Altered dynamic postural control during gait termination following concussion

Clinical gait characteristics in the early post-concussion phase: A systematic review

BACKGROUND

Understanding gait alterations immediately post-concussion can improve identification, management and prognosis of concussion.

OBJECTIVE

To identify and define gait characteristics immediately post-concussion.

METHOD

A review of electronic databases was conducted using terms gait alteration AND mTBI OR concussion. 172 reports were identified. After restricting to English and human studies, 158 remained. Reports were screened to include studies assessing quantifiable gait change post-concussion. 12 studies were included.

DISCUSSION

Multiple gait features are altered post-impact: stability, step length, walking speed and postural control. There is evidence that postural measures in gait initiation and termination may identify more subtle deficits. There is paucity of data evaluating the impact of concussion on gait function acutely and the authors identified no studies examining immediate changes.

CONCLUSION

Acutely post-concussion, various gait alterations are seen and correlate with degree of deficit and prognosis. Slowed gait, instability and postural control are several features. Dynamic gait and postural assessments identify more subtle gait alterations. Given the absence in literature, high quality prospective studies examining immediate gait alterations post-concussion would contribute to improved assessment, management and prognostication. Given difficulty in participant recruitment, technological and standardised gait assessments should be used to assess force of impact and immediate gait alteration.

Short-Term Neurologic Manifestations of Repetitive Head Impacts Among Athletes: A Scoping Review

OBJECTIVE

To summarize the evidence linking contact sports-related repetitive head impacts (RHIs) and short-term declines in neurologic function.

METHODS

A scoping review following the guidelines in the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) and searching 3 databases (PubMed, EMBASE, and Web of Science) was performed. Peer-reviewed research articles were eligible for inclusion if they were full-length English language articles published between 1999 and 2019 examining athletes between the ages of 14 and 40 years exposed to RHIs, and reporting cognitive, vestibular, and/or oculomotor outcomes within 4 weeks of last head hit exposure.

RESULTS

Fifty-two articles met criteria for review: 14 reported oculomotor outcomes, 23 reported vestibular outcomes, and 36 reported cognitive function. Short-term RHI-related declines in neurologic function were reported in 42.9% of oculomotor studies, in 20.8% of vestibular studies, and in 33.3% of cognitive studies. Most of the 52 studies involved American football, soccer, or ice hockey athletes at the collegiate ( n = 23) or high school ( n = 14) level. Twenty-four (46%) studies involved only male athletes. Wearable sensors were used to measure RHIs in 24 studies (46%), while RHIs were not measured in 26 studies (50%). In addition, many studies failed to control for attention-deficit/hyperactivity disorder/learning disability and/or concussion history.

CONCLUSION

The results of this scoping review suggest that the evidence linking RHIs to short-term declines in neurologic function is relatively sparse and lacking in methodological rigor. Although most studies failed to find a link, those that did were more likely to use objective measures of RHIs and to control for confounders. More careful trial design may be needed to definitively establish a causal link between RHIs and short-term neurologic dysfunction.

Reactive Balance Responses After Mild Traumatic Brain Injury: A Scoping Review

OBJECTIVE

Balance testing after concussion or mild traumatic brain injury (mTBI) can be useful in determining acute and chronic neuromuscular deficits that are unapparent from symptom scores or cognitive testing alone. Current assessments of balance do not comprehensively evaluate all 3 classes of balance: maintaining a posture; voluntary movement; and reactive postural response. Despite the utility of reactive postural responses in predicting fall risk in other balance-impaired populations, the effect of mTBI on reactive postural responses remains unclear. This review sought to (1) examine the extent and range of available research on reactive postural responses in people post-mTBI and (2) determine whether reactive postural responses (balance recovery) are affected by mTBI.

DESIGN

Scoping review.

METHODS

Studies were identified using MEDLINE, EMBASE, CINAHL, Cochrane Library, Dissertations and Theses Global, PsycINFO, SportDiscus, and Web of Science. Inclusion criteria were injury classified as mTBI with no confounding central or peripheral nervous system dysfunction beyond those stemming from the mTBI, quantitative measure of reactive postural response, and a discrete, externally driven perturbation was used to test reactive postural response.

RESULTS

A total of 4747 publications were identified, and a total of 3 studies (5 publications) were included in the review.

CONCLUSION

The limited number of studies available on this topic highlights the lack of investigation on reactive postural responses after mTBI. This review provides a new direction for balance assessments after mTBI and recommends incorporating all 3 classes of postural control in future research.

The Effect of Concussion History on Lower Extremity Injury Risk in College Athletes: A Systematic Review and Meta-Analysis

Introduction

Collegiate athletes who suffer a concussion may possess prolonged impairments even after clearance for return-to-participation, which may place them at an increased risk of lower extremity injury.

Objective

To conduct a systematic review and meta-analysis of studies examining risk of lower extremity musculoskeletal injury following a concussion in collegiate athletes.

Methods

A literature search was performed using the following databases: PubMed, CINAHL, SPORTDiscus. The following search terms were used to identify relevant articles, ["concussion" OR "brain injury" OR "mild traumatic brain injury" OR "mTBI"] AND ["lower extremity injury" OR "musculoskeletal injury"]. Articles were included if they were published between January 2000 and July 2021 and examined collegiate athletes' risk of sustaining a lower extremity musculoskeletal injury following a concussion. Methodological quality of included studies was performed with a modified Downs and Black Checklist. The primary outcome of interest was the risk of sustaining a lower extremity musculoskeletal injury following a concussion. A random effects meta-analysis was conducted in which a summative relative risk (RR) for sustaining a lower extremity injury in athletes with and without a history of concussion was calculated.

