Reliability and Validity of the Sport Concussion Assessment Tool-3 (SCAT3) in High School and Collegiate Athletes

Factors Influencing Time to Return to Learn Among NCAA Student-Athletes Enrolled in the Concussion Assessment, Research, and Education (CARE) Study

PURPOSE

The aim was to describe the demographic and post-injury factors that influence time to return to learn (RTL) among student-athletes enrolled in the Concussion Assessment, Research and Education (CARE) Consortium.

METHODS

A total of 47,860 student-athletes enrolled in the National Collegiate Athletic Association-Department of Defense (NCAA-DoD) CARE Consortium study from 2014 to 2020, with 1485 sport-related concussions (SRCs) analyzed in the present dataset. Demographic and post-injury characteristics were calculated using descriptive statistics, followed by Kaplan-Meier estimates to examine median time to return to normal academic performance (i.e., RTL) by sex (male, female), baseline psychiatric conditions (depression, anxiety) and/or learning disorder, NCAA division (I, II, III), SRC history (0, 1, 2, 3+), NCAA sport category (contact, limited contact, non-contact sport), and median difference in baseline/post-injury symptom severity scores (< 21, ≥ 21). Further, a multivariable zero-inflated negative binomial (ZINB) regression model was used to examine their association with RTL.

RESULTS

Overall, time to RTL (mean = 4.96 ± 8.24 days, median = 3.0 [interquartile range = 0.0, 6.0] days) was found to be influenced by several factors resulting in earlier trajectories. Notably, nearly 25% of the sample demonstrated immediate RTL (i.e., 0 days). Among student-athletes who did not immediately RTL, males demonstrated a decreased rate in RTL (rate = 0.79; 95% CI 0.66-0.96) compared to females. Further, student-athletes with a ≥ 21 change in symptom severity score (post-injury baseline) demonstrated a higher rate of RTL (rate = 1.47; 95% CI 1.21-1.79) compared to student-athletes with a symptom severity change score < 21. Lastly, male student-athletes demonstrated two times higher odds (odds ratio = 1.95; 95% CI 1.02-3.73) of immediate RTL compared to female student-athletes. No other covariates were associated with time to RTL.

CONCLUSION

Collectively, the present findings suggest a rapid return to the classroom following concussion. Specifically, males demonstrated higher odds of time to RTL, whereas those with greater differences in symptom severity resulted in a higher rate of time to RTL among those who did not immediately RTL. Ultimately, these findings support prior work emphasizing an individualized approach to SRC management.

Association of Premorbid Anxiety and Depression Symptoms in Concussion Recovery in Collegiate Student-Athletes

BACKGROUND

Mental health disorders are linked to prolonged concussion symptoms. However, the association of premorbid anxiety/depression symptoms with postconcussion return-to-play timelines and total symptom burden is unclear.

OBJECTIVE

To examine the association of self-reported premorbid anxiety/depression symptoms in collegiate student-athletes with (1) recovery times until asymptomatic, (2) return-to-play, and (3) postconcussion symptom burden.

STUDY DESIGN

Athletes in the Concussion Assessment, Research and Education Consortium completed baseline concussion assessments (Sport Concussion Assessment Tool [SCAT3] and Brief Symptom Inventory-18 [BSI-18]). Athletes were tested postinjury at <6 hours, 24 to 48 hours, time of asymptomatic and start of return-to-play protocol, unrestricted return-to-play, and 6 months after injury. Injured athletes were categorized into 4 groups based on BSI-18 scores: (1) B-ANX, elevated anxiety symptoms only; (2) B-DEP, elevated depression symptoms only; (3) B-ANX&DEP, elevated anxiety and depression symptoms; and (4) B-NEITHER, no elevated anxiety or depression symptoms. Relationship between age, sex, BSI-18 group, SCAT3 total symptom and severity scores, and time to asymptomatic status and return-to-play was assessed with Pearson's chi-squared test and robust analysis of variance.

LEVEL OF EVIDENCE

Level 3.

RESULTS

Among 1329 athletes with 1352 concussions, no respondents had a self-reported premorbid diagnosis of anxiety/depression. There was no difference in time until asymptomatic or time until return-to-play between BSI-18 groups (P = 0.15 and P = 0.11, respectively). B-ANX, B-DEP, and B-ANX&DEP groups did not have higher total symptom or severity scores postinjury compared with the B-NEITHER group.

CONCLUSION

Baseline anxiety/depression symptoms in collegiate student-athletes without a mental health diagnosis are not associated with longer recovery times until asymptomatic, longer time to return-to-play, or higher postconcussion total symptom and severity scores compared with athletes without baseline symptoms.

CLINICAL RELEVANCE

Anxiety and depression symptoms without a clear mental health diagnosis should be considered differently from other comorbidities when discussing prolonged recovery in collegiate student-athletes.

Diagnosis of Sports-Related Concussion Using Symptom Report or Standardized Assessment of Concussion

Importance

The Sports Concussion Assessment Tool-5 (SCAT5) has been recommended for concussion evaluation and utilizes both a subjective reported symptom grading scale and objective measures of concussion including a cognitive evaluation: the Standardized Assessment of Concussion (SAC). The SAC includes testing for orientation, immediate memory, concentration, and delayed recall; a 10-word list is used to assess immediate memory and delayed recall.

Objective

To determine the diagnostic accuracy of components of the SCAT5 and to provide a framework for clinical interpretation.

Design, Setting, and Participants

This prospective case-control study of National Collegiate Athletic Association Division I athletes from any sport was conducted from July 2020 to December 2022 at 4 universities. Athletes completed baseline SCAT5 testing using the 10-word list. When an athlete presented acutely with suspected concussion (sideline or within 2 days), the tests were repeated. If a concussion was diagnosed, a control athlete underwent the same tests. Controls were identified and matched on comorbid conditions, sex and gender, sport, season, and baseline scores. Data analysis was conducted from August to October 2023.

Main Outcomes and Measures

The primary outcomes were area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive and negative predictive value, and test-retest reliability of the symptom score; symptom severity score; the total SAC score; and the orientation, immediate memory, concentration, and delayed memory subcomponent scores on the SCAT5 compared with clinical diagnosis of concussion.

Results

Baseline and postinjury data were collected on 92 athletes with concussion and 92 matched control athletes (96 men [52%] and 88 women [48%]; 110 who played a sport other than football [59%]). Diagnostic utility was considered excellent for symptom score (AUC, 0.93; 95% CI, 0.89-0.96) and symptom severity score (AUC, 0.94; 95% CI, 0.90-0.97). An increase of 2 points on the symptom score was associated with a sensitivity of 86% (95% CI, 78%-92%), specificity of 80% (95% CI, 70%-87I%), and positive predictive value of 81% (95% CI, 72%-88%). The total SAC score had poor to fair diagnostic utility (AUC, 0.70; 95% CI, 0.63-0.77); however, 41 athletes with concussion (45%) had a total SAC score at or above their baseline score (ie, within normal limits). The diagnostic utility was poor to fair for immediate memory (AUC, 0.68, 95%CI, 0.61-0.75) and delayed recall (AUC, 0.69; 95% CI, 0.62-0.77) and not useful for orientation (AUC, 0.49; 95% CI, 0.43-0.56) and concentration (AUC, 0.52 95% CI, 0.44-0.61). Test-retest reliability was fair for total SAC and poor for immediate memory and delayed recall, orientation, and concentration.

Conclusions and Relevance

In this case-control study of the diagnostic accuracy of reported symptoms and the SAC, reported symptoms were the most accurate indicator of concussion while the 10-word SAC had limited sensitivity. These findings suggest that understanding the properties of the SAC is important when making the diagnosis of concussion.

Psychological Constructs From the Fear Avoidance Model and Beyond as Predictors for Persisting Symptoms After Concussion: An Integrative Review

OBJECTIVES

To identify the range of evidence for relationships between psychological factors using the Fear Avoidance Model (FAM) as a guiding framework and relevant clinical outcomes in adult patients with persisting symptoms after concussion (PSaC), develop a comprehensive understanding of psychological factors that have been identified as predictors of clinical outcomes for PSaC, and contribute to the theoretical framework of the FAM for PSaC.

DATA SOURCES

Six databases (CINAHL, Embase, PsycINFO, PubMed, SportDiscus, and Web of Science) were searched by a librarian for empirical and theoretical publications and experimental and quasi-experimental study designs. The literature search was not limited by publication date restrictions. Gray literature, with the exception of doctoral dissertations, was excluded.

STUDY SELECTION

We included studies in the English language consisting of human participants aged ≥18 years. Articles must have included both outcomes pertaining to PSaC (≥3mo after injury) and psychological constructs.

DATA EXTRACTION

One reviewer extracted data from the resulting studies using a standardized data extraction form designed for this review. Two reviewers independently assessed risk of bias using the Quality in Prognosis Studies tool.

DATA SYNTHESIS

This review found numerous psychological constructs, some directly linked to the FAM, that have potential prognostic relationships with PSaC. However, research remains limited and some psychological factors central to FAM were only identified in a small number of studies (catastrophizing, cogniphobia, and avoidance), whereas other psychological factors were studied more extensively (anxiety and depression).

CONCLUSIONS

There is the need for additional evidence, and this integrative review provides an adaptation of the FAM for PSaC to be used as a guiding preliminary framework for future research. Future research should aim to include psychological factors proposed in this modified FAM to fully understand PSaC.

The Sport Concussion Assessment Tool: A multidimensional symptom model for detecting elevated post-concussion symptoms

Objective: Investigate whether a four-factor model of post-concussion symptoms (i.e. cognitive, physical, affective, and sleep-arousal) aids in identifying student-athletes with persistent concerns not reflected by a total symptom score. Method: Collegiate student-athletes (N = 32,066) from the Concussion Assessment Research and Education consortium completed the Sport Concussion Assessment Tool, 3rd edition Symptom Evaluation at baseline and two post-injury follow-ups (i.e. beginning RTP and 6-month). Confirmatory factor analysis was used to compare a one- and four-factor model of post-concussion symptoms. Normative reference data were compared across stratifications (e.g. sex, prior concussions, and number of pre-existing conditions) using Mann-Whitney U tests, and elevation rates (i.e. ≥ 84th percentile) for subscales and the total score were recorded. Results: The four-factor model fit well before and after injury (CFIs > .95). Greater symptom severity on the subscale and total scores was associated with female sex (ps<.001, r range: .07 to .14) and more pre-existing conditions (ps<.001, η 2 range: .01 to .04), while having more prior concussions was only related to total symptom scores (ps<.001, η 2<.01). After a concussion, a sizeable portion of student-athletes (i.e., RTP = 11.8%; 6-month = 8.3%) had subscale elevations despite no total score elevation. Physical subscale elevations at RTP were the most common (i.e., 11.9%), driven by head and neck pain. Conclusion: After a sport-related concussion, a four-factor symptom model can be used to assess persistent symptoms in collegiate student-athletes. Identifying athletes with domain-specific elevations may help clinicians identify areas for further assessment and, in some cases, personalized rehabilitation plans.

