No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Brain Injuries in Football
Abstract
American football participation is associated with a relatively high risk of sustaining mild traumatic brain injury or concussion. Concussion management practices have changed significantly over the past two decades due to rapidly progressing research. Several classic and newly emerging clinical tools are available to assist with acute diagnosis. Treatment paradigms have shifted away from prolonged rest toward earlier introduction of physical and cognitive activity. Multiple treatment interventions also exist for athletes with atypically long and complicated recoveries. Researchers are attempting to clarify the notorious heterogeneity associated with concussion presentations by identifying distinct clinical profiles and incorporating physiologic biomarkers intended to capture the complex and diverse biological effects of concussion. While thankfully rare, sports medicine clinicians must also recognize the signs of potential catastrophic injuries stemming from head trauma in football in order to guide proper acute management. Lastly, as researchers continue studying the long-term effects of football-related head trauma, clinicians should be aware of strategies for minimizing head impact exposure and for appropriately referring athletes concerned about cognitive or behavioral problems later in life.
ResearchGate has not been able to resolve any citations for this publication.
Importance
There is potential scientific and clinical value in validation of objective biomarkers for sport-related concussion (SRC).
Objective
To investigate the association of acute-phase blood biomarker levels with SRC in collegiate athletes.
Design, Setting, and Participants
This multicenter, prospective, case-control study was conducted by the National Collegiate Athletic Association (NCAA) and the US Department of Defense Concussion Assessment, Research, and Education (CARE) Consortium from February 20, 2015, to May 31, 2018, at 6 CARE Advanced Research Core sites. A total of 504 collegiate athletes with concussion, contact sport control athletes, and non–contact sport control athletes completed clinical testing and blood collection at preseason baseline, the acute postinjury period, 24 to 48 hours after injury, the point of reporting being asymptomatic, and 7 days after return to play. Data analysis was conducted from March 1 to November 30, 2019.
Main Outcomes and Measures
Glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), neurofilament light chain, and tau were quantified using the Quanterix Simoa multiplex assay. Clinical outcome measures included the Sport Concussion Assessment Tool–Third Edition (SCAT-3) symptom evaluation, Standardized Assessment of Concussion, Balance Error Scoring System, and Brief Symptom Inventory 18.
Results
A total of 264 athletes with concussion (mean [SD] age, 19.08 [1.24] years; 211 [79.9%] male), 138 contact sport controls (mean [SD] age, 19.03 [1.27] years; 107 [77.5%] male), and 102 non–contact sport controls (mean [SD] age, 19.39 [1.25] years; 82 [80.4%] male) were included in the study. Athletes with concussion had significant elevation in GFAP (mean difference, 0.430 pg/mL; 95% CI, 0.339-0.521 pg/mL; P < .001), UCH-L1 (mean difference, 0.449 pg/mL; 95% CI, 0.167-0.732 pg/mL; P < .001), and tau levels (mean difference, 0.221 pg/mL; 95% CI, 0.046-0.396 pg/mL; P = .004) at the acute postinjury time point compared with preseason baseline. Longitudinally, a significant interaction (group × visit) was found for GFAP (F7,1507.36 = 16.18, P < .001), UCH-L1 (F7,1153.09 = 5.71, P < .001), and tau (F7,1480.55 = 6.81, P < .001); the interaction for neurofilament light chain was not significant (F7,1506.90 = 1.33, P = .23). The area under the curve for the combination of GFAP and UCH-L1 in differentiating athletes with concussion from contact sport controls at the acute postinjury period was 0.71 (95% CI, 0.64-0.78; P < .001); the acute postinjury area under the curve for all 4 biomarkers combined was 0.72 (95% CI, 0.65-0.79; P < .001). Beyond SCAT-3 symptom score, GFAP at the acute postinjury time point was associated with the classification of athletes with concussion from contact controls (β = 12.298; 95% CI, 2.776-54.481; P = .001) and non–contact sport controls (β = 5.438; 95% CI, 1.676-17.645; P = .005). Athletes with concussion with loss of consciousness or posttraumatic amnesia had significantly higher levels of GFAP than athletes with concussion with neither loss of consciousness nor posttraumatic amnesia at the acute postinjury time point (mean difference, 0.583 pg/mL; 95% CI, 0.369-0.797 pg/mL; P < .001).
Conclusions and Relevance
The results suggest that blood biomarkers can be used as research tools to inform the underlying pathophysiological mechanism of concussion and provide additional support for future studies to optimize and validate biomarkers for potential clinical use in SRC.
3 Investigators. OBJECTIVE: To assess whether long-term treatment with candesartan/hydrochlorothiazide, rosuvastatin, or their combination can slow cognitive decline in older people at intermediate cardiovascular risk. METHODS: The Heart Outcomes Prevention Evaluation-3 (HOPE-3) study was a double-blind, randomized, placebo-controlled clinical trial using a 2 × 2 factorial design. Participants without known cardiovascular disease or need for treatment were randomized to candesartan (16 mg) plus hydrochlorothiazide (12.5 mg) or placebo and to rosuvastatin (10 mg) or placebo. Participants who were ≥70 years of age completed the Digit Symbol Substitution Test (DSST), the modified Montreal Cognitive Assessment, and the Trail Making Test Part B at baseline and study end. RESULTS: Cognitive assessments were completed by 2,361 participants from 228 centers in 21 countries. Compared with placebo, candesartan/hydrochlorothiazide reduced systolic blood pressure by 6.0 mm Hg, and rosuvastatin reduced low-density lipoprotein cholesterol by 24.8 mg/dL. Participants were followed up for 5.7 years (median), and 1,626 completed both baseline and study-end assessments. Mean participant age was 74 years (SD ±3.5 years); 59% were women; 45% had hypertension; and 24% had ≥12 years of education. The mean difference in change in DSST scores was-0.91 (95% confidence interval [CI]-2.25 to 0.42) for candesartan/hydrochlorothiazide compared with placebo,-0.54 (95% CI-1.88 to 0.80) for rosuvastatin compared with placebo, and-1.43 (95% CI-3.37 to 0.50) for combination therapy vs double placebo. No significant differences were found for other measures. CONCLUSIONS: Long-term blood pressure lowering with candesartan plus hydrochlorothiazide, rosuvastatin, or their combination did not significantly affect cognitive decline in older people. CLINICALTRIALSGOV IDENTIFIER: NCT00468923.
Importance
Sport-related concussion (SRC) is a significant public health problem without an effective treatment.
