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Few studies have analyzed the Sport Concussion Assessment Tool's (SCAT) utility among athletes whose concussion assessment is challenging. Using a previously published algorithm, we identified possible and probable concussions at

Context Nearly 44 million youth participate in organized youth sports programs in the United States each year. However, approximately 25% of parents have considered removing their children from sports due to the fear of concussion. Objective To determine which adult decision-making modifiers (eg, gender, educational attainment, career type) influenced support for youth contact-sports participation. Design Cross-sectional study. Setting Midwestern university and medical center. Patients or Other Participants Convenience sample of staff and faculty (N = 5761; 73.9% female) from 2017 to 2018. Main Outcome Measure(s) Support for youth contact-sports participation using multivariate binary logistic regression to calculate odds ratios and 95% CIs. Results The sample was split between adults with children (AWCs; n = 3465, age = 45.39 ± 13.27 years, 76.72% female) and adults without children (AWOCs; n = 2296, age = 30.84 ± 9.01 years, 70.26% female). Among AWCs, those who obtained a bachelor's degree or higher were more likely to support contact-sports participation. Females were more inclined to allow all contact sports, specifically football (odds ratio [OR] = 2.22; 95% CI = 1.64, 3.01) and ice hockey (OR = 1.98; 95% CI = 1.42, 2.78). Overall, previous adult sport participation, increasing number of children, and child gender were significant modifying variables in greater support of youth contact-sports participation among AWCs (P < .001). Among AWOCs, previous sport participation in football (OR = 3.27; 95% CI = 2.14, 4.87), ice hockey (OR = 4.26; 95% CI = 2.23, 8.17), or soccer (OR = 2.29; 95% CI = 1.48, 3.54) increased the likelihood of an adult supporting contact-sports participation. Lastly, all adults were less inclined to support a daughter participating in any contact sport than a son. Conclusions These results reveal adult- and child-specific variables that may influence youth contact-sports participation. These decisions may be developed through the lens of certain gender role beliefs and may lead adults to perceive certain sports as more appropriate for sons than daughters.

To derive minimum detectable change (MDC) across individual Vestibular-Ocular Motor Screening (VOMS) items and VOMS overall score in 17-25 years old collegiate athletes and to examine false positive rates.Participants (n = 378) completed VOMS pre-season for two consecutive years. MDC was identified for individual VOMS symptom items and NPC distance (cm). Both total and change methods of VOMS scoring were included in analysis.Regarding total scoring, MDC for ocular VOMS symptom items was 1 and MDC for vestibular VOMS symptoms items was 2. MDC for NPC was 4 cm and for VOMS overall score was 10. Regarding change scoring, MDC for each VOMS symptom item was 1, and for VOMS overall score was 8. False positives ranged from 5.3% to 15.9%.This study presents MDCs for each VOMS item and overall VOMS score, using total and change scoring. These values can be considered true change outside measurement error with 95% confidence in a 17-25 year old collegiate athlete population.

Sport-related concussion is recognized as a significant injury with variable recovery rates. This study defined the acute natural history of sport concussion in male and female collegiate athletes participating in a broad array of sports. We conducted a prospective, longitudinal investigation among collegiate student athletes (n = 34,709) from 30 academic institutions. Primary outcomes included the time (days) from injury until initiation of a return to participation (RTP) protocol and time from injury until medical clearance for unrestricted RTP. Concussed athletes (n = 1751, 19.2 years, 63.2% male) participating in 22 different sports began the RTP protocol in a median 6.4 (IQR 3.7–11.8) days. Time to initiate the RTP protocol was lengthened by less frequent post-injury assessments, greater initial post-injury symptom severity, limited contact sports participation, practice/training injuries, and three or more prior concussions. The median total RTP duration was 12.8 (IQR 8.7–20.1) days. Total RTP duration was shorter with ADHD medication usage, males, and greater assessment frequency; while greater initial post-injury symptom severity, practice-/training-related injuries, and three or more prior concussions had longer recoveries. Although median recovery times are consistent with previous guidelines, it was not until 1 month post-injury that a preponderance of collegiate athletes were cleared to begin the RTP protocol (92%) or cleared for unrestricted sport participation (85%). Intrinsic and extrinsic factors had a small effect, altering recovery trajectories by up to 2 days, suggesting a largely unified approach to post-injury monitoring and management across all athletes. These data represent a shift from previous classification parameters of normal clinical recovery.

The purpose of this study was to examine the association between sports participation history, including estimated age of first exposure (eAFE) to high-risk sports, and concussion history in first year (i.e., freshmen) collegiate athletes. Athletes increased their odds of sustaining a pre-college concussion by 5% [odds ratio(OR) = 1.05 (95%CI:1.05-1.06)] for each additional year of contact sports participation - 24% of all student athletes reported one or more pre-college concussions. When eAFE was analysed dichotomously at age 12, a greater proportion of those who started playing football before age 12 reported a positive concussion history compared to those who started playing football at age 12 or later (Х2 = 4.483, p = 0.034, Phi = 0.049). When eAFE was analysed continuously, later eAFE to women's high-risk sports was associated with a lower likelihood of sustaining a pre-college concussion [OR = 0.93 (95%CI:0.88-0.98)]. Our findings suggest that there is a relationship between eAFE to football and to women's high-risk sports and concussion history.

