F (1, 27)= 0.996, p = 0.327] or oVEMP [ F (1, 25)= 1.679, p = 0.206]. The method of calibration also had no significant effect on inter-subject amplitude variability for cVEMP [ F (1, 120)= 0.721, p = 0.397] or oVEMP [ F (1, 120)= 0.447, p = 0.505]. Both methods of calibration adequately protected against unsafe exposure levels. However, there were subjects with ECVs ≥ 0.9 mL who approached unsafe exposure levels from the ECV-calibrated stimulus, suggesting there may be rare cases in which a 125 dB SPL stimulus is unsafe, even for patients with larger ECVs. CONCLUSIONS: The calibration method made no significant difference in intra- or inter-subject variability, indicating that the acoustic environment of the outer ear is not significantly contributing to VEMP amplitude variability. The RECD-adjusted stimulus is effective in protecting against unsafe exposure levels for two trials of both c- and oVEMPs. There may be instances where more than two trials of each test are required, which increases the effective stimulation level. Clinicians should be cautious when delivering VEMPs and not unnecessarily expose patients to unsafe levels of sound.

Age Effects of Bone Conduction Vibration Vestibular-evoked Myogenic Potentials (VEMPs) Using B81 and Impulse Hammer Stimuli.

OBJECTIVE: Recently developed, the Radioear B81 bone oscillator allows for higher bone conduction vibration output; however, normative data are lacking regarding its use in vestibular-evoked myogenic potential (VEMP) testing. The purpose of this study was to examine the effect of age on cervical and ocular VEMP (c- and oVEMP) responses using the B81 and to compare with air conduction stimuli (ACS) and impulse hammer (IH) VEMP response characteristics. DESIGN: c- and oVEMP were completed with ACS, B81, and IH stimuli in healthy participants (age range = 10 to 87 years, n = 85). RESULTS: Regardless of stimulus type, c- and oVEMP amplitudes and response rates decreased with age. For cVEMP response rates, ACS performed better or equal to B81, which was superior to the IH. For cVEMP corrected amplitude, ACS had significantly higher amplitudes compared with B81 and IH. There was no difference in cVEMP corrected amplitude between B81 and IH. For oVEMP, response rates were comparable between stimuli with the largest disparity in response rates occurring in the oldest groups where IH outperformed both ACS and B81. For oVEMP amplitude, IH had significantly higher amplitudes compared with B81 and ACS. There was no difference in oVEMP amplitude between B81 and ACS. CONCLUSIONS: Age significantly affected c- and oVEMP amplitudes regardless of stimulus type (ACS, B81, IH). All stimuli are appropriate for eliciting c- and oVEMP in the young individuals. While ACS resulted in higher cVEMP corrected amplitudes, either ACS or B81 are appropriate for older individuals. However, for oVEMPs, higher response rates and larger amplitudes were noted for IH followed by B81 and ACS. Overall, the B81 performed well across the lifespan for c- and oVEMPs and may be a reasonable bone conduction vibration option for patients with absent ACS VEMPs, but at this time is not recommended as a replacement to ACS.

Bone Conduction Vibration Vestibular Evoked Myogenic Potential (VEMP) Testing: Reliability in Children, Adolescents, and Young Adults.

OBJECTIVES: Bone conduction vibration (BCV) vestibular evoked myogenic potentials (VEMP) are clinically desirable in children for multiple reasons. However, no accepted standard exists for stimulus type and the reliability of BCV devices has not been investigated in children. The objective of the current study was to determine which BCV VEMP method (B-71, impulse hammer, or Mini-shaker) yields the highest response rates and reliability in a group of adults, adolescents, and children. It was hypothesized that the Mini-shaker would yield the highest response rates and reliability because it provides frequency specificity, higher output levels without distortion, and the most consistent force output as compared to the impulse hammer and B-71. DESIGN: Participants included 10 child (ages 5 to 10), 11 adolescent (ages 11 to 18), and 11 young adult (ages 23 to 39) normal controls. Cervical VEMP (cVEMP) and ocular VEMP (oVEMP) were measured in response to suprathreshold air-conducted, 500 Hz tone bursts and 3 types of BCV (B-71, impulse hammer, and Mini-shaker) across 2 test sessions to assess reliability. RESULTS: For cVEMP, response rates were 100% for all methods in all groups with the exception of the adult group in response to the impulse hammer (95%). For oVEMP, response rates varied by group and BCV method. For cVEMP, reliability was highest in adults using the Mini-shaker, in adolescents using the impulse hammer, and in children using the B-71. For oVEMP, reliability was highest in adults using the Mini-shaker, in adolescents using the Mini-shaker or impulse hammer, and in children using the impulse hammer. Age positively correlated with air-conducted oVEMP amplitude, but not cVEMP amplitude or cVEMP corrected amplitude. Age negatively correlated with all BCV VEMP amplitudes with the exception of cVEMP corrected amplitude in response to the Mini-shaker. CONCLUSIONS: All BCV methods resulted in consistent cVEMP responses (response rates 95 to 100%) with at least moderate reliability (intraclass correlation coefficient ≥ 0.5) for all groups. Similarly, all BCV methods resulted in consistent oVEMP responses (89 to 100%) with at least moderate reliability (intraclass correlation coefficient ≥ 0.5) except for the B-71 in adults.