Results

Seven studies met the eligibility criteria to be included in the systematic review. There were 348 athletes in the concussion group and 482 control athletes in the included studies. Most of the studies were of good or excellent quality. Five of the seven studies were able to be included in the meta-analysis. College athletes who suffered a concussion possessed a 58% greater risk of sustaining a lower extremity musculoskeletal injury than those who did not have a history of a concussion (RR = 1.58[1.30, 1.93]).

Conclusions

Lower extremity injury risk is potentially increased in college athletes following a concussion compared to those without a history of a concussion. Further research is needed to investigate the mechanism behind this increased risk. Clinical assessments throughout the concussion return-to-play protocol may need to be improved in order to detect lingering impairments caused by concussions.

Level of Evidence

1.

Association Between Collision Sport Career Duration and Gait Performance in Male Collegiate Student-Athletes

BACKGROUND

Investigations of estimated age of first exposure to repetitive head impacts from collision and contact sports have shown no associations with neurocognitive or neurobehavioral function at the collegiate level, but the effect of career duration may be a more comprehensive factor. Understanding whether longer career duration influences gait performance would provide insights into potential neurological impairment.

PURPOSE

To examine the relationship between career duration of collision sports and single/dual-task gait performance in collegiate student-athletes.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We recruited 168 male student-athletes from collision sports: football, lacrosse, ice hockey, and wrestling (mean ± SD age, 19.2 ± 1.3 years; height, 184.5 ± 7.2 cm; mass, 94.3 ± 15.9 kg; estimated age of first exposure, 8.6 ± 3.1 years; career duration, 10.6 ± 3.0 years). All participants completed a baseline single- and dual-task gait assessment before the start of their athletic season. Inertial measurement units were used to measure gait speed and stride length. During the dual task, participants were asked to perform working memory cognitive tasks while walking. The dependent variables were single/dual-task gait speed and stride length, cognitive accuracy, and dual-task cost. The relationship between career duration, analyzed as a continuous variable, and the dependent variables was analyzed using a linear regression.

RESULTS

There were no significant associations between career duration and single-task gait speed (1.16 ± 0.16 m/s; β = -0.004; P = .35; 95% CI = -0.012 to 0.004; η² = 0.005) or dual-task gait speed (1.02 ± 0.17 m/s; β = -0.003; P = .57; 95% CI = -0.011 to 0.006; η² = 0.002). There were also no significant associations between career duration and single/dual-task stride length, cognitive accuracy, or dual-task cost.

CONCLUSION

Career duration among collegiate collision sport athletes was not associated with single- or dual-task gait performance, suggesting that a greater exposure to repetitive head impacts is not detrimental to dynamic postural control at the college level. However, the effects of diminished gait performance over the lifetime remain to be elucidated.

Arch-Support Induced Changes in Foot-Ankle Coordination in Young Males with Flatfoot during Unplanned Gait Termination

Objective: The efficacy of arch orthoses in posture adjustment and joint coordination improvement during steady-state gait is well documented; however, the biomechanical changes of gait sub-tasks caused by arch support (AS), especially during gait termination, are poorly understood. Hence, this study aimed to investigate how the acute arch-supporting intervention affects foot–ankle coordination and coordination variability (CV) in individuals with flatfoot during unplanned gait termination (UGT). Methods: Twenty-five male patients with flatfoot were selected as subjects participated in this AS manipulation study. A motion capture system was used for the collection of the metatarsophalangeal joint (MPJ) and ankle kinematics during UGT. MPJ-Ankle coordination and CV were quantified using an optimized vector coding technique during the three sub-phases of UGT. A paired-sample t-test from the one-dimensional statistical parametric mapping of one-dimensional was applied to examine the data significance. Results: Significant differences for the joint kinematics between non-arch-support (NAS) and AS were exhibited only in the MPJ transverse plane during the middle and later periods of UGT (p = 0.04–0.026). Frontal plane MPJ-ankle coordination under AS during stimulus delay significantly decreased from 177.16 ± 27.41° to 157.75 ± 32.54° compared with under NAS (p = 0.026); however, the coordination pattern had not changed. Moreover, no significant difference was found in the coupling angle variability between NAS and AS in three planes during sub-phases of UGT (all p > 0.5). Conclusions: The detailed intrinsic characteristic of AS induced acute changes in lower extremity segment coordination in patients with mild flatfoot has been recorded. This dataset on foot-ankle coordination characteristics during UGT is essential for explaining foot function and injury prediction concerning AS manipulation. Further studies are expected to reflect lower limb inter-joint coordination during gait termination through the long-term effects of AS orthoses.

Sport-Specific Increased Risk of Anterior Cruciate Ligament Injury Following a Concussion in Collegiate Female Lacrosse

ABSTRACT

Poor neurocognitive performance has been associated with a greater risk of musculoskeletal injury, and anterior cruciate ligament (ACL) injury prevention protocols include exercises to improve neuromuscular control. Research shows that a concussion elevates the risk for subsequent lower-extremity injury, because concussions lead to lower neurocognitive performance. Studies have been conducted using data within individual male sports, such as football and rugby, or across collegiate sports in aggregate; no study has focused on women's sports. Using 7 years of data collected by athletic training staff at Davidson College, this paper evaluates preconcussive versus postconcussive lower-extremity injury risk across five collegiate women's sports: field hockey, soccer, basketball, volleyball, and lacrosse. Using incidence rate ratios, lacrosse athletes had a five-fold increase in ACL injury risk within 365 d following a concussion. Recognizing that postconcussive ACL tear risk varies across different women's sports is important in informing sport-specific concussion return to play protocols.

