Virtual Reality Application for Vestibular/Ocular Motor Screening: Current Clinical Protocol Versus a Novel Prototype

BACKGROUND

Virtual reality (VR) has been explored to improve baseline and postinjury assessments in sport-related concussion (SRC). Some experience symptoms related to VR, unrelated to concussion. This may deter use of vestibular/ocular motor screening (VOMS) using VR. Baseline VR VOMS symptomatology differentiates baseline from overall symptomatology.

HYPOTHESIS

There will be no difference between current clinical manual VOMS (MAN), a clinical prototype (PRO), and VR for symptom provocation change score (SPCS) and near point of convergence (NPC) average score in a healthy population and sex differences among the 3 modes of administration.

STUDY DESIGN

Cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 688 National Collegiate Athletic Association Division I student-athletes completed VOMS using 3 methods (MAN, N = 111; female athletes, N = 47; male athletes, N = 64; average age, 21 years; PRO, N = 365; female athletes, N = 154; male athletes, N = 211; average age, 21 years; VR, N = 212; female athletes, N = 78; male athletes, N = 134; average age = 20 years) over a 3-year period (2019-2021) during annual baseline testing. Exclusion criteria were as follows: self-reported motion sickness in the past 6 months, existing or previous neurological insult, attention deficit hyperactivity disorder, learning disabilities, or noncorrected vision impairment. Administration of MAN followed the current clinical protocols, PRO used a novel prototype, and VR used an HTC Vive Pro Eye head mounted display. Symptom provocation was compared using Mann-Whitney U tests across each VOMS subtest with total SPCS and NPC average by each method.

RESULTS

MAN had significantly (P < 0.01) more baseline SPCS (MAN = 0.466 ± 1.165, PRO = 0.163 ± 0.644, VR = 0.161 ± 0.933) and significantly (P < 0.01) and more SPCS (MAN = 0.396 ± 1.081, PRO = 0.128 ± 0.427, VR = 0.48 ± 0.845) when compared with PRO and VR. NPC average measurements for VR (average, 2.99 ± 0.684 cm) were significantly greater than MAN (average, 2.91 ± 3.35 cm; P < 0.01; Cohen's d = 0.03) and PRO (average, 2.21 ± 1.81 cm; P < 0.01; Cohen's d = 0.57). For sex differences, female athletes reported greater SPCS with PRO (female athletes, 0.29 ± 0.87; male athletes, 0.06 ± 0.29; P < 0.01) but not in VR or MAN.

CONCLUSION

Using a VR system to administer the VOMS may not elicit additional symptoms, resulting in fewer false positives and is somewhat stable between sexes.

CLINICAL RELEVANCE

VOMS may allow for standardization among administrators and reduce possible false positives.

Minimal Detectable Change for the ImPACT Subtests at Baseline

OBJECTIVE

To establish the minimal detectable change (MDC) of the subtests that comprise the composite scores from remotely administered Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) baselines.

METHOD

Remote ImPACT baseline data from 172 (male = 45, female = 127) National Collegiate Athletic Association Division I student-athletes from the 2020 and 2021 athletic preseasons were used to calculate the MDC at the 95%, 90%, and 80% confidence intervals (CIs) for all subtest scores used to generate the four core composite scores and the impulse control composite.

RESULTS

The MDCs for the verbal memory subtests at the 95% CI were 10.31 for word memory percent correct, 4.68 for symbol match total correct hidden, and 18.25 for three letters percentage correct. Visual memory subtest MDCs were 19.03 for design memory total percent correct and 4.90 for XO total correct memory. Visual motor speed subtest MDCs were 18.89 for XO total correct interference and 5.40 for three letters average counted correctly. Reaction time (RT) MDCs were 0.12 for XO average correct, 0.95 for symbol match average correct RT, and 0.28 for color match average correct. Impulse control MDCs were 5.97 for XO total incorrect and 1.15 for color match total commissions. One-way repeated measures MANOVA, repeated measures ANOVAs, and Wilcoxon signed-ranks test all suggested no significant difference between any subtests across two remote ImPACT baselines.

CONCLUSIONS

The ImPACT subtest scores did not significantly change between athletic seasons. Our study suggests the subtests be evaluated in conjunction with the composite scores to provide additional metrics for clinical interpretation.

Minimal Detectable Change for the ImPACT Test Administered Remotely

CONTEXT

Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) is one of the most widely used computerized neurocognitive assessment batteries in athletics and serves as both a baseline and postinjury assessment. It has become increasingly popular to administer the ImPACT baseline test in an unsupervised remote environment; however, whether the lack of supervision affects the test-retest reliability is unknown.