Effect of Cochlear Implantation on Vestibular Evoked Myogenic Potentials and Wideband Acoustic Immittance.

OBJECTIVES: The objective of this study was to determine if absent air conduction stimuli vestibular evoked myogenic potential (VEMP) responses found in ears after cochlear implantation can be the result of alterations in peripheral auditory mechanics rather than vestibular loss. Peripheral mechanical changes were investigated by comparing the response rates of air and bone conduction VEMPs as well as by measuring and evaluating wideband acoustic immittance (WAI) responses in ears with cochlear implants and normal-hearing control ears. The hypothesis was that the presence of a cochlear implant can lead to an air-bone gap, causing absent air conduction stimuli VEMP responses, but present bone conduction vibration VEMP responses (indicating normal vestibular function), with changes in WAI as compared with ears with normal hearing. Further hypotheses were that subsets of ears with cochlear implants would (a) have present VEMP responses to both stimuli, indicating normal vestibular function and either normal or near-normal WAI, or (b) have absent VEMP responses to both stimuli, regardless of WAI, due to true vestibular loss. DESIGN: Twenty-seven ears with cochlear implants (age range 7 to 31) and 10 ears with normal hearing (age range 7 to 31) were included in the study. All ears completed otoscopy, audiometric testing, 226 Hz tympanometry, WAI measures (absorbance), air conduction stimuli cervical and ocular VEMP testing through insert earphones, and bone conduction vibration cervical and ocular VEMP testing with a mini-shaker. Comparisons of VEMP responses to air and bone conduction stimuli, as well as absorbance responses between ears with normal hearing and ears with cochlear implants, were completed. RESULTS: All ears with normal hearing demonstrated 100% present VEMP response rates for both stimuli. Ears with cochlear implants had higher response rates to bone conduction vibration compared with air conduction stimuli for both cervical and ocular VEMPs; however, this was only significant for ocular VEMPs. Ears with cochlear implants demonstrated reduced low-frequency absorbance (500 to 1200 Hz) as compared with ears with normal hearing. To further analyze absorbance, ears with cochlear implants were placed into subgroups based on their cervical and ocular VEMP response patterns. These groups were (1) present air conduction stimuli response, present bone conduction vibration response, (2) absent air conduction stimuli response, present bone conduction vibration response, and (3) absent air conduction stimuli response, absent bone conduction vibration response. For both cervical and ocular VEMPs, the group with absent air conduction stimuli responses and present bone conduction vibration responses demonstrated the largest decrease in low-frequency absorbance as compared with the ears with normal hearing. CONCLUSIONS: Bone conduction VEMP response rates were increased compared with air-conduction VEMP response rates in ears with cochlear implants. Ears with cochlear implants also demonstrate changes in low-frequency absorbance consistent with a stiffer system. This effect was largest for ears that had absent air conduction but present bone conduction VEMPs. These findings suggest that this group, in particular, has a mechanical change that could lead to an air-bone gap, thus, abolishing the air conduction VEMP response due to an alteration in mechanics and not a true vestibular loss. Clinical considerations include using bone conduction vibration VEMPs and WAI for preoperative and postoperative testing in patients undergoing cochlear implantation.

Clinical Utility of Oculomotor and Electrophysiological Measures in Identifying Concussion History.