The purpose of this study was to describe the mechanism of injury (MOI) and examine factors associated with greater risk for specific MOIs involving concussions in collegiate soccer players.Participants included 3,288 collegiate soccer players from 28 institutions across four competitive seasons, 2014-17. MOIs were documented for 262 soccer-related concussions during the study and placed into one of four categories: collisions, unintentional contact, aerial challenges, and others.70% of the concussions occurred in DI soccer players. Collisions and unintentional contact were the MOIs that resulted in 66.5% of all concussions. DI and DIII soccer players sustained more concussions by unintentional contact versus collisions and aerial challenges when compared to their DII counterparts. Defenders were more likely than midfielders to sustain concussions by aerial challenges than collisions. As expected, the field players experienced more concussions as a result of collisions, unintentional contact, and aerial challenges when compared to goalkeepers.Future research should explore preventive strategies for decreasing collisions, especially during aerial challenges while heading the soccer ball, and unintentional contacts from errant balls in soccer in order to decrease concussion risk.

Concussion is a growing public health concern and generating concussion prevention programs depends on identifying high-risk sports and characteristics. Identifying the roles of sport, sex, and participation level (e.g., high school versus collegiate athletics) in concussion risk would facilitate more informed decision-making regarding sports participation and generate better targeted prevention strategies. The current study’s objectives were to: (1) determine the magnitude and hierarchy of sports-related concussion (SRC) risk across an array of events and (2) evaluate the modifying roles of sex, participation level, and session type on SRC rates. A literature search was conducted on PubMed, searching concussion studies published between 2001 and December 2019. Inclusion criteria for studies required: (1) concussion occurred during sport, (2) that the SRC was clinically diagnosed, and (3) athlete exposures and concussions could be extracted or estimated. A study was excluded if it: (1) was not an original research article, (2) was not written in English language, (3) was an animal study, (4) did not have enough data to calculate SRC rates, (5) included professional or youth sample, and/or (6) contained data collected prior to 2001. The meta-analysis and meta-regression analyses were fit using a random effects model. Search results returned 2695 unique research articles, with 83 studies included in analyses. Sport, sex, participation level, and session type all significantly influenced SRC rates. Overall, rugby had the highest concussion rate and was classified as the highest risk sport (28.25 concussions per 10,000 athlete exposures). Overall, females had a higher concussion rate than males. Only lacrosse demonstrated a higher concussion rate for males compared to females. Collegiate athletes had higher concussion rates than high school athletes. Games were associated with 2.01 more concussions per 10,000 AEs than practices. This meta-analysis demonstrated rugby has the highest concussion risk, followed by American Football, ice hockey, and wrestling. Concussion risk was influenced by sport, sex, participation, and session. Identifying the factors and environments that influence concussion risk can facilitate risk reduction and prevention strategies.

Highlights • Previous concussion was associated with 2 times increased odds of incident concussion, while wearing a mouthguard was protective against incident concussion, reducing odds by 57%. • Overall, concussion mechanisms did not significantly differ between sexes. • Females took significantly longer to reach asymptomatic and return-to-play clearance. Within the first 2 weeks post-concussion, 86.11% of males reached asymptomatic, while only 45.50% of females reached the same phase of recovery. • Most males (91.67%) were cleared for return-to-play within 3 weeks of their concussion, compared to less than one-half (45.50%) of females., Objective Since concussion is the most common injury in ice hockey, the objective of the current study was to elucidate risk factors, specific mechanisms, and clinical presentations of concussion in men's and women's ice hockey. Methods Ice hockey players from 5 institutions participating in the Concussion Assessment, Research, and Education Consortium were eligible for the current study. Participants who sustained a concussion outside of this sport were excluded. There were 332 (250 males, 82 females) athletes who participated in ice hockey, and 47 (36 males, 11 females) who sustained a concussion. Results Previous concussion (odds ratio (OR) = 2.00; 95% confidence interval (95% CI): 1.02‒3.91) was associated with increased incident concussion odds, while wearing a mouthguard was protective against incident concussion (OR = 0.43; 95%CI: 0.22‒0.85). Overall, concussion mechanisms did not significantly differ between sexes. There were specific differences in how concussions presented clinically across male and female ice hockey players, however. Females (9.09%) were less likely than males (41.67%) to have a delayed symptom onset (p = 0.045). Additionally, females took significantly longer to reach asymptomatic (p = 0.015) and return-to-play clearance (p = 0.005). Within the first 2 weeks post-concussion, 86.11% of males reached asymptomatic, while only 45.50% of females reached the same phase of recovery. Most males (91.67%) were cleared for return to play within 3 weeks of their concussion, compared to less than half (45.50%) of females. Conclusion The current study proposes possible risk factors, mechanisms, and clinical profiles to be validated in future concussions studies with larger female sample sizes. Understanding specific risk factors, concussion mechanisms, and clinical profiles of concussion in collegiate ice hockey may generate ideas for future concussion prevention or intervention studies., Graphical Abstract Image, graphical abstract

