Evidence of a conservative gait strategy in athletes with a history of concussions

Measurement Properties of the Activities-Specific Balance Confidence Scale in Adults From the General Population With Concussion: A Report From the Toronto Concussion Study

OBJECTIVE

The aim of this study was to establish the internal consistency and construct validity of the Activities-specific Balance Confidence (ABC) Scale and ABC-6 in adults from the general population with concussion.

DESIGN

Prospective analysis.

SETTING

Outpatient concussion care clinic.

PARTICIPANTS

Adults from the general population with concussion referred to a concussion care clinic within 7 days of injury (N=511).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Balance confidence was assessed with the Activities-specific Balance Confidence (ABC) Scale and the ABC-6. Concussion symptoms were characterized using the Sport Concussion Assessment Tool version 5 (SCAT5) symptom checklist. Instrumented measures of balance and gait included center of pressure velocity and double support time, respectively. Balance was also assessed using the mBESS.

RESULTS

The ABC and ABC-6 were strongly correlated (ρ=0.980, P<.001). Cronbach α for ABC and ABC-6 was 0.966 and 0.940, respectively. Factor analysis verified the existence of 2 components of the ABC, 1 including all items of the ABC-6 as well as 3 additional items. ABC and ABC-6 were moderately significantly correlated with SCAT5 symptom number, severity, and symptom domain (ρ=-0.350 to -0.604). However, correlations between ABC and ABC-6 with instrumented measures of balance and gait were not statistically significant, except for double support time during dual-task gait with ABC-6 (ρ=-0.218).

CONCLUSIONS

In community-dwelling adults with concussion, the ABC and ABC-6 have good internal consistency. Convergent validity is stronger for symptom endorsement measures within SCAT5 domains, which has a similar construct (subjectivity) to balance confidence. Both the ABC and ABC-6 are valid measures of balance self-efficacy in adults from the general population with concussion. The ABC-6 may be a useful tool for characterizing the effect of concussion on perceptions of the ability to perform functional tasks that challenge balance and mobility.

Associations Between Prior Head Injury, Physical Functioning, and Frailty in the Atherosclerosis Risk in Communities Study

BACKGROUND

Older adults have the highest rates of head injury and are at the greatest risk for subsequent dysfunction, yet research on subsequent physical decline is limited. We sought to examine cross-sectional and prospective associations of head injury with physical functioning and frailty among older adults.

METHODS

A total of 5 598 Atherosclerosis Risk in Communities Study participants from Visit 5 (2011-13) underwent assessments of physical functioning (Short Physical Performance Battery [SPPB], comprised of gait speed, chair stands, and balance) and frailty (defined using established criteria) were followed through Visit 7 (2018-19). Head injury was self-reported or based on ICD-9 codes. Adjusted linear and multinomial logistic regression models were used to estimate associations. Prospective models incorporated inverse probability of attrition weights to account for death or attrition.

RESULTS

Participants were a mean age of 75 years, 58% were women, 22% were Black, and 27% had a prior head injury. Compared to individuals without head injury, individuals with head injury had worse physical functioning (SPPB total score, β-coefficient = -0.22, 95% CI: -0.35 to -0.09) and were more likely to be pre-frail (OR = 1.19, 95% CI: 1.04 to 1.35) or frail (OR = 1.40, 95% CI: 1.08 to 1.80) compared to robust. Prospectively, head injury was associated with a 0.02 m/s greater decline (95% CI: -0.04 to -0.01) in gait speed over a median of 5 years. Among baseline robust individuals (n = 1 847), head injury was associated with increased odds of becoming pre-frail (OR = 1.32, 95% CI: 1.04 to 1.67) or frail (OR = 1.92, 95% CI: 1.05 to 3.51) compared to robust.

CONCLUSIONS

Older adults with prior head injury had worse physical functioning and greater frailty at baseline and were more likely to become frail and walk slower over time, compared to individuals without head injury.

Does prior concussion lead to biomechanical alterations associated with lateral ankle sprain and anterior cruciate ligament injury? A systematic review and meta-analysis

OBJECTIVE

To determine whether individuals with a prior concussion exhibit biomechanical alterations in balance, gait and jump-landing tasks with and without cognitive demands that are associated with risk of lateral ankle sprain (LAS) and anterior cruciate ligament (ACL) injury.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Five electronic databases (Web of Science, Scopus, PubMed, SPORTDiscus and CiNAHL) were searched in April 2023.

ELIGIBILITY CRITERIA

Included studies involved (1) concussed participants, (2) outcome measures of spatiotemporal, kinematic or kinetic data and (3) a comparison or the data necessary to compare biomechanical variables between individuals with and without concussion history or before and after a concussion.

RESULTS

Twenty-seven studies were included involving 1544 participants (concussion group (n=757); non-concussion group (n=787)). Individuals with a recent concussion history (within 2 months) had decreased postural stability (g=0.34, 95% CI 0.20 to 0.49, p<0.001) and slower locomotion-related performance (g=0.26, 95% CI 0.11 to 0.41, p<0.001), both of which are associated with LAS injury risk. Furthermore, alterations in frontal plane kinetics (g=0.41, 95% CI 0.03 to 0.79, p=0.033) and sagittal plane kinematics (g=0.30, 95% CI 0.11 to 0.50, p=0.002) were observed in individuals approximately 2 years following concussion, both of which are associated with ACL injury risk. The moderator analyses indicated cognitive demands (ie, working memory, inhibitory control tasks) affected frontal plane kinematics (p=0.009), but not sagittal plane kinematics and locomotion-related performance, between the concussion and non-concussion groups.

CONCLUSION

Following a recent concussion, individuals display decreased postural stability and slower locomotion-related performance, both of which are associated with LAS injury risk. Moreover, individuals within 2 years following a concussion also adopt a more erect landing posture with greater knee internal adduction moment, both of which are associated with ACL injury risk. While adding cognitive demands to jump-landing tasks affected frontal plane kinematics during landing, the altered movement patterns in locomotion and sagittal plane kinematics postconcussion persisted regardless of additional cognitive demands.

PROSPERO REGISTRATION NUMBER

CRD42021248916.

Ankle Sprain History Does Not Significantly Alter Single- and Dual-Task Spatiotemporal Gait Mechanics

CONTEXT

Single- and dual-task walking gait assessments have been used to identify persistent movement and cognitive dysfunction among athletes with concussions. However, it is unclear whether previous ankle sprain injuries confound these outcomes during baseline testing. The purpose of this study was to determine the effects of (1) ankle sprain history and (2) time since prior ankle sprain injury on single- and dual-task spatiotemporal gait outcomes and cognitive measures.

DESIGN

Cross-sectional study.