Fatigue recovery and connected factors following paediatric concussion

OBJECTIVE

Using a biopsychosocial framework and the three-factor fatigue model, we aimed to (1) plot recovery of fatigue over the 3 months following paediatric concussion and (2) explore factors associated with persisting fatigue during the first 3 months postconcussion.

METHODS

240 children and adolescents aged 5-18 years (M=11.64, SD=3.16) completed assessments from time of injury to 3 months postinjury. Separate linear mixed effects models were conducted for child and parent ratings on the PedsQL-Multidimensional Fatigue Scale to plot recovery across domains (General, Cognitive, Sleep/Rest) and Total fatigue, from 1 week to 3 months postinjury. Two-block hierarchical regression analyses were then conducted for parent and child ratings of fatigue at each time point, with age, sex and acute symptoms in block 1 and child and parent mental health variables added to block 2.

RESULTS

There was a significant reduction in both child and parent ratings across the 3 months postinjury for all fatigue domains (all p<0.001). For both child and parent fatigue ratings, child mental health was the most significant factor associated with fatigue at all time points. Adding child and parent mental health variables in the second block of the regression substantially increased the variance explained for both child and parent ratings of fatigue.

CONCLUSION

Our findings confirm that fatigue improves during the first 3 months postconcussion and highlights the importance of considering child and parent mental health screening when assessing patients with persisting postconcussive symptoms.

Adolescent Sport-Related Concussion and the Associated Neurophysiological Changes: A Systematic Review

BACKGROUND

Sport-related concussion (SRC) has been shown to induce cerebral neurophysiological deficits, quantifiable with electroencephalography (EEG). As the adolescent brain is undergoing rapid neurodevelopment, it is fundamental to understand both the short- and long-term ramifications SRC may have on neuronal functioning. The current systematic review sought to amalgamate the literature regarding both acute/subacute (≤28 days) and chronic (>28 days) effects of SRC in adolescents via EEG and the diagnostic accuracy of this tool.

METHODS

The review was registered within the Prospero database (CRD42021275256). Search strategies were created and input into the PubMed database, where three authors completed all screening. Risk of bias assessments were completed using the Scottish Intercollegiate Guideline Network and Methodological Index for Non-Randomized Studies.

RESULTS

A total of 128 articles were identified; however, only seven satisfied all inclusion criteria. The studies ranged from 2012 to 2021 and included sample sizes of 21 to 81 participants, albeit only ∼14% of the included athletes were females. The studies displayed low-to-high levels of bias due to the small sample sizes and preliminary nature of most investigations. Although heterogeneous methods, tasks, and analytical techniques were used, 86% of the studies found differences compared with control athletes, in both the symptomatic and asymptomatic phases of SRC. One study used raw EEG data as a diagnostic indicator demonstrating promise; however, more research and standardization are a necessity.

CONCLUSIONS

Collectively, the findings highlight the utility of EEG in assessing adolescent SRC; however, future studies should consider important covariates including biological sex, maturation status, and development.

Effects of sociodemographic and player characteristics on baseline cognitive performance in 1000 rugby players: A retrospective 8-year follow-up study

OBJECTIVES

To analyze the effects of sociodemographic and player characteristics on the Sport Concussion Assessment Tool and neuropsychological scores over 8 years in a large sample of rugby players.

DESIGN

An 8-year retrospective study of preseason clinical assessments of professional rugby players and players enrolled in training academies at professional clubs.

METHODS

The Sport Concussion Assessment Tool-3 or -5, Trail Making Test and Digit Symbol Substitution Test were administered prior to the start of the competition season for each player. Statistical analyses included: (i) descriptive analyses of sociodemographic, player and neuropsychological characteristics; (ii) multivariate models to identify factors influencing cognitive scores at the first visit; and (iii) linear mixed models to assess the evolution of the scores over the years.

RESULTS

One thousand players were included (mean age: 22.8, males: 92 %). Twenty-two percent of the athletes reported baseline symptoms. A higher level of education was associated with better cognitive scores at the first visit and over the years. Forwards had poorer processing speed performances compared to backs at the first visit and over repeated assessments. Finally, the number of examinations was associated with improved cognitive scores showing a practice effect on all the neuropsychological tests, except for the Standardized Assessment of Concussion 5th edition.

CONCLUSIONS

Results from this retrospective study could help to improve the management of athletes and return-to-play decision-making in collision sports.

Baseline concussion assessments can identify mental disorders: SCAT-5 and other screening tools in South African club rugby

OBJECTIVES

Although mental health screenings are not routinely conducted in rugby, the Sport Concussion Assessment Tool - Fifth Edition (SCAT-5) is widely performed and measures affective, cognitive, sleep, and physical symptoms. This study investigated the psychometric properties of the SCAT-5 to explore its potential as a mental health screening tool.

METHODS

During preseason for the 2021 Western Province Super League A in South Africa, clinicians conducted mental health assessments of 71 adult male rugby union players. The SCAT-5 Symptom Evaluation, Baron Depression Screener for Athletes (BDSA), Athlete Psychological Strain Questionnaire (APSQ), Center for Epidemiologic Studies-Depression (CES-D), and Generalized Anxiety Disorder-7 (GAD-7) were compared to each other and to fully structured diagnostic interviews by mental health professionals using the Mini International Neuropsychiatric Interview (MINI) 7.0.2.

RESULTS

Lifetime MINI-defined mental disorders were common, being identified in 33.8% (95% CI 22.79-46.17%). Only 4.29% of participants had a previous diagnosis. Exploratory Factor Analysis indicated a mental health construct of depression/anxiety being measured by the SCAT-5. The SCAT-5 had strong internal consistency (α = 0.94) and showed moderate convergent validity with the CES-D (r = 0.34; p = 0.008) and GAD-7 (r = 0.49; p < 0.0001). The area under the curve for the ability of the SCAT-5 to identify current disorders was 0.87 (p = 0.003), on par with the CES-D and GAD-7.

CONCLUSION

Since the SCAT-5 has the potential to identify depression and anxiety, it may allow mental health screening without the need for additional measures. Follow-up studies should further explore its discriminative ability in larger samples.

Association Between Symptom Cluster Endorsement at Initiation of a Graduated Return-to-Activity Protocol and Time to Return to Unrestricted Activity After Concussion in United States Service Academy Cadets

BACKGROUND

The endorsement of symptoms upon initiation of a graduated return-to-activity (GRTA) protocol has been associated with prolonged protocols. It is unclear whether there are specific symptom clusters affecting protocol durations.

PURPOSE

To describe the endorsement of specific concussion symptom clusters at GRTA protocol initiation and examine the association between symptom cluster endorsement and GRTA protocol duration.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This study was conducted among cadets enrolled at 3 US service academies. Participants completed an evaluation upon GRTA protocol initiation. Participants endorsing symptoms were binarized based on 6 symptom clusters (cognitive, emotional, insomnia, physical, sensitivity, and ungrouped). The primary outcome of interest was GRTA protocol duration based on symptom cluster endorsement severity. Prevalence rates were calculated to describe symptom cluster endorsement. Kaplan-Meier survival estimates and univariate and multivariable Cox proportional hazards regression models were calculated for all 6 symptom clusters to estimate GRTA protocol duration while controlling for significant covariates.

RESULTS

Data from 961 concussed participants were analyzed. Of these, 636 participants were asymptomatic upon GRTA protocol initiation. Among the 325 symptomatic participants, the physical symptom cluster (80%) was most endorsed, followed by the cognitive (29%), insomnia (23%), ungrouped (19%), sensitivity (15%), and emotional (9%) clusters. Univariate results revealed a significant association between endorsing cognitive (hazard ratio [HR], 0.79; p = .001), physical (HR, 0.84; p < .001), insomnia (HR, 0.83; p = .013), sensitivity (HR, 0.70; p < .001), and ungrouped (HR, 0.75; p = .005) symptom clusters and GRTA protocol duration. Endorsing physical (HR, 0.84; p < .001) and sensitivity (HR, 0.81; p = .036) clusters maintained a significant association with GRTA protocol duration in the multivariable models.

CONCLUSION

Participants endorsing physical or sensitivity symptom clusters displayed GRTA protocols prolonged by 16% to 19% compared with participants not endorsing that respective cluster after controlling for significant covariates.

Head Injuries and Emergencies in Sports

Head injuries are a common occurrence in sports and can involve injuries to the brain, skull, and superficial soft tissues. The most commonly discussed diagnosis is a concussion. Head and cervical spine injuries must be considered together at times, due to the overlapping nature of symptoms present during on-field evaluation. This article presents a range of head injuries, along with critical steps in evaluation and management.

The consideration of post-exercise impact on SCAT3 scores in athletes immediately following a head injury

METHODS

Symptoms were assessed immediately following completion of a rugby match (median 60 minutes). Players removed from the match for assessment due to a head hit were classified as head injured. Controls completed match without head hit.

RESULTS

209 players (67 female; 33 ± 13 years) participated with 80 experiencing a head injury. Symptom severity was significantly greater in head injured (26.2 ± 17.6) compared with controls (8.9 ± 11.5, P < 0.001). 21% of control players reporting >16 symptom severity, misclassifying them as suspected concussion. There were no significant sex differences. Factor analysis produced four symptom clusters of which Headache was most discriminatory between the head injured (median = 1.7) and controls (median = 0.0).