Patient perception of dizziness and imbalance does not correlate with gait measures in adolescent athletes post-concussion

BACKGROUND

Dizziness and gait impairments are commonly observed following a concussion, and both are associated with prolonged concussion recovery.

RESEARCH QUESTION

Is there a correlation between combined self-reported dizziness and balance impairment severity with objective gait impairments after concussion?

METHODS

Participants (n = 51; 15.4 ± 1.6 years; 51 % female; 7.3 ± 3.2 days post-injury) age 12-18 years self-reported ratings of dizziness and balance impairment using the Post-Concussion Symptom Inventory (PCSI) within 14 days of injury. Individual ratings of dizziness, balance impairment, and moving clumsily on the PCSI were combined to create a comprehensive dizziness and imbalance score. Participants also completed a smartphone-based gait evaluation under single-task and dual-task conditions. Correlation coefficients (Pearson r for normally distributed and Spearman rho for non-normally distributed variables) were calculated between self-reported symptoms and single and dual-task spatiotemporal gait parameters, specifically step velocity, step time, and step length.

RESULTS

Correlation coefficients indicated that there was low to no correlation between self-reported dizziness and imbalance impairment severity and smartphone-obtained gait parameters under single- or dual-task conditions, including step velocity (single-task: r=-0.22, p = 0.13; dual-task: r=-0.05, p = 0.72), step time (single-task: rho = 0.16, p = 0.27; dual-task: rho = 0.14, p = 0.33), and step length (single-task: r=-0.15, p = 0.30; dual-task: r = 0.03, p = 0.84).

SIGNIFICANCE

Self-reported dizziness and balance impairment severity within the first two weeks of concussion may not reflect objectively measured gait performance, given the lack of association between subjective symptom ratings and functional measures. Further, smartphone collected gait parameters may not provide the necessary sensitivity to detect an association with dizziness. The lack of significant correlation between self-reported symptoms and objective gait performance highlights the importance of using both objective and subjective measures to obtain a more complete picture of concussion deficits.

Gait Performance Is Associated with Subsequent Lower Extremity Injury following Concussion

PURPOSE

The purpose was to examine gait characteristics between collegiate athletes who did and did not sustain a lower-extremity musculoskeletal (LEMSK) injury in the year after concussion.

METHODS

Thirty-four NCAA collegiate athletes with diagnosed concussions were divided into two groups based on if they did (n = 16) or did not (n = 18) sustain a LEMSK in the year after concussion. Participants completed baseline testing before the start of the season and again at return to play postconcussion. Injuries were tracked using an electronic medical database. Participants were instrumented with three APDM Opal triaxial accelerometers and performed five single-task (ST) and five dual-task (DT) gait trials. Participants traversed a 10-meter walkway, turned around a specified endpoint, and returned to the original line. During DT, participants simultaneously walked and answered mini-mental style questions. A linear mixed-effects model assessed interactions and/or main effects between groups for gait speed, double support time, cadence, stride length, and cognitive accuracy.

RESULTS

The LEMSK group walked slower (ST, 1.15 ± 0.10 m·s; DT, 1.01 ± 0.10 m·s) than the uninjured group (ST, 1.23 ± 0.11 m·s; DT, 1.10 ± 0.11 m·s) during both ST (P = 0.04) and DT (P = 0.03). The injury group spent longer in double support (ST, 20.19% ± 2.34%; DT, 21.92% ± 2.13%) than the uninjured group (ST, 18.16% ± 2.60%; DT, 20.00% ± 2.32%) during both ST (P = 0.02) and DT (P = 0.02). The injury group had a significantly lower cognitive accuracy (89.56% ± 6.48%) than the uninjured group (95.40% ± 7.08%) across time points (P = 0.02).

CONCLUSIONS

There were significant differences in gait characteristics and cognitive accuracy between those who did and did not sustain a LEMSK injury after concussion. The LEMSK group demonstrated a conservative gait strategy both before and after their concussive injury.

Predicting Sport-related mTBI Symptom Resolution Trajectory Using Initial Clinical Assessment Findings: A Retrospective Cohort Study

OBJECTIVES

To identify which aspects of initial clinical assessment for sport-related mild traumatic brain injury (SR-mTBI) predict whether an athlete achieves symptom resolution within 14 days of the injury.

RESEARCH DESIGN

Retrospective cohort study using prospectively collected data.

METHODS

Clinical assessment data were collected from 568 patients diagnosed with SR-mTBI at a single medical clinic between February 2017 and December 2018. Demographic data, medical history, SCAT-5 testing, and physician notes were included in the data set. Data were processed and analysed to identify a shortlist of predictor variables to develop a logistic regression model to discriminate between SR-mTBI symptom resolution that occurred in ≤ 14-days or > 14-days. The data were randomly divided into model development and validation subsamples. The top 15 models were analysed to determine the predictor variables to be included in the final logistic regression model. The final model was then applied to the validation subsample.

RESULTS

Half of the athlete participants in this study experienced > 14-day symptom resolution. The final logistic regression model included sex, symptom reporting at initial assessment and presentation with a physiological predominant symptom cluster. The model accounted for 0.90 and 0.85 of the area under the curve and predicted recovery trajectory with 81% and 76% accuracy for the training and validation subsamples, respectively.

CONCLUSIONS

Being female, reporting a higher Positive Symptom Total at initial assessment, and being less likely to have a physiological predominant symptom cluster at initial assessment predicted > 14 versus ≤ 14-day SR-mTBI symptom resolution with a high level of accuracy.

Tandem gait test performance in healthy, physically active adults: Clinical implications for concussion evaluation

OBJECTIVES

To identify factors affecting performance on the tandem gait test in healthy, physically active adults.

