Test–retest reliability and responsiveness of gaze stability and dynamic visual acuity in high school and college football players

An evaluation of the test-retest reliability of the functional head impulse test in healthy young adults

AIM

To determine the test and retest reliability of the functional head impulse test (fHIT) in healthy young adults.

MATERIALS AND METHODS

Thirty-three healthy participants (17 women, 16 men) aged 18-30 years were included in the study. Each participant underwent the fHIT twice, 1 week apart, by the same experienced clinician. Intraclass correlation coefficients (ICCs) were used to determine test-retest reliability.

RESULTS

There was no statistically significant difference between the results of total percentage of correct answer (CA%) of the fHIT obtained in session 1 and session 2 measurements in the lateral, anterior, and posterior semicircular canals (SCCs) (p > 0.05). ICC values for test-retest reliability were found to range from 0.619 to 0.665 for the three semicircular canals (SCCs).

CONCLUSION

The test-retest reliability of the fHIT device was moderate. Attention, cognition, and fatigue may be the factors reducing reliability. In the diagnosis, follow-up, and rehabilitation processes of vestibular diseases in clinics, changes in the fHIT CA% can be used to assess vestibulo-ocular reflex (VOR) functionality.

Sports-related concussion: assessing the comprehension, collaboration, and contribution of chiropractors

Over the last 2 decades, sports-related concussion (SRC) awareness and management have evolved from an emphasis on complete cognitive and physical rest to evidence-based protocols and interventions. Chiropractors are primary care providers with exposure to athletes and teams in collision sports and, in addition, manage patients with concussion-like symptoms including neck pain, dizziness, and headache. With SRC frequently occurring in the absence of a medical practitioner, the role of allied health practitioners like chiropractors should be emphasised when it comes to the recognition, assessment, and management of SRC. This commentary discusses the potential contribution of chiropractors in SRC and the specific role their expertise in the cervical spine may play in symptom evaluation and management. A PubMed and Google scholar review of the chiropractic SRC literature suggests that the chiropractic profession appears under-represented in concussion research in athletic populations compared to other medical and allied health fields. This includes an absence of chiropractic clinicians with a focus on SRC participating in the Concussion in Sport Group (CISG) and the International Consensus Conferences on Concussion. Furthermore, with evolving evidence suggesting the importance of cervicogenic manifestations in SRC, there is an opportunity for chiropractors to participate in SRC diagnosis and management more fully and contribute scientifically to an area of specialised knowledge and training. With a dearth of chiropractic orientated SRC science, clinical SRC expertise, and clinical chiropractic representation in the CISG; it is incumbent on chiropractic clinicians and scientists to take up this opportunity through meaningful contribution and involvement in the SRC field.

Gaze stability in youth athletes: A normative observational study

BACKGROUND

The Gaze Stabilization Test (GST) assesses vestibulo-ocular reflex (VOR) function by determining the maximum head velocity at which an individual can accurately perceive a fixed-size visual target. There is limited information about gaze stability performance in youth athletes.

OBJECTIVE

The purpose of this study is to describe baseline performance of athletes ages 17 years and under on a computerized GST and explore the influence of demographic characteristics on performance.

METHODS

Baseline GST and demographic data were acquired via retrospective chart review.

RESULTS

The sample included 106 athletes aged 8 to 17 years (mean 13.9 years±1.79; 78% male). The median values for baseline GST function were 180 (IQR: 150-210) degrees per second (d/sec) in the leftward direction, and 190 d/sec (IQR: 160-220) in the rightward direction. There were no significant effects of sex/gender or concussion history on GST performance.

CONCLUSIONS

The GST is one of many tools available for clinicians to use in a multi-modal approach to concussion management. Understanding how healthy young athletes perform can assist clinicians in determining vestibular impairment, formulating the exercise prescription, and estimating physiologic recovery.

Determining the Agreement Between Common Measures Related to Vestibulo-ocular Reflex Function After a Mild Traumatic Brain Injury in Children and Adolescents

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A battery of complementary tests is needed to assess vestibulo-ocular reflex (VOR) in pediatric mild traumatic brain injury (mTBI).

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This battery should include both symptom- and performance-based measures.

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Best practice recommendation is needed for such a battery in clinical settings.

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Cervical injury presence may influence symptoms induced during VOR testing.

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There is value of assessing for cervical injury post pediatric mTBI.