METHODS

We assessed 60 college Division-I athletes (31 with ankle sprain history; 13 females and 18 males, 19.3 [0.8] y; 29 with no ankle sprain history, 14 females and 15 males, 19.7 [0.9] y) who completed injury history forms and underwent concussion baseline testing. Athletes completed single- and dual-task gait assessments by walking back and forth along an 8-m walkway for 40 seconds. Athletes wore a smartphone with an associated mobile application on their lumbar spine to record spatiotemporal gait parameters and dual-task cognitive performance. Separate multivariate analyses of variance were used to assess the effects of ankle sprain injury history on spatiotemporal measures, gait variability, and cognitive performance. We performed a multivariate regression subanalysis on athletes who reported time since injury (n = 23) to assess temporal effects on gait and cognitive performance.

RESULTS

Athletes with and without a history of ankle sprains had comparable spatiotemporal and gait variability outcomes during single- (P = .42; P = .13) and dual-task (P = .75; P = .55) conditions. Additionally, ankle sprain injury history did not significantly influence cognitive performance (P = .35). Finally, time since ankle sprain did not significantly affect single- (P = .75) and dual-task gait (P = .69), nor cognitive performance (P = .19).

CONCLUSIONS

Ankle sprain injury history did not significantly alter spatiotemporal gait outcomes nor cognitive performance during this common clinical assessment. Future studies may consider including athletes with ankle sprain injury history during concussion assessments.

A Hybrid Assessment of Clinical Mobility Test Items for Evaluating Individuals With Mild Traumatic Brain Injury

BACKGROUND AND PURPOSE

The Functional Gait Assessment (FGA) and High Level Mobility Assessment Tool (HiMAT) are clinical batteries used to assess people with mild traumatic brain injury (mTBI). However, neither assessment was specifically developed for people with mTBI; the FGA was developed to evaluate vestibular deficits, and the HiMAT was developed for individuals with more severe TBI. To maximize the sensitivity and reduce the time burden of these assessments, the purpose of this study was to determine the combination of FGA and HiMAT items that best discriminates persons with persistent symptoms from mTBI from healthy controls.

METHODS

Fifty-three symptomatic civilians with persistent symptoms from mTBI (21% male, aged 31 (9.5) years, 328 [267] days since concussion) and 57 healthy adults (28% male, aged 32 (9.6) years) participated across 3 sites. The FGA and HiMAT were evaluated sequentially as part of a larger study. To determine the best combination of items, a lasso-based generalized linear model (glm) was fit to all data.

RESULTS

The area under the curve (AUC) for FGA and HiMAT total scores was 0.68 and 0.66, respectively. Lasso regression selected 4 items, including FGA Gait with Horizontal Head Turns and with Pivot Turn, and HiMAT Fast Forward and Backward Walk, and yielded an AUC (95% confidence interval) of 0.71 (0.61-0.79) using standard scoring.

DISCUSSION AND CONCLUSIONS

The results provide initial evidence supporting a reduced, 4-Item Hybrid Assessment of Mobility for mTBI (HAM-4-mTBI) for monitoring individuals with mTBI. Future work should validate the HAM-4-mTBI and investigate its utility for tracking progression throughout rehabilitation.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A409 ).

The Toronto Concussion Study: Reference Data for Balance and Gait Measures in Community-Dwelling Adults With Concussion

OBJECTIVE

Concussion can cause deficits in balance and gait. Much of what is known about how concussion affects balance and gait has been derived from studies involving youth, high school, and university athletes. However, investigation into the effects of concussion on balance and gait in community-dwelling young, middle-age, and older aged adults is limited. This study aimed to present descriptive reference values for common balance and gait measures in community-dwelling adults between the ages of 20 and 69 years with concussion.

METHODS

In this observational study, 318 participants were enrolled from a concussion care clinic at a rehabilitation hospital in an urban center and were assessed within 7 days of injury. Balance measures included the Balance Error Scoring System (BESS), modified BESS, and center-of-pressure root mean square during quiet standing. Gait measures included velocity (absolute and height adjusted), cadence, and step length during self-paced gait. Data were binned by decade-long age range.

RESULTS

Mean (SD) per-decade scores for the BESS ranged from 14.8 (5.1) to 21.8 (5.6) errors and 4.0 (3.0) to 9.4 (4.6) errors for the modified BESS. Mean values for center-of-pressure root mean square in the anteroposterior direction ranged from 0.42 (0.18) to 0.52 (0.26) with the eyes open, and from 0.49 (0.19) to 0.62 (0.39) with eyes closed. Mean absolute gait velocity ranged from 98.5 (9.1) to 119.3 (21.3) cm/s. The range of step length values was 58.2 (6.8) to 66.3 (7.3) cm and cadence ranged from 102.1 (9.8) to 108.6 (10.8) steps/min across age groups.

CONCLUSION

These data provide insight into the impact of concussion on balance and mobility in community-dwelling adults across the lifespan.

IMPACT

Community-dwelling adults can experience concussion across the lifespan. Availability of reference values for commonly used balance and gait measures can help to inform clinical strategies and progression of recovery of balance and mobility after injury.

Dizziness, Psychosocial Function, and Postural Stability Following Sport-Related Concussion

OBJECTIVE

To examine if self-reported dizziness is associated with concussion symptoms, depression and/or anxiety symptoms, or gait performance within 2 weeks of postconcussion.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PARTICIPANTS

Participants were diagnosed with a concussion within 14 days of initial testing (N = 40). Participants were divided into 2 groups based on their Dizziness Handicap Inventory (DHI) score: 36 to 100 = moderate/severe dizziness and 0 to 35 = mild/no dizziness.

INTERVENTIONS

Participants were tested on a single occasion and completed the DHI, hospital anxiety and depression scale (HADS), Patient Health Questionnaire-9 (PHQ-9), and Post-Concussion Symptom Inventory (PCSI). Three different postural control tests were use: modified Balance Error Scoring System, single-/dual-task tandem gait, and a single-/dual-task instrumented steady-state gait analysis.

MAIN OUTCOME MEASURES

Comparison of patient-reported outcomes and postural control outcomes between moderate/severe (DHI ≥ 36) and mild/no (DHI < 36) dizziness groups.

RESULTS

Participants with moderate/severe dizziness (n = 19; age = 17.1 ± 2.4 years; 63% female) reported significantly higher symptom burden (PSCI: 43.0 ± 20.6 vs 22.8 ± 15.7; P = 0.001) and had higher median HADS anxiety (6 vs 2; P < 0.001) and depression (6 vs 1; P = 0.001) symptom severity than those with no/minimal dizziness (n = 21; age = 16.5 ± 1.9; 38% female). During steady-state gait, moderate/severe dizziness group walked with significantly slower single-task cadence (mean difference = 4.8 steps/minute; 95% confidence interval = 0.8, 8.8; P = 0.02) and dual-task cadence (mean difference = 7.4 steps/minute; 95% confidence interval = 0.7, 14.0; P = 0.04) than no/mild dizziness group.