Objective
To assess the effectiveness of subsymptom threshold aerobic exercise vs a placebo-like stretching program prescribed to adolescents in the acute phase of recovery from SRC.
Design, Setting, and Participants
This multicenter prospective randomized clinical trial was conducted at university concussion centers. Male and female adolescent athletes (age 13-18 years) presenting within 10 days of SRC were randomly assigned to aerobic exercise or a placebo-like stretching regimen.
Interventions
After systematic determination of treadmill exercise tolerance on the first visit, participants were randomly assigned to a progressive subsymptom threshold aerobic exercise or a progressive placebo-like stretching program (that would not substantially elevate heart rate). Both forms of exercise were performed approximately 20 minutes per day, and participants reported daily symptoms and compliance with exercise prescription via a website.
Main Outcomes and Measures
Days from injury to recovery; recovery was defined as being asymptomatic, having recovery confirmed through an assessment by a physician blinded to treatment group, and returning to normal exercise tolerance on treadmill testing. Participants were also classified as having normal (<30 days) or delayed (≥30 days) recovery.
Results
A total of 103 participants were included (aerobic exercise: n = 52; 24 female [46%]; stretching, n = 51; 24 female [47%]). Participants in the aerobic exercise group were seen a mean (SD) of 4.9 (2.2) days after the SRC, and those in the stretching group were seen a mean (SD) of 4.8 (2.4) days after the SRC. There were no differences in age, sex, previous concussions, time from injury, initial symptom severity score, or initial exercise treadmill test and physical examination results. Aerobic exercise participants recovered in a median of 13 (interquartile range [IQR], 10-18.5) days, whereas stretching participants recovered in 17 (IQR, 13-23) days (P = .009 by Mann-Whitney test). There was a nonsignificant lower incidence of delayed recovery in the aerobic exercise group (2 participants [4%] in the aerobic group vs 7 [14%] in the placebo group; P = .08).
Conclusions and Relevance
This is, to our knowledge, the first RCT to show that individualized subsymptom threshold aerobic exercise treatment prescribed to adolescents with concussion symptoms during the first week after SRC speeds recovery and may reduce the incidence of delayed recovery.
Trial Registration
clinicaltrials.gov Identifier: NCT02710123.
Abstract Background Inflammation is considered a hallmark of concussion pathophysiology in experimental models, yet is understudied in human injury. Despite the growing use of blood biomarkers in concussion, inflammatory biomarkers have not been well characterized. Furthermore, it is unclear if the systemic inflammatory response to concussion differs from that of musculoskeletal injury. The purpose of this paper was to characterize systemic inflammation after injury in athletes with sport-related concussion or musculoskeletal injury. Methods A prospective, observational cohort study was conducted employing 175 interuniversity athletes (sport-related concussion, n = 43; musculoskeletal injury, n = 30; healthy, n = 102) from 12 sports at a sports medicine clinic at an academic institution. High-sensitivity immunoassay was used to evaluate 20 inflammatory biomarkers in the peripheral blood of athletes within 7 days of injury (subacute) and at medical clearance. Healthy athletes were sampled prior to the start of their competitive season. Partial least squares regression analyses were used to identify salient biomarker contributions to class separation between injured and healthy athletes, as well as to evaluate the relationship between biomarkers and days to recovery in injured athletes. Results In the subacute period after injury, compared to healthy athletes, athletes with sport-related concussion had higher levels of the chemokines’ monocyte chemoattractant protein-4 (p
Traumatic brain injury (TBI) is a major cause of death and disability worldwide, with mild TBI (mTBI) accounting for 85% of cases. mTBI is also implicated in serious long-term sequelae including second impact syndrome and chronic traumatic encephalopathy. mTBI often goes undiagnosed due to delayed symptom onset and limited sensitivity of conventional assessment measures compared with severe TBI. Current efforts seek to identify accurate and reliable non-invasive biomarkers associated with functional measures relevant to long-term outcomes. Here we evaluated the utility of serum and salivary microRNAs (miRNAs) to serve as sensitive and specific peripheral biomarkers of possible mTBI. Our primary objectives were to establish the relationship between peripheral measures of miRNA, objective quantification of head impacts, and sensitive indices of balance and cognitive function in healthy young adult athletes. A secondary objective was to compare the sensitivity of miRNA versus commonly used blood-based protein biomarkers. 50 amateur mixed martial arts (MMA) fighters participated. 216 saliva and serum samples were collected at multiple time points, both pre- and post-fight. Levels of 10 serum proteins were compared in a subset of the fighters (n = 24). Levels of miRNAs were obtained by next generation sequencing. Functional outcomes were evaluated using a computerized assessment system that measured cognitive performance, body sway, and combined cognitive performance and body sway during dual task completion. Data were analyzed using multivariate logistic regression for predictive classification, analysis of variance, correlation analysis and principal component analysis. We identified a subset of salivary and serum miRNAs that showed robust utility at predicting TBI likelihood and demonstrated quantitative associations with head impacts as well as cognitive and balance measures. In contrast, serum proteins demonstrated far less utility. We also found that the timing of the responses varies in saliva and serum, which is a critical observation for biomarker studies to consider.
Objectives
An observational study to compare the laminar distributions in frontal and temporal cortex of the tau-immunoreactive pathologies in chronic traumatic encephalopathy (CTE) and Alzheimer’s disease neuropathologic change (ADNC).
Patients
Post-mortem material of (1) four cases of CTE without ADNC, (2) seven cases of CTE with ADNC (CTE/ADNC), and (3) seven cases of ADNC alone.
Results
In CTE and CTE/ADNC, neurofibrillary tangles (NFT), neuropil threads (NT), and dot-like grains (DLG) were distributed either in upper cortex or across all layers. Low densities of astrocytic tangles (AT) and abnormally enlarged neurons (EN) were not localized to any specific layer. Surviving neurons exhibited peaks of density in both upper and lower cortex, and vacuole density was greatest in superficial layers. In ADNC, neuritic plaques (NP) were more frequent, AT rare, NFT and NT were more widely distributed, NT affected lower layers more frequently, and surviving neurons were less frequently bimodal than in CTE and CTE/ADNC.
Conclusion
Tau pathology in CTE and CTE/ADNC consistently affected the upper cortex but was more widely distributed in ADNC. The presence of CTE may encourage the development of ADNC pathology later in the course of the disease.