Objective

To (1) determine the level of agreement between symptom provocation and performance-based tests of vestibulo-ocular reflex (VOR) function after pediatric mild traumatic brain injury (mTBI) and (2) describe the level of symptom provocation induced by a VOR task in individuals with and without cervical findings.

Design

Cross-sectional.

Setting

This study was conducted at a tertiary care pediatric hospital.

Participants

A total of 101 participants (N=101) aged 6-18 years within 3 weeks of mTBI diagnosis were included (54.5% female; mean age, 13.92±2.63 years; mean time since injury at assessment, 18.26±6.16 days).

Interventions

None.

Main Outcome Measures

Symptom provocation (Vestibular/Ocular Motor Screening tool), performance (clinician-observed VOR performance, head thrust test [HTT], computerized dynamic visual acuity test, video head impulse test), and cervical impairment (cervical flexion-rotation test, range of motion test, self-reported neck pain). Agreement was evaluated using Cohen's κ statistic.

Results

No outcomes demonstrated agreement with symptom provocation (κ=−0.15 to 0.14). Fair agreement demonstrated between clinician-observed VOR performance and HTT (κ=0.32), with little to no agreement demonstrated between other measures. Proportions reporting test-induced dizziness and headache were greater among individuals with cervical findings (29.1%-41.8%) than without (2.3%-6.8%).

Conclusions

Findings support that symptom provocation and performance-based tests measure different constructs and thus have distinct roles when assessing VOR function. Findings suggest results from measures of symptom provocation may be influenced by coexisting cervical impairments, underlining the value of assessing for cervical injury after pediatric mTBI.

Characterizing the evolution of oculomotor and vestibulo-ocular function over time in children and adolescents after a mild traumatic brain injury

Background

Impairments to oculomotor (OM) and vestibulo-ocular reflex (VOR) function following pediatric mTBI have been demonstrated but are poorly understood. Such impairments can be associated with more negative prognosis, affecting physical and mental wellbeing, emphasizing the need to more fully understand how these evolve.

Objectives

to determine i) the extent to which performance on clinical and computerized tests of OM and VOR function varies over time in children and adolescents at 21 days, 3-, and 6-months post-mTBI; ii) the proportion of children and adolescents with mTBI presenting with abnormal scores on these tests at each timepoint.

Design

Prospective longitudinal design.

Setting

Tertiary care pediatric hospital.

Participants

36 participants with mTBI aged 6 to18.

Procedures

Participants were assessed on a battery of OM and VOR tests within 21 days, at 3- and 6-months post injury.

Outcome measures

Clinical measures: Vestibular/ocular motor screening tool (VOMS) (symptom provocation and performance); Computerized measures: reflexive saccade test (response latency), video head impulse test (VOR gain), and dynamic visual acuity test (LogMAR change).

Analysis

Generalized estimating equations (parameter estimates and odd ratios) estimated the effect of time. Proportions above and below normal cut-off values were determined.

Results

Our sample consisted of 52.8% females [mean age 13.98 (2.4) years, assessed on average 19.07 (8–33) days post-injury]. Older children performed better on visual motion sensitivity (OR 1.43, p = 0.03) and female participants worse on near point of convergence (OR 0.19, p = 0.03). Change over time (toward recovery) was demonstrated by VOMS overall symptom provocation (OR 9.90, p = 0.012), vertical smooth pursuit (OR 4.04, p = 0.03), voluntary saccade performance (OR 6.06, p = 0.005) and right VOR gain (0.068, p = 0.013). Version performance and VOR symptom provocation showed high abnormal proportions at initial assessment.

Discussion

Results indicate impairments to the VOR pathway may be present and driving symptom provocation. Vertical smooth pursuit and saccade findings underline the need to include these tasks in test batteries to comprehensively assess the integrity of OM and vestibular systems post-mTBI.

Implications

Findings demonstrate 1) added value in including symptom and performance-based measures in when OM and VOR assessments; 2) the relative stability of constructs measured beyond 3 months post mTBI.

Gaze stability in young adults with previous concussion history

BACKGROUND

Disruption of visual-vestibular interaction after concussion can cause gaze instability with head movements. The long-term impact of concussion on gaze stability is unknown.

OBJECTIVE

This cross-sectional comparative pilot study examined gaze stability in the chronic stage after concussion (greater than one year). A secondary objective was to examine the relationship between gaze stability and sleep.

METHODS

Outcome measures included: 1. Gaze stability in logMAR (mean loss of dynamic visual acuity (DVA) in the yaw and pitch planes); 2. Pittsburgh Sleep Quality Index (PSQI); 3. Epworth Sleepiness Scale (ESS). Post-Concussion Symptom Scale (PCSS), time since injury, and number of concussions were collected for the people with concussion.