OBJECTIVE

To establish the minimal detectable change (MDC) of composite scores from the ImPACT test when administered to National Collegiate Athletic Association Division I student-athletes in an unsupervised remote environment before 2 consecutive athletic seasons.

DESIGN

Cross-sectional study.

SETTING

Participants were provided with a unique link and detailed written instructions on how to complete the ImPACT test at home.

PATIENTS OR OTHER PARTICIPANTS

Division I student-athletes.

MAIN OUTCOME MEASURE(S)

Remote baseline ImPACT results from the 2020-2021 and 2021-2022 athletic seasons were analyzed. The MDC was calculated at the 95%, 90%, and 80% CIs for each of the ImPACT composite scores as well as the average and SD.

RESULTS

The MDC at the 95% CI was 18.6 for the verbal memory composite score, 24.44 for visual memory, 8.76 for visual motor, 0.14 for reaction time, and 6.13 for impulse control. One-way repeated-measures multivariate analysis of variance, repeated-measures analysis of variance, and Wilcoxon signed ranks tests suggested no difference in the composite scores and impulse control between time points.

CONCLUSIONS

The ImPACT composite scores and impulse control did not change between the 2 remote testing time points when administered approximately 1 year apart. Our study suggests that the MDC serves as a clinician's guide for evaluating changes in ImPACT baseline scores and in making clinical judgments on sport-related concussion when the test is administered at home.

Preliminary Examination of Guardian Cap Head Impact Kinematics Using Instrumented Mouthguards

CONTEXT

Guardian Caps (GCs) are currently the most popular external helmet-add on designed to reduce the head impact magnitude experienced by American football players. GCs have been endorsed by influential professional organizations, however few studies evaluating the efficacy of GCs are publicly available.

OBJECTIVE

The objective of this study is to present preliminary on-field head kinematics data for NCAA Division I American football players using instrumented mouthguards through closely matched pre-season workouts both with and without GCs.

DESIGN

Case Series.

SETTING

The study took place during the 2022 American football pre-season.

PATIENTS OR OTHER PARTICIPANTS

25 Male NCAA Division I student-athletes participating in American football completed some portion of the 6 workouts included in this study. Of the 25 total participants, 7 completed all 6 workouts using their instrumented mouthguards.

MAIN OUTCOME MEASURE(S)

The peak linear acceleration (PLA), peak angular acceleration (PAA) and total impacts were collected using instrumented mouthguards (iMG) during 3 pre-season workouts using traditional helmets (TRAD), and 3 with Guardian Caps used in additional to a traditional helmet (GC). The TRAD and GC values for PLA, PAA and total impacts were analyzed using ANOVAs.

RESULTS

There was no significant difference between the collapsed mean values for the entire sample between TRAD and GC for PLA (TRAD=16.3±2.0, GC=17.2±3.3Gs; p=0.20), PAA (TRAD=992.1±209.2, GC=1029.4±261.1rad/s2; p=0.51 and the total amount of impacts (TRAD=9.3±4.7, GC=9.7±5.7; p=0.72). Similarly, no difference was observed between TRAD and GC for PLA (TRAD=16.1±1.2, GC=17.2±2.79Gs; p=0.32), PAA (TRAD=951.2±95.4, GC=1038.0±166.8rad/s2; p=0.29 and total impacts (TRAD=9.6±4.2, GC=9.7±5.04s; p=0.32) between sessions for the7 repeated players.

CONCLUSIONS

These data suggest no difference in head kinematics data (PLA, PAA and total impacts) when GCs are worn. This study suggests GCs may not be effective in reducing the magnitude of head impacts experienced by NCAA Division I American football players.

Preliminary Examination of Guardian Cap Head Impact Data Using Instrumented Mouthguards

Purpose The objective of this study is to present preliminary on-field head kinematics data for NCAA Division I American football players through closely matched pre-season workouts both with and without Guardian Caps (GCs). Methods 42 NCAA Division I American football players wore instrumented mouthguards (iMMs) for 6 closely matched workouts, 3 in traditional helmets (PRE) and 3 with GCs (POST) affixed to the exterior of their helmets. This includes 7 players who had consistent data through all workouts. Results There was no significant difference between the collapsed mean values for the entire sample between PRE and POST for peak linear acceleration (PLA) (PRE=16.3, POST=17.2Gs; p=0.20), Peak Angular Acceleration (PAA) (PRE=992.1, POST=1029.4rad/s2; p=0.51 and the total amount of impacts (PRE=9.3, POST=9.7; p=0.72). Similarly, no difference was observed between PRE and POST for PLA (PRE=16.1, POST=17.2Gs; p=0.32), PAA (PRE=951.2, POST=1038.0rad/s2; p=0.29 and total impacts (PRE=9.6, POST=9.7; p=0.32) between sessions for the 7 repeated players. Conclusion These data suggest no difference in head kinematics data (PLA, PAA and total impacts) when GCs are worn. This study suggests GCs are not effective in reducing the magnitude of head impacts experienced by NCAA Division I American football players.