DESIGN

Cross-sectional.

METHODS

Participants completed the tandem gait test according to Sport Concussion Assessment Tool 3 (SCAT3) guidelines. Dependent variables included time for best trial (initial 3m, turn, final 3m and total) and whether the trial was "pass" or "fail". Independent variables included sex, concussion history, foot length, height and total number of trials.

RESULTS

55% (35/64) of participants passed the first trial of the tandem gait test; 19% (12/64) had a best time <14s. Sex and concussion history did not affect performance (p>0.05). There were no differences in turn times for those with and without a history of concussion (t=0.26, p=0.80). The number of trials was not significantly correlated with best time (þ=-0.04, p=0.74). There were low (þ=-0.31) to negligible (þ<0.30) correlations between foot length, height and all portions of the test. There was more variability in times for the turn (COV=27%) than during the straight portions (COV=18%).

CONCLUSIONS

Current recommendations for the tandem gait test led to a high false-positive rate in healthy, physically active adults. Sex, concussion history, number of trials and foot length had little to no influence on scores on the test. Turning times were more variable than times on the straight portions of the test. Clinicians may use these results as a guideline when interpreting performance on the tandem gait test in healthy physically active adults.

Using functional movement tests to investigate the presence of sensorimotor impairment in amateur athletes following sport-related concussion: A prospective, longitudinal study

OBJECTIVE

To longitudinally investigate the presence of sensorimotor impairments in amateur athletes following sport-related concussion using two functional movement tests.

DESIGN

Prospective, longitudinal study.

SETTING

Human movement analysis laboratory.

PARTICIPANTS

Athletes who presented to a hospital emergency department and were diagnosed with sport-related concussion, and sex-, age-, and activity-matched non-concussed, control athletes. Concussed participants were assessed within one-week following sport-related concussion, upon clearance to return-to-sporting activity (RTA), and two weeks after RTA. Control participants were assessed at an initial time-point and approximately two and four weeks following their initial study assessment.

MAIN OUTCOMES MEASURES

At each laboratory assessment, participants completed two functional movement tests: the Star Excursion Balance Test to evaluate anterior reach distance (normalised for leg length) and fractal dimension (centre of pressure path complexity), and the Multiple Hop Test to evaluate corrective postural strategies and time-to-stabilisation.

RESULTS

Fifty concussed athletes and 50 control athletes completed the study. There were no significant differences at any study assessment between the concussion and control group on the Star Excursion Balance Test anterior reach distance or fractal dimension (centre of pressure path complexity). During the Multiple Hop Test, the concussion group used a significantly greater number of corrective postural strategies than the control group one-week following sport-related concussion and upon clearance to RTA, but not two weeks following RTA.

CONCLUSION

Recently concussed athletes made a greater number of corrective postural strategies than control participants during the Multiple Hop Test upon clearance to RTA but not two weeks after RTA. The Multiple Hop Test may offer a clinically useful tool for practitioners to examine the recovery of subtle sensorimotor impairments and related RTA readiness.

A Proposal for Complex Gait Evaluation Using Dual-Task Gait Termination Time

CONTEXT

Gait termination time (GTT) has been used to predict falls in older adults but has not been explored in the sport rehabilitation setting. The incorporation of a concurrent cognitive task as a complex measure of gait in this clinical population could lead to better health-related outcomes.

OBJECTIVE

To compare the effect of planned and unplanned gait termination with and without a concurrent cognitive task on reaction time (RT), gait velocity, and GTT.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

Twenty young adults (females 60.0%, age 20.1 [0.9] y, height 169.5 [8.8] cm, mass 67.4 [10.8] kg).

INTERVENTION

Participants completed 6 planned and 6 unplanned gait termination trials on an instrumented gait mat with and without a cognitive task.

MAIN OUTCOME MEASURES

The authors measured RT (s), gait velocity (m/s), GTT (s), and normalized GTT (s2/m). A 2 (motor) × 2 (cognitive) repeated-measures analysis of variance (α = .05) was used; significant interaction effects were explored using Bonferroni-corrected t tests (α < .008).

RESULTS

Participants walked more slowly during dual-task trials compared with single-task trials (F1,19 = 4.401, P = .050). Participants walked significantly more slowly with a cognitive task during planned (P < .001, mean difference = -0.184 m/s, 95% CI, -0.256 to -0.111) and unplanned (P = .001, mean difference = -0.111 m/s, 95% CI, -0.173 to -0.050) gait termination. Participants walked significantly more slowly (P < .001, mean difference = -0.142 m/s, 95% CI, -0.210 to -0.075) when performing the most difficult task, unplanned termination with a cognitive task, than when performing the least difficult task, planned termination with no cognitive task. We observed a cognitive task main effect such that adding a cognitive task increased RT (F1,19 = 16.375, P = .001, mean difference = -0.118 s, 95% CI, -0.178 to -0.057) and slowed normalized GTT (F1,19 = 5.655, P = .028, mean difference = -0.167 s2/m, 95% CI, -0.314 to -0.020).

CONCLUSIONS

Overall, participants displayed more conservative gait strategies and slower RT, normalized GTT, and gait velocity as task difficulty increased. More investigation is needed to truly understand the clinical meaningfulness of these measures in athletic injuries.

Effect of motor-assisted elliptical training speed and body weight support on center of pressure movement variability

BACKGROUND

A motor-assisted elliptical trainer is being used clinically to help individuals with physical disabilities regain and/or retain walking ability and cardiorespiratory fitness. Unknown is how the device's training parameters can be used to optimize movement variability and regularity. This study examined the effect of motor-assisted elliptical training speed as well as body weight support (BWS) on center of pressure (CoP) movement variability and regularity during training.