RESULTS

The study sample included thirty-four adults (mean age 23.35±1.3 years). Seventeen had a history of 1-9 concussions, with a mean duration of 4.4±1.9 years since last concussion; and 17 were age and sex-matched controls. Mean pitch plane DVA loss was greater in the concussion group compared to the control group (p = 0.04). Participants with previous concussion had lower sleep quality based on the PSQI (p = 0.01) and increased daytime sleepiness based on the ESS (p = 0.01) compared to healthy controls. Mean DVA loss in the pitch plane was significantly correlated with the PSQI (r = 0.43, p = 0.01) and the ESS (r = 0.41, p = 0.02).

CONCLUSION

Significant differences in dynamic visual acuity may be found in young adults long after a concussion, compared with those who have no concussion history. Furthermore, loss of dynamic visual acuity was associated with poorer sleep quality and higher daytime sleepiness.

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

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

Eye tracking to assess concussions: an intra-rater reliability study with healthy youth and adult athletes of selected contact and collision team sports

Eye movements that are dependent on cognition hold promise in assessing sports-related concussions but research on reliability of eye tracking measurements in athletic cohorts is very limited. This observational test-retest study aimed to establish whether eye tracking technology is a reliable tool for assessing sports-related concussions in youth and adult athletes partaking in contact and collision team sports. Forty-three youth (15.4 ± 2.2 years) and 27 adult (22.2 ± 2.9 years) Rugby Union and soccer players completed the study. Eye movements were recorded using SMIRED250mobile while participants completed a test battery twice, with a 1-week interval that included self-paced saccade (SPS), fixation stability, memory-guided sequence (MGS), smooth pursuit (SP), and antisaccades (AS) tasks. Intra-class correlation coefficient (ICC), measurement error (SEM) and smallest real difference (SRD) were calculated for 47 variables. Seventeen variables achieved an ICC > 0.50. In the adults, saccade count in SPS had good reliability (ICC = 0.86, SRD = 146.6 saccades). In the youth, the average blink duration in MGS had excellent reliability (ICC = 0.99, SRD = 59.4 ms); directional errors in AS tasks and gain of diagonal SP had good reliability (ICC = 0.78 and 0.77, SRD = 25.3 and 395.1%, respectively). Four metrics were found in this study to be reliable candidates for further biomarker validity research in contact and collision sport cohorts. Many variables failed to present a sufficient level of robustness for a practical diagnostic tool; possibly, because athletic cohorts have higher homogeneity, along with latent adverse effects of undetected concussions and repetitive head impacts. Since reliability of a measure can influence type II error, effect sizes, and confidence intervals, it is strongly advocated to conduct dedicated reliability evaluations prior to any validity studies.

Detection of VOR dysfunction during the gaze stabilization test: Does target size matter?

BACKGROUND

The Gaze Stabilization Test (GST) identifies vestibulo-ocular reflex (VOR) dysfunction using a decline in target recognition with increasing head velocity, but there is no consensus on target (optotype) size above static visual acuity.

OBJECTIVE

To determine the optimal initial optotype size above static visual acuity to be used during the GST in subjects with unilateral vestibular dysfunction and healthy individuals.

METHODS

Eight subjects with unilateral vestibular dysfunction (UVD) and 19 age-matched, healthy control subjects were studied with the standard GST protocol using two optotype sizes, 0.2 and 0.3 logMAR above static visual acuity (ΔlogMAR). Maximal head velocity achieved while maintaining fixation on both optotypes was measured. Sensitivity, specificity and receiver-operator characteristic area under the curve (ROC AUC) analyses were performed to determine the optimal head velocity cut off point for each optotype, based on ability to identify the lesioned side of the UVD group from the control group.

RESULTS

There was a significant difference in maximal head velocity between the UVD group and control group using 0.2 ΔlogMAR (p = 0.032) but not 0.3 ΔlogMAR (p = 0.061). While both targets produced similar specificities (90%) for distinguishing normal from subjects with UVD, 0.2 ΔlogMAR targets yielded higher sensitivity (75%) than 0.3 logMAR (63%) and accuracy (86% vs 80%, respectively) in detecting the lesioned side in subjects with UVD versus controls with maximal head velocities≤105 deg/s (p = 0.017). Furthermore, positive likelihood ratios were nearly twice as high when using 0.2 ΔlogMAR targets (+ LR 10) compared to 0.3 ΔlogMAR (+ LR 6.3).