CONCLUSION

Participants who reported moderate/severe dizziness reported higher concussion symptom burden, higher anxiety scores, and higher depression scores than those with no/mild dizziness. Cadence during gait was also associated with the level of dizziness reported.

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.

Dual-Task Gait Performance Following Head Impact Exposure in Male and Female Collegiate Rugby Players

Background

Gait impairments have been well-studied in concussed athletes. However, the sex-specific effect of cumulative head impacts on gait is not well understood. When a cognitive task is added to a walking task, dual-task gait assessments can help amplify deficits in gait and are representative of tasks in everyday life. Dual-task cost is the difference in performance from walking (single-task) to walking with a cognitive load (dual-task).

Purpose

The objectives of this study were to explore the differences between sexes in 1) dual-task gait metrics, 2) gait metric changes from pre-season to post-concussion and post-season, and 3) the dual-task costs associated with gait metrics.

Study Design

Cross-sectional study.

Methods

Over two seasons, 77 female athlete-seasons and 64 male athlete-seasons from collegiate club rugby teams participated in this study. Subjects wore inertial sensors and completed walking trials with and without a cognitive test at pre-season, post-season, and post-concussion (if applicable).

Results

Females athletes showed improvement in cadence (mean = 2.7 step/min increase), double support time (mean = -0.8% gait cycle time decrease), gait speed (mean = 0.1 m/s increase), and stride length (mean = 0.2 m increase) in both task conditions over the course of the season (p < 0.030). Male athletes showed no differences in gait metrics over the course of the season, except for faster gait speeds and longer stride lengths in the dual-task condition (p < 0.034). In all four gait characteristics, at baseline and post-season, females had higher dual-task costs (mean difference = 4.4, p < 0.003) than the males.

Conclusions

This results of this study showed little evidence suggesting a relationship between repetitive head impact exposure and gait deficits. However, there are sex-specific differences that should be considered during the diagnosis and management of sports-related concussion.

Level of Evidence

Level 2b.

Saccade and Fixation Eye Movements During Walking in People With Mild Traumatic Brain Injury

Background: Clinical and laboratory assessment of people with mild traumatic brain injury (mTBI) indicate impairments in eye movements. These tests are typically done in a static, seated position. Recently, the use of mobile eye-tracking systems has been proposed to quantify subtle deficits in eye movements and visual sampling during different tasks. However, the impact of mTBI on eye movements during functional tasks such as walking remains unknown.

Objective: Evaluate differences in eye-tracking measures collected during gait between healthy controls (HC) and patients in the sub-acute stages of mTBI recovery and to determine if there are associations between eye-tracking measures and gait speed.

Methods: Thirty-seven HC participants and 67individuals with mTBI were instructed to walk back and forth over 10-m, at a comfortable self-selected speed. A single 1-min trial was performed. Eye-tracking measures were recorded using a mobile eye-tracking system (head-mounted infra-red Tobbii Pro Glasses 2, 100 Hz, Tobii Technology Inc. VA, United States). Eye-tracking measures included saccadic (frequency, mean and peak velocity, duration and distance) and fixation measurements (frequency and duration). Gait was assessed using six inertial sensors (both feet, sternum, right wrist, lumbar vertebrae and the forehead) and gait velocity was selected as the primary outcome. General linear model was used to compare the groups and association between gait and eye-tracking outcomes were explored using partial correlations.

Results: Individuals with mTBI showed significantly reduced saccade frequency (p = 0.016), duration (p = 0.028) and peak velocity (p = 0.032) compared to the HC group. No significant differences between groups were observed for the saccade distance, fixation measures and gait velocity (p > 0.05). A positive correlation was observed between saccade duration and gait velocity only for participants with mTBI (p = 0.025).

Conclusion: Findings suggest impaired saccadic eye movement, but not fixations, during walking in individuals with mTBI. These findings have implications in real-world function including return to sport for athletes and return to duty for military service members. Future research should investigate whether or not saccade outcomes are influenced by the time after the trauma and rehabilitation.

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.

Associations Between Neurochemistry and Gait Performance Following Concussion in Collegiate Athletes

OBJECTIVE

To evaluate the strength of associations between single-task and dual-task gait measures and posterior cingulate gyrus (PCG) neurochemicals in acutely concussed collegiate athletes.

SETTING

Participants were recruited from an NCAA Division 1 University.

PARTICIPANTS

Nineteen collegiate athletes acutely (<4 days) following sports-related concussion.

DESIGN

We acquired magnetic resonance spectroscopy (MRS) in the PCG and gait performance measurements in the participants, acutely following concussion. Linear mixed-effects models were constructed to measure the effect of gait performance, in the single- and dual-task settings, and sex on the 6 neurochemicals quantified with MRS in mmol. Correlation coefficients were also calculated to determine the direction and strength of the relationship between MRS neurochemicals and gait performance, postconcussion symptom score, and number of previous concussions.

MAIN MEASURES

Average gait speed, average cadence, N-acetyl aspartate, choline, myo-inositol, glutathione, glutamate plus glutamine, and creatine.

RESULTS

Single-task gait speed (P = .0056) and cadence (P = .0065) had significant effects on myo-inositol concentrations in the PCG, independent of sex, in concussed collegiate athletes. Single-task cadence (P = .047) also had a significant effect on glutathione in the PCG. No significant effects were observed between dual-task gait performance and PCG neurochemistry.

CONCLUSIONS

These findings indicate that increased concentrations of neuroinflammatory markers in the PCG are associated with slower single-task gait performance within 4 days of sports-related concussion.

Age of First Exposure to Collision Sports Does Not Affect Patient Reported Outcomes in Women and Men Community Rugby Players

PURPOSE

This study aimed to determine the relationship between age of first exposure (AFE) to repetitive head impacts through contact/collision sports and patient-reported outcomes in community rugby players.

METHODS

We recruited community rugby players older than 18 yr with at least 1 yr of contact rugby participation to complete an online survey. Participants completed the Brief Symptom Inventory-18 (BSI-18), Short-Form Health Survey 12 (SF-12), and Satisfaction with Life Scale (SWLS) via Qualtrics. We used generalized linear models to examine the association between AFE (continuous) and patient-reported outcomes by sex, while controlling for cumulative years contact/collision sport history, age, and concussion history (yes/no). In addition, we used Mann-Whitney U tests to compare patient-reported outcomes between AFE <12 and AFE ≥12.

RESULTS

A total of 1037 rugby players (31.6 ± 11.3 yr (range, 18-74 yr), 59.1% men) participated in this study. Whether analyzed continuously or dichotomously at age 12 yr, younger AFE was not associated with worse patient-reported outcomes for either men or women. Positive concussion history was a significant predictor of worse BSI-18 subscores, SF-12 subscores, and SWLS in women and worse BSI-18 subscores in men. Cumulative contact/collision sport history was a significant predictor of better BSI-18 Depression and SF-12 (Mental Component Summary) subscores in men only. In men and women, older age was a significant predictor of better BSI-18 Depression, Anxiety, and GSI subscores; better SWLS (in men only); and better SF-12 Mental Component Summary, but worse SF-12 (Physical Component Summary).