OBJECTIVE: To examine whether oculomotor and electrophysiological measures improve the clinical performance of the typical concussion protocol for classifying collegiate athletes with a history of concussion. DESIGN: Cross-sectional. SETTING: University Athletic Medicine and Research Facility. PARTICIPANTS: Forty-five varsity collegiate athletes. INDEPENDENT VARIABLES: Collegiate varsity athletes with or without a history of a diagnosed concussion. MAIN OUTCOME MEASURES: Multivariate receiver operating curve and area under the curve (AUC) analyses tested the clinical performance of the typical concussion protocol (symptoms, postural control, neuropsychological abilities). We examined differences in clinical performance between this protocol and after adding reflexive saccade and event-related potential (ERP) indices. Hypotheses were formed after data collection. RESULTS: Significant AUCs were demonstrated for the typical concussion protocol (model 1: AUC = 0.75, P = 0.007), after adding reflexive saccade eye excursion gain (model 2: AUC = 0.80, P = 0.001), and ERPs (model 3: AUC = 0.79, P = 0.002). The AUC for reflexive saccades and ERPs was significant (model 4: AUC = 0.70, P = 0.030). Model 2's increased clinical performance compared with model 1 was nonsignificant, χ(2) = 1.871, P = 0.171. CONCLUSIONS: All 4 models demonstrated adequate sensitivity and specificity for classifying athletes with a previous concussion. Adding reflexive saccades and ERPs did not significantly increase clinical performance of the typical concussion protocol. Future research should determine the clinical utility of saccades and ERPs for acute postconcussion assessments.

Gaze Stabilization Test Asymmetry Score as an Indicator of Previous Concussion in a Cohort of Collegiate Football Players.

OBJECTIVE: Vestibular dysfunction may lead to decreased visual acuity with head movements, which may impede athletic performance and result in injury. The purpose of this study was to test the hypothesis that athletes with history of concussion would have differences in gaze stabilization test (GST) as compared with those without a history of concussion. DESIGN: Cross-sectional, descriptive. SETTING: University Athletic Medicine Facility. PARTICIPANTS: Fifteen collegiate football players with a history of concussion, 25 collegiate football players without a history of concussion. INTERVENTION: Participants completed the dizziness handicap inventory (DHI), static visual acuity, perception time test, active yaw plane GST, stability evaluation test (SET), and a bedside oculomotor examination. MAIN OUTCOME MEASURES: Independent samples t test was used to compare GST, SET, and DHI scores per group, with Bonferroni-adjusted alpha at P < 0.01. Receiver operating characteristic curve analysis and area under the curve (AUC) were used to assess the clinical performance of the GST and SET. RESULTS: Athletes with previous concussion had a larger GST asymmetry score [mean (M) = 12.40, SD = 9.09] than those without concussion (M = 4.92, SD = 4.67; t (18.70) = -2.955, P = 0.008, 95% CI, -12.79 to -2.18, d = -1.37). Clinical performance of the GST (AUC = 0.77) was better than the SET (AUC = 0.61). CONCLUSIONS: Results suggest peripheral vestibular or vestibular-visual interaction deficits in collegiate athletes with a history of concussion. The results support further research on the use of GST for sport-related concussion evaluation and monitoring. CLINICAL RELEVANCE: Inclusion of objective vestibular tests in the concussion protocol may reveal the presence of peripheral vestibular or visual-vestibular deficits. Therefore, the GST may add an important perspective on the effects of concussion.

Electrode Montage for Bilateral Cervical Vestibular Evoked Myogenic Potential (cVEMP) Testing.