METHODS

CoP was recorded using in-shoe pressure insoles as participants motor-assisted elliptical trained at three speeds (20, 40 and 60 cycles per minute) each performed at four BWS levels (0 %, 20 %, 40 %, and 60 %). Separate two-way repeated measures ANOVAs (3 × 4) evaluated impact of training speed and BWS on linear variability (standard deviation) and non-linear regularity (sample entropy) of CoP excursion (anterior-posterior, medial-lateral) for 10 dominant limb strides.

FINDINGS

Training speed and BWS did not significantly affect the linear variability of CoP in the anterior-posterior or medial-lateral directions. However, sample entropy in both directions revealed the main effect of training speed (p < 0.0001), and a main effect of BWS was observed in the medial-lateral direction (p = 0.004). Faster training speeds and greater levels of BWS resulted in more irregular CoP patterns.

INTERPRETATION

The finding that speed and BWS can be used to manipulate CoP movement variability when using a motor-assisted elliptical has significant clinical implications for promoting/restoring walking capacity. Further research is required to determine the impact of motor-assisted elliptical speed and BWS manipulations on functional recovery of walking in individuals who have experienced a neurologic injury or illness.

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.

Differential Effects of Acute and Multiple Concussions on Gait Initiation Performance

OBJECTIVE

To identify the effect of acute and multiple concussions on gait initiation performance.

DESIGN

Cohort study.

SETTING

University research center.

PARTICIPANTS

A population-based sample of participants (N=45) divided into 3 groups: No Prior Concussion, ≥3 Prior Concussions, and Acute Concussion. The Acute Concussion participants were assessed within 24 hours of their concussion. Participants were matched based on (1) sport, (2) position, and (3) anthropometric measures.

INTERVENTIONS

Participants were tested on a single occasion and performed 5 trials of gait initiation on 4 force plates. The No Prior Concussion and ≥3 Prior Concussions groups were tested out of their primary athletic season.

MAIN OUTCOME MEASURES

The dependent variables were the posterior and lateral displacement and velocity of the center of pressure (COP) during the anticipatory postural adjustment phase and initial step kinematics (step length and step velocity). Comparisons between groups used a 1-way analysis of variance with Tukey post hoc when significant effects were identified and effect sizes were calculated.

RESULTS

There were significant effects for group for all 6 outcome measures with large effect sizes. Post hoc tests identified differences between Acute Concussion and No Prior Concussion groups for all measures. The ≥3 Prior Concussions group and No Prior Concussion group were different for COP posterior displacement (4.91±1.09 and 4.91±1.09cm, respectively, P=.032, d=0.91) and velocity (0.18±0.06 and 0.27±0.08m/s, respectively, P=.002, d=1.27).

CONCLUSION

There was continuum of performance identified whereby the Acute Concussion participants performed worse and the No Prior Concussion participants performed the best. The ≥3 Prior Concussions generally fell between these 2 groups, but only statistical significance on COP posterior displacement and velocity. These results suggest there may be subtle neurophysiological deficits present in collegiate student-athletes with ≥3 Prior Concussions group, and further investigation over the lifespan 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.

Dual-Task Tandem Gait and Average Walking Speed in Healthy Collegiate Athletes

OBJECTIVES

To (1) examine the association between a commonly used concussion test, tandem gait, in single/dual-task conditions with single-task and dual-task average walking speed, (2) characterize the prevalence of tandem gait false positives, and (3) develop a normative reference range of dual-task tandem gait times.

DESIGN

Cross-sectional study.

SETTING

Two NCAA collegiate athletic facilities.

INDEPENDENT VARIABLES

Athletes completed the tandem gait test and a gait evaluation in single/dual-task conditions during a preseason examination.

MAIN OUTCOME MEASURES

Associations between tandem gait times and average walking speeds were evaluated using multiple linear regression models. Various tandem gait test time pass/fail cutoffs were calculated to examine false-positive rates.

RESULTS

Among the 171 participants (103 men, 19.8 ± 1.2 years of age), dual-task tandem gait completion times were independently associated with dual-task average walking speed [β = -4.018; 95% confidence interval (CI), -7.153 to -0.883], but single-task associations were not found. Male gender was associated with faster tandem gait times in both single-task (β = -0.880, 95% CI, -1.731 to -0.029) and dual-task conditions (β = -2.225, 95% CI, -3.691 to -0.759). A pass/fail cutoff threshold of 14 seconds resulted in a 2% false-positive rate for single-task tandem gait, while it resulted in a 29% false-positive rate during dual-task tandem gait.

CONCLUSIONS

Average walking speed and dual-task tandem gait represent objective measures that are useful in concussion management. While a single-task tandem gait cutoff of 14 seconds seems appropriate for males, adjustments may be necessary based on sex and alternate pass/fail criteria may be appropriate for dual-task tandem gait.

Efficacy of Tandem Gait to Identify Impaired Postural Control after Concussion

PURPOSE

The purpose was to evaluate tandem gait (TG), Balance Error Scoring System (BESS), and modified Balance Error Scoring System (mBESS) performance acutely after concussion in collegiate student-athletes. In addition, we sought to evaluate the psychometric properties of TG, including minimal detectable change (MDC), sensitivity, and specificity.

METHODS

Seventy-six National Collegiate Athletic Association student-athletes performed TG and BESS tests: 38 acutely after concussion and 38 controls. Participants were tested at baseline (time 1) and again acutely after concussion, or the following year for controls (time 2). Ten controls, tested simultaneously by two researchers, established a TG interrater minimal detectable change. A 2 × 2 mixed-design ANOVA compared each outcome variable. An receiver operating characteristic curve analysis was used to evaluate sensitivity, specificity, and area under the curve (AUC).