Preliminary evidence indicates that genetic factors associated with having a family history of neurodegenerative disease (fhNDD) may predispose an individual to persistent symptoms and poorer cognitive performance after concussion. No previous study, however, longitudinally examined athletes with (+) and without (-) a fhNDD. Therefore, we aimed to compare clinical symptoms and cognitive performance of fhNDD+ and fhNDD- athletes at baseline and at multiple time points after concussion. Questionnaire data from the Concussion Assessment, Research and Education (CARE) Consortium were used to identify male athletes and cadets with (

Symptom resolution is a key marker in determining fitness for return to activity following concussion, but in some cases, distinguishing persistent symptoms due to concussion versus symptoms related to other factors can be challenging. To determine base rates of postconcussional syndrome (PCS) diagnostic categorization in healthy cadets and student athletes with no recent concussion. 13,009 cadets and 21,006 student athletes completed baseline preseason testing. After inclusion/exclusion criteria were applied, the final sample included 12,039 cadets [9123 men (75.8%); 2916 women (24.2%)] and 18,548 student athletes [10,192 men (54.9%); 8356 women (45.1%)]. Participants completed the Sport Concussion Assessment Tool–3rd Edition (SCAT3) symptom evaluation as part of baseline preseason testing. The PCS diagnostic categorization was classified by the International Classification of Diseases, 10th Revision (ICD-10) symptom criteria for PCS. In the absence of recent concussion, subgroups of cadets (17.8% of men; 27.6% of women) and student athletes (11.4% of men; 20.0% of women) reported a cluster of symptoms that would meet the ICD-10 symptom criteria for PCS. Participants with insufficient sleep and/or preexisting conditions (e.g., mental health problems), freshmen cadets, and cadets at the U.S. Coast Guard Academy and at the U.S. Air Force Academy (freshmen were tested during basic cadet training) were more likely to report a cluster of symptoms that would meet the ICD-10 symptom criteria for PCS. The ICD-10 symptom criteria for PCS can be mimicked by preexisting conditions, insufficient sleep, and/or stress. Findings support person-specific assessment and management of symptoms following concussion.

Objective: As part of an initiative led by the Brain Injury Special Interest Group Mild Traumatic Brain Injury (TBI) Task Force of the American Congress of Rehabilitation Medicine (ACRM) to update the 1993 ACRM definition of mild TBI, the present study aimed to characterize current expert opinion on diagnostic considerations. Design: Cross-sectional web-based survey. Setting: Not applicable. Participants: An international, interdisciplinary group of clinician-scientists (N=31) with expertise in mild TBI completed the survey by invitation between May and July 2019 (100% completion rate). Interventions: Not applicable. Main Outcome Measures: Ratings of agreement with statements related to the diagnosis of mild TBI and ratings of the importance of various clinical signs, symptoms, test findings, and contextual factors for increasing the likelihood that the individual sustained a mild TBI, on a scale ranging from 1 (“not at all important”) to 10 (“extremely important”). Results: Men (n=25; 81%) and Americans (n=21; 68%) were over-represented in the sample. The survey revealed areas of expert agreement (eg, acute symptoms are diagnostically useful) and disagreement (eg, whether mild TBI with abnormal structural neuroimaging should be considered the same diagnostic entity as “concussion”). Observable signs were generally rated as more diagnostically important than subjective symptoms (Wilcoxon signed ranks test, Z=3.77; P