CONCLUSION

The 0.2 ΔlogMAR optotype demonstrated significantly superior identification of subjects with UVD, better sensitivity and positive likelihood ratios than 0.3 ΔlogMAR for detection of VOR dysfunction. Using a target size 0.2logMAR above static visual acuity (ΔlogMAR) during GST may yield better detection of VOR dysfunction to serve as a baseline for gaze stabilization rehabilitation therapy.

Sport-specific differences in dynamic visual acuity and gaze stabilization in division-I collegiate athletes

BACKGROUND:

The vestibular-ocular reflex (VOR) integrates the vestibular and ocular systems to maintain gaze during head motion. This reflex is often negatively affected following sport-related concussion. Objective measures of gaze stability, a function mediated by the VOR, such as the computerized dynamic visual acuity test (DVAT) and gaze stabilization test (GST), may have utility in concussion management. However, normative data specific to sport, sex, or concussion history have not been established in collegiate athletes.

OBJECTIVE:

The objective of this study was to establish normative values for the DVAT and GST in collegiate athletes and explore the effect of sport, sex, and concussion history on VOR assessments.

METHODS:

The DVAT and GST were completed by 124 collegiate athletes (72 male, 52 female, mean±SD, age: 19.71±1.74 years, height: 173.99±13.97 cm, weight: 80.06±26.52 kg) recruited from Division-I athletic teams (football, soccer and cheerleading). The DVAT and GST were performed in the rightward and leftward directions during a single session in a standardized environment. Normative values for DVAT and GST measures were expressed as percentiles. Non-parametric statistics were used to compare differences between groups based on sex, sport, and concussion history. Alpha was set a-priori at 0.05.

RESULTS:

Overall, the median LogMAR unit for 124 athletes completing the DVAT was 0 (IQR = 0.17) for both leftward and rightward. The median velocities achieved on the GST were 145 °/sec and 150 °/sec (IQR = 45 and 40) for the leftward and rightward directions respectively. Significant differences were observed between sports (p = 0.001–0.17) for the GST with cheerleading demonstrating higher velocities than the other sports. However, no significant differences were identified based on sex (p≥0.09) or history of concussion (p≥0.15).

CONCLUSIONS:

Normative estimates for the DVAT and GST may assist in the clinical interpretation of outcomes when used in post-concussion evaluation for collegiate athletes. Although sex and previous concussion history had no effect on the DVAT or GST, performance on these measures may be influenced by type of sport. Sport-related differences in the GST may reflect VOR adaptations based on individual sport-specific demands.

Sensorimotor training for injury prevention in collegiate soccer players: An experimental study

OBJECTIVES

Deliver a sensorimotor training intervention; quantify the change in clinical measurements of sensorimotor control; and compare injury rate to a historical control.

DESIGN

One-arm experimental pilot; Level 3.

SETTING

NCAA Division II university athletic facilities.

PARTICIPANTS

75 collegiate soccer players (38 males; 37 females) were enrolled, including 30 (40%) with history of concussion, and participated in eight training sessions.

OUTCOMES

Change in pre-to post-intervention for: static balance on the Sway app, near-point convergence, self-reported symptoms on the Post-Concussion Symptom Scale, cervical flexor neuromotor control/endurance, measured by the Cranial-Cervical Flexion Test and Joint Position Error test, and gaze stability on the Dynamic Visual Acuity Test. Injury incidence rate in 2018 was calculated using the number of traumatic injuries across the season and athlete exposure counts, as compared to a historical control.

RESULTS

Significant improvements were obtained in static balance, cervical flexor neuromotor control/endurance, and near-point convergence (p-values<0.01-0.03). Increases in symptom report (p = 0.02) and a decline in dynamic gaze stability (p < 0.01) were observed. There were 11.8 injuries/1000 athlete exposures in 2017 and 8.9 injuries/1000 athlete exposures in 2018 after the treatment (p = 0.18).

CONCLUSION

This intervention holds promise as a preventive strategy for sports-injury as a comprehensive population-based intervention.

Vestibular Rehabilitation Is Associated With Visuovestibular Improvement in Pediatric Concussion

BACKGROUND AND PURPOSE

Vision and vestibular-related deficits are common after concussion and are associated with prolonged recovery times, substantially impacting the quality of life for children. The utility of targeted vestibular rehabilitation for these deficits in children after concussion is unknown. The purpose of this study was to determine whether active vestibular rehabilitation is associated with an improvement in visuovestibular signs and symptoms in children with concussion.