Older adults with a history of falling exhibit altered cortical oscillatory mechanisms during continuous postural maintenance

Background and Aim

The significant risk of falling in older adults 65 years or older presents a substantial problem for these individuals, their caretakers, and the health-care system at large. As the proportion of older adults in the United States is only expected to grow over the next few decades, a better understanding of physiological and cortical changes that make an older adult more susceptible to a fall is crucial. Prior studies have displayed differences in postural dynamics and stability in older adults with a fall history (FH) and those who are non-fallers (NF), suggesting surplus alterations that occur in some older adults (i.e., FH group) in addition to the natural aging process.

Methods

The present study measured postural dynamics while the FH, NF, and young adult (YA) groups performed continuous postural maintenance. In addition, electroencephalography activity was recorded while participants performed upright postural stance to examine any group differences in cortical areas involved in postural control.

Results

As expected, older participants (FH and NF) exhibited worse postural stability, as evidenced by increased excursion, compared to the YA group. Further, while NF and YA show increased alpha activity in occipital areas during the most demanding postural task (eyes closed), the FH group did not show any differences in occipital alpha power between postural tasks.

Conclusions

As alpha activity reflects suppression of bottom-up processing and thus diversion of cognitive resources toward postural centers during more demanding postural maintenance, deficits in this regulatory function in the FH group are a possible impaired cortical mechanism putting these individuals at greater fall risk.

Relevance for Patients

Impaired inhibitory function in older adults may impact postural control and increase their risk of falling. Interventions that aim at addressing cortical processing deficits may improve postural stability and facilitate independent living in this population.

A-09 Challenges in Measuring Repetitive Head Impacts, Cognition, and Eye Movements in High School Football Players

Purpose: Assess the feasibility of measuring Repetitive Head Impacts (RHI), cognition, and eye movements across a single season of high school football. Methods: Twelve players were provided an instrumented mouthguard (3200 Hz; Prevent Biometrics, Edina, MA) to evaluate RHI. Mouthguard use was assessed by total impacts and number of games/practices. Seven players also agreed to complete cognitive (ImPACT) and custom eye-tracking (500 Hz; EyeLink II) assessments pre-, mid-, and post-season. Multiple repeated measure ANOVA’s were completed using standard composite scores for ImPACT and oculomotor metrics. Results: Fifty percent of players ever used their mouthguard, and substantial variability in total impacts (M = 86.5, SD = 98.0, Range = 7–277) and number of games/practices (M = 9.8, SD = 7.6, Range = 2–23) were observed among players who did use their mouthguard. Specific completion rates for the 3 cognitive and 3 eye-tracking assessments were 71% each, and 57% of players completed all 6 scheduled assessments. Repeated measures ANOVA indicated Visual Motor Speed (VMS) improved between assessments (p = 0.015). Post hoc analysis showed both VMS and Verbal Memory increased from pre- to mid-season (−5.30(95%CI, −10.47 to −0.12), p = 0.046), (−0.20(95%CI, −13.00 to −1.41), p = 0.024). Conclusions: Variability in mouthguard use and missing assessment rates represent practical challenges in prospectively measuring RHI and utilizing multiple longitudinal assessment methods in high school football players. Although ImPACT results should be interpreted cautiously, future research should consider the potential role of practice effects and/or intentionally poor pre-season effort to explain the increase in performance during the season. A larger sample size will increase the possibility of measuring the effect of RHI on assessment outcomes.

A novel smartphone application is reliable for repeat administration and comparable to the Tekscan Strideway for spatiotemporal gait

Smartphone applications are increasingly being used to measure gait due to their portability and cost-effectiveness. Important reliability metrics are not available for most of these devices. The purpose of this article was to evaluate the test-retest reliability and concurrent validity of spatiotemporal gait using the novel Gait Analyzer smartphone application compared to the Tekscan Strideway. Healthy participants (n=23) completed 12 trials of 10-meter walking, at two separate time points, using Gait Analyzer and while walking across the Tekscan Strideway. The results suggest excellent test-retest reliability for the Gait Analyzer and good test-retest reliability for the Tekscan Strideway for both velocity and cadence. At both time points, these devices were moderately to strongly correlated to one another for both velocity and cadence. These data suggest that the Gait Analyzer and Tekscan Strideway are reliable over time and can comparably calculate velocity and cadence.