Purpose: Contact sport athletes are exposed to a unique environment where they sustain repeated head impacts throughout the season and can sustain hundreds of head impacts over a few months. Accordingly, recent studies outlined the role that head impact exposure (HIE) has in concussion biomechanics and in the development of cognitive and brain-based changes. Those studies focused on time-bound effects by quantifying exposure leading up to the concussion, or cognitive changes after a season in which athletes had high HIE. However, HIE may have a more prolonged effect. This study identified associations between HIE and concussion incidence during different periods of the college football fall season. Methods: This study included 1120 athlete seasons from six National Collegiate Athletic Association Division I football programs across 5 yr. Athletes were instrumented with the Head Impact Telemetry System to record daily HIE. The analysis quantified associations of preseason/regular season/total season concussion incidence with HIE during those periods. Results: Strong associations were identified between HIE and concussion incidence during different periods of the season. Preseason HIE was associated with preseason and total season concussion incidence, and total season HIE was associated with total season concussion incidence. Conclusions: These findings demonstrate a prolonged effect of HIE on concussion risk, wherein elevated preseason HIE was associated with higher concussion risk both during the preseason and throughout the entire fall season. This investigation is the first to provide evidence supporting the hypothesis of a relationship between elevated HIE during the college football preseason and a sustained decreased tolerance for concussion throughout that season. Grand Alliance Concussion Assessment, Research, and Education (CARE) Consortium; National Collegiate Athletic Association and the Department of Defense (DOD); US ArmyMedical Research Acquisition Activity (Fort DetrickMD); Office of the Assistant Secretary of Defense for Health Affairs through the Psychological Health and Traumatic Brain Injury Program [NO W81XWH-14-2-0151]; Veterans Affairs Medical Research; Department of Veterans Affairs Rehabilitation Research and Development Service; Department of Transportation, Office of Naval Research; National Institutes of Health (NIH); DOD; NIH; Department of Veterans Affairs; Abbott Laboratories; National Football League (NFL); Centers for Disease Control and Prevention; DOD-USA Medical Research Acquisition Activity, National Collegiate Athletic Association; National Athletic Trainers' Association Foundation; NFL/Under Armour/GE; Simbex; ElmindA; National Operating Committee on Standards for Athletic Equipment; NFL Published version This publication was made possible, in part, with support from the Grand Alliance Concussion Assessment, Research, and Education (CARE) Consortium, funded in part by the National Collegiate Athletic Association and the Department of Defense (DOD). The US ArmyMedical Research Acquisition Activity (Fort DetrickMD) is the awarding and administering acquisition office. This work was supported by the Office of the Assistant Secretary of Defense for Health Affairs through the Psychological Health and Traumatic Brain Injury Program under Award NO W81XWH-14-2-0151. Opinions, interpretations, conclusions, and recommendations are those of the author and are not necessarily endorsed by the Department of Defense (DHP funds). This work was also supported by Veterans Affairs Medical Research.; Beyond funding for this study reported in the Acknowledgments section, some authors also acknowledge other potential conflicts of interest. Dr. Stemper reported research funding from the DOD, Department of Veterans Affairs Rehabilitation Research and Development Service, the Department of Transportation, Office of Naval Research, and National Institutes of Health (NIH). Dr. McCrea reported additional research funding from the DOD, NIH, Department of Veterans Affairs, Abbott Laboratories, and the National Football League (NFL). Dr. Broglio has current or past research funding from the NIH; Centers for Disease Control and Prevention; DOD-USA Medical Research Acquisition Activity, National Collegiate Athletic Association; National Athletic Trainers' Association Foundation; NFL/Under Armour/GE; Simbex; and ElmindA. He is coauthor of Biomechanics of Injury (third edition, Human Kinetics), and he has consulted for US Soccer (paid), US Cycling (unpaid), and medicolegal litigation, and received speaker honorarium and travel reimbursements for talks given. He has a patent pending on "Brain Metabolism Monitoring Through CCO Measurements Using All-FiberIntegrated Super-Continuum Source" (US Application No. 17/164,490). Dr. Mihalik declares unrelated funding from the DOD, Centers for Disease Control and Prevention, NIH, National Operating Committee on Standards for Athletic Equipment, and the NFL.

Objective: To assess the concurrent validity and test re-test reliability of the Michigan Traumatic Brain Injury Identification Method (MTBIIM). The psychometric properties of this concussion index...

To develop a predictive model for sport-related concussion in collegiate athletes and military service academy cadets using baseline data collecting during the pre-participation examination. Baseline assessments were performed in 15,682 participants from 21 US academic institutions and military service academies participating in the CARE Consortium Study during the 2015–2016 academic year. Participants were monitored for sport-related concussion during the subsequent season. 176 baseline covariates mapped to 957 binary features were used as input into a support vector machine model with the goal of learning to stratify participants according to their risk for sport-related concussion. Performance was evaluated in terms of area under the receiver operating characteristic curve (AUROC) on a held-out test set. Model inputs significantly associated with either increased or decreased risk were identified. 595 participants (3.79%) sustained a concussion during the study period. The predictive model achieved an AUROC of 0.73 (95% confidence interval 0.70–0.76), with variable performance across sports. Features with significant positive and negative associations with subsequent sport-related concussion were identified. This predictive model using only baseline data identified athletes and cadets who would go on to sustain sport-related concussion with comparable accuracy to many existing concussion assessment tools for identifying concussion. Furthermore, this study provides insight into potential concussion risk and protective factors.

To optimally care for concussed individuals, a multi-dimensional approach is critical and a key component of this assessment in the athletic environment is computer-based neurocognitive testing. However, there continues to be concerns about the reliability and validity of these testing tools. The purpose of this study was to determine the sensitivity and specificity of three common computer-based neurocognitive tests (Immediate Post-Concussion Assessment and Cognitive Testing [ImPACT], CNS Vital Signs, and CogState Computerized Assessment Tool [CCAT]), to provide guidance on their clinical utility. This study analyzed assessments from a cohort of collegiate athletes and non-varsity cadets from the NCAA-DoD CARE Consortium. The data were collected from 2014–2018. Study participants were divided into two testing groups [concussed, n = 1414 (baseline/24–48 h) and healthy, n = 8305 (baseline/baseline)]. For each test type, change scores were calculated for the components of interest. Then, the Normative Change method, which used normative data published in a similar cohort, and the Reliable Change Index (RCI) method were used to determine if the change scores were significant. Using the Normative Change method, ImPACT performed best with an 87.5%-confidence interval and 1 number of components failed (NCF; sensitivity = 0.583, specificity = 0.625, F1 = 0.308). CNS Vital Signs performed best with a 90%-confidence interval and 1 NCF (sensitivity = 0.587, specificity = 0.532, F1 = 0.314). CCAT performed best when using a 75%-confidence interval and 2 NCF (sensitivity = 0.513, specificity = 0.715, F1 = 0.290). When using the RCI method, ImPACT performed best with an 87.5%-confidence interval and 1 NCF (sensitivity = 0.626, specificity = 0.559, F1 = 0.297). When considering all three computer-based neurocognitive tests, the overall low sensitivity and specificity results provide additional evidence for the use of a multi-dimensional assessment for concussion diagnosis, including symptom evaluation, postural control assessment, neuropsychological status, and other functional assessments.