BACKGROUND: Cervical vestibular evoked myogenic potentials (cVEMPs) are predominantly ipsilateral, myogenic responses originating from saccular activation. Some individuals have contralateral-crossed cVEMP responses with monaural air-conducted stimulation (ACS) which can contaminate cVEMP responses with bilateral stimulation. While the origin of the contralateral-crossed response is under debate, its presence has implications for cVEMP testing with midline bone conduction vibration (BCV). PURPOSE: The purpose of this study was to determine the origin of the contralateral-crossed cVEMP response. It was hypothesized that the crossed response is due to electrode contamination and would disappear with a modified electrode montage. RESEARCH DESIGN: Cross-sectional research study. STUDY SAMPLE: Fifteen healthy participants (30 ears; mean age: 27.4 19-39; 10 females). DATA COLLECTION AND ANALYSIS: Participants completed cVEMP testing using three stimulation methods (monoaural ACS, binaural ACS, and midline BCV) and two electrode montages (sternum reference and Fp reference). RESULTS: In the monoaural ACS with sternum reference condition, 53.3% ears had contralateral-crossed cVEMP responses that were in-phase with the ipsilateral response for all but 3 ears. Whereas in the monoaural ACS with Fp reference condition, 3% had a contralateral-crossed cVEMP response. ACS and BCV cVEMP corrected amplitudes were significantly larger in the sternum reference conditions, which is attributed to artificial enhancement from the in-phase contralateral-crossed responses. CONCLUSIONS: The significant reduction of contralateral-crossed responses in the Fp reference condition suggests that the contralateral-crossed cVEMP response is due to reference electrode contamination and may be a more appropriate reference placement when completing cVEMPs with midline BCV. PURPOSE: The purpose of this study was to determine the origin of the contralateral-crossed cVEMP response. It was hypothesized that the crossed response is due to electrode contamination and would disappear with a modified electrode montage. RESEARCH DESIGN: Cross-sectional research study. STUDY SAMPLE: Fifteen healthy participants (30 ears; mean age: 27.4 19-39; 10 females). DATA COLLECTION AND ANALYSIS: Participants completed cVEMP testing using three stimulation methods (monoaural ACS, binaural ACS, and midline BCV) and three electrode montages (sternum reference, Fp reference, and active on Fp). RESULTS: In the monoaural ACS with sternum reference condition, 53.3% ears had contralateral-crossed cVEMP responses that were in-phase with the ipsilateral response for all but 3 ears. Whereas in the monoaural ACS with Fp reference condition, 3% had a contralateral-crossed cVEMP response. No participants demonstrated responses using Fp for the active electrode suggesting this is a neutral site. ACS and BCV cVEMP corrected amplitudes were significantly larger in the sternum reference conditions, which is attributed to artificial enhancement from the in-phase contralateral-crossed responses. CONCLUSIONS: The significant reduction of contralateral-crossed responses in the Fp reference condition suggests that the contralateral-crossed cVEMP response is due to reference electrode contamination and may be a more appropriate reference placement when completing cVEMPs with midline BCV.

Clinical Utility of Remote Camera Video Head Impulse Testing Children Less Than 3 Years.

The purpose of this case report is to highlight both the feasibility and clinical utility of remote camera video head impulse testing (vHIT) in children <3 years. Five cases are described where remote camera vHIT was used to quantify ear specific semicircular function in children at risk for vestibular dysfunction. Remote camera vHIT is a helpful clinical tool for quantifying ear specific semicircular function in children between 6 and 31 months. Remote camera vHIT is feasible and provides ear specific information regarding semicircular canal function, which can be used to augment or validate the presence of vestibular dysfunction in children <3 years. Laryngoscope, 2024.

The effects of vestibular dysfunction on balance and self-concept in children with cochlear implants.

OBJECTIVES: Children with cochlear implants (CCI) have an increased rate of vestibular dysfunction. Vestibular dysfunction is associated with decreased balance and dynamic visual acuity ability. Hearing loss alone is associated with reduced speech perception and vocabulary in children. In adults, vestibular dysfunction is associated with reduced quality of life; however, similar relationships have not been studied in children with vestibular dysfunction. Therefore, the objective of the present study was to evaluate the effect of hearing loss and vestibular dysfunction on self-concept in CCI (n = 33) compared to children with normal hearing (CNH, n = 38). It was hypothesized that children with vestibular dysfunction would have reduced self-concept beyond that from hearing loss, secondary to the presence of balance and visual acuity deficits. METHODS: The Piers-Harris Children's Self-Concept Scale - 2, speech perception, vocabulary, video head impulse test (vHIT), rotary chair, balance using the Bruininks-Oseretsky Test of Motor Proficiency (BOT-2), and dynamic visual acuity (DVA) testing were completed on all participants. RESULTS: In the 34 CCI, 24 had normal vestibular function, 6 had unilateral vestibular dysfunction, and 4 had bilateral vestibular dysfunction. There were no significant mean differences in the Piers-Harris Children's Self-Concept Scale - 2 between groups. A Principal Component Analysis (PCA) was conducted on the predictor variables (average horizontal canal vHIT gain, BOT-2 score, DVA, speech perception, and vocabulary) resulting in two factors; factor 1 represented "vestibular" components (vHIT, BOT-2, and DVA) and factor 2 represented "auditory-language" components (speech perception and vocabulary). In addition to age and gender, the 2 PCA factors were analyzed using multivariate regression with stepwise selection to determine which factors best predicted self-concept. The PCA auditory-language factor was the only significant predictor of self-concept. CONCLUSIONS: Auditory-language, not vestibular related factors, contribute to the self-concept of CCI. While adults with vestibular dysfunction have reduced quality of life, it could be that children with vestibular dysfunction have some psychosocial resilience.