CONCLUSIONS

Younger AFE to contact/collision sport is not associated with worse patient-reported outcomes in early adult rugby players. Concussion history was predictive of worse patient-reported outcomes.

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.

MOVEMENT PATTERNS DIFFER BETWEEN ATHLETES AFTER SPORT-RELATED CONCUSSION COMPARED TO HEALTHY CONTROLS DURING JUMP LANDING TASK

CONTEXT

A relationship between a positive history of sport-related concussion (SRC) and lower extremity (LE) injury has been well established in the literature.

OBJECTIVE

The purpose of this study was to determine if biomechanical differences exist during a double limb jump landing (DLJ) between athletes who had been released for return to play after SRC and healthy matched controls (Healthy).

DESIGN

Cross-Sectional Study Setting: Health system-based Outpatient Sports Medicine Center Participants: 21 participants (16.33±12.7 days out from being released to return to sport after SRC) (age: 15.38±1.77; height: 169.23±8.59; mass: 63.43±7.39) were compared to 21 age, sex, activity-matched healthy controls (age: 15.36±1.73; height: 169.92±11.1; mass: 65.62±12.08). No significant differences existed between groups for descriptive data.

MAIN OUTCOME MEASURE(S)

Biomechanical performance during DLJ was assessed using Motion Capture System and force plates. The average of five consecutive trials was used to calculate lower extremity joint kinetic and kinematics. Variables of interest included internal knee extension moment, internal varus moment, and total sagittal plane knee displacement for both the dominant and non-dominant limbs. Independent t-tests were performed to examine the differences between SRC and Healthy groups for variables of interest.

RESULTS

The SRC group demonstrated greater internal knee extension moments on their dominant (KEDomDiff=-.028±.009; p=.003) and non-dominant (KENonDomDiff=-.018±.007, p=.019) limbs. The SRC group also demonstrated greater internal varus moments on their dominant (VDomDiff=.012±.004, p=.005) and non-dominant (VNonDomDiff=.010±.003, p=.005) limbs. For sagittal plane knee displacement, the SRC group demonstrated less knee flexion displacement on their dominant (DispDomDiff=-12.56±4.67, p=.011) but not their non-dominant limb (DispNonDomDiff=-8.30±4.91, p=.099).

CONCLUSIONS

Athletes who have been released for return to sport after SRC land in greater knee valgus compared to healthy matched controls.

Gait Assessment in College Athletes: Do Concussion History, Symptoms, Gender, and Type of Sport Matter?

CONTEXT

Though previous research has focused on examining the effects of concussion history using a dual-task paradigm, the influence of factors like symptoms (unrelated to concussion), gender, and type of sport on gait in college athletes is unknown.

OBJECTIVE

To examine the effect of concussion history, symptoms, gender, and type of sport (noncontact/limited contact/contact) individually on gait among college athletes.

DESIGN

Exploratory cross-sectional study.

SETTING

Laboratory.

PARTICIPANTS

In total, 98 varsity athletes (age, 18.3 [1.0] y; height, 1.79 [0.11] m; mass, 77.5 [19.2] kg; 27 with concussion history, 58 reported at least one symptom, 44 females; 8 played noncontact sports and 71 played contact sports) walked under single- and dual-task (walking while counting backward by 7) conditions.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Dual-task cost (DTC; % difference between single task and dual task) of gait speed, cadence, step length and width, percentage of swing and double-support phases, symptom score, and total symptom severity score. Independent samples t tests and 1-way analysis of variance were conducted (α value = .05).

RESULTS

Self-reported concussion history resulted in no significant differences (P > .05). Those who reported symptoms at testing time showed significantly greater DTC of step length (mean difference [MD], 2.7%; 95% confidence interval [CI], 0.3% to 5.1%; P = .012), % of swing phase (MD, 1.0%; 95% CI, -0.2 to 2.1%; P = .042), and % of double-support phase (MD, 3.9%; 95% CI, 0.2% to 7.8%; P = .019). Females demonstrated significantly higher DTC of gait speed (MD, 5.3%; 95% CI, 1.3% to 9.3%; P = .005), cadence (MD, 4.0%; 95% CI, 1.4% to 6.5%; P = .002), % of swing phase (MD, 1.2%; 95% CI, 0.1% to 2.3%; P = .019), and % of double-support phase (MD, 4.1%; 95% CI, 0.4% to 7.9%; P = .018). Noncontact sports athletes had significantly greater step width DTC than contact sports athletes (MD, 14.2%; 95% CI, 0.9% to 27.6%; P = .032).

CONCLUSIONS

Reporting symptoms at testing time may influence gait under dual-task conditions. Additionally, female athletes showed more gait changes during a dual task. Sports medicine professionals should be aware that these variables, while unrelated to injury, may affect an athlete's gait upon analysis.

Centre of pressure velocity shows impairments in NCAA Division I athletes six months post-concussion during standing balance

Sport-related concussion return to play (RTP) decisions are largely based on the resolution of self-reported symptoms and neurocognitive function. Some evaluators also incorporate balance; however, an objective approach to balance that can detect effects beyond the acute condition is warranted. The purpose of this study is to examine linear measures of biomechanical balance up to 6 months post-concussion, and to present preliminary diagnostic thresholds useful for RTP. Each concussed athlete participated in instrumented standing balance tasks at 4 timepoints post-concussion. The measures from concussed athletes were compared to the sport-matched non-concussed athlete group at each timepoint. Centre of pressure (COP) mediolateral (ML) velocity in double-leg stance on a hard surface discriminated well between non-concussed and concussed athletes. COP anterior-posterior (AP) velocity in tandem stance on foam showed sensitivity to concussion. Sixty per cent of athletes at 6 months post-concussion did not recover to within the proposed COP ML velocity threshold in double-leg stance on a hard surface. Seventy-one per cent of athletes at 6 months post-concussion did not recover to within the COP AP velocity threshold in tandem stance on foam. This lack of recovery potentially indicates vestibular and motor control impairments long past the typical period of RTP.

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.

Reliability of Objective Eye-Tracking Measures Among Healthy Adolescent Athletes

OBJECTIVE

To determine the test-retest correlation of an objective eye-tracking device among uninjured youth athletes.

DESIGN

Repeated-measures study.

SETTING

Sports-medicine clinic.

PARTICIPANTS

Healthy youth athletes (mean age = 14.6 ± 2.2 years; 39% women) completed a brief, automated, and objective eye-tracking assessment.

INDEPENDENT VARIABLES

Participants completed the eye-tracking assessment at 2 different testing sessions.