OBJECTIVEPrevious studies have shown that clinically asymptomatic high-acceleration head impacts (HHIs) may be associated with neuronal and axonal injury, as measured by advanced imaging and biomarkers. Unfortunately, these methods of measurement are time-consuming, invasive, and costly. A quick noninvasive measurement tool is needed to aid studies of head injury and its biological impact. Quantitative pupillometry is a potential objective, rapid, noninvasive measurement tool that may be used to assess the neurological effects of HHIs. In this study, the authors investigated the effect of HHIs on pupillary metrics, as measured using a pupillometer, in the absence of a diagnosed concussion.METHODSA prospective observational cohort study involving 18 high school football athletes was performed. These athletes were monitored for both the frequency and magnitude of head impacts that they sustained throughout a playing season by using the Head Impact Telemetry System. An HHI was defined as an impact exceeding 95g linear acceleration and 3760 rad/sec2 rotational acceleration. Pupillary assessments were performed at baseline, midseason, after occurrence of an HHI, and at the end of the season by using the NeurOptics NPi-200 pupillometer. The Sport Concussion Assessment Tool, 5th Edition (SCAT5), was also used at each time point. Comparisons of data obtained at the various time points were calculated using a repeated-measures analysis of variance and a t-test.RESULTSSeven athletes sustained HHIs without a related diagnosed concussion. Following these HHIs, the athletes demonstrated decreases in pupil dilation velocity (mean difference 0.139 mm/sec; p = 0.048), percent change in pupil diameter (mean difference 3.643%; p = 0.002), and maximum constriction velocity (mean difference 0.744 mm/sec; p = 0.010), compared to measurements obtained at the athletes’ own midseason evaluations. No significant changes occurred between the SCAT5 subtest scores calculated at midseason and those after a high impact, although the effect sizes (Cohen’s d) on individual components ranged from 0.41 to 0.65.CONCLUSIONSMeasurable changes in pupil response were demonstrated following an HHI. These results suggest that clinically asymptomatic HHIs may affect brain reflex pathways, reflecting a biological injury previously seen when more invasive methods were applied.

Introduction Increased risk of musculoskeletal (MSK) injury post-concussion has been reported in collegiate athletes, yet it is unknown if professional football athletes are at the same risk of secondary injury. The objective of this study was to determine if the risk of MSK injury in National Football League (NFL) athletes increases after concussion. Methods NFL injury reports from 2013 to 2017 were collected from public websites. Concussed athletes (n=91) were equally matched to a non-injured control and an athlete with an incident of musculoskeletal (MSK) injury. Results Following their return to sport, concussed athletes were 2.35 times more likely to have a subsequent MSK injury relative to non-injured controls (95% CI: 2.35 [1.25, 4.44], P = 0.01), but were no more likely than athletes with an incident MSK injury (P = 0.55). Likewise, athletes with an incident MSK injury were no more likely to have a subsequent MSK injury than controls (P = 0.08). Discussion Increased odds of MSK injury in the 12-week period following a concussion in professional football athletes warrants future research on the acute effects of concussion and the relationship to MSK injury risk.

Concussion tolerance and head impact exposure are highly variable among football players. Recent findings highlight that head impact data analyses need to be performed at the subject level. In this paper, we describe a method of characterizing concussion risk between individuals using a new survival analysis technique developed with real-world head impact data in mind. Our approach addresses the limitations and challenges seen in previous risk analyses of football head impact data. Specifically, this demonstrative analysis appropriately models risk for a combination of left-censored recurrent events (concussions) and right-censored recurrent non-events (head impacts without concussion). Furthermore, the analysis accounts for uneven impact sampling between players. In brief, we propose using the Consistent Threshold method to develop subject-specific risk curves and then determine average risk point estimates between subjects at injurious magnitude values. We describe an approach for selecting an optimal cumulative distribution function to model risk between subjects by minimizing injury prediction error. We illustrate that small differences in distribution fit can result in large predictive errors. Given the vast amounts of on-field data researchers are collecting across sports, this approach can be applied to develop population-specific risk curves that can ultimately inform interventions that reduce concussion incidence.