CONCLUSION

These findings demonstrate that exercise and contact during a game affect symptom assessment, increasing the likelihood of misclassifying players with suspected concussion. Factor characterization of symptoms associated with head injury using an exercised comparison group provides more useful discrimination. These results highlight the necessity for objective measures to diagnose concussions outside of symptom self-report.

Beyond acute concussion assessment to office management: a systematic review informing the development of a Sport Concussion Office Assessment Tool (SCOAT6) for adults and children

OBJECTIVES

To systematically review the scientific literature regarding the assessment of sport-related concussion (SRC) in the subacute phase (3-30 days) and provide recommendations for developing a Sport Concussion Office Assessment Tool (SCOAT6).

DATA SOURCES

MEDLINE, Embase, PsycINFO, Cochrane CENTRAL, CINAHL, SPORTDiscus and Web of Science searched from 2001 to 2022. Data extracted included study design, population, definition of SRC diagnosis, outcome measure(s) and results.

ELIGIBILITY CRITERIA

(1) Original research, cohort studies, case-control studies, diagnostic accuracy and case series with samples >10; (2) SRC; (3) screening/technology that assessed SRC in the subacute period and (4) low risk of bias (ROB). ROB was performed using adapted Scottish Intercollegiate Guidelines Network criteria. Quality of evidence was evaluated using the Strength of Recommendation Taxonomy classification.

RESULTS

Of 9913 studies screened, 127 met inclusion, assessing 12 overlapping domains. Results were summarised narratively. Studies of acceptable (81) or high (2) quality were used to inform the SCOAT6, finding sufficient evidence for including the assessment of autonomic function, dual gait, vestibular ocular motor screening (VOMS) and mental health screening.

CONCLUSION

Current SRC tools have limited utility beyond 72 hours. Incorporation of a multimodal clinical assessment in the subacute phase of SRC may include symptom evaluation, orthostatic hypotension screen, verbal neurocognitive tests, cervical spine evaluation, neurological screen, Modified Balance Error Scoring System, single/dual task tandem gait, modified VOMS and provocative exercise tests. Screens for sleep disturbance, anxiety and depression are recommended. Studies to evaluate the psychometric properties, clinical feasibility in different environments and time frames are needed.

PROSPERO REGISTRATION NUMBER

CRD42020154787.

Questionnaire and structural imaging data accurately predict headache improvement in patients with acute post-traumatic headache attributed to mild traumatic brain injury

BACKGROUND

Our prior work demonstrated that questionnaires assessing psychosocial symptoms have utility for predicting improvement in patients with acute post-traumatic headache following mild traumatic brain injury. In this cohort study, we aimed to determine whether prediction accuracy can be refined by adding structural magnetic resonance imaging (MRI) brain measures to the model.

METHODS

Adults with acute post-traumatic headache (enrolled 0-59 days post-mild traumatic brain injury) underwent T1-weighted brain MRI and completed three questionnaires (Sports Concussion Assessment Tool, Pain Catastrophizing Scale, and the Trait Anxiety Inventory Scale). Individuals with post-traumatic headache completed an electronic headache diary allowing for determination of headache improvement at three- and at six-month follow-up. Questionnaire and MRI measures were used to train prediction models of headache improvement and headache trajectory.

RESULTS

Forty-three patients with post-traumatic headache (mean age = 43.0, SD = 12.4; 27 females/16 males) and 61 healthy controls were enrolled (mean age = 39.1, SD = 12.8; 39 females/22 males). The best model achieved cross-validation Area Under the Curve of 0.801 and 0.805 for predicting headache improvement at three and at six months. The top contributing MRI features for the prediction included curvature and thickness of superior, middle, and inferior temporal, fusiform, inferior parietal, and lateral occipital regions. Patients with post-traumatic headache who did not improve by three months had less thickness and higher curvature measures and notably greater baseline differences in brain structure vs. healthy controls (thickness: p < 0.001, curvature: p = 0.012) than those who had headache improvement.

CONCLUSIONS

A model including clinical questionnaire data and measures of brain structure accurately predicted headache improvement in patients with post-traumatic headache and achieved improvement compared to a model developed using questionnaire data alone.

Primary and Secondary Risk Factors Associated With Concussion Symptom Clusters in Collegiate Athletes: Results From the NCAA-DoD Grand Alliance CARE Consortium

Background

There is a broad and diverse range of symptoms after a concussion, from irritability to nausea. This heterogeneity of symptoms is a challenge for clinicians managing the different presentations among injuries. Prior research has investigated the structure of postconcussive symptoms to determine if they can be grouped into clusters of related symptoms.

Purpose/Hypothesis

The purpose of this study was to identify symptom clusters during the acute phase after a sports-related concussion using exploratory factor analysis and to understand the relationship between risk factors for postconcussion symptoms (ie, demographics, injury characteristics, mental health, and sleep qualities) and different symptom clusters. We hypothesized that certain factors would be predictive of specific symptom clusters.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Collegiate athletes (N = 1104) from the Concussion, Assessment, Research, and Education (CARE) Consortium completed the Sport Concussion Assessment Tool-Third Edition symptom assessment tool 24 to 48 hours after concussion. Exploratory factor analysis was conducted on the symptom evaluation to determine symptom clusters 24 to 48 hours after concussion. Regression analysis was used to examine the effects of pre- and postinjury characteristics.

Results

Exploratory factor analysis revealed a 4-cluster structure for acute postconcussive symptoms that explained 62% of the variance in symptom reporting: vestibular-cognitive, migrainous, cognitive fatigue, and affective. Delayed reporting, less sleep before assessment, female sex, and being hurt outside of competition (during practice/training) was correlated with increased symptoms for 4 symptom clusters. Depression predicted higher vestibular-cognitive and affective symptoms. Amnesia was correlated with higher vestibular-cognitive and migrainous symptoms, whereas migraine history was associated with more migrainous and affective symptoms.

Conclusion

Symptoms can be grouped into 1 of 4 distinct clusters. Certain variables were associated with increased symptoms across multiple clusters and may be indicative of greater injury severity. Other factors (ie, migraine history, depression, amnesia) were associated with a more specific symptom presentation and may be mechanistically related to concussion outcomes and biological markers.

A comparison of clinical assessment with common diagnostic tools for monitoring concussion recovery in adolescent rugby union players

OBJECTIVES

To characterise the incidence, severity and recovery of sport-related concussion (SRC) in schoolboy rugby players and explore whether the Sports Concussion Assessment Tool (SCAT), Cogstate Brief Battery (CBB) and the King-Devick test (K-D test) can be used to monitor concussion status through to full recovery.

DESIGN

Prospective cohort study.

SETTING

Rugby union has a high rate of SRC; however, there is little research investigating how concussion affects adolescent rugby players.

PARTICIPANTS

Schoolboy rugby players.

MAIN OUTCOME MEASURES

Participants completed baseline tests in the preseason. Participants diagnosed with SRC during the season attended for post-concussion testing on a weekly basis until recovered.

RESULTS

135 schoolboy rugby players (16.7 ± 0.82y) participated in the study. There were 18 SRCs in 16 participants. Concussion incidence was 9/1000 player hours. CBB and K-D tests were poorly associated with clinical assessment and produced high false negative rates (0.58 and 0.52 respectively).

CONCLUSIONS

This study reports a relatively high match SRC incidence for an adolescent population. Analysis of clinical recovery with CBB and K-D test revealed a relatively poor ability to accurately monitor concussion status compared to clinical assessment suggesting that these tools should not be used in isolation for monitoring SRC recovery in adolescents.

Microglial activation persists beyond clinical recovery following sport concussion in collegiate athletes

Introduction

In concussion, clinical and physiological recovery are increasingly recognized as diverging definitions. This study investigated whether central microglial activation persisted in participants with concussion after receiving an unrestricted return-to-play (uRTP) designation using [18F]DPA-714 PET, an in vivo marker of microglia activation.

Methods

Eight (5 M, 3 F) current athletes with concussion (Group 1) and 10 (5 M, 5 F) healthy collegiate students (Group 2) were enrolled. Group 1 completed a pre-injury (Visit1) screen, follow-up Visit2 within 24 h of a concussion diagnosis, and Visit3 at the time of uRTP. Healthy participants only completed assessments at Visit2 and Visit3. At Visit2, all participants completed a multidimensional battery of tests followed by a blood draw to determine genotype and study inclusion. At Visit3, participants completed a clinical battery of tests, brain MRI, and brain PET; no imaging tests were performed outside of Visit3.

Results

For Group 1, significant differences were observed between Visits 1 and 2 (p < 0.05) in ImPACT, SCAT5 and SOT performance, but not between Visit1 and Visit3 for standard clinical measures (all p > 0.05), reflecting clinical recovery. Despite achieving clinical recovery, PET imaging at Visit3 revealed consistently higher [18F]DPA-714 tracer distribution volume (VT) of Group 1 compared to Group 2 in 10 brain regions (p < 0.001) analyzed from 164 regions of the whole brain, most notably within the limbic system, dorsal striatum, and medial temporal lobe. No notable differences were observed between clinical measures and VT between Group 1 and Group 2 at Visit3.

Discussion

Our study is the first to demonstrate persisting microglial activation in active collegiate athletes who were diagnosed with a sport concussion and cleared for uRTP based on a clinical recovery.

Motor vehicle crash concussion mechanism displays a greater total number of symptoms and greater affective symptom severity but no neurocognitive differences compared with sport-related concussion mechanism

Previous research among adolescents has shown differences in symptoms and neurocognitive performance between sport-related (SRC) and motor vehicle crash (MVC) concussion mechanisms. Limited research has focused on young adults. The purpose of our study was to compare symptoms, balance, and neurocognitive performance between SRC and MVC mechanisms in young adults. Forty-three (58.1% female, age = 25.5 ± 3.2 years, days since concussion = 12.8 ± 12.7) and 26 (76.9% female, age = 24.1 ± 5.6 years, days since concussion = 12.6 ± 8.3) individuals with an SRC and MVC mechanism, respectively, participated. Primary outcome measures included the total number, severity, cluster (disorientation, migraine, lethargy, and affective) of post-concussion symptoms endorsed, Balance Error Scoring System (BESS), and CNS Vital Signs scores. Clusters are subgroups of symptoms used for targeted rehabilitation. We used independent t-tests and Mann-Whitney U tests to compare symptoms, BESS, and neurocognitive performance. Cliff's Delta effect size was interpreted as negligible (<0.15), small (0.15-0.33), medium (0.34-0.47), and large (≥0.48). There were no group differences for any demographic factors or preexisting conditions (p-range = 0.112-0.991). Participants with an MVC mechanism reported a greater number of total post-concussion symptoms (p = 0.025, Cliff's Delta = 0.32) and a more severe affective symptom cluster (p = 0.010, Cliff's Delta = 0.37). There were no group differences for BESS or neurocognitive performance after correcting for multiple comparisons. The MVC mechanism resulted in a greater total symptom burden relative to the SRC mechanism. Medical practitioners and individuals experiencing a concussion should know that concussions are heterogeneous within and across various mechanisms.