METHODS

A retrospective cohort study of children diagnosed with concussion and referred to vestibular rehabilitation between 2012 and 2014 was conducted. Patient-reported symptoms and visuovestibular performance measures were assessed in the medical practice and physical therapy settings.

RESULTS

One hundred nine children were included in the study with a mean age of 11.8 (3.4) years. Among this group, 59 (54%) were male and 48 (44%) had a sports-related concussion. Children presented to a pediatric sports medicine office and physical therapy a median of 24 (interquartile range [IQR], 14-42) and 55 (IQR, 39-94) days after injury, respectively. Concussion symptoms decreased from a median of 9 (IQR, 5-13) symptoms at initial evaluation to a median of 0 (IQR, 0-2) symptoms at final assessment. Performance on all visuovestibular tasks improved significantly over the course of therapy except for near point of convergence. For the 45 children who completed the Balance Error Scoring System at both initial and final therapy visits, there was a significant improvement in mean level of performance (P < 0.0001). Characteristics between those who completed a full versus partial course of physical therapy were similar.

DISCUSSION AND CONCLUSIONS

Vestibular rehabilitation in children with concussion is associated with improvement in symptoms as well as visuovestibular performance. This active intervention may benefit children with persistent symptoms after concussion. Future prospective studies are needed to determine the efficacy and optimal postinjury timing of vestibular rehabilitation.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A208).

Gaze stability in the elite athlete: A normative observational study

BACKGROUND

The ability to clearly perceive an object while the head is in motion is important in athletics, as it relates to performance and potentially to injury prevention. Normative data for healthy adults on measures of gaze stability have been established. However, data for elite athletes is scarce.

OBJECTIVE

To describe performance of elite athletes on computerized gaze stability testing and establish normative data for reference.

METHODS

Data were acquired via retrospective chart review. 134 male professional baseball players completed computerized Visual Acuity, Visual Perception Time and Gaze Stability Tests as part of a multi-modal baseline testing session.

RESULTS

Performance of all athletes was superior to general population norms reported in the literature. There were no significant differences between the optimal and suboptimal consistency groups or between English-speaking and non- or limited-English speaking players.

CONCLUSIONS

Similar to prior studies with smaller samples that have examined GST in athletes, we found high levels of GST performance in professional baseball players relative to normative data for the general population. Normative data for elite athletes was established using this healthy sample. This study underscores the importance of understanding the unique abilities of elite athletes when providing therapy after injury.

The Gaze Stabilization Test Following Concussion

BACKGROUND

Concussion can cause vestibular dysfunction and oculomotor abnormalities which can lead to dizziness and protracted recovery time. There are few clinically useful, functional measures of the vestibulo-ocular reflex (VOR) post-concussion.

PURPOSE

The purpose of this study was to examine the gaze stabilization test (GST) in those referred for vestibular physical therapy following concussion, to determine the association between GST and other measures of recovery following concussion, and to examine the effect of demographic variables on GST performance.

RESEARCH DESIGN

Retrospective chart review.

STUDY SAMPLE

One hundred fifty-eight individuals who sustained a concussion and were referred to vestibular physical therapy.

DATA COLLECTION AND ANALYSIS

Horizontal and vertical GST scores (HGST and VGST), neurocognitive testing results, and demographic data were extracted retrospectively from the patient health record. Correlations between GST velocity and neurocognitive test results and between GST and patient-reported outcomes were examined. Differences in GST performance among patient subgroups were examined using one-way analysis of variance.

RESULTS

Subjects included individuals aged 12 to 43 years (mean = 20, standard deviation [SD] = 7), with most having sport-related concussion (67%). The mean time from injury to GST was 215 days (SD = 241) and the mean time from physical therapy evaluation to GST was 48 days (SD = 54). HGST and VGST had a weak positive correlation to the Activities-Specific Balance Confidence Scale (r = 0.20, r = 0.21) and weak negative correlation to the Dizziness Handicap Inventory (r = -0.18, r = -0.22). HGST had a weak positive correlation to the visual motor processing speed domain of the immediate post-concussion assessment and cognitive test (r = 0.20). Male patients achieved significantly higher velocities than female patients on HGST and VGST (p = 0.02, p = 0.01).