Stability of Vestibular Testing in Children With Hearing Loss.

PURPOSE: The purpose of this study was to evaluate the stability of rotary chair, video head impulse test (vHIT), and vestibular evoked myogenic potential (VEMP) responses in children with normal hearing (NH) and children with cochlear implants (CIs). METHOD: Retrospective analysis of 66 children (33 males, M age = 11.4 years, range: 3-18 years) seen in a tertiary clinic and/or research laboratory who completed rotary chair, VEMP, and vHIT across two test sessions between 2012 and 2019. The stability of these measures was compared between two groups: children with NH (n = 35) and children with CI (n = 31). For each outcome, the session difference was calculated by subtracting Session 1 from Session 2. RESULTS: For rotary chair (gain and phase) and vHIT (gain), linear mixed-effects models revealed that there were no significant interactions or main effects for group (CI vs. NH), time between session, gender, or age on the session difference, suggesting that the outcomes of these measures are stable across sessions. For cervical and ocular VEMP amplitude, there was a significant interaction between group and time between sessions on the session difference. Specifically, children with NH demonstrated larger amplitudes at Session 2, whereas children with CI demonstrated smaller amplitudes at Session 2. Next, test findings were classified as normal, unilaterally abnormal, or bilaterally abnormal for Sessions 1 and 2. Misclassification was defined as a mismatch of classification between sessions. Rotary chair and vHIT had the fewest misclassifications, whereas cervical VEMPs had the most misclassifications in children with CI and ocular VEMPs had the most misclassifications in children with NH. Misclassifications in children with CI were mostly consistent with progressive vestibular loss, whereas misclassifications in children with NH were mostly consistent with improved vestibular function. CONCLUSIONS: Stability and misclassification rates varied between tests and groups. Overall, rotary chair and vHIT outcomes were stable in both groups; however, VEMPs differentially changed between groups, improving in children with NH and declining in children with CI. Furthermore, despite relative stability, some children with CI evidenced progressive vestibular loss on all measures suggesting that vestibular testing should be completed serially due to the possibility of progression.

Using Functional Outcomes to Predict Vestibular Loss in Children.

OBJECTIVE: The purpose of this study was to determine: (1) the relationship between vestibular loss severity and functional performance, (2) which functional performance outcomes best predict vestibular loss, and (3) which vestibular rate sensors (canals vs. otoliths) provide the most weighting during different functional measures. STUDY DESIGN: Prospective. SETTING: Tertiary referral center. PATIENTS: Fifty-seven children with normal hearing (mean age: 12.3 years, 32 males) and 55 children with cochlear implants (mean age 12.8 years, 29 males). INTERVENTION: Diagnostic. MAIN OUTCOME MEASURES: Video head impulse test, cervical vestibular evoked myogenic potential (cVEMP), ocular VEMP (oVEMP), single leg stance, Standing Balance Test, active and passive dynamic visual acuity, and the balance subtest of the Bruininks-Oseretsky Test of Motor Proficiency (BOT-2). RESULTS: Performance worsened as vestibular loss severity worsened for all functional outcomes except the standing balance test conditions 1 and 2. The best outcomes for classifying children with vestibular loss were the single leg stance (cut-off criterion: 5 seconds; sensitivity and specificity of 88% and 86%) and the BOT-2 balance subtest (cut-off criterion of 27.5 points; sensitivity and specificity of 88% and 88%). Average horizontal canal vHIT gain was a significant predictor of all functional outcomes while neither corrected cVEMP amplitude nor oVEMP amplitude predicted performance. CONCLUSION: Functional performance declines as vestibular loss severity worsens. Single leg stance is fast and efficient for predicting vestibular loss in school age children. Average horizontal canal vHIT best predicts functional performance; if using a tiered approach, horizontal canal vHIT should be completed first.

The Dizzy Child.

Dizziness occurs in children with an estimated prevalence of 0.45% to 15.0%. Vestibular disorders in the pediatric population can impact gross motor function development, visual acuity, and contribute to psychological distress. Appropriate case history and focused direct examination can be helpful when determining the etiology of dizziness. Vestibular testing can be completed in children and guide management of suspected vestibular dysfunction. Vestibular dysfunction is commonly seen in patients with sensorineural hearing loss. Migraine disorders are the most common cause of dizziness in childhood. Etiologies of dizziness in children differ from those commonly seen in adults.

The Relationship Between Rotary Chair and Video Head Impulse Testing in Children and Young Adults With Cochlear Implants.