Sensitivity and Specificity of the ImPACT Neurocognitive Test in Collegiate Athletes and US Military Service Academy Cadets with ADHD and/or LD: Findings from the NCAA-DoD CARE Consortium

BACKGROUND AND OBJECTIVE

Computer-based neurocognitive tests are widely used in sport-related concussion management, but the performance of these tests is not well understood in the participant population with attention-deficit/hyperactivity disorder (ADHD) and/or learning disorder (LD). This research estimates the sensitivity and specificity performance of the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) computer-based neurocognitive test in identifying concussion in this population.

METHODS

Study participants consisted of collegiate university athletes and military service academy cadets from the National Collegiate Athletic Association-Department of Defense CARE Consortium who completed the ImPACT test between 2014 and 2021. Participants who self-identified as belonging to one of the subgroups of interest (ADHD with or without LD [ADHD:LD+/-], LD with or without ADHD [LD:ADHD+/-], ADHD and/or LD [ADHD a/o LD]) and completed a baseline (1874 ADHD:LD+/-, 779 LD:ADHD+/-, 2338 ADHD a/o LD) or 24-48 h post-concussion (175 ADHD:LD+/-, 77 LD:ADHD+/-, 216 ADHD a/o LD) ImPACT assessment were included. Sensitivity and specificity were calculated using a normative data method and three machine learning classification methods: logistic regression, classification and regression tree, and random forest.

RESULTS

Using the four methods, participants with ADHD:LD+/- had sensitivities that ranged from 0.474 to 0.697, and specificities that ranged from 0.538 to 0.686. Participants with LD:ADHD+/- had sensitivities that ranged from 0.455 to 0.688, and specificities that ranged from 0.456 to 0.588. For participants with ADHD a/o LD, sensitivities ranged from 0.542 to 0.755, and specificities ranged from 0.451 to 0.724.

CONCLUSIONS

For all subgroups and analytical methods, the results illustrate sensitivity and specificity values below typically accepted levels indicative of clinical utility. These findings support that using ImPACT alone may be insufficient to inform concussion diagnoses and encourages the use of a multi-dimensional concussion assessment.

Lower Extremity Somatosensory Function Throughout Concussion Recovery: A Prospective Cohort Study

OBJECTIVE

Balance impairments may suggest somatosensory disruption beyond concussion clinical recovery, but somatosensory subsystems have never been directly assessed. Our objective was to examine somatosensory function between individuals with a concussion and healthy matched-controls at acute (<7 days) and asymptomatic (<72 hours of being symptom-free) time points.

SETTING

Laboratory.

PARTICIPANTS

Participants with a concussion and matched controls ( n = 24; 58% male, age: 19.3 ± 1.1 years, mass: 70.3 ± 16.4 kg, height: 177.3 ± 12.7 cm).

DESIGN

Prospective cohort.

MAIN MEASURES

Somatosensory assessments on the dominant limb at both time points included: (1) plantar touch sensation threshold via Semmes-Weinstein monofilaments, (2) plantar pressure pain threshold via algometry, and (3) knee absolute passive joint repositioning (PJR) error via Biodex across 3 arcs (105°-75°, 30°-60°, 90°-45° knee-flexion). We used mixed-model analyses of variance, post hoc Tukey honestly significant difference t tests with mean difference, 95% CI, and Hedges' g effect sizes to examine outcomes.

RESULTS

Touch sensation had a group effect with the concussion cohort needing 0.95 grams of force (gf) more relative to controls (95% CI: 0.03 to 1.87; P = .043). No touch sensation interaction was present, but medium and large effects were observed for greater gf needed among the concussed cohort at the acute (1.11 gf; 95% CI: 0.17 to 2.05; g = 0.96) and asymptomatic time points (0.79 gf; 95% CI: -0.15 to 1.73; g = 0.73). No plantar pressure pain threshold effects were observed ( P ≥ .311), with negligible pressure difference magnitudes at the acute (0.26 pound force [lbf]/cm 2 ; 95% CI: -1.54 to 2.06; g = 0.13) and medium magnitudes at the asymptomatic time points (0.99 lbf/cm 2 ; 95% CI: -0.81 to 2.80; g = 0.42) for the concussed cohort needing more pressure to detect pain. The 30° to 60° PJR had a time effect, with asymptomatic time point having 3.12° better accuracy (95% CI: 1.23° to 5.02; P = .002). The concussed cohort had small-to-medium magnitude differences relative to controls at the acute time point for PJR during 105° to 75° (0.89°; g = 0.30) and 90° to 45° (0.62°; g = 0.17), but not 30° to 60° (-1.75°; g = -0.40).

CONCLUSIONS

Individuals with a concussion exhibited large effects for diminished plantar touch sensation and small to medium effects for inhibited plantar pressure pain sensation compared with controls, which may indicate altered somatosensory function. Negligible PJR differences suggest knee joint position sense is not altered post-concussion. Pre- and postconcussion examination is warranted to understand causal somatosensory mechanisms.

Single-Leg Hop Stabilization Throughout Concussion Recovery: A Preliminary Biomechanical Assessment

CONTEXT

Aberrant movement patterns among individuals with concussion history have been reported during sport-related movement. However, the acute postconcussion kinematic and kinetic biomechanical movement patterns during a rapid acceleration-deceleration task have not been profiled and leaves their progressive trajectory unknown. Our study aimed to examine single-leg hop stabilization kinematics and kinetics between concussed and healthy-matched controls acutely (≤7 d) and when asymptomatic (≤72 h of symptom resolution).

DESIGN

Prospective, cohort laboratory study.

METHODS

Ten concussed (60% male; 19.2 [0.9] y; 178.7 [14.0] cm; 71.3 [18.0] kg) and 10 matched controls (60% male; 19.5 [1.2] y; 176.1 [12.6] cm; 71.0 [17.0] kg) completed the single-leg hop stabilization task under single and dual task (subtracting by 6's or 7's) at both time points. Participants stood on a 30-cm tall box set 50% of their height behind force plates while in an athletic stance. A synchronized light was illuminated randomly, queuing participants to initiate the movement as rapidly as possible. Participants then jumped forward, landed on their nondominant leg, and were instructed to reach and maintain stabilization as fast as possible upon ground contact. We used 2 (group) × 2 (time) mixed-model analyses of variance to compare single-leg hop stabilization outcomes separately during single and dual task.

RESULTS

We observed a significant main group effect for single-task ankle plantarflexion moment, with greater normalized torque (mean difference = 0.03 N·m/body weight; P = .048, g = 1.18) for concussed individuals across time points. A significant interaction effect for single-task reaction time indicated that concussed individuals had slower performance acutely relative to asymptomatic (mean difference = 0.09 s; P = .015, g = 0.64), while control group performance was stable. No other main or interaction effects for single-leg hop stabilization task metrics were present during single and dual task (P ≥ .051).

CONCLUSIONS

Greater ankle plantarflexion torque coupled with slower reaction time may indicate stiff, conservative single-leg hop stabilization performance acutely following concussion. Our findings shed preliminary light on the recovery trajectories of biomechanical alterations following concussion and provide specific kinematic and kinetic focal points for future research.

Lower-Extremity Neuromuscular Function Following Concussion: A Preliminary Examination

CONTEXT

Neuromuscular function is altered acutely following concussion and theoretically linked to the subsequent postconcussion musculoskeletal injury risk. Existing research has only examined voluntary muscle activation, limiting mechanistic understanding. Therefore, our study aimed to examine voluntary and involuntary muscle activation between college-aged, concussed individuals when symptom-free and healthy matched controls.

DESIGN

Prospective, cross-sectional cohort laboratory study.

METHODS

Concussed and healthy participants (n = 24; 58% male, age: 19.3 [1.1] y, mass: 70.3 [16.4] kg, height: 177.3 [12.7] cm) completed the superimposed burst (SB) neuromuscular assessment on their dominant limb within 72 hours after self-reporting asymptomatic (22.4 [20.2] d postinjury). Unnormalized and bodyweight-normalized quadriceps maximal voluntary isometric contraction torque (in newton meters), unnormalized and bodyweight-normalized electrically stimulated SB torque, pain (numeric 1-10) during SB, and the central activation ratio (in percentage) were assessed via the SB. Parametric and nonparametric analyses, 95% confidence intervals (95% CIs), and Hedges g (parametric) and Spearman ρ (nonparametric) effect sizes were used to examine group differences (α = .05).

RESULTS

The maximal voluntary isometric contraction torque (concussed: 635.60 N·m [300.93] vs control: 556.27 N·m [182.46]; 95% CI, -131.36 to 290.02; P = .443; d = 0.33), SB torque (concussed: 203.22 N·m [97.17], control: 262.85 N·m [159.07]; 95% CI, -171.22 to 51.97; P = .280; d = -0.47), and central activation ratio (concussed: 72.16% [17.16], control: 70.09% [12.63]; 95% CI, -10.68 to 14.83; P = .740; d = 0.14) did not differ between the concussed and control groups regardless of bodyweight normalization (P ≥ .344). Pain during the SB was significantly higher with a medium effect for participants with a concussion versus healthy controls (concussed: median = 7, control: median = 5; P = .046; ρ = -0.42).

DISCUSSION

These findings suggest concussed participants do not have statistically altered voluntary or involuntary quadricep neuromuscular function once asymptomatic compared with controls. Therefore, the elevated postconcussion musculoskeletal injury risk may not be attributed to lower-extremity muscle activation. Concussed participants displayed greater pain perception during the SB, which suggests somatosensory or perception changes requiring further examination.