ObjectiveTo examine the association between estimated age at first exposure (eAFE) to American football and clinical measures throughout recovery following concussion.MethodsParticipants were recruited across 30 colleges and universities as part of the National Collegiate Athletic Association (NCAA)–Department of Defense Concussion Assessment, Research and Education Consortium. There were 294 NCAA American football players (age 19 ± 1 years) evaluated 24–48 hours following concussion with valid baseline data and 327 (age 19 ± 1 years) evaluated at the time they were asymptomatic with valid baseline data. Participants sustained a medically diagnosed concussion between baseline testing and postconcussion assessments. Outcome measures included the number of days until asymptomatic, Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) composite scores, Balance Error Scoring System (BESS) total score, and Brief Symptom Inventory 18 (BSI-18) subscores. The eAFE was defined as participant's age at the time of assessment minus self-reported number of years playing football.ResultsIn unadjusted regression models, younger eAFE was associated with lower (worse) ImPACT Visual Motor Speed (R2 = 0.031, p = 0.012) at 24–48 hours following injury and lower (better) BSI-18 Somatization subscores (R2 = 0.014, p = 0.038) when the athletes were asymptomatic. The effect sizes were very small. The eAFE was not associated with the number of days until asymptomatic, other ImPACT composite scores, BESS total score, or other BSI-18 subscores.ConclusionEarlier eAFE to American football was not associated with longer symptom recovery, worse balance, worse cognitive performance, or greater psychological distress following concussion. In these NCAA football players, longer duration of exposure to football during childhood and adolescence appears to be unrelated to clinical recovery following concussion.

ObjectiveTo study longitudinal recovery trajectories of white matter after sports-related concussion (SRC) by performing diffusion tensor imaging (DTI) on collegiate athletes who sustained SRC.MethodsCollegiate athletes (n = 219, 82 concussed athletes, 68 contact-sport controls, and 69 non–contact-sport controls) were included from the Concussion Assessment, Research and Education Consortium. The participants completed clinical assessments and DTI at 4 time points: 24 to 48 hours after injury, asymptomatic state, 7 days after return-to-play, and 6 months after injury. Tract-based spatial statistics was used to investigate group differences in DTI metrics and to identify white-matter areas with persistent abnormalities. Generalized linear mixed models were used to study longitudinal changes and associations between outcome measures and DTI metrics. Cox proportional hazards model was used to study effects of white-matter abnormalities on recovery time.ResultsIn the white matter of concussed athletes, DTI-derived mean diffusivity was significantly higher than in the controls at 24 to 48 hours after injury and beyond the point when the concussed athletes became asymptomatic. While the extent of affected white matter decreased over time, part of the corpus callosum had persistent group differences across all the time points. Furthermore, greater elevation of mean diffusivity at acute concussion was associated with worse clinical outcome measures (i.e., Brief Symptom Inventory scores and symptom severity scores) and prolonged recovery time. No significant differences in DTI metrics were observed between the contact-sport and non–contact-sport controls.ConclusionsChanges in white matter were evident after SRC at 6 months after injury but were not observed in contact-sport exposure. Furthermore, the persistent white-matter abnormalities were associated with clinical outcomes and delayed recovery time.

Context Assessments of the duration of concussion recovery have primarily been limited to sport-related concussions and male contact sports. Furthermore, whereas durations of symptoms and return-to-activity (RTA) protocols encompass total recovery, the trajectory of each duration has not been examined separately. Objective To identify individual (eg, demographics, medical history), initial concussion injury (eg, symptoms), and external (eg, site) factors associated with symptom duration and RTA-protocol duration after concussion. Design Cohort study. Setting Three US military service academies. Patients or Other Participants A total of 10 604 cadets at participating US military service academies enrolled in the study and completed a baseline evaluation and up to 5 postinjury evaluations. A total of 726 cadets (451 men, 275 women) sustained concussions during the study period. Main Outcome Measure(s) Number of days from injury (1) until the participant became asymptomatic and (2) to complete the RTA protocol. Results Varsity athlete cadets took less time than nonvarsity cadets to become asymptomatic (hazard ratio [HR] = 1.75, 95% confidence interval = 1.38, 2.23). Cadets who reported less symptom severity on the Sport Concussion Assessment Tool, third edition (SCAT3), within 48 hours of concussion had 1.45 to 3.77 times shorter symptom-recovery durations than those with more symptom severity. Similar to symptom duration, varsity status was associated with a shorter RTA-protocol duration (HR = 1.74, 95% confidence interval = 1.34, 2.25), and less symptom severity on the SCAT3 was associated with a shorter RTA-protocol duration (HR range = 1.31 to 1.47). The academy that the cadet attended was associated with the RTA-protocol duration (P < .05). Conclusions The initial total number of symptoms reported and varsity athlete status were strongly associated with symptom and RTA-protocol durations. These findings suggested that external (varsity status and academy) and injury (symptom burden) factors influenced the time until RTA.