CONCLUSIONS

The present study details the use of GST in patients with concussion and demonstrates an association with common outcome measures in vestibular rehabilitation. Results indicate that patients who achieved higher velocities on GST perceived lower handicap due to dizziness and had higher confidence in their balance. GST may be a relevant test of VOR in this population, as it is a more functional test of the VOR required for sports. Future work is needed to further evaluate the role of GST in concussion management.

Evidence of dynamic visual acuity impairment in asymptomatic mixed martial arts fighters

AIM

The purpose of this study was to determine the amount of visual acuity loss with head movement in actively training mixed martial arts (MMA) fighters.

METHODS

Vestibulo-ocular reflex function of 22 asymptomatic, male MMA fighters (age = 29.2 ± 5.1) was assessed by taking the difference between static visual acuity and the dynamic visual acuity test, in both yaw and pitch planes.

RESULTS

The mean static visual acuity testing logMAR was -0.173 (standard deviation [SD] = 0.114). Mean dynamic visual acuity test values decreased with head movement to 0.196 logMAR (SD = 0.103) in yaw; p < 0.001, and to 0.283 logMAR (SD = 0.133) in pitch; p < 0.001.

CONCLUSION

MMA fighters had a decay, beyond normal ranges, in visual acuity during head movement. These decreases may suggest vestibulo-ocular reflex impairment and were unrelated to self-reported concussion history. These results should be cautiously interpreted since there was not a control group.

Reliability and Normative Data for the Dynamic Visual Acuity Test for Vestibular Screening

HYPOTHESIS

The purpose of this study was to determine reliability of computerized dynamic visual acuity (DVA) testing and to determine reference values for younger and older adults.

BACKGROUND

A primary function of the vestibular system is to maintain gaze stability during head motion. The DVA test quantifies gaze stabilization with the head moving versus stationary. Commercially available computerized systems allow clinicians to incorporate DVA into their assessment; however, information regarding reliability and normative values of these systems is sparse.

METHODS

Forty-six healthy adults, grouped by age, with normal vestibular function were recruited. Each participant completed computerized DVA testing including static visual acuity, minimum perception time, and DVA using the NeuroCom inVision System. Testing was performed by two examiners in the same session and then repeated at a follow-up session 3 to 14 days later. Intraclass correlation coefficients (ICCs) were used to determine inter-rater and test-retest reliability.

RESULTS

ICCs for inter-rater reliability ranged from 0.323 to 0.937 and from 0.434 to 0.909 for horizontal and vertical head movements, respectively. ICCs for test-retest reliability ranged from 0.154 to 0.856 and from 0.377 to 0.9062 for horizontal and vertical head movements, respectively. Overall, raw scores (left/right DVA and up/down DVA) were more reliable than DVA loss scores.

CONCLUSION

Reliability of a commercially available DVA system has poor-to-fair reliability for DVA loss scores. The use of a convergence paradigm and not incorporating the forced choice paradigm may contribute to poor reliability.

Assessing subacute mild traumatic brain injury with a portable virtual reality balance device

PURPOSE

Balance impairment is a common sensorimotor symptom in mild traumatic brain injury (mTBI). We designed an affordable, portable virtual reality (VR)-based balance screening device (Virtual Environment TBI Screen [VETS]), which will be validated relative to the Neurocom Sensory Organization Test (SOT) to determine if it can replace commonly used postural assessments.

METHODS

This preliminary study examines healthy adults (n = 56) and adults with mTBI (n = 11). Participants performed six upright postural tasks on the VETS and the SOT. Analysis of variance was used to determine between-group differences. Pearson's correlations were used to establish construct validity. Known-groups approach was used to establish classification accuracy.

RESULTS

The mTBI cohort performed significantly worse than the healthy cohort on the new device (p = 0.001). The new device has 91.0% accuracy and an ROC curve with a significant area-under-the-curve (AUC = 0.865, p < 0.001). Conditions with dynamic visual stimulation were the most sensitive to health status. The SOT had an 84.8% accuracy and AUC =0.703 (p = 0.034).

CONCLUSIONS

The new VR-based device is a valid measure for detecting balance impairment following mTBI and can potentially replace more expensive and cumbersome equipment. Assessments that test visual-vestibular processing, such as VETS, increase sensitivity to mTBI-related balance deficits, which can be used to guide rehabilitation. Implications for rehabilitation Emerging technology using virtual reality can be economically integrated into the clinical setting for easy testing of postural control in neurologically impaired populations. Tailoring postural assessments to include tasks that rely on visual and vestibular integration will increase the accuracy of detecting balance impairment following mild traumatic brain injury.