Developing multivariable models for predicting headache improvement in patients with acute post-traumatic headache attributed to mild traumatic brain injury: A preliminary study

OBJECTIVES/BACKGROUND

Post-traumatic headache (PTH) is a common symptom after mild traumatic brain injury (mTBI). Although there have been several studies that have used clinical features of PTH to attempt to predict headache recovery, currently no accurate methods exist for predicting individuals' improvement from acute PTH. This study investigated the utility of clinical questionnaires for predicting (i) headache improvement at 3 and 6 months, and (ii) headache trajectories over the first 3 months.

METHODS

We conducted a clinic-based observational longitudinal study of patients with acute PTH who completed a battery of clinical questionnaires within 0-59 days post-mTBI. The battery included headache history, symptom evaluation, cognitive tests, psychological tests, and scales assessing photosensitivity, hyperacusis, insomnia, cutaneous allodynia, and substance use. Each participant completed a web-based headache diary, which was used to determine headache improvement.

RESULTS

Thirty-seven participants with acute PTH (mean age = 42.7, standard deviation [SD] = 12.0; 25 females/12 males) completed questionnaires at an average of 21.7 (SD = 13.1) days post-mTBI. The classification of headache improvement or non-improvement at 3 and 6 months achieved cross-validation area under the curve (AUC) of 0.72 (95% confidence interval [CI] 0.55 to 0.89) and 0.84 (95% CI 0.66 to 1.00). Sub-models trained using only the top five features still achieved 0.72 (95% CI 0.55 to 0.90) and 0.77 (95% CI 0.52 to 1.00) AUC. The top five contributing features were from three questionnaires: Pain Catastrophizing Scale total score and helplessness sub-domain score; Sports Concussion Assessment Tool Symptom Evaluation total score and number of symptoms; and the State-Trait Anxiety Inventory score. The functional regression model achieved R = 0.64 for modeling headache trajectory over the first 3 months.

CONCLUSION

Questionnaires completed following mTBI have good utility for predicting headache improvement at 3 and 6 months in the future as well as the evolving headache trajectory. Reducing the battery to only three questionnaires, which assess post-concussive symptom load and biopsychosocialecologic factors, was helpful to determine a reasonable prediction accuracy for headache improvement.

Patient Characteristics Predictive of Immediate and Delayed Word Recall Performance Following Adolescent Concussion

Clinicians rely on objective concussion assessments that may be influenced by patient characteristics, creating difficulties in isolating the effect of concussion on patient function. The purpose of our study was to identify characteristics associated with performance on the Sport Concussion Assessment Tool 5th edition (SCAT5) 10-word recall test following adolescent concussion. We evaluated patients seen for care within 14 days of concussion (n=125; 15.2±1.6 years of age, range=11-18 years; 46% female; 6.9±3.4 days post-concussion). Patient demographic (age, sex, medical and concussion history, etc.), injury (timing of presentation, symptom severity, sport-type, etc.), and clinical test (Modified Balance Error Scoring System [mBESS], tandem gait) characteristics were assessed, in addition to SCAT5 immediate and delayed memory testing using the 10-word recall list. Immediate and delayed recall performance was significantly associated with concussion symptom burden and cognitive accuracy during tandem gait, although effect sizes were notably small. Specific variables such as age, sex, diagnosis of ADD/ADHD, and performance on other clinical assessments were not significantly associated with recall performance after controlling for covariates. Further, the 10-word recall list demonstrates specific advantages over previously used 5-word lists by way of decreased ceiling effects and reduced interference of inherent patient characteristics.

One-year stability of preseason Sport Concussion Assessment Tool 5 (SCAT5) values in university level collision and combative sport athletes

OBJECTIVES

To determine the stability of the Sport Concussion Assessment Tool (SCAT) 5 between consecutive seasons in uninjured collision and combative varsity athletes.

METHODS

Thirty-six athletes (19 females) were recruited to participate (wrestling [n = 12], rugby [n = 14], and hockey [n = 10]). The SCAT5 was administration at the start of the 2017 and 2018 seasons. Median baseline demographics for 2017 were as follows: age (19 years [range: 17-24 years]), height (174 cm [range: 149-195 cm]), and weight (76 kg [range: 57-118 kg]). Outcome metrics included subcomponents of the SCAT5: symptom reporting, standardized assessment of concussion (SAC), neurological screening, and balance performance measured with the modified balance error scoring system (mBESS). Wilcoxon signed-rank tests and Cronbach's alpha (α) values were calculated to determine the stability between consecutive years for the SCAT5 variables in the same cohort of athletes. Bonferroni corrections were applied for Wilcoxon signed-rank tests, where alpha = 0.006 (0.05/9).

RESULTS

Between the 2017 and 2018 seasons, no differences were noted in symptom reporting (p = 0.14), SAC (p = 0.32), neurological screening (p = 0.98), and balance performance on the mBESS (p = 0.01). The Cronbach's alpha displayed unacceptable to questionable levels of within-subject stability (range: α = 0.34-0.70) for all subcomponents, except months in reverse order (α = 0.92).

CONCLUSIONS

While no statistical differences were present for all SCAT5 subcomponent metrics between 2017 and 2018 baselines, all but one displayed unacceptable to questionable stability (α ≤ 0.70) when retested one year later. Further research is needed to understand the appropriate time duration baseline SCAT5 values can reliably be utilized within longitudinal studies; as well as the normal variation of SCAT5 reporting/scoring.

The Clinical Utility of the Child SCAT5 for Acute Concussion Assessment

Background

The Child Sport Concussion Assessment Tool 5th Edition (Child SCAT5) was developed to evaluate children between 5 and 12 years of age for a suspected concussion. However, limited empirical evidence exists demonstrating the value of the Child SCAT5 for acute concussion assessment. Therefore, the purpose of our study was to examine differences and assess the diagnostic properties of Child SCAT5 scores among concussed and non-concussed middle school children on the same day as a suspected concussion.

Methods

Our participants included 34 concussed (21 boys, 13 girls; age = 12.8 ± 0.86 years) and 44 non-concussed (31 boys, 13 girls; age = 12.4 ± 0.76 years) middle school children who were administered the Child SCAT5 upon suspicion of a concussion. Child SCAT5 scores were calculated from the symptom evaluation (total symptoms, total severity), child version of the Standardized Assessment of Concussion (SAC-C), and modified Balance Error Scoring System (mBESS). The Child SCAT5 scores were compared between the concussed and non-concussed groups. Non-parametric effect sizes (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r=\frac{Z}{\sqrt{n}}$$\end{document}r=Zn) were calculated to assess the magnitude of difference for each comparison. The diagnostic properties (sensitivity, specificity, diagnostic accuracy, predictive values, likelihood ratios, and diagnostic odds ratio) of each Child SCAT5 score were also calculated.

Results

Concussed children endorsed more symptoms (p < 0.001, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.45), higher symptom severity (p < 0.001, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.44), and had higher double leg (p = 0.046, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.23), single leg (p = 0.035, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.24), and total scores (p = 0.022, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.26) for the mBESS than the non-concussed children. No significant differences were observed for the SAC-C scores (p’s ≥ 0.542). The quantity and severity of endorsed symptoms had the best diagnostic accuracy (AUC = 0.76–0.77), negative predictive values (NPV = 0.84–0.88), and negative likelihood ratios (-LR = 0.22–0.31) of the Child SCAT5 scores.

Conclusions

Clinicians should prioritize interpretation of the symptom evaluation form of the Child SCAT5 as it was the most effective component for differentiating between concussed and non-concussed middle school children on the same day as a suspected concussion.

Relationship and Latent Factors Between Clinical Concussion Assessments and the Functional Standardized Assessment of Reaction Time (StART)

OBJECTIVE

To examine the relationships and latent factors within the Standardized Assessment of Reaction Time (StART), and between StART and current clinical assessments.

DESIGN

Cross-sectional study.

SETTING

Clinical medicine facility.

PARTICIPANTS

Eighty-nine healthy collegiate student-athletes (63% male, age: 19.5 ± 0.9 years, 28% ≥1 concussion history).

ASSESSMENT OF RISK FACTORS

Student-athletes completed StART and clinical assessments during preinjury testing.

MAIN OUTCOME MEASURES

Standardized Assessment of Reaction Time consisted of 3 conditions (standing, single-leg balance, cutting) under 2 cognitive states (single task and dual task) for 3 trials each condition. Clinical assessments were the Sport Concussion Assessment Tool (SCAT) symptom checklist, Standardized Assessment of Concussion (SAC), tandem gait (single task and dual task), and Immediate PostConcussion Assessment and Cognitive Testing (ImPACT). We used Pearson- r correlation coefficients and exploratory factor analysis (EFA) to examine relationships and latent factors between StART and clinical assessments.

RESULTS

Null to moderate correlations presented among the StART outcomes (r range: 0.06-0.70), and null to small correlations between StART and clinical assessments (r range: -0.16 to 0.34). The three-factor EFA for solely StART explained 70.6% total variance: functional movement (cutting), static dual-task (standing and single-leg balance), and static single task (standing and single-leg balance). The five-factor EFA for StART and clinical assessments explained 65.8% total variance: gait (single-task and dual-task tandem gait), functional movement (StART single-task and dual-task cutting), static dual-task (StART standing, single-leg balance), neurocognitive (ImPACT verbal memory, visual memory, visual-motor speed), and static single task (StART standing, single-leg balance). No other outcomes met the factor loading threshold.

CONCLUSIONS

StART displayed 3 distinct categories and had minimal redundancy within its subtests. StART did not meaningfully correlate with clinical assessments, suggesting that StART provides unique information by examining more functional, reactive movement.

A Pilot Randomized Controlled Trial of Docosahexaenoic Acid for the Treatment of Sport-Related Concussion in Adolescents

The objective was to examine the use of docosahexaenoic acid (DHA) for the treatment of sport-related concussion (SRC) in adolescent athletes. We hypothesize that participants who intake 2 g of DHA daily will not experience differences in recovery compared with participants who take a placebo. This double-blind, randomized controlled pilot trial was performed in a tertiary pediatric sports medicine clinic from 2013 to 2017 in adolescents (14-18 years) presenting with diagnosed SRC within 4 days of injury. Forty participants were randomized into DHA or PLACEBO group and were instructed to take 2 capsules twice daily for 12 weeks. Participants in the DHA group were symptom-free earlier than the PLACEBO group (11.0 vs 16.0 days, P = .08) and were cleared to begin the Return to Sport progression (14.0 vs 19.5 days, P = .12) sooner. The use of 2 g/day of DHA was well-tolerated and did not significantly affect recovery times in adolescent athletes following SRC.Clinical Trial Registration: ClincalTrials.gov, NCT01903525.