RESULT

There was a significant interaction (F = 8.757, P = 0.004) for TG whereby the concussion group was slower after concussion (10.59 ± 1.53 vs 11.80 ± 2.67 s), whereas there was no difference for controls (10.13 ± 1.72 vs 9.93 ± 1.85 s). There was no significant interaction for BESS (F = 0.235, P = 0.630) or mBESS (F = 0.007, P = 0.935). TG had a sensitivity of 0.632, a specificity of 0.605, and an AUC of 0.704. BESS had a sensitivity of 0.447, a specificity of 0.500, and an AUC of 0.508. mBESS had a sensitivity of 0.474, a specificity of 0.632, and an AUC of 0.535.

CONCLUSIONS

Participants completed TG significantly slower after concussion, whereas no change across time was detected for controls. In contrast, BESS and mBESS performances were similar at both testing times in both groups. Our AUC analysis was acceptable for TG, but a failure for both BESS and mBESS; thus, TG may be a useful alternative for clinicians conducting postconcussion postural control assessments.

Neuromuscular Control Deficits and the Risk of Subsequent Injury after a Concussion: A Scoping Review

An emerging area of research has identified that an increased risk of musculoskeletal injury may exist upon returning to sports after a sport-related concussion. The mechanisms underlying this recently discovered phenomenon, however, remain unknown. One theorized reason for this increased injury risk includes residual neuromuscular control deficits that remain impaired despite clinical recovery. Thus, the objectives of this review were: (1) to summarize the literature examining the relationship between concussion and risk of subsequent injury and (2) to summarize the literature for one mechanism with a theorized association with this increased injury risk, i.e., neuromuscular control deficits observed during gait after concussion under dual-task conditions. Two separate reviews were conducted consistent with both specified objectives. Studies published before 9 December, 2016 were identified using PubMed, Web of Science, and Academic Search Premier (EBSCOhost). Inclusion for the objective 1 search included dependent variables of quantitative measurements of musculoskeletal injury after concussion. Inclusion criteria for the objective 2 search included dependent variables pertaining to gait, dynamic balance control, and dual-task function. A total of 32 studies were included in the two reviews (objective 1 n = 10, objective 2 n = 22). According to a variety of study designs, athletes appear to have an increased risk of sustaining a musculoskeletal injury following a concussion. Furthermore, dual-task neuromuscular control deficits may continue to exist after patients report resolution of concussion symptoms, or perform normally on other clinical concussion tests. Therefore, musculoskeletal injury risk appears to increase following a concussion and persistent motor system and attentional deficits also seem to exist after a concussion. While not yet experimentally tested, these motor system and attentional deficits may contribute to the risk of sustaining a musculoskeletal injury upon returning to full athletic participation.

Risk for Lower Extremity Injury After Concussion: A Matched Cohort Study in Soldiers

Background Rates of lower extremity musculoskeletal injury are reportedly higher in professional and collegiate athletes following concussions. However, there is a paucity of evidence on this relationship in individuals who are not high-level athletes. Objectives To examine the risk of acute lower extremity musculoskeletal injury in soldiers within 2 years of an incident concussion, compared to matched nonconcussed soldiers. Methods This was a matched-cohort study that used the medical encounter and personnel data of active-duty US Army soldiers from 2005 to 2011. Incident concussions were identified using International Classification of Diseases-Ninth Revision codes in medical encounter data of all soldiers from 2005 to 2009. One nonconcussed soldier in the US Army during the same month was matched by age, sex, rank, length of service, deployment status, and military career field to each concussed soldier. Hazard ratio (HR) and 95% confidence interval (CI) were calculated for the risk of lower extremity injury within 2 years of the incident concussion. Monthly HRs were compared to identify differences in injury rates between the groups, and an HR for the period of greatest difference was also calculated. Results A total of 23 044 individuals (11 522 concussed and 11 522 nonconcussed) were included in the study. Within 2 years of concussion, the hazard of lower extremity injury was 38% greater in concussed compared to nonconcussed soldiers (HR, 1.38; 95% CI: 1.30, 1.46), while the 15-month hazard was 45% greater (HR, 1.45; 95% CI: 1.36, 1.56). Conclusion The rate of lower extremity musculoskeletal injury among this population of physically active adults is higher following concussion, and the risk remains elevated for more than a year following injury. Level of Evidence Prognosis, level 2b. J Orthop Sports Phys Ther 2018;48(7):533-540. Epub 8 May 2018. doi:10.2519/jospt.2018.8053.

Detecting gait abnormalities after concussion or mild traumatic brain injury: A systematic review of single-task, dual-task, and complex gait

BACKGROUND

While a growing number of studies have investigated the effects of concussion or mild traumatic brain injury (mTBI) on gait, many studies use different experimental paradigms and outcome measures. The path for translating experimental studies for objective clinical assessments of gait is unclear.

RESEARCH QUESTION

This review asked 2 questions: 1) is gait abnormal after concussion/mTBI, and 2) what gait paradigms (single-task, dual-task, complex gait) detect abnormalities after concussion.

METHODS

Data sources included MEDLINE/PubMed, Scopus, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) accessed on March 14, 2017. Original research articles reporting gait outcomes in people with concussion or mTBI were included. Studies of moderate, severe, or unspecified TBI, and studies without a comparator were excluded.