Purpose Conflicts among video head impulse testing (vHIT) and rotary chair have occurred; therefore, the purpose of this study was to determine the relationship between rotary chair and vHIT outcome parameters to understand when these two tests disagree and determine if one or both test outcomes are needed in children. Method Data from 141 child and young adult subjects (73 males, 68 females, M age = 15 years, range: 6-35) were retrospectively reviewed. Of those, 56 had a cochlear implant and 85 were normal controls. All subjects completed rotary chair and vHIT, which were categorized as (a) normal vestibular function, (b) unilateral vestibular loss, or (c) bilateral vestibular loss. vHIT tracings were analyzed to determine if gain and corrective saccade velocity, frequency, or latency were helpful parameters for determining vestibular loss. Results Of the 141 subjects, the misclassification rate was 13/141 (9%). All normal control subjects were classified as having normal rotary chair and normal vHIT. In subjects with a cochlear implant (n = 56), the misclassification rate was 13/56 (23%). There were four misclassification patterns. Using rotary chair as the gold standard, receiver operating characteristic analysis revealed optimal cut-points for vHIT gain (< 0.84), corrective saccade frequency (≥ 50%), amplitude (≥ 75°/s), and latency (≤ 320 ms). Using these vHIT cut-points improved the agreement between rotary chair and vHIT, resulting in an overall misclassification rate of 10/141 (7%) and 9/56 (16%) in subjects with a cochlear implant. Conclusions When testing children, caloric testing is often not an option due to tolerability or time. However, discordant results occur between rotary chair and vHIT. These data suggest vHIT is a sufficient first-tier assessment. If abnormal, rotary chair is not necessary. If normal, rotary chair can be helpful for uncovering other indicators of vestibular loss. When interpreting vHIT, including gain and all corrective saccade outcomes may improve sensitivity.

Effect of Gaze Angle During the Vertical Video Head Impulse Test Across Two Devices in Healthy Adults and Subjects With Vestibular Loss.

OBJECTIVE: To evaluate the effect of gaze angle on vertical vestibulo-ocular reflex (VOR) gain using two different video head impulse (vHIT) devices in healthy adults and subjects with bilateral vestibular loss (BVL). STUDY DESIGN: Prospective study. SETTING: Hospital research laboratory. SUBJECTS: Twenty-four healthy adults (mean [standard deviation {SD}] age = 32 [4.8]; 23-42; 8 men) and four subjects with previously diagnosed BVL (mean age [SD] = 32 [8.2]; 21-40; 3 men) participated. INTERVENTION: Vertical canal vHIT was administered with two different devices using three gaze angles (-45 degrees, 0 degree, +45 degrees). These devices have different gain calculation algorithms and different head and gaze angle protocols. MAIN OUTCOME MEASURES: Vertical canal gain and presence or absence of reset saccades. RESULTS: A significant stepwise reduction in vHIT gain was noted as gaze moved away from the plane of the canals stimulated (from -45 degrees to 0 degree, to +45 degrees) for both healthy adults and subjects with BVL. vHIT gain was able to separate the two groups using gaze angles -45 degrees and 0 degree. CONCLUSIONS: In spite of their differences in gain algorithm and recommended head position and gaze angle, each device was able to appropriately separate healthy adults from subjects with BVL with high sensitivity/specificity.

Video Head Impulse Test (vHIT): The Role of Corrective Saccades in Identifying Patients With Vestibular Loss.

OBJECTIVE: 1) Characterize corrective saccades (CS) in normal controls, and 2) examine the sensitivity of the video head impulse test (vHIT) for identifying vestibular loss using both gain and CS. STUDY DESIGN: Prospective combined with retrospective review. SETTING: Tertiary referral center. PATIENTS: Seventy subjects with normal vestibular function served as controls (mean age, 44.1 yr; range, 10-78) and data from 49 patients with unilateral and bilateral vestibular loss was retrospectively reviewed (mean age, 50; range, 7-81). INTERVENTION: vHIT; individual horizontal head impulses were then analyzed in MATLAB. MAIN OUTCOME MEASURES: Horizontal vHIT gain, CS peak velocity, frequency, and latency. RESULTS: There was not an age effect for CS velocity or latency, and only a weak relationship between CS frequency and age in the control group. Gain and CS latency were the only parameters affected by impulse side, demonstrating higher gain and longer latency on the right. The group with vestibular loss had significantly lower mean vHIT gain, higher mean CS frequency, higher mean CS velocity, earlier CS latency, and smaller mean CS standard deviations of the latency compared with the control group.When all factors were analyzed separately by logistic regression, vHIT gain provided the best classification (83.8%), closely followed by CS frequency (83.1%). Using a two variable approach (both gain and CS frequency) yielded the best diagnostic accuracy (overall classification = 84.6%). CONCLUSIONS: Along with gain, incorporating CS frequency in interpreting vHIT improves diagnostic accuracy. A repeatable CS (>81.89%) and/or low gain (<0.78) indicate vestibular loss.