Monitoring the acute and subacute recovery of cognitive ocular motor changes after a sports-related concussion

Identifying when recovery from a sports-related concussion (SRC) has occurred remains a challenge in clinical practice. This study investigated the utility of ocular motor (OM) assessment to monitor recovery post-SRC between sexes and compared to common clinical measures. From 139 preseason baseline assessments (i.e. before they sustained an SRC), 18 (12 males, 6 females) consequent SRCs were sustained and the longitudinal follow-ups were collected at 2, 6, and 13 days post-SRC. Participants completed visually guided, antisaccade (AS), and memory-guided saccade tasks requiring a saccade toward, away from, and to a remembered target, respectively. Changes in latency (processing speed), visual–spatial accuracy, and errors were measured. Clinical measures included The Sports Concussion Assessment Tool, King-Devick test, Stroop task, and Digit span. AS latency was significantly longer at 2 days and returned to baseline by 13-days post-SRC in females only (P &lt; 0.001). Symptom numbers recovered from 2 to 6 days and 13 days (P &lt; 0.05). Persistently poorer AS visual–spatial accuracy was identified at 2, 6 and 13 days post-SRC (P &lt; 0.05) in both males and females but with differing trajectories. Clinical measures demonstrated consistent improvement reminiscent of practice effects. OM saccade assessment may have improved utility in tracking recovery compared to conventional measures and between sexes.

Evidence to Eliminate Double-Leg Conditions From the Modified Balance Error Scoring System and Balance Error Scoring System

OBJECTIVE

The purpose of our study was to assess the differences between the Balance Error Scoring System (BESS), modified BESS (mBESS), and both measures with the double-leg (DL) stances removed [BESS-revised (BESS-R) and mBESS-revised (mBESS-R)] among healthy and concussed collegiate student-athletes.

DESIGN

Retrospective, repeated-measures cohort study.

SETTING

Clinical.

PATIENTS OR OTHER PARTICIPANTS

Healthy and concussed collegiate athletes (baseline n = 622, postinjury n = 41) from 12 National Collegiate Athletic Association Division I sports cheer and dance at a single university.

INTERVENTION OR INDEPENDENT VARIABLES

Balance Error Scoring System, mBESS, BESS-R, and mBESS-R test versions from baseline and postinjury testing.

MAIN OUTCOME MEASURES

The mBESS and BESS and their revised versions with DL stances removed (mBESS-R and BESS-R) scores were compared at baseline. Baseline and postinjury scores for all 4 BESS variations and the 6 BESS conditions were compared for those who sustained a concussion.

RESULTS

The BESS and BESS-R were statistically different at baseline for the entire sample (99.6% confidence interval 0.32, 0.38, P > 0.0001). None of the other comparisons were significantly different ( P > 0.004).

CONCLUSION

Although our results do suggest statistically significant differences between the BESS and BESS-R test versions, they do not represent clinically meaningful differences. The greatest mean difference between all test versions was <1 error; therefore, these BESS versions may not be specific enough to identify balance deficits at baseline or postinjury. Elimination of the time intensive DL measures in the revised BESS variations may be a more clinically practical alternative.

Association of Preexisting Mental Health Conditions With Increased Initial Symptom Count and Severity Score on SCAT5 When Assessing Concussion

Background:

Mental health conditions, such as depression, anxiety, and learning disabilities, are associated with symptoms that can overlap with those seen in persons with concussion. While concussion screening tools such as the Sport Concussion Assessment Tool–5th Edition (SCAT5) quantify the number of symptoms and symptom severity, it is not known whether these outcomes differ among individuals with concurrent mental health conditions compared with those without them.

Purpose:

To determine whether, during initial concussion assessment, individuals with a self-reported mental health condition have a significantly different number of self-reported concussion symptoms or symptom severity compared with those without a self-reported mental health condition (controls).

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A retrospective chart review was performed on consecutive patients aged ≥13 years who underwent post-concussion assessment at the Fowler Kennedy Sport Medicine Clinic between May 2018 and March 2020 (N = 765). Most participants did not self-report a mental health condition (n = 606; 79.2%). Participants with a self-reported mental health condition (n = 159) were classified as having a learning disability (n = 14; 8.8%), anxiety (n = 62; 39.0%), depression (n = 20; 12.6%), or multiple conditions (≥2 conditions: n = 63; 39.6%). Each participant with a mental health condition was matched with 2 control participants (overall pool, n = 318) based on age, sex, student status, and sport-related risk. Mann-Whitney U tests were used to determine the statistical significance of differences between each subgroup and their matched controls for the self-reported number of concussion symptoms and symptom severity as measured using the SCAT5.

Results:

The anxiety and multiple-conditions subgroups had a significantly greater number of reported symptoms than their corresponding control subgroups (median, 17 vs 15 [P = .004] and 18 vs 14.5 [P < .001], respectively). Additionally, the SCAT5 symptom severity score was significantly greater in the anxiety and multiple-conditions subgroups than their corresponding controls (median, 49 vs 34.5 [P = .018] and 62 vs 32 [P < .001], respectively).

Conclusion:

During initial concussion assessment, both the number of concussion-related symptoms and the symptom severity were greater in study participants with anxiety and multiple mental health conditions than participants without these conditions.

The Association Between Concussion History and Increased Symptom Severity Reporting Is Independent of Common Medical Comorbidities, Personality Factors, and Sleep Quality in Collegiate Athletes

OBJECTIVE

We investigated the degree to which the association between history of concussion with psychological distress and general symptom severity is independent of several factors commonly associated with elevated symptom severity. We also examined whether symptom severity endorsement was associated with concussion injury specifically or response to injury in general.

SETTING

Academic medical center.

PARTICIPANTS

Collegiate athletes ( N = 106; age: M = 21.37 ± 1.69 years; 33 female) were enrolled on the basis of strict medical/psychiatric exclusion criteria.

DESIGN

Cross-sectional single-visit study. Comprehensive assessment, including semistructured interviews to retrospectively diagnose the number of previous concussions, was completed. Single-predictor and stepwise regression models were fit to examine the predictive value of prior concussion and orthopedic injuries on symptom severity, both individually and controlling for confounding factors.

MAIN OUTCOME MEASURES

Psychological distress was operationalized as Brief Symptom Inventory-18 Global Severity Index (BSI-GSI) ratings; concussion-related symptom severity was measured using the Sport Concussion Assessment Tool.

RESULTS

Controlling for baseline factors associated with the symptom outcomes (agreeableness, neuroticism, negative emotionality, and sleep quality), concussion history was significantly associated with psychological distress ( B = 1.25 [0.55]; P = .025, Δ R2 = 0.034) and concussion-like symptom severity ( B = 0.22 [0.08]; P = .005, Δ R2 = 0.064) and accounted for a statistically significant amount of unique variance in symptom outcomes. Orthopedic injury history was not individually predictive of psychological distress ( B = -0.06 [0.53]; P = .905) or general symptom severity ( B = 0.06 [0.08]; P = .427) and did not explain the relationship between concussion history and symptom outcomes.

CONCLUSIONS

Concussion history is associated with subtle elevations in symptom severity in collegiate-aged athletes; this relationship is independent of medical, lifestyle (ie, sleep), and personality factors. Furthermore, this relationship is associated with brain injury (ie, concussion) and is not a general response to injury history.

Ten-Word List Performance in Healthy Athletes and Athletes at 3-to-5 Days Following Concussion

OBJECTIVE

Although the word recall component of the Sport Concussion Assessment Tool (SCAT) was updated from 5-to-10 words, its clinical utility across athletic populations remains unknown. The purpose of this study was to provide normative data on the SCAT-5 10-word test and examine its discriminative ability between healthy university level athletes and those with sport-related concussion (SRC).

DESIGN

Cross-sectional.

SETTING

University.

PARTICIPANTS

Three hundred sixty-three (363, M = 220, F = 153) healthy athletes and 49 (M = 30, F = 19) athletes following SRC.

INDEPENDENT VARIABLE

Healthy athletes measured preseason were compared with athletes following an SRC (median = 4.0 days postinjury).

MAIN OUTCOME MEASURE

Ten-word list performance from the SCAT-5.

RESULTS

There were no significant differences in either immediate ( P = 0.228, Cohen's D = 0.18) or delayed ( P = 0.908, Cohen's D = 0.02) recall tests between athletes with SRC and healthy athletes; the null findings extended to both the male and female subset comparisons. Among healthy athletes, females outperformed males on both immediate (mean difference = 1.0, P < 0.001) and delayed (mean difference = 0.5, P = 0.006) recall tasks.

CONCLUSION

Concussion does not seem to impact immediate or delayed recall of the 10-word list in the subacute period following injury. Practitioners should be mindful of sex differences and the time point of administration following injury.

Combining MRI and cognitive evaluation to classify concussion in university athletes

Current methods of concussion assessment lack the objectivity and reliability to detect neurological injury. This multi-site study uses combinations of neuroimaging (diffusion tensor imaging and resting state functional MRI) and cognitive measures to train algorithms to detect the presence of concussion in university athletes. Athletes (29 concussed, 48 controls) completed symptom reports, brief cognitive evaluation, and MRI within 72 h of injury. Hierarchical linear regression compared groups on cognitive and neuroimaging measures while controlling for sex and data collection site. Logistic regression and support vector machine models were trained using cognitive and neuroimaging measures and evaluated for overall accuracy, sensitivity, and specificity. Concussed athletes reported greater symptoms than controls (∆R² = 0.32, p < .001), and performed worse on tests of concentration (∆R² = 0.07, p < .05) and delayed memory (∆R² = 0.17, p < .001). Concussed athletes showed lower functional connectivity within the frontoparietal and primary visual networks (p < .05), but did not differ on mean diffusivity and fractional anisotropy. Of the cognitive measures, classifiers trained using delayed memory yielded the best performance with overall accuracy of 71%, though sensitivity was poor at 46%. Of the neuroimaging measures, classifiers trained using mean diffusivity yielded similar accuracy. Combining cognitive measures with mean diffusivity increased overall accuracy to 74% and sensitivity to 64%, comparable to the sensitivity of symptom report. Trained algorithms incorporating both MRI and cognitive performance variables can reliably detect common neurobiological sequelae of acute concussion. The integration of multi-modal data can serve as an objective, reliable tool in the assessment and diagnosis of concussion.