Objectives
The Sport Concussion Assessment Tool-5 (SCAT5) was published in 2017; however, normative performance within the college athlete population on the optional 10-item word list has not been described. This study reports normative values for immediate memory trials, total immediate memory score and delayed recall of the 10-item word list.
Methods
The SCAT5 was administered as part of the preparticipation medical testing to 514 collegiate student-athletes, aged 17–23 (M=19.65, SD=1.40; 64% male) prior to the 2017–2018 athletic season.
Results
On the SCAT5’s optional 10-item word list, with a total possible immediate memory score of 30, participants recalled an average of 20.57 (SD=3.22) words over three learning trials, with an average for trial 3 of 8.13 (SD=1.32). The average delayed memory score was 6.59 (SD=1.85). Small but significant demographic comparisons were found. Women scored higher on both immediate and delayed recall, non-native speakers scored higher on delayed recall, and Black/African-American athletes scored lower than White athletes on immediate, and lower than White and Hispanic/Latino athletes on delayed recall.
Conclusion
The 10-item word list on the SCAT5 eliminates the ceiling effect observed on the five-item word list of the SCAT3, therefore, increasing its clinical utility in the diagnosis of sports-related concussions. Significant demographic differences suggest use of category-specific norms for sex, native language and race/ethnicity.
Sport-related concussion (SRC) is a physiological brain injury that produces cerebral and systemic effects, including exercise intolerance. Exercise intolerance after concussion is believed to be the result of autonomic nervous system (ANS) dysfunction. Ventilation is inappropriately low for the level of exercise intensity, raising arterial carbon dioxide (PaCO2) levels. Elevated PaCO2 increases cerebral blood flow (CBF) out of proportion to exercise intensity, which is associated with symptoms that limit exercise performance. Thus, elevated exercise PaCO2 may signal incomplete recovery from SRC. This article reviews recent observational and experimental data and presents the evidence that subthreshold aerobic exercise normalizes the cerebrovascular physiological dysfunction and is "medicine" for patients with concussion and persistent postconcussive symptoms (PPCS). It discusses the systematic evaluation of exercise tolerance after concussion using the Buffalo Concussion Treadmill Test (BCTT) and reviews the utility of the Buffalo Concussion Bike Test (BCBT), the data from which are used to establish an individualized heart rate "dose" of subthreshold exercise to safely speed recovery, which also may work in the acute recovery phase after SRC with the potential to reduce the incidence of PPCS. Evaluation and treatment approaches based on the physiology of concussion suggest that exercise is medicine for concussion, potentially adding a new dimension to concussion care to help safely speed recovery and prevent PPCS in some patients.
Concussion is difficult to diagnose, particularly when symptoms are atypical or late in presenting. An accurate and timely initial assessment is crucial for clinical management. Cerebral spinal fluid (CSF) and blood markers of traumatic brain injury show promising results but their clinical applicability in concussion has significant limitations. In the study, we explored saliva as a new source of biomarkers of concussion. Saliva samples of concussed players were collected after 48-72 hours from concussion and analyzed by high-throughput technologies. A discovery group of 10 concussed rugby professional and semiprofessional athletes and 10 non-concussed matched controls was used for the analysis of 92 inflammatory proteins by the Proseek-Multiplex-Inflammation technology. In addition, saliva samples of 6 concussed and 6 non-concussed athletes were used to screen 800 human microRNAs (miRNAs) by the Nanostring technology. The results were then validated by RT-qPCR in an enlarged cohort (validation group) comprising 22 concussed athletes. Results showed, no significant variations of the 65 inflammatory proteins detected in saliva between groups but 5 microRNAs, miR-27b-3p (p=0.016), let-7i-5p (p=0.001), miR-142-3p (p=0.008), miR-107 (p=0.028), miR-135b-5p (p=0.017) significantly upregulated in concussed athletes. Univariate ROC curve analysis showed that the differentially expressed miRNAs could be considered good classifiers of concussion. Further analyses showed significant correlation between these microRNAs and Reaction Time component of the ImPACT concussion assessment tool. In addition, biocomputation analysis predicted the involvement of these microRNAs in important biological processes that might be related to trauma, such as response to hypoxia, cell death, neurogenesis, axon repair and myelination. Ease of access and non-invasiveness of saliva samples make these biomarkers particularly suitable for concussion assessment.
Objective:
To describe the methods of the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) and High School Reporting Information Online (HS RIO) system as a complement to the sport-specific manuscripts that will follow.
Background:
The NCAA-ISP and HS RIO collect injury and exposure data from samples of collegiate and high school sports programs, respectively. The NCAA-ISP, which the NCAA has maintained since 1982, was relaunched as a Web-based platform at the beginning of the 2004-2005 academic year. In 2005, the HS RIO was introduced to capture data on high school athletes and modeled after the NCAA-ISP. Relevant data are shared with the NCAA and high school sport and policy committees to develop evidence-based rules and programs that help protect the health and safety of student-athletes.
Description:
The NCAA-ISP and HS RIO monitor participation in school-sanctioned competitions and practices that occur from the first preseason practice to the final postseason contest for more than 25 sports. For this series of publications in the Journal of Athletic Training, injury information on 13 sports at the collegiate level during the 2004-2005 through 2013-2014 academic years and the high school level during the 2005-2006 through 2013-2014 academic years was evaluated.
Conclusions:
Athletic trainers have been a vital source of data collection over the past decade to help produce the largest datasets of high school and collegiate sports injuries. Such data have helped various sport and policy committees advance protocols that aim to increase sports safety. This series of publications will aid by continuing to provide data to stakeholders in the sports community.
This article presents results of a systematic review of the literature (2000–2017) examining the prevalence and correlates of psychological distress among retired elite athletes. Forty articles were selected and included. Our review suggests the prevalence of psychological distress among retired athletes is similar to that found in the general population. However, subgroups reporting medical comorbidities, significant pain, a greater number of concussions, less social support, and adverse psychosocial factors were at greater risk for psychological distress. Additionally, athletes experiencing psychological distress in retirement often do not seek treatment for their distress. Based on the existing literature, there is a need for greater standardization and use of reliable measures, as well as use of diagnostic interviews in order to assess the most accurate prevalence of psychological distress among these athletes. Longitudinal designs, matched control groups, more heterogeneous samples, and use of multivariate analyses would also help to more accurately determine the prevalence and risk factors of psychological distress in this population. This review suggests a number of different clinical implications and highlights directions for future research to enhance our understanding of the long-term psychological health of former elite athletes.