Test-Retest Reliability of Remote ImPACT Administration

OBJECTIVE

To evaluate the performance and test-retest reliability obtained when administering a computerized baseline neurocognitive exam to NCAA Division I student-athletes in a controlled laboratory setting versus an uncontrolled remote location.

METHOD

A sample of 129 (female = 100) Division I student-athletes completed Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) pre-season assessments for two distinct and respective sports seasons in a controlled laboratory environment and an uncontrolled remote environment. Depending on the environment, participants were given verbal (controlled) or written (uncontrolled) guidelines for taking the test.

RESULTS

Multivariate repeated-measures ANOVA's determined that there were no within-subject differences between testing environments on ImPACT composite scores and cognitive efficiency index (CEI). The Chi-square test did not find any significant differences in impulse control or the number of invalid test scores, as determined by ImPACT, between environments. Intraclass correlations found the ImPACT subtest scores to range in test-retest reliability across testing environments, demonstrating moderate (verbal memory composite, r = 0.46; visual memory composite, r = 0.64; reaction time, r = 0.61; impulse control, r = 0.52; and CEI, r = 0.61) and good (visual motor composite, r = 0.77) test-retest reliability.

CONCLUSIONS

Results indicate that ImPACT is reliable between controlled and uncontrolled testing environments. This further suggests that ImPACT can be administered in a remote environment, pending specific adherence to testing instructions, or in the event of social distancing or isolation policies.

Impaired visual working memory and reduced connectivity in undergraduates with a history of mild traumatic brain injury

Mild traumatic brain injury (mTBI), or concussion, accounts for 85% of all TBIs. Yet survivors anticipate full cognitive recovery within several months of injury, if not sooner, dependent upon the specific outcome/measure. Recovery is variable and deficits in executive function, e.g., working memory (WM) can persist years post-mTBI. We tested whether cognitive deficits persist in otherwise healthy undergraduates, as a conservative indicator for mTBI survivors at large. We collected WM performance (change detection, n-back tasks) using various stimuli (shapes, locations, letters; aurally presented numbers and letters), and wide-ranging cognitive assessments (e.g., RBANS). We replicated the observation of a general visual WM deficit, with preserved auditory WM. Surprisingly, visual WM deficits were equivalent in participants with a history of mTBI (mean 4.3 years post-injury) and in undergraduates with recent sports-related mTBI (mean 17 days post-injury). In seeking the underlying mechanism of these behavioral deficits, we collected resting state fMRI (rsfMRI) and EEG (rsEEG). RsfMRI revealed significantly reduced connectivity within WM-relevant networks (default mode, central executive, dorsal attention, salience), whereas rsEEG identified no differences (modularity, global efficiency, local efficiency). In summary, otherwise healthy current undergraduates with a history of mTBI present behavioral deficits with evidence of persistent disconnection long after full recovery is expected.

Impairments in Dynamic Postural Control across Concussion Clinical Milestones

The aim of this study was to assess gait initiation (GI) performance longitudinally across clinical concussion recovery milestones through return to participation (RTP). We recruited 54 collegiate student-athletes, 27 with concussions and 27 matched controls (15 female and 12 male per group). Participants performed five trials of GI at baseline and again at five post-concussion clinical milestones: 1) Acute, the day clinical tests achieved baseline values on the 2) Balance Error Scoring System (BESS), 3) Immediate Post-Concussion Assessment and Cognitive Test ImPACT, 4) Asymptomatic, and 5) RTP Day. GI performance on six outcome measures (anterior/posterior and medial/lateral center of pressure displacements and velocities during the anticipatory postural adjustment [APA] phase and initial step length and velocity) with repeated-measures mixed model and pair-wise post hoc. A reliable change index (RCI) was calculated, and post-concussion participant's performance was compared to the RCI at milestones. There were significant interactions for APA posterior and lateral displacement, APA posterior velocity, step length, and step velocity. The post-hoc tests identified significant deficits across clinical milestones and at RTP for APA posterior and lateral displacement, step length, and step velocity. There were no post-hoc differences for any outcome measure in the control group. At RTP, 85.2-88.9% of concussion participants had at least one outcome measure which exceeded the 80% or 95% RCI. The primary finding of this study was persistent impairments in dynamic postural control, suggesting ongoing neurophysiological impairment despite clinical recovery. These results suggest that collegiate student-athletes may be RTP before neurophysiological recovery and potentially exposing themselves to elevated risk of recurrent concussion or subsequent musculoskeletal injury.