MAIN OUTCOME MEASURES

During the assessment, participants watched a 220-second video clip while it moved around a computer monitor in a clockwise direction as an eye tracker recorded eye movements. We obtained 13 eye movement outcome variables and assessed correlations between the assessments made at the 2 time points using Spearman's Rho (rs).

RESULTS

Thirty-one participants completed the eye-tracking evaluation at 2 time points [median = 7 (interquartile range = 6-9) days between tests]. No significant differences in outcomes were found between the 2 testing times. Several eye movement variables demonstrated moderate to moderately high test-retest reliability. Combined eye conjugacy metric (BOX score, rs = 0.529, P = 0.008), the variance of the ratio for both eye movements in the horizontal (rs = 0.497, P = 0.013) and vertical (rs = 0.446; P = 0.029) movement planes along the top/bottom of the computer screen, and the variance of the left and right eye movement along the bottom segment of the computer screen (rs = 0.565; P = 0.004) each demonstrated moderate between-test correlations.

CONCLUSIONS

Automated and quantitative eye movement and conjugacy metrics provide relatively stable measurements among a group of healthy youth athletes. Thus, their inclusion as a visual tracking metric may be complementary to other visual examination techniques when monitoring concussion recovery across time.

Gait Performance in People with Symptomatic, Chronic Mild Traumatic Brain Injury

There is a dearth of knowledge about how symptom severity affects gait in the chronic (>3 months) mild traumatic brain injury (mTBI) population despite up to 53% of people reporting persisting symptoms after mTBI. The aim of this investigation was to determine whether gait is affected in a symptomatic, chronic mTBI group and to assess the relationship between gait performance and symptom severity on the Neurobehavioral Symptom Inventory (NSI). Gait was assessed under single- and dual-task conditions using five inertial sensors in 57 control subjects and 65 persons with chronic mTBI (1.0 year from mTBI). The single- and dual-task gait domains of Pace, Rhythm, Variability, and Turning were calculated from individual gait characteristics. Dual-task cost (DTC) was calculated for each domain. The mTBI group walked (domain z-score mean difference, single-task = 0.70; dual-task = 0.71) and turned (z-score mean difference, single-task = 0.69; dual-task = 0.70) slower (p < 0.001) under both gait conditions, with less rhythm under dual-task gait (z-score difference = 0.21; p = 0.001). DTC was not different between groups. Higher NSI somatic subscore was related to higher single- and dual-task gait variability as well as slower dual-task pace and turning (p < 0.01). Persons with chronic mTBI and persistent symptoms exhibited altered gait, particularly under dual-task, and worse gait performance related to greater symptom severity. Future gait research in chronic mTBI should assess the possible underlying physiological mechanisms for persistent symptoms and gait deficits.

Youth With Concussion Have Less Adaptable Gait Patterns Than Their Uninjured Peers: Implications for Concussion Management

OBJECTIVE

To compare cross-recurrence quantification analysis measurements obtained during gait between adolescents who sustained a diagnosed concussion within 14 days of assessment and healthy adolescents.

DESIGN

Cross-sectional study.

METHODS

Youth athletes with concussion (n = 43; mean ± SD age, 14.4 ± 2.3 years; 56% female; tested median, 7 days post concussion) and healthy controls (n = 38; age, 14.9 ± 2.0 years; 55% female) completed a single-task and dual-task gait protocol while wearing a set of inertial sensors. We used cross-recurrence quantification analysis techniques to quantify the similarity between accelerations obtained from the sensor on the dorsum of each foot. Four outcome variables were compared between groups: percent determinism, average diagonal-line length, laminarity, and trapping time.

RESULTS

Athletes with concussion had significantly higher percent determinism, laminarity, and trapping time than the control group in single-task and dual-task conditions (P<.05). Gait patterns, when simultaneously completing a secondary cognitive task (dual task), were no different from gait patterns under a single-task condition.

CONCLUSION

Higher percent determinism, laminarity, and trapping time among athletes with concussion suggest that concussion may be associated with a more stuck and predictable gait pattern. These altered movement patterns may be one reason for underlying slower gait speeds that have been observed following concussion. J Orthop Sports Phys Ther 2020;50(8):438-446. Epub 22 May 2020. doi:10.2519/jospt.2020.9133.

Turn Characteristics During Gait Differ With and Without a Cognitive Demand Among College Athletes

CONTEXT

Sports often involve complex movement patterns, such as turning. Although cognitive load effects on gait patterns are well known, little is known on how it affects biomechanics of turning gait among athletes. Such information could help evaluate how concussion affects turning gait required for daily living and sports.

OBJECTIVE

To determine the effect of a dual task on biomechanics of turning while walking among college athletes.

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

Fifty-three participants performed 5 trials of a 20-m walk under single- and dual-task conditions at self-selected speed with a 180° turn at 10-m mark. The cognitive load included subtraction, spelling words backward, or reciting the months backward.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Turn duration, turning velocity, number of steps, SD of turn duration and velocity, and coefficient of variation of turn duration and velocity.

RESULTS

Participants turned significantly slower (155.99 [3.71] cm/s vs 183.52 [4.17] cm/s; P < .001) and took longer time to complete the turn (2.63 [0.05] s vs 2.33 [0.04] s; P < .001) while dual tasking, albeit taking similar number of steps to complete the turn. Participants also showed more variability in turning time under the dual-task condition (SD of turn duration = 0.39 vs 0.31 s; P = .004).

CONCLUSIONS

Overall, college athletes turned slower and showed more variability during turning gait while performing a concurrent cognitive dual-task turning compared with single-task turning. The slower velocity increased variability may be representative of specific strategy of turning gait while dual tasking, which may be a result of the split attention to perform the cognitive task. The current study provides descriptive values of absolute and variability turning gait parameters for sports medicine personnel to use while they perform their concussion assessments on their college athletes.

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.

Comparison of forward and backward gait characteristics between those with and without a history of breast cancer

BACKGROUND

Decreased muscular strength and poorer postural stability impact the physical function of breast cancer survivors (BCS) and increases their risk of falls. Gait assessment, particularly in the backward direction, is often used as an indicator of fall risk in several populations. However this information is unknown in BCS.

RESEARCH QUESTION

What are the differences in forward, backward, and accelerated forward walking in BCS in comparison to individuals without a prior cancer diagnosis?

METHODS

17 postmenopausal BCS (mean age: 58.5 (8.5) years) and 17 age-matched women without a prior cancer diagnosis (mean age: 59.11 (5.55) years) completed 5 trials each of forward, backward, and fast forward walking conditions. Absolute (Means) and variability (Coefficient of variation) estimates were obtained for spatio-temporal gait parameters. Lower body, upper body and handgrip strengths were measured.