Background:
Many concussion assessment methods exist, but few studies quantify the performance of these methods to determine which can best assess acute concussion alone or in combination.
Objectives:
The objectives of this study were to evaluate: (1) selected concussion assessments for acute concussion assessment; (2) the utility of change scores for acute concussion assessment; and (3) concussion assessment capabilities when constrained to limited clinical data or objective clinical measures.
Methods:
The 'acute concussion' group contained assessments from < 6 h post-injury (n = 560) and 24-48 h post-injury (n = 733). The 'normal performance' group contained assessments from baseline testing (n = 842) and unrestricted return to play (n = 707) timepoints. Univariate and multivariate logistic regression models were created separately for < 6- and 24- to 48-h timepoints. Models were evaluated on sensitivity, specificity, and area under the receiver operating characteristic curve.
Results:
Within the univariate analysis, Sport Concussion Assessment Tool symptom assessments had the highest combination of sensitivity, specificity, and area under the receiver operating characteristic curve, with values up to 0.93, 0.97, and 0.98, respectively. Full models had a sensitivity, specificity, and area under the receiver operating characteristic curve up to 0.94, 0.97, and 0.99, respectively, and outperformed all univariate models, raw score models, and objective models. Objective models were outperformed by all multivariate models and the univariate models containing only Sport Concussion Assessment Tool symptom assessments.
Conclusion:
Results support the use of multidimensional assessment batteries over single instruments and suggest the importance of self-reported symptoms in acute concussion assessment. Balance assessments, however, may not provide additional benefit when symptom and neurocognitive assessments are available. Additionally, change scores provide some clinical utility over raw scores, but the difference may not be clinically meaningful.
IMPORTANCE Players of American football may be at increased risk of long-term neurological conditions, particularly chronic traumatic encephalopathy (CTE).
OBJECTIVE To determine the neuropathological and clinical features of deceased football players with CTE.
DESIGN, SETTING, AND PARTICIPANTS Case series of 202 football players whose brains were donated for research. Neuropathological evaluations and retrospective telephone clinical assessments (including head trauma history) with informants were performed blinded. Online questionnaires ascertained athletic and military history.
EXPOSURES Participation in American football at any level of play.
MAIN OUTCOMES AND MEASURES Neuropathological diagnoses of neurodegenerative diseases, including CTE, based on defined diagnostic criteria; CTE neuropathological severity (stages I to IV or dichotomized into mild [stages I and II] and severe [stages III and IV]); informant-reported athletic history and, for players who died in 2014 or later, clinical presentation, including behavior, mood, and cognitive symptoms and dementia.
RESULTS Among 202 deceased former football players (median age at death, 66 years [interquartile range, 47-76 years]), CTE was neuropathologically diagnosed in 177 players (87%; median age at death, 67 years [interquartile range, 52-77 years]; mean years of football participation, 15.1 [SD, 5.2]), including 0 of 2 pre–high school, 3 of 14 high school (21%), 48 of 53 college (91%), 9 of 14 semiprofessional (64%), 7 of 8 Canadian Football League (88%), and 110 of 111 National Football League (99%) players. Neuropathological severity of CTE was distributed across the highest level of play, with all 3 former high school players having mild pathology and the majority of former college (27 [56%]), semiprofessional (5 [56%]), and professional (101 [86%]) players having severe pathology. Among 27 participants with mild CTE pathology, 26 (96%) had behavioral or mood symptoms or both, 23 (85%) had cognitive symptoms, and 9 (33%) had signs of dementia. Among 84 participants with severe CTE pathology, 75 (89%) had behavioral or mood symptoms or both, 80 (95%) had cognitive symptoms, and 71 (85%) had signs of dementia.
CONCLUSIONS AND RELEVANCE In a convenience sample of deceased football players who donated their brains for research, a high proportion had neuropathological evidence of CTE, suggesting that CTE may be related to prior participation in football.
Objective
A systematic review of factors that might be associated with, or influence, clinical recovery from sport-related concussion. Clinical recovery was defined functionally as a return to normal activities, including school and sports, following injury.
Design
Systematic review.
Data sources
PubMed, PsycINFO, MEDLINE, CINAHL, Cochrane Library, EMBASE, SPORTDiscus, Scopus and Web of Science.
Eligibility criteria for selecting studies
Studies published by June of 2016 that addressed clinical recovery from concussion.
Results
A total of 7617 articles were identified using the search strategy, and 101 articles were included. There are major methodological differences across the studies. Many different clinical outcomes were measured, such as symptoms, cognition, balance, return to school and return to sports, although symptom outcomes were the most frequently measured. The most consistent predictor of slower recovery from concussion is the severity of a person’s acute and subacute symptoms. The development of subacute problems with headaches or depression is likely a risk factor for persistent symptoms lasting greater than a month. Those with a preinjury history of mental health problems appear to be at greater risk for having persistent symptoms. Those with attention deficit hyperactivity disorder (ADHD) or learning disabilities do not appear to be at substantially greater risk. There is some evidence that the teenage years, particularly high school, might be the most vulnerable time period for having persistent symptoms—with greater risk for girls than boys.
Conclusion
The literature on clinical recovery from sport-related concussion has grown dramatically, is mostly mixed, but some factors have emerged as being related to outcome.
Objective:
Systematic review of possible long-term effects of sports-related concussion in retired athletes.
Data sources:
Ten electronic databases.
Study selection:
Original research; incidence, risk factors or causation related to long-term mental health or neurological problems; individuals who have suffered a concussion; retired athletes as the subjects and possible long-term sequelae defined as >10 years after the injury.
Data extraction:
Study population, exposure/outcome measures, clinical data, neurological examination findings, cognitive assessment, neuroimaging findings and neuropathology results. Risk of bias and level of evidence were evaluated by two authors.
Results:
Following review of 3819 studies, 47 met inclusion criteria. Some former athletes have depression and cognitive deficits later in life, and there is an association between these deficits and multiple prior concussions. Former athletes are not at increased risk for death by suicide (two studies). Former high school American football players do not appear to be at increased risk for later life neurodegenerative diseases (two studies). Some retired professional American football players may be at increased risk for diminishment in cognitive functioning or mild cognitive impairment (several studies), and neurodegenerative diseases (one study). Neuroimaging studies show modest evidence of macrostructural, microstructural, functional and neurochemical changes in some athletes.