Deep brain stimulation enhances movement complexity during gait in individuals with Parkinson's disease

Deep brain stimulation (DBS) is associated with substantial improvements in motor symptoms of PD. Emerging evidence has suggested that nonlinear measures of complexity may provide greater insight into the efficacy of anti-PD treatments. This study investigated sample entropy and complexity index values in individuals with PD when DBS was OFF compared to ON. Five individuals with PD using DBS performed a four-minute treadmill walking task while 3D kinematics were collected over two periods of 30 s. Participants were tested in the DBS-ON and DBS-OFF conditions. Sample entropy (SE) and complexity index (CI) values were calculated for ankle, knee and hip joint angles. Paired samples t-tests were used to compare mean SE and CI values between the DBS-OFF and DBS-ON conditions, respectively. No differences in SE or CI were observed between the DBS-ON and DBS-OFF conditions at the ankle. At the knee, the DBS-ON was associated with greater SE and CI values than the DBS-OFF condition. At the hip, DBS-ON was associated with greater SE and CI values than the DBS-OFF condition. DBS enhances complexity of movement at the hip and knee joints while complexity at the ankle joint is not significantly altered. Greater complexity of knee and hip joint motion may represent increased adaptability and a greater number of available strategies to complete the gait task.

Repetitive head impacts affect mediolateral postural sway entropy in the absence of vision following a competitive athletic season: preliminary findings

BACKGROUND

Repetitive head impacts (RHIs) have received more notice over the past decade. More sensitive measures, such as postural control, have been used to evaluate if there are biomechanical changes after RHI exposure. Similar to the clinical findings, most of the studies have failed to find any significant changes across an athletic season. However, these studies included those with a concussion history and only assessed postural control in the eyes open (EO) condition, rather than in both the EO and eyes closed (EC) conditions.

AIM

The purpose of this study was to investigate postural control changes during quiet stance following a season of RHI in Division I football athletes who did not have a prior diagnosed signet ring cell compared to a group of non-RHI athletes with no history of a diagnosed sport-related concussion.

MATERIALS AND METHODS

Eighteen male Division I athletes were recruited and met the inclusion criteria: Nine football athletes (RHI group) and nine baseball athletes (CON group). All athletes performed three 30 s trials while standing with feet together on a force platform during EC and EO conditions. Center of pressure data was analyzed with sample entropy (SampEn) in the anteroposterior (AP) and mediolateral (ML) directions. SampEn data were analyzed with a three-level linear mixed effects model or the multilevel model, with the three levels being condition, time, and group.

RESULTS

The analysis reported no significant effect for SampEn AP, but reported a significant three-way interaction (Group by Task by Time) for SampEn ML. Specifically, SampEn ML was significantly higher for EC than EO for both groups.

CONCLUSIONS

There are postural control changes from pre- to post-season, with the main contributor being EC postural control. Thus, there could be a change in the sensory reweighting dynamics due to RHI and the effect of sport.

RELEVANCE FOR PATIENTS

RHI may be better assessed in the clinical setting with EC, rather than with EO. Furthermore, clinicians should include tasks that deprive sensory inputs to examine the effects of RHI.

Effects of exercise on symptoms, vestibular/ocular motor screening and postural stability in a college-aged sample

Aim:

To examine the effects of maximal exercise on symptoms, vestibular/ocular motor screening (VOMS) and postural stability.

Methodology:

A total of 17 college-aged individuals completed a symptom scale, VOMS and the modified Clinical Test for Sensory Interaction and Balance (m-CTSIB), followed by a graded maximal exercise treadmill test. Assessments were repeated post exercise, 20 and 40 min post-exercise.

Results:

Significant increases in total symptoms, symptom severity scores and m-CTSIB scores from baseline to immediate post exercise were reported. Following 20-min recovery, improvements were noted on symptoms, visual motion sensitivity on VOMS and m-CTSIB.

Conclusion:

Symptoms and postural stability are influenced by exercise and following 20 min of rest, returned to baseline, indicating that a period of 20 min following a suspected concussion may be needed to negate exercise effects.

Baseline concussion testing is often completed by athletes in a rested state, prior to beginning their respective sports season. However, concussions are often sustained while the athlete has undergone physical exertion and is in a fatigued state. Therefore, it may be inaccurate to compare fatigue-state sideline assessments with resting-state baselines. The purpose of this study was to compare the effects of pre- and post-exercise performance on common concussion assessment tools. Worse performance was noted between pre- and immediately post-exercise on these tools. A duration of 20 min after exercise, performance returned to pretest levels, indicating that clinicians should wait at least 20 min before conducting a sideline examination after a sustained concussion, to cancel out the effects of exercise.