Context Preseason testing can be time intensive and cost prohibitive. Therefore, using normative data for postconcussion interpretation in lieu of preseason testing is desirable. Objective To establish the recovery trajectory for clinical reaction time (RTclin) and assess the usefulness of changes from baseline (comparison of postconcussion scores with individual baseline scores) and norm-based cutoff scores (comparison of postconcussion scores with a normative mean) for identifying impairments postconcussion. Design Case-control study. Setting Multisite clinical setting. Patients or Other Participants An overlapping sample of 99 participants (age = 19.0 ± 1.1 years) evaluated within 6 hours postconcussion, 176 participants (age = 18.9 ± 1.1 years) evaluated at 24 to 48 hours postconcussion, and 214 participants (age = 18.9 ± 1.1 years) evaluated once they were cleared to begin a return-to-play progression were included. Participants with concussion were compared with 942 control participants (age = 19.0 ± 1.0 years) who did not sustain a concussion during the study period but completed preseason baseline testing at 2 points separated by 1 year (years 1 and 2). Main Outcome Measure(s) At each time point, follow-up RTclin (ie, postconcussion or year 2) was compared with the individual year 1 preseason baseline RTclin and normative baseline data (ie, sex and sport specific). Receiver operating characteristic curves were calculated to compare the sensitivity and specificity of RTclin change from baseline and norm-based cutoff scores. Results Clinical reaction time performance declined within 6 hours (18 milliseconds, 9.2% slower than baseline). The decline persisted at 24 to 48 hours (15 milliseconds, 7.6% slower than baseline), but performance recovered by the time of return-to-play initiation. Within 6 hours, a change from baseline of 16 milliseconds maximized combined sensitivity (52%) and specificity (79%, area under the curve [AUC] = 0.702), whereas a norm-based cutoff score of 19 milliseconds maximized combined sensitivity (46%) and specificity (86%, AUC = 0.700). At 24 to 48 hours, a change from baseline of 2 milliseconds maximized combined sensitivity (64%) and specificity (61%, AUC = 0.666), whereas a norm-based cutoff score of 0 milliseconds maximized combined sensitivity (63%) and specificity (62%, AUC = 0.647). Conclusions Norm-based cutoff scores can be used for interpreting RTclin scores postconcussion in collegiate athletes when individual baseline data are not available, although low sensitivity and specificity limit the use of RTclin as a stand-alone test.

Context Comprehensive assessments are recommended to evaluate sport-related concussion (SRC). The degree to which the King-Devick (KD) test adds novel information to an SRC evaluation is unknown. Objective To describe relationships at baseline among the KD and other SRC assessments and explore whether the KD provides unique information to a multimodal baseline concussion assessment. Design Cross-sectional study. Setting Five National Collegiate Athletic Association institutions participating in the Concussion Assessment, Research and Education (CARE) Consortium. Patients or Other Participants National Collegiate Athletic Association student-athletes (N = 2258, age = 20 ± 1.5 years, 53.0% male, 68.9% white) in 11 men's and 13 women's sports. Main Outcome Measure(s) Participants completed baseline assessments on the KD and (1) the Symptom Inventory of the Sport Concussion Assessment Tool–3rd edition, (2) the Brief Symptom Inventory-18, (3) the Balance Error Scoring System, (4) the Standardized Assessment of Concussion (SAC), (5) the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) test battery, and (6) the Vestibular/Ocular Motor Screening tool during their first year in CARE. Correlation coefficients between the KD and the 6 other concussion assessments in isolation were determined. Assessments with ρ magnitude >0.1 were included in a multivariate linear regression analysis to evaluate their relative association with the KD. Results Scores for SAC concentration, ImPACT visual motor speed, and ImPACT reaction time were correlated with the KD (ρ = −0.216, −0.276, and 0.164, respectively) and were thus included in the regression model, which explained 16.8% of the variance in baseline KD time (P < .001, Cohen f2 = 0.20). Better SAC concentration score (β = −.174, P < .001), ImPACT visual motor speed (β = −.205, P < .001), and ImPACT reaction time (β = .056, P = .020) were associated with faster baseline KD performance, but the effect sizes were small. Conclusions Better performance on cognitive measures involving concentration, visual motor speed, and reaction time was weakly associated with better baseline KD performance. Symptoms, psychological distress, balance, and vestibular-oculomotor provocation were unrelated to KD performance at baseline. The findings indicate limited overlap at baseline among the CARE SRC assessments and the KD.