Conclusion:
Multiple concussions appear to be a risk factor for cognitive impairment and mental health problems in some individuals. More research is needed to better understand the prevalence of chronic traumatic encephalopathy and other neurological conditions and diseases, and the extent to which they are related to concussions and/or repetitive neurotrauma sustained in sports.
The 2017 Concussion in Sport Group (CISG) consensus statement is designed to build on the principles outlined in the previous statements1–4 and to develop further conceptual understanding of sport-related concussion (SRC) using an expert consensus-based approach. This document is developed for physicians and healthcare providers who are involved in athlete care, whether at a recreational, elite or professional level. While agreement exists on the principal messages conveyed by this document, the authors acknowledge that the science of SRC is evolving and therefore individual management and return-to-play decisions remain in the realm of clinical judgement.
This consensus document reflects the current state of knowledge and will need to be modified as new knowledge develops. It provides an overview of issues that may be of importance to healthcare providers involved in the management of SRC. This paper should be read in conjunction with the systematic reviews and methodology paper that accompany it. First and foremost, this document is intended to guide clinical practice; however, the authors feel that it can also help form the agenda for future research relevant to SRC by identifying knowledge gaps.
A series of specific clinical questions were developed as part of the consensus process for the Berlin 2016 meeting. Each consensus question was the subject of a specific formal systematic review, which is published concurrently with this summary statement. Readers are directed to these background papers in conjunction with this summary statement as they provide the context for the issues and include the scope of published research, search strategy and citations reviewed for each question. This 2017 consensus statement also summarises each topic and recommendations in the context of all five CISG meetings (that is, 2001, 2004, 2008, 2012 as well as 2016). Approximately 60 000 published articles were screened by the expert panels for the Berlin …
BACKGROUND
Currently, there is no evidence-based definition for concussion that is being uniformly applied in clinical and research settings.
OBJECTIVE
To conduct a systematic review of the highest-quality literature about concussion and to assemble evidence about the prevalence and associations of key indicators of concussion. The goal was to establish an evidence-based foundation from which to derive, in future work, a definition, diagnostic criteria, and prognostic indicators for concussion.
METHODS
Key questions were developed, and an electronic literature search from 1980 to 2012 was conducted to acquire evidence about the prevalence of and associations among signs, symptoms, and neurologic and cognitive deficits in samples of individuals exposed to potential concussive events. Included studies were assessed for potential for bias and confound and rated as high, medium, or low potential for bias and confound. Those rated as high were excluded from the analysis. Studies were further triaged on the basis of whether the definition of a case of concussion was exclusive or inclusive; only those with wide, inclusive case definitions were used in the analysis. Finally, only studies reporting data collected at fixed time points were used. For a study to be included in the conclusions, it was required that the presence of any particular sign, symptom, or deficit be reported in at least 2 independent samples.
RESULTS
From 5437 abstracts, 1362 full-text publications were reviewed, of which 231 studies were included in the final library. Twenty-six met all criteria required to be used in the analysis, and of those, 11 independent samples from 8 publications directly contributed data to conclusions. Prevalent and consistent indicators of concussion are (1) observed and documented disorientation or confusion immediately after the event, (2) impaired balance within 1 day after injury, (3) slower reaction time within 2 days after injury, and/or (4) impaired verbal learning and memory within 2 days after injury.
CONCLUSION
The results of this systematic review identify the consistent and prevalent indicators of concussion and their associations, derived from the strongest evidence in the published literature. The product is an evidence-based foundation from which to develop diagnostic criteria and prognostic indicators.
Background:
Conventional management for concussion involves prescribed rest and progressive return to activity. Recent evidence challenges this notion and suggests that active approaches may be effective for some patients. Previous concussion consensus statements provide limited guidance regarding active treatment.
Objective:
To describe the current landscape of treatment for concussion and to provide summary agreements related to treatment to assist clinicians in the treatment of concussion.
Methods:
On October 14 to 16, 2015, the Targeted Evaluation and Active Management (TEAM) Approaches to Treating Concussion meeting was convened in Pittsburgh, Pennsylvania. Thirty-seven concussion experts from neuropsychology, neurology, neurosurgery, sports medicine, physical medicine and rehabilitation, physical therapy, athletic training, and research and 12 individuals representing sport, military, and public health organizations attended the meeting. The 37 experts indicated their agreement on a series of statements using an audience response system clicker device.
Results:
A total of 16 statements of agreement were supported covering (1) Summary of the Current Approach to Treating Concussion, (2) Heterogeneity and Evolving Clinical Profiles of Concussion, (3) TEAM Approach to Concussion Treatment: Specific Strategies, and (4) Future Directions: A Call to Research. Support (ie, response of agree or somewhat agree) for the statements ranged from to 97% to 100%.
Conclusion:
Concussions are characterized by diverse symptoms and impairments and evolving clinical profiles; recovery varies on the basis of modifying factors, injury severity, and treatments. Active and targeted treatments may enhance recovery after concussion. Research is needed on concussion clinical profiles, biomarkers, and the effectiveness and timing of treatments.
Abbreviations:
ARS, audience response systemCDC, Centers for Disease Control and PreventionDoD, Department of DefensemTBI, mild traumatic brain injuryNCAA, National Collegiate Athletic AssociationNFL, National Football LeagueNIH, National Institutes of HealthRCT, randomized controlled trialRTP, return to playSRC, sport- and recreation-related concussionTBI, traumatic brain injuryTEAM, Targeted Evaluation and Active Management.
Background:
Sports medicine clinicians routinely use computerized neurocognitive testing in sport-related concussion management programs. Debates continue regarding the appropriateness of normative reference comparisons versus obtaining individual baseline assessments, particularly for populations with greater likelihood of having below- or above-average cognitive abilities. Improving normative reference methods could offer alternatives to perceived logistical and financial burdens imposed by universal baseline testing.
Objectives:
To develop and validate the Concussion Assessment, Research, and Education (CARE) Consortium Multiple Variable Prediction (MVP) norms for the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT).
Methods:
We developed the CARE-MVP norms for ImPACT composite scores using regression-based equations. Predictor variables included sex, race (white/Caucasian, black/African American, Asian, or Multiple Races), medical history [attention-deficit/hyperactivity disorder (ADHD), learning disorder (LD), prior concussion(s), prior psychiatric diagnosis], and an estimate of premorbid intellect (Wechsler Test of Adult Reading). CARE-MVP norms were first validated in an independent sample of healthy collegiate athletes by comparing predicted and actual baseline test scores using independent-samples t-tests and Cohen's d effect sizes. We then evaluated base rates of low scores in athletes self-reporting ADHD/LD (vs. non-ADHD/LD) and black/African American race (vs. white/Caucasian) across multiple normative reference methods (Chi square, Cramer's V effect size). Lastly, we validated the CARE-MVP norms in a concussed sample (dependent samples t test, Cohen's d effect size).