Smooth Pursuit and Saccades after Sport-Related Concussion

Smooth pursuit eye movements (SPEMs) and saccadic eye movements are both commonly impaired following sport-related concussion (SRC). Typical oculomotor assessments measure individual eye movements in a series of restrictive tests designed to isolate features such as response times. These measures lack ecological validity for athletes because athletes are adept at simple tasks designed for the general population. Yet, because eye movement metrics are sensitive and well-characterized neuroanatomically, it would be valuable to test whether athletes exhibit abnormal eye movements with more challenging tasks. To address this gap in knowledge, we collected eye-tracking data during a sport-like task to gain insight on gaze behavior during active self-motion. SPEMs and saccadic eye movements were recorded during a sport-like visual task within 24-48 h following SRC. Thirty-six Division I student-athletes were divided into SRC and control (CON) groups. All participants completed two blocks of the Wii Fit© soccer heading game (WF) while wearing a monocular infrared eye tracker. Eye movement classification systems quantified saccadic amplitude (SA), velocity (SV), and count (SC); as well as SPEM velocity (SPV) and amplitude (SPA). Separate Mann-Whitney U tests evaluated SPA and SC and found no significant effects (SPA, p = 0.11; SC, p = 0.10). A multi-variate analysis of variance (MANOVA) for remaining variables revealed SPV was significantly greater in CON (p < 0.05), but the SRC group had greater SA and SV (p < 0.05). These findings suggest that during a sport-like task, to maintain foveation SRC subjects used larger amplitude, faster saccades, but exhibited slower SPEMs. Measuring oculomotor function during ecologically valid, sport-like tasks may serve as a concussion biomarker and provide insights into eye movement control after SRC.

Effects of attention deficit hyperactivity disorder and learning disability on vestibular and ocular baseline concussion assessment in pediatric athletes

Vestibular and ocular motor assessment has gained popularity as a tool for sport-related concussion among healthcare professionals. With awareness of premorbid risk factors, such as attentional problems, it is imperative to understand their effects at baseline. The purpose of this study was to examine the effects of attention deficit/hyperactivity disorder (ADHD) and diagnosed learning disability (LD) on vestibular and oculomotor baseline concussion assessment in pediatrics. Pediatric athletes between the ages of 8 and 14 years with ADHD/LD (n = 30) and match controls without ADHD/LD (n = 30) completed baseline concussion testing, consisting of symptom provocation on the Vestibular/Ocular Motor Screening (VOMS) and oculomotor performance on near point of convergence (NPC) and King-Devick (K-D) tools. Those diagnosed with ADHD/LD performed worse on baseline saccades (p range = .02-.10), convergence (p = .04), vestibular ocular reflex (VOR) (p = .03) and visual motion sensitivity (VMS) (p = .04) of the VOMS. Base rate analyses revealed that 26% of athletes in the ADHD/LD group had ≥1 and 13.3% had ≥2 VOMS domains over clinical cutoff levels, compared to 3.3% (≥1 domain) and 0 (≥2 domains) of controls. Individuals with ADHD/LD also performed worse on K-D assessment (p = .005). However, no differences were reported on NPC distance (p = .19). These findings suggest worse baseline concussion assessment scores on vestibular/ocular motor assessment domains in pediatric athletes diagnosed with ADHD/LD. Additional research is needed on assessment outcomes to determine if special consideration to those diagnosed with ADHD/LD is warranted.

Repetitive Head Impacts in Football Do Not Impair Dynamic Postural Control

PURPOSE

The purpose of this study was to assess the effect of repetitive head impacts experienced by football players compared to noncontact athletes on dynamic postural control during both single-task (ST) and dual-task (DT) conditions.

METHODS

Thirty-four football players wearing accelerometer instrumented helmets and 13 cheerleaders performed a dynamic postural control battery, consisting of ST and DT gait initiation, gait, and gait termination, both prior to and following the football season. A 2 (group) × 2 (time) repeated measures ANOVA compared performance across 32 dynamic postural outcomes. A linear regression was performed on postural control change scores with common head impact kinematics serving as the independent variables.

RESULTS

The football players experienced a mean of 538.1 ± 409.1 head impacts in the season with a mean linear acceleration of 27.8g ± 3.2g. There were no significant interactions for any of the ST or DT dynamic postural control tasks. There was a significant relationship between head impact kinematics and the lateral center of pressure displacement during the anticipatory postural adjustment phase (r = 0.26, P = 0.010) and transitional phase (r = 0.511, P = 0.042) during ST gait initiation. For both measures, the number of impacts exceeding 98g was the only significant predictor of decreased center of pressure displacement.

CONCLUSIONS

A single competitive football season did not adversely affect dynamic postural control when comparing football players to cheerleaders who do not experience repetitive head impacts. Furthermore, there were limited relationships with head impact kinematics suggesting that a single season of football does not adversely affect most outcome measures of instrumented dynamic postural control. These findings are consistent with most studies which fail to identify clinical differences related to repetitive head impacts.