ContextThe King-Devick (KD) test has received considerable attention in the literature as an emerging concussion assessment. However, important test psychometric properties remain to be addressed in large-scale independent studies.ObjectiveTo assess (1) test-retest reliability between trials, (2) test-retest reliability between years 1 and 2, and (3) reliability of the 2 administration modes.DesignCross-sectional study.SettingCollegiate athletic training facilities.Patients or Other ParticipantsA total of 3248 intercollegiate student-athletes participated in year 1 (male = 55.3%, age = 20.2 ± 2.3 years, height = 1.78 ± 0.11 m, weight = 80.7 ± 21.0 kg) and 833 participated in both years.Main Outcome Measure(s)Time, in seconds, to complete the KD error free. The KD test reliability was assessed between trials and between annual tests over 2 years and stratified by test modality (spiral-bound cards [n = 566] and tablet [n = 264]).ResultsThe KD test was reliable between trials (trial 1 = 43.2 ± 8.3 seconds, trial 2 = 40.8 ± 7.8 seconds; intraclass correlation coefficient [ICC] (2,1) = 0.888, P < .001), between years (year 1 = 40.8 ± 7.4 seconds, year 2 = 38.7 ± 7.7 seconds; ICC [2,1] = 0.827, P < .001), and for both spiral-bound cards (ICC [2,1] = 0.834, P < .001) and tablets (ICC [2,1] = 0.827, P < .001). The mean change between trials for a single test was −2.4 ± 3.8 seconds. Although most athletes improved from year 1 to year 2, 27.1% (226 of 883) of participants demonstrated worse (slower) KD times (3.2 ± 3.9 seconds) in year 2.ConclusionsThe KD test was reliable between trials and years and when stratified by modality. A small improvement of 2 seconds was identified with annual retesting, likely due to a practice effect; however, 27% of athletes displayed slowed performance from year 1 to year 2. These results suggest that the KD assessment was a reliable test with modest learning effects over time and that the assessment modality did not adversely affect baseline reliability.

Objective: Neuropsychological evaluations include hold tests like word-reading ability as estimates of premorbid intellect thought to be resilient to the effects of neurologic insult. We te...

Background: Sport-related concussions (SRCs) are associated with short-term disablement, characterized as increased concussion symptoms and lower health-related quality of life (HRQoL). However, there are limited longitudinal data detailing how an SRC affects disablement beyond short-term injury recovery. Purpose: To longitudinally assess the effect of SRCs on symptoms and HRQoL in high school athletes through the 12 months after injury. Study Design: Cohort study; Level of evidence, 2. Methods: The 125 participants included high school athletes who sustained an SRC (female patients, 36%; mean ± SD age, 15.9 ± 1.1 years). The Post-concussion Symptom Scale (PCSS) from the Sport Concussion Assessment Tool–3 and the Pediatric Quality of Life Inventory 4.0 (PedsQL) were completed at enrollment and repeated at 24 to 72 hours (onset) and at 7 days (D7) after the SRC; on the date of return to play (RTP); and at 3, 6, and 12 months (M12) after the SRC. Scores at each time point were compared with the athletes’ own baseline via linear mixed models for repeated measures, controlling for age, sex, and history of previous SRC and with patient as a random effect. Results: Relative to baseline, female patients reported higher PCSS symptom and severity scores at onset ( P < .001) and D7 ( P < .001), while scores were not higher ( P > .05) for RTP through M12. As compared with baseline, male patients reported higher PCSS scores at onset ( P < .001) and D7 ( P = .003) and severity scores at onset ( P < .001) and D7 ( P = .016), while the symptom and severity scores were not higher ( P > .05) at RTP through M12. Female participants reported lower PedsQL physical scores at onset ( P = .006), while scores were not lower ( P > .05) from D7 through M12. Female psychosocial scores were not lower ( P > .05) at any time after the SRC, while the total PedsQL score was lower at onset ( P = .05) but not from D7 through M12. Male physical scores were lower at onset ( P < .001) and D7 ( P = .001) but not lower ( P > .05) from RTP through M12. Male psychosocial and PedsQL scores were unchanged ( P > .05) from baseline at onset through M12. Conclusion: After an SRC, high school athletes reported initial disablement (increased symptoms and lower HRQoL) through their RTP. However, after RTP, no similar disablement was detected through 12 months after injury.

Researchers have been collecting head impact data from instrumented football players to characterize the biomechanics of concussion for the past 15 years, yet the link between biomechanical input and clinical outcome is still not well understood. We have previously shown that even though concussive biomechanics might be unremarkable in large datasets of head impacts, the impacts causing injury are of high magnitude for the concussed individuals relative to their impact history. This finding suggests a need to account for differences in tolerance at the individual level. In this study, we identified control subjects for our concussed subjects who demonstrated traits we believed were correlated to factors thought to affect injury tolerance, including height, mass, age, race, and concussion history. A total of 502 college football players were instrumented with helmet-mounted accelerometer arrays and provided complete baseline assessment data, 44 of which sustained a total of 49 concussion. Biomechanical measures quantifying impact frequency and acceleration magnitude were compared between groups. On average, we found that concussed subjects experienced 93.8 more head impacts (p = 0.0031), 10.2 more high magnitude impacts (p = 0.0157), and 1.9 × greater risk-weighted exposure (p = 0.0175) than their physically matched controls. This finding provides further evidence that head impact data need to be considered at the individual level and that cohort wide assessments may be of little value in the context of concussion. Published version

Kutcher and Giza suggested incorporating levels of certainty in concussion diagnosis decisions. These guidelines were based on clinical experience rather than objective data. Therefore, we combined data-driven optimization with predictive modeling to identify which athletes are unlikely to have concussion and to classify remaining athletes as having possible, probable, or definite concussion with diagnostic certainty. We developed and validated our framework using data from the Concussion Assessment, Research, and Education (CARE) Consortium. Acute concussions had assessments at6 h (