Results:
A total of 5233 collegiate athletes (18.8 ± 1.2 years, 70.5% white/Caucasian, 39.1% female) contributed to the CARE-MVP norms (development N = 2616; internal validation N = 2617). Race and WTAR score were the strongest and most consistent ImPACT score predictors. There were negligible mean differences between observed and predicted (CARE-MVP) baseline scores (Cohen's d < 0.1) for all ImPACT composite scores except Reaction Time (predicted ~ 20 ms faster than observed, d = - 0.28). Low score base rates were similar for athletes across subpopulations when using CARE-MVP norms (ADHD/LD, V = 0.017-0.028; black/African American, V = 0.043-0.053); while, other normative reference methods resulted in disproportionately higher rates of low scores (ADHD/LD, V = 0.062-0.101; black/African American race, V = 0.163-0.221). Acute (24-48 h) postconcussion ImPACT scores were significantly worse than CARE-MVP norms but notably varied as a function of concussion symptom severity.
Conclusions:
Results support CARE-MVP norm use in populations typically underrepresented or not adjusted for in traditional normative reference samples, such as those self-reporting ADHD/LD or black/African American race. CARE-MVP norms improve upon prior normative methods and may offer a practical, simple alternative for collegiate institutions concerned about logistical and financial burden associated with baseline testing. An automated scoring program is provided.
We prospectively evaluated serum concentrations of glial fibrillary acidic protein (GFAP), ubiquitin c-terminal hydrolase L1 (UCH-L1), total tau (T-Tau), and neurofilament light (NF-L) from collegiate athletes at baseline and acutely after sport-related concussion (SRC) using the Quanterix Neurology 4Plex "B" (N4PB) multiplex assay. Uninjured controls were matched on age, sex, race, sport, and concussion history. Clinical outcomes included acute symptom severity, balance, rapid automated naming, computerized cognitive testing, and recovery duration. Baseline (n=110; median [IQR] age =19 [18-20] years, 54% male, 61% white/Caucasian) and post-SRC (n=36; median [IQR] age = 19 [18-20] years, 50% male, 61% white/Caucasian) blood samples were analyzed. We observed post-SRC elevations from baseline for GFAP (p=.001, d=1.7), T-Tau (p=.004, d=1.3), and NF-L (p=.010, d=1.1). GFAP (AUC=.958, 95%CI .927-.989, p<.001) and NF-L (AUC=.904, 95%CI .851-.957, p<.001) accurately discriminated SRC from control cases. There were no associations between biomarker concentrations and clinical measurements post-SRC or recovery duration. These findings suggest that, using the multiplex assay, GFAP, T-Tau, and NF-L elevate from baseline acutely after SRC, and both GFAP and NF-L excellently distinguished concussed from control cases. Serum biomarker changes do not necessarily correspond with clinical measurements or recovery duration. Key Words: Concussion, TBI, biomarkers, multiplex, brain injury.
Sport-related concussion (SRC) is a heterogeneous injury that involves varied symptoms and impairment that presents a significant clinical challenge to sports medicine professionals. In response to this challenge, clinical researchers have proposed clinical profiles or subtype models for assessing and treating athletes with SRC. One such model emphasizes five concussion clinical profiles including cognitive/fatigue, vestibular, ocular, migraine, and anxiety/mood. Sleep is a common modifier that co-occurs across these clinical profiles. A combination of medical history, risk factors, injury information, clinical characteristics, and assessment outcomes can inform each clinical profile. Preliminary data involving 236 patients from a concussion specialty clinic indicate that the migraine (26%) and anxiety/mood (24%) profiles are the most common, with vestibular and ocular profiles combined representing more than one third (35%) of clinical profiles. Findings also support several relationships among different clinical profiles including vestibular and migraine, suggesting that many athletes present with multiple clinical profiles. Targeted, active treatments for each profile are discussed.
Sport-related concussion (SRC) is a common injury in recreational and organized sport. Over the past 30 years, there has been significant progress in our scientific understanding of SRC, which in turn has driven the development of clinical guidelines for diagnosis, assessment, and management of SRC. In addition to a growing need for knowledgeable health care professionals to provide evidence-based care for athletes with SRC, media attention and legislation have created awareness and, in some cases, fear about many issues and unknowns surrounding SRC. The American Medical Society for Sports Medicine formed a writing group to review the existing literature on SRC, update its previous position statement, and address current evidence and knowledge gaps regarding SRC. The absence of definitive outcomes-based data is challenging and requires relying on the best available evidence integrated with clinical experience and patient values. This statement reviews the definition, pathophysiology, and epidemiology of SRC, the diagnosis and management of both acute and persistent concussion symptoms, the short- and long-term risks of SRC and repetitive head impact exposure, SRC prevention strategies, and potential future directions for SRC research. The American Medical Society for Sports Medicine is committed to best clinical practices, evidence-based research, and educational initiatives that positively impact the health and safety of athletes.
Objective: Explore changes in micro-RNA (miRNA) expression in blood after sport-related concussion (SRC) in collegiate athletes.
Methods: Twenty-seven collegiate athletes (~41% male, ~75% white, age 18.8 ± 0.8 years) provided both baseline and post-SRC blood samples. Serum was analyzed for expression of miR-153-3p (n = 27), miR-223-3p (n = 23), miR-26a-5p (n = 26), miR-423-3p (n = 23), and miR-let-7a-5p (n = 23) at both time points via quantitative polymerase chain reaction (qPCR). Nonparametric analyses were used to compare miRNA expression changes between baseline and SRC and to evaluate associations with clinical outcomes (symptom severity, cognition, balance, and oculomotor function, and clinical recovery time).
Results: Participants manifested a significant increase in miRNA expression following SRC for miR153-3p (Z = −2.180, p = .029, 59% of the participants increased post-SRC), miR223-3p (Z = −1.998, p = .046, 70% increased), and miR-let-7a-5p (Z = −2.190, p = .029, 65% increased). There were no statistically significant associations between changes in miRNA expression and clinical test scores, acute symptom severity, or clinical recovery time.