RESULTS

After screening 233 articles, 38 studies were included and assigned to one or more sections based on the protocol and reported outcomes. Twenty-six articles reported single-task simple gait outcomes, 24 reported dual-task simple gait outcomes, 21 reported single-task complex gait outcomes, and 10 reported dual-task complex gait outcomes.

SIGNIFICANCE

Overall, this review provides evidence for two conclusions: 1) gait is abnormal acutely after concussion/mTBI but generally resolves over time; and 2) the inconsistency of findings, small sample sizes, and small number of studies examining homogenous measures at the same time-period post-concussion highlight the need for replication across independent populations and investigators. Future research should concentrate on dual-task and complex gait tasks, as they showed promise for detecting abnormal locomotor function outside of the acute timeframe. Additionally, studies should provide detailed demographic and clinical characteristics to enable more refined comparisons across studies.

Self-reported sleep duration affects tandem gait, but not steady-state gait outcomes among healthy collegiate athletes

BACKGROUND

Sleep deficits are associated with motor and cognitive function deficits, even in the absence of a recent concussion.

RESEARCH QUESTION

Does the amount of self-reported sleep prior to pre-season concussion testing affect single-task and dual-task instrumented steady-state gait and timed tandem gait test performance?

METHODS

One hundred and fourteen healthy collegiate athletes (mean age 18.8 ± 0.7 years; 60% female) reported the amount of sleep they received during the prior night and completed a timed tandem gait test and an instrumented assessment of steady-state gait in both single-task and dual-task conditions. Outcome variables included spatio-temporal gait parameters during steady-state gait, best and mean tandem gait times, and cognitive test accuracy.

RESULTS

Participants who reported sleeping <7 h of sleep during the night prior to testing (n = 62) had significantly longer tandem gait times in single-task and dual-task conditions (11.1 ± 2.2 vs. 10.1 ± 2.0 s and 14.5 ± 4.3 vs. 12.3 ± 2.6 s, respectively; p = .009) compared to those who reported sleeping ≥7 h (n = 52). No significant differences between groups were observed for spatio-temporal steady-state gait variables or for cognitive test accuracy.

SIGNIFICANCE

Self-reported sleep duration may be associated with baseline testing tandem gait performance. Thus, as sleep can play a role in motor abilities, clinicians may consider interpreting tandem gait performance in light of sleep duration during the night prior to testing.

Detection of Acute and Long-Term Effects of Concussion: Dual-Task Gait Balance Control Versus Computerized Neurocognitive Test

OBJECTIVE

To examine the acute (within 72h of injury) and long-term (2mo postinjury) independent associations between objective dual-task gait balance and neurocognitive measurements among adolescents and young adults with a concussion and matched controls.

DESIGN

Longitudinal case-control.

SETTING

Motion analysis laboratory.

PARTICIPANTS

A total of 95 participants completed the study: 51 who sustained a concussion (mean age, 17.5±3.3y; 71% men) and 44 controls (mean age, 17.7±2.9y; 72% men). Participants who sustained a concussion underwent a dual-task gait analysis and computerized neurocognitive testing within 72 hours of injury and again 2 months later. Uninjured controls also completed the same test protocol in similar time increments.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We compared dual-task gait balance control and computerized neurocognitive test performance between groups using independent samples t tests. Multivariable binary logistic regression models were then constructed for each testing time to determine the association between group membership (concussion vs control), dual-task gait balance control, and neurocognitive function.

RESULTS

Medial-lateral center-of-mass displacement during dual-task gait was independently associated with group membership at the initial test (adjusted odds ratio [aOR], 2.432; 95% confidence interval [CI], 1.269-4.661) and 2-month follow-up test (aOR, 1.817; 95% CI, 1.014-3.256) tests. Visual memory composite scores were significantly associated with group membership at the initial hour postinjury time point (aOR, .953; 95% CI, .833-.998). However, the combination of computerized neurocognitive test variables did not predict dual-task gait balance control for participants with concussion, and no single neurocognitive variable was associated with dual-task gait balance control at either testing time.

CONCLUSIONS

Dual-task assessments concurrently evaluating gait and cognitive performance may allow for the detection of persistent deficits beyond those detected by computerized neurocognitive deficits alone.

Comparison of Psychological Response between Concussion and Musculoskeletal Injury in Collegiate Athletes

The psychological response to musculoskeletal injuries has been well documented, however, research on the psychological response to concussion is limited. The Profile of Mood States (POMS) and the State-Trait Anxiety Inventory (STAI) have recently been used to assess the psychological recovery of concussions. Although some studies indicate that psychological response is different for musculoskeletal injuries and concussion, there is currently not enough information to indicate this difference occurs at specific clinical milestones. The purpose of this study was to compare the psychological responses of student-athletes who have been diagnosed with a concussion to those of athletes diagnosed with musculoskeletal injuries with similar recovery duration. Fifteen collegiate athletes who sustained a musculoskeletal injury were recruited and matched with 15 previously collected concussion participants. The main outcome measures were the scores of POMS constructs: tension-anxiety, anger-hostility, fatigue-inertia, depression-dejection, vigor-activity, confusion-bewilderment, and total mood disturbance and STAI (state anxiety only). Two-way MANOVAs was run to determine the effects of group and time on POMS and STAI constructs. There were no significant interactions identified, but follow-up ANOVAs identified a main effect for time for most POMS subscales, with POMS scores improving over time in both groups. Analyses also revealed that tension-anxiety, vigor-activity and the STAI were not affected by time or group. The findings of this study, that both groups' psychological response to injury improves over time and at similar clinical milestones suggests reduction in sports and team related activities may play a substantial role in the psychological response to either concussion or musculoskeletal injury.