Concussion history associated with increased postural control deficits after subsequent injury

OBJECTIVE

Postural control deficits have been extensively reported following sport-related concussions. Concussed athletes demonstrate these deficits as early as 24 h post-concussion and may persist for up to six months. Many of these prior studies have included mixed samples with prior injury history that may affect the postural control data. The purpose of this investigation was to evaluate the effect of concussion history on postural control 24-48 h following sport-related concussion in Division I athletes.

APPROACH

Twenty-eight Division I athletes (seven athlete controls (CON), seven no history (SRC0), seven with a previous concussion (SRC1), and seven with 2-3 concussions (SRC3) participated in this study. All participants were assessed within 24-48 h post-subsequent SRC and performed three trials of quiet stance in the eyes closed (EC) conditions for 30 s each on a force platform (1000 Hz). The data were analyzed with root mean square (RMS) and mean excursion velocity (MEV) in the anteroposterior (AP) and mediolateral (ML) directions. Two 3  ×  2 MANOVAs were run by direction for group comparisons.

MAIN RESULTS

SRC2 had significantly greater RMS than CON, SRC0, and SRC1 in the AP direction and ML direction. SRC2 exhibited significantly greater AP and ML MEV than CON, SRC0, and SRC1.

SIGNIFICANCE

These results demonstrate that having 2-3 prior concussions negatively affects the postural system after a subsequent head injury. Sports medicine staff should approach the recovery process with caution with those that have a prior history of concussion, due to the negative effects that history of concussion has on postural control strategies.

Clinical Assessments of Balance in Adults with Concussion: An Update

Postural instability is a cardinal indicator of concussion. Assessments of the postural control system range from clinical to laboratory tests that assess the balance of the individual. In a previous article regarding clinical assessment of balance in adults with concussion, we reviewed the importance of balance as a component in concussion evaluations. The purpose of this review article is to update the information previously published in 2014. Since 2014, research has provided evidence for the incorporation of dynamic methods for evaluating balance postconcussion with particular emphasis on sensory system integration and dual tasking. Therefore, this review will examine the current state of knowledge on how concussion injuries affect postural control, advancements in evaluating balance postconcussion, such as novel eye-tracking techniques, and current recommendations for best practices for balance assessment.

Repetitive head impacts do not affect postural control following a competitive athletic season

Evidence suggests that Repetitive Head Impacts (RHI) directly influence the brain over the course of a single contact collision season yet do not significantly impact a player's performance on the standard clinical concussion assessment battery. The purpose of this study was to investigate changes in static postural control after a season of RHI in Division I football athletes using more sensitive measures of postural control as compared to a non-head contact sports. Fourteen Division I football players (CON) (age=20.4±1.12years) and fourteen non-contact athletes (NON) (2 male, 11 female; age=19.85±1.21years) completed a single trial of two minutes of eyes open quiet upright stance on a force platform (1000Hz) prior to athletic participation (PRE) and at the end of the athletic season (POST). All CON athletes wore helmets outfitted with Head Impact Telemetry (HIT) sensors and total number of RHI and linear accelerations forces of each RHI were recorded. Center of pressure root mean square (RMS), peak excursion velocity (PEV), and sample entropy (SampEn) in the anteroposterior (AP) and mediolateral (ML) directions were calculated. CON group experienced 649.5±496.8 mean number of impacts, 27.1±3.0 mean linear accelerations, with ≈1% of total player impacts exceeded 98g over the course of the season. There were no significant interactions for group x time RMS in the AP (p=0.434) and ML (p=0.114) directions, PEV in the AP (p=0.262) and ML (p=0.977) directions, and SampEn in the AP (p=0.499) and ML (p=0.984) directions. In addition, no significant interactions for group were observed for RMS in the AP (p=0.105) and ML (p=0.272) directions, PEV in the AP (p=0.081) and ML (p=0.143) directions, and SampEn in the AP (p=0.583) and ML (p=0.129) directions. These results suggest that over the course of a single competitive season, RHI do not negatively impact postural control even when measured with sensitive non-linear metrics.

ASB clinical biomechanics award winner 2016: Assessment of gaze stability within 24-48hours post-concussion

BACKGROUND

Approximately 90% of athletes with concussion experience a certain degree of visual system dysfunction immediately post-concussion. Of these abnormalities, gaze stability deficits are denoted as among the most common. Little research quantitatively explores these variables post-concussion. As such, the purpose of this study was to investigate and compare gaze stability between a control group of healthy non-injured athletes and a group of athletes with concussions 24-48hours post-injury.