Conclusion: MiR-153-3p, miR-223-3p, and miR-let-7a-5p were significantly upregulated acutely following SRC in male and female collegiate athletes compared to baseline levels, though several athletes demonstrated no change or a decrease in expression. The biological mechanisms and functional implications of the increased expression of these circulating miRNA are unclear and require more research, as does their relevance to clinical outcomes.
Sport-related concussion (SRC) is a common injury in recreational and organised sport. Over the past 30 years, there has been significant progress in our scientific understanding of SRC, which in turn has driven the development of clinical guidelines for diagnosis, assessment and management of SRC. In addition to a growing need for knowledgeable healthcare professionals to provide evidence-based care for athletes with SRC, media attention and legislation have created awareness and, in some cases, fear about many issues and unknowns surrounding SRC. The American Medical Society for Sports Medicine (AMSSM) formed a writing group to review the existing literature on SRC, update its previous position statement, and to address current evidence and knowledge gaps regarding SRC. The absence of definitive outcomes-based data is challenging and requires relying on the best available evidence integrated with clinical experience and patient values. This statement reviews the definition, pathophysiology and epidemiology of SRC, the diagnosis and management of both acute and persistent concussion symptoms, the short-term and long-term risks of SRC and repetitive head impact exposure, SRC prevention strategies, and potential future directions for SRC research. The AMSSM is committed to best clinical practices, evidence-based research and educational initiatives that positively impact the health and safety of athletes.
The term chronic traumatic encephalopathy (CTE) has recently entered public consciousness via media reports and even a Hollywood movie. However, in contrast to general impressions, the incidence of CTE is unknown, the clinical diagnostic criteria have not been agreed upon and the current neuropathological characterization of CTE is acknowledged as preliminary. Additionally, few studies have compared the pathologies of CTE with those of other neurodegenerative disorders or of age-matched controls. Consequently, disagreement continues about the neuropathological aspects that make CTE unique. Furthermore, CTE is widely considered to be a consequence of exposure to repeated head blows, but evidence suggests that a single moderate or severe traumatic brain injury can also induce progressive neuropathological changes. These unresolved aspects of CTE underlie disparate claims about its clinical and pathological features, leading to confusion among the public and health-care professionals alike.
Previous studies have shown that mild traumatic brain injury (mTBI) can cause abnormalities in clinically relevant magnetic resonance imaging (MRI) sequences. No large-scale study, however, has prospectively assessed this in athletes with sport-related concussion (SRC). The aim of the current study was to characterize and compare the prevalence of acute, trauma-related MRI findings and clinically significant, non-specific MRI findings in athletes with and without SRC. College and high-school athletes were prospectively enrolled and participated in scanning sessions between January 2015 through August 2017. Concussed contact sport athletes (n = 138; 14 female [F]; 19.5 ± 1.6 years) completed up to four scanning sessions after SRC. Non-concussed contact (n = 135; 15 F; 19.7 ± 1.6) and non-contact athletes (n = 96; 15 F; 20.0 ± 1.7) completed similar scanning sessions and served as controls. Board-certified neuroradiologists, blinded to SRC status, reviewed T1-weighted and T2-weighted fluid-attenuated inversion recovery and T2*-weighted and T2-weighted images for acute (i.e., injury-related) or non-acute findings that prompted recommendation for clinical follow-up. Concussed athletes were more likely to have MRI findings relative to contact (30.4% vs. 15.6%; odds ratio [OR] = 2.32; p = 0.01) and non-contact control athletes (19.8%; OR = 2.11; p = 0.04). Female athletes were more likely to have MRI findings than males (43.2% vs. 19.4%; OR = 2.62; p = 0.01). One athlete with SRC had an acute, injury-related finding; group differences were largely driven by increased rate of non-specific white matter hyperintensities in concussed athletes. This prospective, large-scale study demonstrates that <1% of SRCs are associated with acute injury findings on qualitative structural MRI, providing empirical support for clinical guidelines that do not recommend use of MRI after SRC.
The kickoff return in football, in which athletes run at speed toward each other over a long distance with the potential for significant impacts, has been associated with a substantial number of concussions.¹ In 2015 in the Ivy League, a Division 1 conference of 8 private universities in the National Collegiate Athletic Association (NCAA), kickoffs accounted for 6% of all plays but 21% of concussions.² In response, Ivy League football coaches recommended a rule change. In 2016, the kickoff line was moved from the 35-yd to the 40-yd line and the touchback line was moved from the 25-yd to the 20-yd line. The intention was to have more kickoffs land in the end zone and thereby reduce the likelihood the receiving player will advance the ball, thus increasing touchbacks. However, moving the touchback line to the 20-yd line could cause receivers to try to advance the ball, possibly decreasing touchbacks.
Context:
The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of football injury data.
Objective:
To describe the epidemiology of injuries sustained in high school football in the 2005-2006 through 2013-2014 academic years and collegiate football in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance.
Design:
Descriptive epidemiology study.
Setting:
Online injury surveillance from football teams of high school boys (annual average = 100) and collegiate men (annual average = 43).
Patients or other participants:
Football players who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school and the 2004-2005 through 2013-2014 academic years in college.
Main outcome measure(s):
Athletic trainers collected time-loss injury (≥24 hours) and exposure data. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), injury proportions by body site and diagnosis were calculated.
Results:
The High School Reporting Information Online system documented 18 189 time-loss injuries during 4 539 636 AEs; National Collegiate Athletic Association Injury Surveillance Program documented 22 766 time-loss injuries during 3 121 476 AEs. The injury rate was higher among collegiate than high school (7.29 versus 4.01/1000 AEs; IRR = 1.82; 95% CI = 1.79, 1.86) athletes. Most injuries occurred during competitions in high school (53.2%) and practices in college (60.9%). The competition injury rate was higher than the practice injury rate among both high school (IRR = 5.62; 95% CI = 5.46, 5.78) and collegiate (IRR = 6.59; 95% CI = 6.41, 6.76) players. Most injuries at both levels affected the lower extremity and the shoulder/clavicle and were diagnosed as ligament sprains and muscle/tendon strains. However, concussion was a common injury during competitions among most positions.
Conclusions:
Injury rates were higher in college than in high school and higher for competitions than for practices. Concussion was a frequent injury sustained during competitions, which confirms the need to develop interventions to mitigate its incidence and severity.