Heterogeneity in Blood Biomarker Trajectories After Mild TBI Revealed by Unsupervised Learning

Concussions, also known as mild traumatic brain injury (mTBI), are a growing health challenge. Approximately four million concussions are diagnosed annually in the United States. Concussion is a heterogeneous disorder in causation, symptoms, and outcome making precision medicine approaches to this disorder important. Persistent disabling symptoms sometimes delay recovery in a difficult to predict subset of mTBI patients. Despite abundant data, clinicians need better tools to assess and predict recovery. Data-driven decision support holds promise for accurate clinical prediction tools for mTBI due to its ability to identify hidden correlations in complex datasets. We apply a Locality-Sensitive Hashing model enhanced by varied statistical methods to cluster blood biomarker level trajectories acquired over multiple time points. Additional features derived from demographics, injury context, neurocognitive assessment, and postural stability assessment are extracted using an autoencoder to augment the model. The data, obtained from FITBIR, consisted of 301 concussed subjects (athletes and cadets). Clustering identified 11 different biomarker trajectories. Two of the trajectories (rising GFAP and rising NF-L) were associated with a greater risk of loss of consciousness or post-traumatic amnesia at onset. The ability to cluster blood biomarker trajectories enhances the possibilities for precision medicine approaches to mTBI.

Determining Sport Concussion Assessment Tool fifth Edition (SCAT5) reliable change in male professional hockey players

OBJECTIVES

The purpose of this paper is to provide reliable change metrics and assess the test-retest psychometrics of the Sport Concussion Assessment Tool fifth Edition (SCAT5) in a multilingual sample of professional ice hockey players.

METHODS

The SCAT5 was administered to National Hockey League and American Hockey League male professional ice hockey players as part of the 2018 and 2019 season medical evaluations. We extracted data from an existing clinical database of players who were administered two consecutive baseline evaluations and had no intervening concussions to assess psychometric properties (eg, test-retest reliability) and develop reliable change metrics.

RESULTS

Overall, 1007 players met inclusion criteria. Players were reassessed on average 344.52 (±62.52) days following their first baseline. Test-retest reliability ranged from r=0.3 to r=0.5. Reliable change metrics for Immediate Memory varied considerably dependent on form order. Significant differences were found between English versus non-English language preference on Immediate Memory and Concentration but not Delayed Memory or the modified Balance Error Scoring System (mBESS). Reliable change indices at the 90% CI were: Symptom Severity (5), Total Symptoms (3), Immediate Memory (3-8), Concentration (2), mBESS (5) and Delayed Memory (2-4).

CONCLUSIONS

Our findings highlight the importance of considering form differences and language preference when determining reliable change from baseline on the SCAT5 in male professional hockey players. The relatively modest test-retest reliability of the measures leaves room for improved psychometric properties and increased sensitivity to concussion in future iterations of the SCAT.

Association Between Symptom Burden at Initiation of a Graduated Return to Activity Protocol and Time to Return to Unrestricted Activity After Concussion in Service Academy Cadets

BACKGROUND

Current consensus and position statements recommend that concussed patients be asymptomatic upon the initiation of the graduated return to activity (RTA) protocol. However, a significant number of concussed patients are beginning their RTA protocols while endorsing symptoms.

PURPOSE

To characterize symptom endorsement at the beginning of the RTA protocol and examine the association between symptom endorsement and RTA protocol duration in service academy cadets.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A prospective cohort study was conducted with cadets at 3 US service academies. Postconcussion symptom inventories were recorded upon the initiation of an RTA protocol. The Sport Concussion Assessment Tool Symptom Inventory was used to classify participants into 3 groups (0 symptoms, 1 symptom, and ≥2 symptoms) upon the initiation of the RTA protocol. The primary outcome of interest was RTA protocol duration. Kaplan-Meier survival estimates were calculated to estimate RTA protocol duration by symptom endorsement, sex, varsity status, academic break, and time to graduated RTA initiation. Univariate and multivariable Cox proportional hazards models were used to estimate the association between symptom endorsement at the initiation of the RTA protocol and RTA protocol duration (α < .05).

RESULTS

Data were analyzed from 966 concussed cadets (36% women). Headache (42%) and faintness/dizziness (44%) were the most commonly endorsed symptoms on the Sport Concussion Assessment Tool-Third Edition and the Brief Symptom Inventory-18, respectively. Univariate results revealed a significant association between endorsing ≥2 symptoms and RTA protocol duration. In the multivariable model, endorsing ≥2 symptoms maintained a statistically significant association with RTA protocol duration. Significant associations were observed between RTA protocol duration and nonvarsity status (27% longer), women (15% longer), academic breaks (70% longer), and time to the initiation of the RTA protocol (1.1% longer daily incremental increase) after controlling for covariates.

CONCLUSION

Symptom endorsement at the initiation of an RTA protocol was associated with RTA protocol duration. Cadets who had returned to preinjury baseline symptom burden or improved from baseline symptom burden and endorsed ≥2 symptoms at the initiation of the RTA protocol took longer to RTA.

Utility of VOMS, SCAT3, and ImPACT Baseline Evaluations for Acute Concussion Identification in Collegiate Athletes: Findings From the NCAA-DoD Concussion Assessment, Research and Education (CARE) Consortium

BACKGROUND

The Vestibular/Ocular-Motor Screening (VOMS) is a valuable component of acute (<72 hours) sports-related concussion (SRC) assessments and is increasingly used with the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) instrument and the third edition of the Sport Concussion Assessment Tool (SCAT3). Research has suggested that VOMS acute postinjury scores are useful in identifying acute concussion. However, the utility of preseason baseline measurements to improve diagnostic accuracy remains ambiguous. To this end, there is a need to determine how reliable VOMS baseline assessments are across years and whether incorporating individuals' baseline performance improves diagnostic yield for acute concussions.

PURPOSE

To analyze VOMS, SCAT3, and ImPACT to evaluate the test-retest reliability of consecutive-year preseason baseline assessments to directly compare the diagnostic utility of these tools when incorporating baseline assessments versus using postinjury data alone to identify acute SRC.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Preseason and postinjury VOMS, SCAT3, ImPACT Post-Concussion Symptom Scale (PCSS), and ImPACT composite scores were analyzed for 3958 preseason (47.7% female) and 496 acute (≤48 hours) SRC (37.5% female) collegiate athlete evaluations in the National Collegiate Athletic Association-Department of Defense Concussion Assessment Research and Education Consortium. Descriptive statistics, Kolmogorov-Smirnov significance, and Cohen d effect size were calculated. Consecutive-year baseline reliability was evaluated for a subset of 447 athlete encounters using Pearson r, Cohen κ, Cohen d, and 2-way mixed intraclass correlation coefficients (ICCs). Wilcoxon signed rank tests were used to determine the statistical significance between population performances, and the 90% reliable change index (RCI) was calculated from the test-retest results. Preseason to postinjury change scores were then calculated from each tool's RCI. Finally, receiver operating characteristic (ROC) curve analyses were conducted, and DeLong method was used to compare the area under the curve (AUC) of raw postinjury scores versus change scores from preseason baseline assessments. Potential effects of sex, medical history (learning disorders or attention-deficit/hyperactivity disorder), and outlier data were also explored.

RESULTS

Effect sizes were large, and overall predictive utilities were clinically useful for postinjury VOMS Total (d = 2.44; AUC = 0.85), the SCAT3 Symptom Evaluation total severity score (d = 1.74; AUC = 0.82), and the ImPACT PCSS total severity score (d = 1.67; AUC = 0.80). Comparatively, effect sizes were small and predictive utilities were poor for Standardized Assessment of Concussion (SAC), modified Balance Error Scoring System (mBESS), and all ImPACT composites (d = 0.11-0.46; AUC = 0.48-0.59). Preseason baseline test-retest reliability was poor to moderate (r = 0.23-0.52; κ = 0.32-0.36; ICC = 0.36-0.68) for all assessments except ImPACT Visual Motion Sensitivity (r = 0.73; ICC = 0.85). Incorporating baseline scores for VOMS Total, SCAT3 (Symptom Evaluation, SAC, mBESS), ImPACT PCSS, or ImPACT composites did not significantly improve AUCs.

CONCLUSION

VOMS Total and symptom severity (SCAT3, PCSS) total scores had large effect sizes and clinically useful AUCs for identifying acute concussion. However, all tools demonstrated high within-patient test-retest variability, resulting in poor reliability. The findings in this sample of collegiate athletes suggest that incorporating baseline assessments does not significantly increase diagnostic yield for acute concussion.

Effects of Pre-Collegiate Sport Specialization on Cognitive, Postural, and Psychological Functions: Findings from the NCAA-DoD CARE Consortium

Background: Early sport specialization has been associated with an increased risk of musculoskeletal injuries and unfavorable psychological outcomes; however, it is unknown whether sport specialization is associated with worse cognitive, postural, and psychological functions in first-year collegiate student-athletes. Methods: First-year collegiate multisport (MA) and single-sport (SA) student-athletes were identified using a pre-collegiate sport experience questionnaire. The cognitive, postural, and psychological functions were assessed by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and Brief Symptom Inventory 18 (BSI-18). Results: MA student-athletes performed higher in cognitive outcomes (e.g., higher ImPACT visual memory composite scores [ß = 0.056, p < 0.001]), but had higher psychological distress (e.g., higher BSI-18 global severity index [ß = 0.057, p < 0.001]) and no difference in postural stability (p > 0.05) than SA student-athletes. Conclusions: This study indicated first-year collegiate athletes with a history of sport specialization demonstrate lower cognitive performance but decreased psychological distress and no differences in static postural stability as compared to their MA counterparts. Future studies should consider involving different health measures to better understand the influence of sport specialization on overall physical and mental health.