Examining Effects of Physical Exertion on the Dynamic Visual Acuity Test in Collegiate Athletes.

BACKGROUND: Acute symptoms of dizziness and/or imbalance commonly experienced in athletes postconcussion are speculated to arise from dysfunction at multiple levels (i.e., inner ear or central vestibular system) to appropriately integrate afferent sensory information. Disruption along any pathway of the balance system can result in symptoms of dizziness, decreased postural control function (vestibulospinal reflex), and reduced vestibulo-ocular reflex function. This may also lead to decreased gaze stability with movements of the head and may account for symptoms of blurred vision or diplopia reported in almost half of athletes sustaining a concussion. Current concussion position statements include measures of postural control to examine changes to the balance system postconcussion. The Balance Error Scoring System (BESS) is a commonly used low-cost postural control measure for concussion assessment. Although this is a widely used measure for documenting balance function on both immediate (sideline) and recovery monitoring, the BESS has been shown to be affected by physical exertion. Therefore, the BESS may not be the most efficient means of examining functional changes to the balance system immediately after head injury. Dynamic Visual Acuity Test (DVAT) has been found to effectively evaluate and monitor changes to the gaze stability system postinjury. Thus, DVAT may be an additional measure in the concussion assessment battery, as well as an alternative for more immediate sideline assessment to help make objective return-to-play decisions. PURPOSE: The aim of the study was to determine the effects of physical exertion on a clinical vestibular assessment, the DVAT, in collegiate athletes, as a first step in defining the role of this measure in the concussion assessment battery. RESEARCH DESIGN: Cross-sectional, repeated-measures design. STUDY SAMPLE: Twenty-eight healthy collegiate athletes (20 males, 8 females; age = 20.25 ± 1.46 yr, range = 18-25 yr) volunteered to participate in the study. DATA COLLECTION AND ANALYSIS: Participants were randomly assigned to complete a 20-min protocol of physical exertion or rest. DVAT was completed pre-exertion or rest (pre-DVAT), immediately following the 20-min protocol (post-DVAT I), and again 10 min after the completion of the 20-min protocol (post-DVAT II). Ratings of perceived exertion (RPE) and heart rate (HR) were monitored throughout testing. Repeated-measures analysis of the variance were used to examine the effects of exertion on DVAT. Additionally, intraclass correlation coefficients were used to examine test reliability. RESULTS: No significant main effect was observed for right and left DVAT logarithm of the minimal angle of resolution loss between groups or across time points (p > 0.05). A significant main effect was observed for RPE and HR for groups and time points (p < 0.001), indicating adequate physical exertion and rest. Fair to good reliability (intraclass correlation coefficient values between 0.4 and 0.74) was observed for both rightward and leftward movements of the head across the three time points. CONCLUSIONS: Findings from this study suggest that DVAT is not affected by physical exertion and may provide a more immediate assessment of the balance system that may be of use for the sideline concussion assessment. Future studies will be performed to examine additional factors (e.g., background noise, complex visual backgrounds) that may affect DVAT performance in the sideline environment.

Effects of Device on Video Head Impulse Test (vHIT) Gain.