RESULTS

For absolute estimates of gait, significant group main effects indicated that BCS had 7% shorter step length (P = 0.019) and 8% slower gait speed (P = 0.048). For variability estimates of gait, there was a significant interaction for stance time (P = 0.035). BCS had greater stance time variability during forward and fast forward conditions, but lesser variability during backward condition. Averaged across all the conditions, BCS had 38% greater step length variability (P = 0.043), 50% greater gait speed variability (P = 0.028), and 28.5% greater single support time variability (P = 0.004). Averaged across both the groups, all the variables except for swing time variability were significantly different among the conditions (all P< = 0.013). BCS also had significantly reduced upper body strength (P = 0.036).

SIGNIFICANCE

Slower and shorter steps while walking both forwards and backwards could be indicative of a more cautious gait strategy by BCS. Also, BCS possibly focused on controlling spatial parameters during forward walking but temporal parameters while backward walking. Whether these alterations are related to an increased fall risk within BCS needs to be determined.

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.

Balance and Gait Alterations Observed More Than 2 Weeks After Concussion: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of the study was to systematically review and quantitatively synthesize the existing evidence of balance and gait alterations lasting more than 2 wks after concussion in adults.

DESIGN

A systematic review was conducted through PubMed, CINAHL, SPORTDiscus, and Web of Science. Investigations must include adult participants with at least one concussion, were measured for 14 days after injury, and reported balance or gait measures. Balance error scoring system scores, center of pressure sway area and displacement, and gait velocity were extracted for the meta-analysis.

RESULTS

Twenty-two studies were included. Balance alterations were observed for 2 wks after concussion when participants were tested with eyes closed, for longer durations of time, and with nonlinear regulatory statistics. The meta-analysis of center of pressure sway area with no visual feedback indicated that concussed individuals had greater sway area (P < 0.001). Various gait alterations were also observed, which may indicate that concussed individuals adopt a conservative gait strategy. The meta-analysis revealed that concussed participants walked 0.12 m/sec (P < 0.001) and 0.06 m/sec (P = 0.023) slower in single and dual-task conditions, respectively.

CONCLUSIONS

Subtle balance and gait alterations were observed after 2 wks after a concussion. Understanding these alterations may allow clinicians to improve concussion diagnosis and prevent subsequent injury.

Balance control in youth hockey players with and without a history of concussions during a lower limb reaching task

BACKGROUND

Sport-related concussion (SRC) is a functional injury that affects several clinical domains, including balance and cognition. The purpose of this study was, 1) to determine whether a lower limb visuomotor task could identify balance control differences between youth athletes with and without previous SRC; and 2) if balance is affected by training over time.

METHODS

Youth hockey players (n = 34) who reported previous SRC (CONCUSSED; n = 12; mean age = 14.4 yrs., SD = 1.6, mean time from injury = 1.9 yrs., median = 1.7 yrs. [0.6-4.6]) and no history of SRC (CONTROL; n = 22; mean age = 14.7, SD = 1.5) were tested twice over 70 days. Participants stood in single support on a Nintendo Wii Balance board sampled at 100 Hz and performed Go/No-Go tasks with each foot. Five FitLight Trainer™ (Aurora, ON) lights were arranged on the floor at 60°, 30°, and 0° and illuminated in random GREEN (Go) or RED (No-Go). Balance was assessed using root mean square displacement and velocity of CoP in anterior-posterior and medial-lateral directions.

FINDINGS

CONCUSSED had significantly lower velocity of CoP in the anterior-posterior (F_{(1, 32)} = 13.81, p < .001) and medial-lateral (F_{(1, 32)} = 13.80, p < .001) directions than CONTROL, with no learning effects over time (anterior-posterior: F_{(1, 32)} = 0.30, p = .137: F_{(1, 32)} = 0.91, p = .346; medial-lateral: F_{(1, 32)} = 0.91, p = .346). These findings suggest that CONCUSSED consistently performed the task more conservatively.

INTERPRETATION

A lower limb Go/No-Go task may objectively identify differences between youth athletes with and without previous SRC. These visuomotor and balance control deficits may persist beyond clinical recovery.

Longitudinal Assessment of Balance and Gait After Concussion and Return to Play in Collegiate Athletes

CONTEXT

In longitudinal studies tracking recovery after concussion, researchers often have not considered the timing of return to play (RTP) as a factor in their designs, which can limit the understanding of how RTP may affect the analysis and resulting conclusions.

OBJECTIVE

To evaluate the recovery of balance and gait in concussed athletes using a novel linear mixed-model design that allows an inflection point to account for changes in trend that may occur after RTP.

DESIGN

Cohort study.

SETTING

University athletics departments, applied field setting.

PATIENTS OR OTHER PARTICIPANTS

Twenty-three concussed (5 women, 18 men; age = 20.1 ± 1.3 years) and 25 healthy control (6 women, 19 men; age = 20.9 ± 1.4 years) participants were studied. Participants were referred by their team athletic trainers.

MAIN OUTCOME MEASURE(S)

Measures consisted of the Balance Error Scoring System (BESS) total score, sway (instrumented root mean square of mediolateral sway), single-task gait speed, gait speed while simultaneously reading a handheld article (dual-task gait speed), dual-task cost of reading on gait speed, and dual-task cost of walking on reading.

RESULTS

We observed no significant effects or interactions for the BESS. Instrumented sway was worse in concussed participants, and a change in the recovery trend occurred after RTP. We observed group and time effects and group × time and group × RTP change interactions (P ≤ .046). No initial between-groups differences were found for single-task or dual-task gait. Both groups increased gait speed initially and then leveled off after the average RTP date. We noted time and RTP change effects and positive group × time interactions for both conditions (P ≤ .042) and a group × RTP change interaction for single-task gait speed (P = .005). No significant effects or interactions were present for the dual-task cost of reading on gait speed or the dual-task cost of walking on reading.

CONCLUSIONS

Changes in the rate of recovery were coincident with the timing of RTP. Although we cannot suggest these changes were a result of the athletes returning to play, these findings demonstrate the need for further research to evaluate the effects of RTP on concussion recovery.

Concussion and National Hockey League Player Performance: An Advanced Hockey Metrics Analysis

CONTEXT

Postconcussion deficits in neurocognitive performance and postural control may persist at the time of return to sport participation. How these deficits, if present, affect athletic performance is largely unknown, with prior studies showing mixed results.

OBJECTIVE

To evaluate postconcussion National Hockey League player performance using advanced hockey metrics over short- (5 games), medium- (10 games), and long-term (remainder of the season) seasonal performance.

DESIGN

Retrospective cohort study.

PATIENTS OR OTHER PARTICIPANTS

National Hockey League players who sustained a sport-related concussion (SRC; n = 93) and returned during the same season and players (n = 51) who missed time for non-injury-related reasons.