Sport concussion assessment in New Zealand high school rugby players: a collaborative approach to the challenges faced in primary care

PRIMARY OBJECTIVE

To describe the collaborative development of a New Zealand Rugby Concussion Assessment (NZRCA) for primary care and to provide normative baseline data from a representative group of high school rugby players.

METHODS

This study, conducted over the 2018 and 2019 community rugby season where players were baseline tested during the pre- or start of season period.

RESULTS

Data were collected from 1428 players (males n = 1121, females n = 307) with a mean age of 15.9 ± 1.4 years. The mean ± SD symptom severity score was 11.3 ± 8.6, the mean number of endorsed symptoms was 8.5 ± 5.3 and the percentage feeling "normal" was 80.2 ± 15.3%. Only 5.3% of players reported no symptoms at baseline. The most common reported were: 'distracted easily' (72.5%), 'forgetful' (68.5%), and 'often tired' (62.6%). None of the participants achieved a perfect score for the SAC50. The majority of participants (89.7%) passed the tandem gait test with a time of 12.2 ± 1.7 seconds. Age, gender, and ethnicity were associated with NZRCA performance; albeit weakly.

CONCLUSION

This study provides normative reference values for high-school rugby players. These data will aid healthcare providers in their identification of suspected concussion in the absence of individualized baselines.

Quantitative Assessment of Balance for Accurate Prediction of Return to Sport From Sport-Related Concussion

BACKGROUND

Determining when athletes are able to return to sport after sports-related concussion (SRC) can be difficult.

HYPOTHESIS

A multimodal algorithm using cognitive testing, postural stability, and clinical assessment can predict return to sports after SRC.

STUDY DESIGN

Prospective cohort.

LEVEL OF EVIDENCE

Level 2b.

METHODS

Athletes were evaluated within 2 to 3 weeks of SRC. Clinical assessment, Immediate Post Concussion and Cognitive Testing (ImPACT), and postural stability (Equilibrate) were conducted. Resulting data and machine learning techniques were used to optimize an algorithm discriminating between patients ready to return to sports versus those who are not yet recovered. A Fisher discriminant analysis with leave-one-out cross-validation assessed every combination of 2 to 5 factors to optimize the algorithm with lowest combination of type I and type II errors.

RESULTS

A total of 193 athletes returned to contact sports after SRC at a mean 84.6 days (±88.8). Twelve subjects (6.2%) sustained repeat SRC within 12 months after return to sport. The combination of (1) days since injury, (2) total symptom score, and (3) nondominant foot tandem eyes closed postural stability score created the best algorithm for discriminating those ready to return to sports after SRC with lowest type I error (13.85%) and type II error (11.25%). The model was able to discriminate between patients who were ready to successfully return to sports versus those who were not with area under the receiver operating characteristic (ROC) curve of 0.82.

CONCLUSION

The algorithm predicts successful return to sports with an acceptable sensitivity and specificity. Tandem balance with eyes closed measured with a video-force plate discriminated athletes ready to return to sports from SRC when combined in multivariate analysis with symptom score and time since injury. The combination of these factors may pose advantages over computerized neuropsychological testing when evaluating young athletes with SRC for return to contact sports.

CLINICAL RELEVANCE

When assessing young athletes sustaining an SRC in a concussion clinic, measuring postural stability in tandem stance with eyes closed combined with clinical assessment and cognitive recovery is effective to determine who is ready to successfully return to sports.

Proteomic Discovery of Noninvasive Biomarkers Associated With Sport-Related Concussions

BACKGROUND AND OBJECTIVES

Sport-related concussions affect millions of individuals across the United States each year, and current techniques to diagnose and monitor them rely largely on subjective measures. Our goal was to discover and validate objective, quantifiable noninvasive biomarkers with the potential to be used in sport-related concussion diagnosis.

METHODS

Urine samples from a convenience series of healthy control collegiate athletes who had not sustained a concussion and athletes who sustained a concussion as diagnosed by a sports medicine physician within 7 days were collected prospectively and studied. Participants also completed an instrumented single-task gait analysis as a functional measure. Participants were recruited from a single collegiate athletic program and were ≥18 years of age and were excluded if they had a concomitant injury, active psychiatric conditions, or preexisting neurologic disorders. Using Tandem Mass Tags (TMT) mass spectroscopy and ELISA, we identified and validated urinary biomarkers of concussion.

RESULTS

Forty-eight control and 47 age- and sex-matched athletes with concussion were included in the study (51.6% female, 48.4% male, average age 19.6 years). Participants represented both contact and noncontact sports. All but 1 of the postconcussion participants reported experiencing symptoms at the time of data collection. Insulin-like growth factor 1 (IGF-1) and IGF binding protein 5 (IGFBP5) were downregulated in the urine of athletes with concussions compared to healthy controls. Multivariable risk algorithms developed to predict the probability of sport-related concussion showed that IGF-1 multiplexed with single-task gait velocity predicts concussion risk across a range of postinjury time points (area under the curve [AUC] 0.786, 95% confidence interval [CI] 0.690-0.884). When IGF-1 and IGFBP5 are multiplexed with single-task gait velocity, they accurately distinguish between healthy controls and individuals with concussion at acute time points (AUC 0.835, 95% CI 0.701-0.968, p < 0.001).

DISCUSSION

These noninvasive biomarkers, discovered in an objective and validated manner, may be useful in diagnosing and monitoring sport-related concussions in both acute phases of injury and several days after injury.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov Identifier: NCT02354469 (submitted February 2015, first patient enrolled August 2015).

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that urinary IGF-1 and IGFBP5 multiplexed with single-task gait velocity may be useful in diagnosing sport-related concussion.

Attention-Deficit/Hyperactivity Disorder and Outcome from Concussion: Examining Duration of Active Rehabilitation and Clinical Recovery

AIMS

The objective of this study was to compare recovery time and duration of active rehabilitation following concussion between adolescents with and without attention-deficit/hyperactivity disorder (ADHD).

METHODS

A retrospective cohort study was conducted among adolescents presenting to a specialty concussion clinic. One-quarter of the eligible episodes of care were selected. The final sample included 540 adolescents (ages 13-17 years, median age 15 years; 49.8% girls), of which 65 (12.0%) had a pre-injury diagnosis of ADHD. Days to recovery and days of active rehabilitation were examined.

RESULTS

ADHD was not associated with recovery time (ADHD: median = 49 days, IQR = 25-77; No ADHD: median = 47 days, IQR = 29-85) in univariate (Z = -0.45; p = 0.65) or multivariable analyses (Hazard Ratio: 1.17 (0.85-1.61); χ²(1) = 0.95; p = 0.33). The duration of active rehabilitation services received did not differ between youth with ADHD (median = 38.5 days, IQR = 27.5-54.5) and without ADHD (median = 37.5 days, IQR = 18.5-66) in univariate (Z = -0.19; p = 0.85) or multivariable analyses (Hazard Ratio: 1.04 (0.67-1.63); χ²(1) = 0.03; p = 0.85).

CONCLUSIONS

Our findings support accumulating evidence that ADHD, in and of itself, is not a risk factor for longer recovery or worse outcomes following pediatric concussion.

Deep Learning Recurrent Neural Network for Concussion Classification in Adolescents Using Raw Electroencephalography Signals: Toward a Minimal Number of Sensors

Artificial neural networks (ANNs) are showing increasing promise as decision support tools in medicine and particularly in neuroscience and neuroimaging. Recently, there has been increasing work on using neural networks to classify individuals with concussion using electroencephalography (EEG) data. However, to date the need for research grade equipment has limited the applications to clinical environments. We recently developed a deep learning long short-term memory (LSTM) based recurrent neural network to classify concussion using raw, resting state data using 64 EEG channels and achieved high accuracy in classifying concussion. Here, we report on our efforts to develop a clinically practical system using a minimal subset of EEG sensors. EEG data from 23 athletes who had suffered a sport-related concussion and 35 non-concussed, control athletes were used for this study. We tested and ranked each of the original 64 channels based on its contribution toward the concussion classification performed by the original LSTM network. The top scoring channels were used to train and test a network with the same architecture as the previously trained network. We found that with only six of the top scoring channels the classifier identified concussions with an accuracy of 94%. These results show that it is possible to classify concussion using raw, resting state data from a small number of EEG sensors, constituting a first step toward developing portable, easy to use EEG systems that can be used in a clinical setting.

Dynamic Visual Stimulations Produced in a Controlled Virtual Reality Environment Reveals Long-Lasting Postural Deficits in Children With Mild Traumatic Brain Injury

Motor control deficits outlasting self-reported symptoms are often reported following mild traumatic brain injury (mTBI). The exact duration and nature of these deficits remains unknown. The current study aimed to compare postural responses to static or dynamic virtual visual inputs and during standard clinical tests of balance in 38 children between 9 and 18 years-of-age, at 2 weeks, 3 and 12 months post-concussion. Body sway amplitude (BSA) and postural instability (vRMS) were measured in a 3D virtual reality (VR) tunnel (i.e., optic flow) moving in the antero-posterior direction in different conditions. Measures derived from standard clinical balance evaluations (BOT-2, Timed tasks) and post-concussion symptoms (PCSS-R) were also assessed. Results were compared to those of 38 healthy non-injured children following a similar testing schedule and matched according to age, gender, and premorbid level of physical activity. Results highlighted greater postural response with BSA and vRMS measures at 3 months post-mTBI, but not at 12 months when compared to controls, whereas no differences were observed in post-concussion symptoms between mTBI and controls at 3 and 12 months. These deficits were specifically identified using measures of postural response in reaction to 3D dynamic visual inputs in the VR paradigm, while items from the BOT-2 and the 3 timed tasks did not reveal deficits at any of the test sessions. PCSS-R scores correlated between sessions and with the most challenging condition of the BOT-2 and as well as with the timed tasks, but not with BSA and vRMS. Scores obtained in the most challenging conditions of clinical balance tests also correlated weakly with BSA and vRMS measures in the dynamic conditions. These preliminary findings suggest that using 3D dynamic visual inputs such as optic flow in a controlled VR environment could help detect subtle postural impairments and inspire the development of clinical tools to guide rehabilitation and return to play recommendations.