BACKGROUND: Numerous video head impulse test (vHIT) devices are available commercially; however, gain is not calculated uniformly. An evaluation of these devices/algorithms in healthy controls and patients with vestibular loss is necessary for comparing and synthesizing work that utilizes different devices and gain calculations. PURPOSE: Using three commercially available vHIT devices/algorithms, the purpose of the present study was to compare: (1) horizontal canal vHIT gain among devices/algorithms in normal control subjects; (2) the effects of age on vHIT gain for each device/algorithm in normal control subjects; and (3) the clinical performance of horizontal canal vHIT gain between devices/algorithms for differentiating normal versus abnormal vestibular function. RESEARCH DESIGN: Prospective. STUDY SAMPLE: Sixty-one normal control adult subjects (range 20-78) and eleven adults with unilateral or bilateral vestibular loss (range 32-79). DATA COLLECTION AND ANALYSIS: vHIT was administered using three different devices/algorithms, randomized in order, for each subject on the same day: (1) Impulse (Otometrics, Schaumberg, IL; monocular eye recording, right eye only; using area under the curve gain), (2) EyeSeeCam (Interacoustics, Denmark; monocular eye recording, left eye only; using instantaneous gain), and (3) VisualEyes (MicroMedical, Chatham, IL, binocular eye recording; using position gain). RESULTS: There was a significant mean difference in vHIT gain among devices/algorithms for both the normal control and vestibular loss groups. vHIT gain was significantly larger in the ipsilateral direction of the eye used to measure gain; however, in spite of the significant mean differences in vHIT gain among devices/algorithms and the significant directional bias, classification of "normal" versus "abnormal" gain is consistent across all compared devices/algorithms, with the exception of instantaneous gain at 40 msec. There was not an effect of age on vHIT gain up to 78 years regardless of the device/algorithm. CONCLUSIONS: These findings support that vHIT gain is significantly different between devices/algorithms, suggesting that care should be taken when making direct comparisons of absolute gain values between devices/algorithms.

Modified head shake sensory organization test: Sensitivity and specificity.

The Sensory Organization Test (SOT) of Computerized Dynamic Posturography (EquiTest™ equipment) is a valuable tool for investigating how an individual uses balance system sensory input (vestibular, vision, proprioception/somatosensory) to maintain quiet stance; however, it is limited as a screening tool for identifying peripheral vestibular system dysfunction. Previous research has shown that adding horizontal head-shake to portions of the standard SOT battery improved the identification of peripheral vestibular system asymmetry; however, flaws in the methods were noted. The objective of this work was to evaluate the sensitivity and specificity of the modified head-shake SOT (HS-SOT) protocol for identification of peripheral vestibular system lesion. Fifteen patients with chief complaint of instability, vertigo, and/or lightheadedness, with and without a caloric unilateral weakness (UW) and fifteen age-matched healthy controls were included in the final analysis. Ten of the 15 patients demonstrated a caloric UW≥25%. Participants completed standard conditions 2 and 5 of SOT with head still and during four horizontal head-shaking tasks (i.e., HS-SOT2-60°/s, HS-SOT2-120°/s, HS-SOT5-15°/s, and HS-SOT5-60°/s). Average equilibrium scores decreased as condition difficulty increased (SOT2, HS-SOT2-60°/s, HS-SOT2-120°/s, SOT 5, HS-SOT5-15°/s, and HS-SOT5-60°/s) for each group; as expected, a lower decline was noted for controls (slope=-6.59) compared to patients (slope=-11.69). The HS-SOT5-15°/s condition was superior for identifying peripheral vestibular asymmetry (AUC=0.90 sensitivity=70%, specificity=100%), with the strongest correlation to caloric UW% (rs=-0.743, p=0.000006). HS-SOT5-15°/s appears to be a promising screening measure for peripheral vestibular asymmetry.

Effects of Hand Placement Technique on the Video Head Impulse Test (vHIT) in Younger and Older Adults.

OBJECTIVE: To investigate the effects of hand placement techniques on the video head impulse test (vHIT) responses (i.e., gain, velocity) in older and younger adults and to determine intra-rater and inter-rater reliability of the horizontal vHIT. DESIGN: Descriptive, reliability study. SETTING: University research laboratory. SUBJECTS: Forty healthy adults grouped by age with negative history of current or previous vestibular diseases between the ages of 20 and 88 years (mean = 46.60, standard deviation 23.20). MAIN OUTCOME MEASURES: Three examiners each used two hand placement techniques (chin and head) to elicit the horizontal vHIT responses. Both the examiner and hand placement orders were counterbalanced to account for order and fatigue effects. The outcome measures of interest were vHIT gain and velocity. RESULTS: A two-way between-subject factorial analysis of variance revealed a significant main effect for hand placement technique and gain response. Mean values for vHIT gain were higher for head technique. Significant main effects were observed for the velocity response for hand placement technique and age group. Mean velocity values were higher for chin technique and lower velocities were observed in the older age group. Intra- and inter-rater reliability scores were consistent for gain values; however, poor to fair inter-rater reliability scores were observed for velocity values. CONCLUSION: It is suggested that clinical sites select one hand placement technique for the measure to provide consistency of protocol. Establishing clinical norms using the one selected method to verify reliability within and across clinicians is suggested before examination with a disordered population.