MAIN OUTCOME MEASURE(S)

Six performance metrics were used: (1) points per 60 minutes, (2) Corsi percentage, (3) personal Fenwick shooting percentage, (4) scoring chances per 60 minutes, (5) penalty difference, and (6) PDO (not an acronym but sometimes referred to as SVSP% [save percentage shooting percentage]). Performance was compared using 2 (group) × 2 (time) repeated-measures analyses of variance for 3 time windows: (1) ±5 games, (2) ±10 games, and (3) the remainder of the season postconcussion. Alpha values were set at a conservative .01 to account for the lack of independence among dependent variables.

RESULTS

No significant interactions were present for any of the 6 dependent variables at any of the 3 time windows. Overall, none of the secondary variables differed.

CONCLUSIONS

Using advanced, sport-specific metrics, we found that National Hockey League players did not display worse seasonal performance during 3 postinjury time frames after they sustained an SRC. Whereas laboratory studies have identified lingering neurologic deficits after concussion, our results suggest that these deficits, if present, either do not translate to worse athletic performance or were not captured by these 44 metrics. Further, prospective efforts are needed to accurately quantify performance after SRC among professional hockey players.

Concussions in Sports

Although concussions are common, they are complex, variable, and not entirely understood in terms of pathophysiology and treatment. The incidence of concussion is expected to continue to rise with the increased participation of youth in sports and improved awareness. The role of orthopedic surgeons in concussion management is murky. However, the existing literature does provide a foundation from which orthopedic surgeons who are exposed to concussed patients can function. [Orthopedics. 2019; 42(1):12-21.].

Alterations in dual-task walking persist two months after mild traumatic brain injury in young adults

Objectives

To compare dual-task performance involving different cognitive-locomotor combinations between healthy controls and participants with sub-acute mild traumatic brain injury (mTBI) and to correlate dual-task performances to history of prior head injuries.

Methods

Eighteen participants having recently sustained mTBI and 15 controls performed nine dual-tasks combining locomotor (level-walking, narrow obstacle, deep obstacle) and cognitive (Stroop task, Verbal fluency, Counting backwards) tasks. Previous history of concussion was also investigated.

Results

Slower gait speeds were observed in the mTBI group compared to controls during both single and dual-tasks. Longer response times to cognitive tasks in the mTBI group further suggested the presence of residual impairments two months following injury. No combination of dual-task was more sensitive. Correlations were observed between history of mTBI and several measures of dual-task performance, underlying the need to further consider the effects of multiple injuries in relation to dual-task walking.

Conclusion

Dual-tasks using simultaneously locomotor and cognitive functions represent an ecological way for clinicians to detect residual, but subtle, alterations post-mTBI. History of previous mTBI needs to be considered as a personal characteristic which may influence dual-task walking performance.

Examining Motor Tasks of Differing Complexity After Concussion in Adolescents

OBJECTIVES

(1) To determine the effects of concussion-related motor impairments at different task complexities in isolation and with a cognitive dual-task and (2) to determine if self-reported balance deficits after concussion are associated with gait, quiet stance, or cognitive dual-task impairments.

DESIGN

Cross-sectional study.

SETTING

Sports medicine clinic.

PARTICIPANTS

Adolescent athletes clinically diagnosed with a sport-related concussion and those without concussion. Forty-nine patients with concussion (mean age=14.9±1.9y; 51% female; tested 7.0±3.0d postinjury) and 65 control participants (mean age=14.9±1.6y; 52% female) completed the study (N=114).

INTERVENTIONS

Athletes with concussion completed a single-task and dual-task standing and walking protocol within 14 days of injury and were compared to those without concussion.

MAIN OUTCOME MEASURES

Outcome measures included gait speed, quiet stance (root mean square [RMS] coronal/sagittal plane sway), and cognitive performance (accuracy). Dual-task costs were calculated as the percentage change between single-task and dual-task conditions. Participants with concussion were then stratified by those who did and did not report subjective balance problems at the time of testing and compared using objective balance and gait metrics.

RESULTS

The concussion group walked slower during dual-task gait than controls (0.83±0.17 m/s vs 0.92±0.15 m/s; Cohen's d=0.53). Dual-task quiet stance RMS sway values were similar for concussion and control groups in coronal (1.20±0.52 m/s^-2 vs 1.26±0.65 m/s^-2; d=0.09) and sagittal (0.56±0.24 m/s^-2 vs 0.73±0.44 m/s^-2; d=0.20) movement planes. The concussion participants with subjectively-reported balance problems had significantly greater walking speed dual-task costs than concussion participants without self-reported balance problems (-25±10% vs -19±9%; P=.02).

CONCLUSIONS

Following concussion, adolescents demonstrate slower gait speeds, but similar quiet stance values relative to those without concussion. The study results indicate that tasks requiring greater motor coordination may elicit greater alterations following a concussion.

Influences of Mental Illness, Current Psychological State, and Concussion History on Baseline Concussion Assessment Performance

BACKGROUND

A student-athlete's mental state, including history of trait anxiety and depression, or current psychological state may affect baseline concussion assessment performance.

PURPOSE

(1) To determine if mental illness (anxiety, depression, anxiety with depression) influences baseline scores, (2) to determine if psychological state correlates with baseline performance, and (3) to determine if history of concussion affects Brief Symptom Inventory-18 (BSI-18) subscores of state anxiety, depression, and somatization.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A sample of 8652 collegiate student-athletes (54.5% males, 45.5% females) participated in the Concussion Assessment, Research and Education (CARE) Consortium. Baseline assessments included a demographic form, a symptom evaluation, Standardized Assessment of Concussion, Balance Error Scoring System, a psychological state assessment (BSI-18), and Immediate Post-concussion Assessment and Cognitive Test. Baseline scores were compared between individuals with a history of anxiety (n = 59), depression (n = 283), and anxiety with depression (n = 68) and individuals without a history of those conditions (n = 8242). Spearman's rho correlations were conducted to assess the relationship between baseline and psychological state subscores (anxiety, depression, somatization) (α = .05). Psychological state subscores were compared between individuals with a self-reported history of concussions (0, 1, 2, 3, 4+) using Kruskal-Wallis tests (α = .05).