METHODS

Ten collegiate NCAA Division I athletes with concussions and ten healthy control collegiate athletes completed two trials of a sport-like antisaccade postural control task, the Wii Fit Soccer Heading Game. During play all participants were instructed to minimize gaze deviations away from a central fixed area. Athletes with concussions were assessed within 24-48 post-concussion while healthy control data were collected during pre-season athletic screening. Raw ocular point of gaze coordinates were tracked with a monocular eye tracking device (240Hz) and motion capture during the postural task to determine the instantaneous gaze coordinates. This data was exported and analyzed using a custom algorithm. Independent t-tests analyzed gaze resultant distance, prosaccade errors, mean vertical velocity, and mean horizontal velocity.

FINDINGS

Athletes with concussions had significantly greater gaze resultant distance (p=0.006), prosaccade errors (p<0.001), and horizontal velocity (p=0.029) when compared to healthy controls.

INTERPRETATION

These data suggest that athletes with concussions had less control of gaze during play of the Wii Fit Soccer Heading Game. This could indicate a gaze stability deficit via potentially reduced cortical inhibition that is present within 24-48hours post-concussion.

Assessment of the Wii Basic Balance Test in measuring postural deficits post-concussion

Background and Aim: To evaluate the Wii Basic Balance Test (WBBT), as a tool for detecting postural instability in athletes with concussions. Methods: Seventy-nine healthy physically active controls (NORM) (mean age 21.23 ± 1.78), and fifty-six athletes with concussions (CONC) (mean age 19.39 ± 2.145) participated in this study. All participants performed the Wii Basic Balance Test, which requires the participants to shift weight mediolaterally to maintain a red bar within a blue area denoted on the screen for three seconds during set levels of difficulty. CONC were included in the study within 24-48 hours of the initial concussion injury. Seven one-way ANOVAs assessed differences for each (1) Mean total number of WBBT Levels completed (TL), (2) Mean total seconds to complete all WBBT Level (TT), (3) Time to complete Level 1 (LI), (4) Time to complete Level 2 (L2), (5) Time to complete Level 3 (L3), (6) Time to complete Level 4 (L4), (7) Time to complete Level 5 (L5). Results: CONC completed significantly fewer Levels of the WBBT (p=0.032) when compared to NORM. Athletes with Concussions took a significantly longer time to complete LI (p=0.002) when compared to CONC. Post-hoc Chi-Square analysis determined a significantly greater (p=0.015) proportion (39%) of CONC successfully completed WBBT L5 when compared to the proportion (19%) of CONC. Follow up ROC curves revealed an Sn = 0.392 and an Sp = 0.821 for TL with a cutoff value of 4 levels, Sn=0.875 and an Sp = 0.253 for LI with a cutoff value of 4.4 seconds, and Sn = 0.804 and an Sp = 0.392 for those who successfully completed the WBBT L5. Conclusions: WBBT could be a low cost object method of assessing postural instability within 24-48 hours post-concussion. Relevance for patients: This data could provide health providers with an alternative method to measure the presence of postural instability post-concussion injury.

Constraining eye movement in individuals with Parkinson's disease during walking turns

Walking and turning is a movement that places individuals with Parkinson's disease (PD) at increased risk for fall-related injury. However, turning is an essential movement in activities of daily living, making up to 45 % of the total steps taken in a given day. Hypotheses regarding how turning is controlled suggest an essential role of anticipatory eye movements to provide feedforward information for body coordination. However, little research has investigated control of turning in individuals with PD with specific consideration for eye movements. The purpose of this study was to examine eye movement behavior and body segment coordination in individuals with PD during walking turns. Three experimental groups, a group of individuals with PD, a group of healthy young adults (YAC), and a group of healthy older adults (OAC), performed walking and turning tasks under two visual conditions: free gaze and fixed gaze. Whole-body motion capture and eye tracking characterized body segment coordination and eye movement behavior during walking trials. Statistical analysis revealed significant main effects of group (PD, YAC, and OAC) and visual condition (free and fixed gaze) on timing of segment rotation and horizontal eye movement. Within group comparisons, revealed timing of eye and head movement was significantly different between the free and fixed gaze conditions for YAC (p < 0.001) and OAC (p < 0.05), but not for the PD group (p > 0.05). In addition, while intersegment timings (reflecting segment coordination) were significantly different for YAC and OAC during free gaze (p < 0.05), they were not significantly different in PD. These results suggest individuals with PD do not make anticipatory eye and head movements ahead of turning and that this may result in altered segment coordination during turning. As such, eye movements may be an important addition to training programs for those with PD, possibly promoting better coordination during turning and potentially reducing the risk of falls.