Decreased Anticipatory Postural Adjustments During Gait Initiation Acutely Postconcussion

OBJECTIVE

To investigate anticipatory postural adjustments (APAs) during the transitional movement task of gait initiation (GI) in individuals acutely after a concussion.

DESIGN

Cohort study.

SETTING

University research center.

PARTICIPANTS

A population-based sample of participants (N=84) divided into 2 equal groups of acutely postconcussion and healthy student athletes.

INTERVENTION

Participants were tested on 2 occasions: a preinjury baseline test and then the concussion group was retested acutely postconcussion and the healthy student athlete group again at a similar time. All participants completed 5 trials of GI on 4 forceplates.

MAIN OUTCOME MEASURES

The dependent variables were the displacement and velocity of the center of pressure (COP) during the APA phase and initial step kinematics. Comparisons were made with a 2 (group) × 2 (time) repeated-measures analysis of variance.

RESULTS

There was a significant interaction for COP posterior displacement (P<.001) and lateral displacement (P<.001). Posteriorly, post hoc testing identified a significant reduction in the concussion group (pretest: 5.7±1.6cm; posttest: 2.6±2.1cm; P<.001), but no difference in the healthy student athlete group (pretest: 4.0±1.6cm; posttest: 4.0±2.5cm; P=.921). Laterally, post hoc testing identified a significant reduction in the concussion group (pretest: 5.8±2.1cm; posttest: 3.8±1.8cm; P<.001), but no difference in the healthy student athlete group (pretest: 5.0±2.5cm; posttest: 5.2±2.4cm; P=.485).

CONCLUSIONS

The results of this study suggest difficulty in the planning and execution of GI acutely postconcussion, and posterior APA displacement and velocity are highly effective measures of impaired postural control. Finally, the APA phase is linked to the supplementary motor area, which suggests a supraspinal contribution to postconcussion impaired postural control.

Normative Tandem Gait in Collegiate Student-Athletes: Implications for Clinical Concussion Assessment

BACKGROUND

Impaired balance is common after concussion. The third edition of the Sport Concussion Assessment Tool (SCAT-3) recommends the Balance Error Scoring System (BESS) and/or tandem gait for postconcussion balance assessment. The limitations of the BESS are well documented; however, tandem gait has received little attention throughout concussion literature. The purpose of this study was to provide normative data for tandem gait in collegiate student-athletes based on sport type, concussion history, and gender.

HYPOTHESIS

Tandem gait will be influenced by concussion history, sport, and gender.

STUDY DESIGN

Cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Four hundred collegiate student-athletes from both collision/contact (n = 200) and limited contact/noncontact (n = 200) sports performed 4 tandem gait trials, consistent with SCAT-3 guidelines. The dependent variables included the best of the 4 trials (BEST), the mean of the 4 trials (MEAN), and the mean of each of the trials individually (ORDER). Separate multivariate analyses of variance were performed for each of the independent variables to determine effect on BEST and MEAN trial times. Significant main effects were followed up with a 1-way analysis of variance (ANOVA). A separate 1-way ANOVA was used to assess ORDER differences.

RESULTS

The mean BEST was 10.37 ± 1.76 seconds, and the MEAN was 11.32 ± 0.70 seconds. There were no significant differences in BEST or MEAN tandem gait times, respectively, between those with and without concussion history ( P = 0.41 and P = 0.69, respectively), sport type ( P = 0.57 and P = 0.42, respectively), or gender ( P = 0.73 and P = 0.49, respectively). There were significant differences ( P < 0.05) between ORDER of the 4 tandem gait trials across the population, with improved times at each trial.

CONCLUSION

The results of this study provide a normative data set for tandem gait in healthy collegiate student-athletes and suggest that common determinants of balance, including concussion history, collision sport participation, and gender do not appear to influence performance, but ORDER could have significant clinical implications.

CLINICAL RELEVANCE

Clinicians may use these data to distinguish important determinants of tandem gait performance and improve awareness when returning an individual to play after a concussion.

Association Between Concussion and Lower Extremity Injuries in Collegiate Athletes

Background:

Concussions have been associated with elevated musculoskeletal injury risk; however, the influence of unreported and unrecognized concussions has not been investigated.

Hypothesis:

The purpose of this study was to examine the association between concussion and lower extremity musculoskeletal injury rates across a diverse array of sports among collegiate student-athletes at the conclusion of their athletic career. The hypothesis was that there will be a positive association between athletes who reported a history of concussions and higher rates of lower extremity injuries.

Study Design:

Cross-sectional study.

Level of Evidence:

Level 3.

Methods:

Student-athletes (N = 335; 62.1% women; mean age, 21.2 ± 1.4 years) from 13 sports completed a reliable injury history questionnaire. Respondents indicated the total number of reported, unreported, and potentially unrecognized concussions as well as lower extremity injuries including ankle sprains, knee injuries, and muscle strains. Chi-square analyses were performed to identify the association between concussion and lower extremity injuries.

Results:

There were significant associations between concussion and lateral ankle sprain (P = 0.012), knee injury (P = 0.002), and lower extremity muscle strain (P = 0.031). There were also significant associations between reported concussions and knee injury (P = 0.003), unreported concussions and knee injury (P = 0.002), and unrecognized concussions and lateral ankle sprain (P = 0.001) and lower extremity muscle strains (P = 0.006), with odds ratios ranging from 1.6 to 2.9.

Conclusion:

There was a positive association between concussion history and lower extremity injuries (odds ratios, 1.6-2.9 elevated risk) among student-athletes at the conclusion of their intercollegiate athletic careers.

Clinical Relevance:

Clinicians should be aware of these elevated risks when making return-to-participation decisions and should incorporate injury prevention protocols.