RESULTS

Student-athletes with anxiety, depression, and anxiety with depression demonstrated higher scores in number of symptoms reported (anxiety, 4.3 ± 4.2; depression, 5.2 ± 4.8; anxiety with depression, 5.4 ± 3.9; no anxiety/depression, 2.5 ± 3.4), symptom severity (anxiety, 8.1 ± 9.8; depression, 10.4 ± 12.4; anxiety with depression, 12.4 ± 10.7; no anxiety/depression, 4.1 ± 6.9), and psychological distress in state anxiety (anxiety, 3.7 ± 4.7; depression, 2.5 ± 3.6; anxiety with depression, 3.8 ± 4.2; no anxiety/depression, 0.8 ± 1.8), depression (anxiety, 2.4 ± 4.0; depression, 3.2 ± 4.5; anxiety with depression, 3.8 ± 4.8; no anxiety/depression, 0.8 ± 1.8), and somatization (anxiety, 2.3 ± 2.9; depression, 1.8 ± 2.8; anxiety with depression, 2.2 ± 2.4; no anxiety/depression, 0.9 ± 1.7). A moderate positive relationship existed between all BSI-18 subscores and total symptom number (n = 8377; anxiety: r_s = 0.43, P < .001; depression: r_s = 0.42, P < .001; somatization: r_s = 0.45, P < .001), as well as total symptom severity (anxiety: r_s = 0.43, P < .001; depression: r_s = 0.41, P < .001; somatization: r_s = 0.45, P < .001). Anxiety, depression, and somatization subscores were greater among student-athletes that self-reported more concussions.

CONCLUSION

Clinicians should be cognizant that student-athletes with a history of trait anxiety, depression, and anxiety with depression may report higher symptom score and severity at baseline. Individuals with extensive concussion history may experience greater state anxiety, depression, and somatization.

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.

Near Point of Convergence and Gait Deficits in Adolescents After Sport-Related Concussion

OBJECTIVE

To prospectively examine gait characteristics of participants acutely after concussion with and without receded near point of convergence (NPC), compared with healthy controls.

DESIGN

Cross-sectional study.

SETTING

Sports-medicine clinic.

PARTICIPANTS

Patients examined after concussion (n = 33; mean ± SD = 7.2 ± 3.1 days) and a group of uninjured athletes (n = 31) completed a Postconcussion Symptom Scale, underwent NPC testing, and single/dual-task gait assessments.

INDEPENDENT VARIABLES

Near point of convergence was defined as the patient-reported diplopia distance when a fixation target moved toward the nose. Receded NPC was defined as a distance >5 cm from the tip of the nose.

MAIN OUTCOME MEASURES

Spatiotemporal gait characteristics in single-task and dual-task conditions were evaluated with analysis of variance; correlations were calculated between NPC and gait measures.

RESULTS

Eighteen of 33 (55%) patients with concussion presented with receded NPC. Those with receded NPC exhibited slower gait speed (single-task = 1.06 ± 0.14 m/s vs 1.19 ± 0.15 m/s; dual-task = 0.80 ± 0.13 m/s vs 0.94 ± 0.13 m/s; P = 0.003) and shorter stride lengths (single-task = 1.11 ± 0.10 m vs 1.24 ± 0.11 m; dual-task = 0.97 ± 0.11 m vs 1.09 ± 0.11 m; P = 0.001) than healthy controls. Near point of convergence was moderately correlated with dual-task average walking speed for the normal NPC group (ρ = -0.56; P = 0.05). Postconcussion Symptom Scale scores did not significantly differ between groups (27 ± 18 vs 28 ± 16).

CONCLUSIONS

After concussion, adolescents with receded NPC exhibited significant gait-related deficits compared with healthy controls, whereas those with normal NPC did not. Vergence and gross motor system dysfunction may be associated after concussion. Gait and vergence measures may contribute useful information to postconcussion evaluations.

Using concurrent gait and cognitive assessments to identify impairments after concussion: a narrative review

Understanding how a concussion affects an individual is oftentimes difficult for clinicians due to the varying symptom profiles reported by the patient and the multifaceted and heterogeneous nature of the injury. Accordingly, the interpretation of postconcussion performance can be challenging, because many different testing paradigms have been reported as potentially useful in the literature. Among the types of tests clinicians use to understand how concussion affects an individual, both gait and neurocognitive evaluations have demonstrated utility. Our purpose is to describe how combined gait and cognitive (i.e., dual task), as well as single-task gait and computerized neurocognitive examinations can assist clinical decision-making.

Proof-of-Concept Testing of a Real-Time mHealth Measure to Estimate Postural Control During Walking: A Potential Application for Mild Traumatic Brain Injuries

Background: Most individuals with mild traumatic brain injury (mTBI) experience post-injury deficits in postural control. Currently available measures of postural control are lab-based or supervised, which may hinder timely symptom assessment for individuals with mTBI, including Asian populations, who do not seek initial screening post-injury. In this proof-of-concept testing study, we introduce a real-time mobile health (mHealth) system to measure postural control during walking. The proposed mHealth system can be used for home-based symptom assessment and management of mTBI.

Methods: In our proposed mHealth system, a smartwatch, a smartphone, and a cloud server communicate to measure, collect, and store body balance data in real time. Specifically, we focus on the rotation vector data that have been reported to be the most effective in terms of differentiating balance control during walking across different participants.

Results: Constant motion change in four participants (two females and two males; three healthy participants, and one individual with reduced physical mobility) was collected and analyzed. The results of our data analysis show that, compared to healthy participants, the individual was reduced physical mobility had a wider range of motion between right and left, up and down, and forward and backward while walking. We also found that female participants had narrower ranges of right-to-left and up-and-down motions than their male counterparts.

Conclusions: Our results highlight the potential of the proposed real-time mHealth system for home-based symptom assessment and management of mTBI, which may benefit Asian and other nonwhite racial minority groups that appear to be more reluctant to access post-acute rehabilitation services.

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.

Dual-task gait differences in female and male adolescents following sport-related concussion

Concussion may affect females and males differentially. Identification of gender-related differences after concussion, therefore, may help clinicians with individualized evaluations. We examined potential differences in dual-task gait between females and males after concussion. Thirty-five participants diagnosed with a concussion (49% female, mean age=15.0±2.1 years, 7.5±3.0 days post-injury) and 51 controls (51% female, mean age=14.4±2.1 years) completed a symptom inventory and single/dual-task gait assessment. The primary outcome variable, the dual-task cost, was calculated as the percent change between single-task and dual-task conditions to account for individual differences in spatio-temporal gait variables. No significant differences in symptom severity measured by the post-concussion symptom scale were observed between females (32.0±18.0) and males (27.8±18.2). Compared with males, adolescent females walked with significantly decreased cadence dual-task costs after concussion (-19.7%±10.0% vs. -11.3%±9.2%, p=0.007) when adjusted for age, height, and prior concussion history. No significant differences were found between female and male control groups on other dual-task cost gait measures. Females and males with concussion also walked with significantly shorter stride lengths than controls during single-task (females: 1.13±0.11m vs. 1.26±0.11m, p=0.001; males: 1.14±0.14m vs. 1.22±0.15m, p=0.04) and dual-task gait (females: 0.99±0.10m vs. 1.10±0.11m, p=0.001; males: 1.00±0.13m vs. 1.08±0.14m, p=0.04). Females demonstrated a significantly greater amount of cadence change between single-task and dual-task gait than males after a sport-related concussion. Thus, differential alterations may exist during gait among those with a concussion; gender may be one prominent factor affecting dual-task gait.

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.