This study investigated drill-specific head impact biomechanics in a Division 1 collegiate football team using the Head Impact Telemetry System (HITS). A total of 32,083 impacts were recorded across 2 years of practices. Precise tracking of instrumented athletes, head impacts, and drill participation allowed quantification of hits sustained per person per minute (H/P/M) for each specific drill. We found significant H/P/M variability between 14 drills and player position, ranging from 0.02 to 0.41 H/P/M for Linemen and 0.01 to 0.15 H/P/M for Non-Linemen. Impact magnitude data are also reported for practice term (Spring, Training Camp, In-Season) and dress-type (Helmets Only, Spyders, Shells, Full Pads). Recommendations for shortening high-risk drills, based on H/P/M drill impact frequencies, suggest possible "friendly fire" reductions of 1000 impacts for Linemen and 300 impacts for Non-Linemen over their collegiate career. Over 80% of potentially avoidable head impacts were attributable to just three drills-"Team Run," "Move the Field," and "Team." Recommending drill-specific modifications based on practical considerations (the drill's impact frequency, dress-types when performing the drill, and duration) could improve acceptance from coaches and efficiently reduce head impact exposure without drastically altering overall practice structure.
Objective:
Evaluate the rate of concussions across Big 12 Conference football programs based on (1) equipment worn, (2) contact level, (3) preseason practice versus in-season practice versus games, and (4) mechanism of injury for concussion.
Design:
Descriptive epidemiology study.
Setting:
Big 12 Conference football practices and competitions.
Patients (or participants):
Big 12 Conference football teams.
Assessment of risk factors:
All Big 12 Conference institutions collected data on practice types, equipment worn, practice and game participation, and concussions during the fall, preseasons and regular seasons, from 2013 to 2016.
Main outcome measures:
Injury rates and injury rate ratios were reported with 95% confidence intervals (CIs).
Results:
From 2013 to 2016, there were 375 concussions reported [0.98/1000 athlete exposures (AEs) (95% CI, 0.88-1.08)], an average of approximately 9 concussions per team per year. Concussion rates were highest in games (5.73/1000 AE), but among practices, concussion rates were highest in full-pad (1.18/1000 AEs) and live-contact (1.28/1000 AEs) practices. Concussion rates increased with increasing contact and equipment worn. Concussion rates were higher in the preseason than in the regular season, even when stratifying by contact level and equipment worn.
Conclusions:
Practice concussion rates are highest during fully padded and live-contact practices, supporting limitations on practice contact and equipment worn to reduce the risk associated with head-impact exposure. Higher concussion rates in the preseason and during games indicate an effect of play intensity on concussion risk, and further research is needed to evaluate the direct effect of practice contact level and equipment guidelines and restrictions on concussion incidence.
Post-concussion driving restrictions are eminent, but we lack understanding of current behaviors and opinions about driving following concussion among populations at risk of concussion. We aimed to describe post-concussion driving behaviors and opinions among collegiate student-athletes. Student-athletes completed a survey (response rate=45.3%, 223/492) regarding their post-concussion driving behaviors and opinions. Response frequencies and percentages are presented. Student-athletes self-reported a total of 169 lifetime concussions (0.76±1.02 each). Of the 169 concussions, 52.1% (88/169) were diagnosed and 52.7% (89/169) occurred while the student-athlete possessed a valid driver's license. Student-athletes refrained from driving following 43.8% (39/89) of the concussive events. Student-athletes that refrained most commonly did so for only 24-48 hours (20.5%, 8/39) and because a health care provider advised them to (33.3%: 13/39). Student-athletes most commonly reported that they would feel "very unsafe" driving a car immediately following injury (38.4%, 84/219). When asked whether driving restrictions would influence your decision to report the injury to a health care provider, 7.9% reported that it "definitely would" (17/214), 26.6% "probably would" (57/214), 17.8% "neutral" (38/214), 24.8% "probably would not" (53/214), and 22.9% "definitely would not" (49/214). Despite generally believing that driving immediately following a concussion is unsafe, a majority of student-athletes did not refrain from driving at any point following their previous concussions. Post-concussion driving restrictions may have some influence on student-athletes' decisions to report the injury to a health care provider. Health care providers play a critical role in post-concussion driving restriction, but lack standardized recommendations to guide their care.
Background:
Timely removal from activity after concussion symptoms remains problematic despite heightened awareness. Previous studies indicated potential adverse effects of continuing to participate in physical activity immediately after sustaining a concussion. Hypothesis/Purpose: The purpose was to determine the effect of timing of removal from play after concussion on clinical outcomes. It was hypothesized that immediate removal from activity after sport-related concussion (SRC) would be associated with less time missed from sport, a shorter symptomatic period, and better outcomes on acute clinical measures.
Study design:
Cohort study; Level of evidence, 3.
Methods:
Data were reported from the National Collegiate Athletic Association and Department of Defense Grand Alliance: Concussion Awareness, Research, and Education (CARE) Consortium. Participants with 506 diagnosed SRCs from 18 sports and 25 institutions and military service academies were analyzed and classified as either immediate removal from activity (I-RFA) or delayed removal from activity (D-RFA). Outcomes of interest included time missed from sport attributed to their SRC, symptom duration, and clinical assessment scores.
Results:
There were 322 participants (63.6%) characterized as D-RFA. I-RFA status was associated with significantly less time missed from sport ( R2change = .022-.024, P < .001 to P = .001) and shorter symptom duration ( R2change = .044-.046, P < .001 [all imputations]) while controlling for other SRC recovery modifiers. These athletes missed approximately 3 fewer days from sport participation. I-RFA athletes had significantly less severe acute SRC symptoms and were at lower risk of recovery taking ≥14 days (relative risk = .614, P < .001, small-medium effect size) and ≥21 days (relative risk = .534, P = .010, small effect size).
Conclusion:
I-RFA is a protective factor associated with less severe acute symptoms and shorter recovery after SRC. Conveying this message to athletes, coaches, and others involved in the care of athletes may promote timely injury reporting.
One of the National Football League’s (NFL) Head, Neck and Spine Committee’s principal goals is to create a ‘best practice’ protocol for concussion diagnosis and management for its players. The science related to concussion diagnosis and management continues to evolve, thus the protocol has evolved contemporaneously. The Fifth International Conference on Concussion in Sport was held in Berlin in 2016, and guidelines for sports concussion diagnosis and management were revised and refined. The NFL Head, Neck and Spine Committee has synthesised the most recent empirical evidence for sports concussion diagnosis and management including the Berlin consensus statement and tailored it to the game played in the NFL. One of the goals of the Committee is to provide a standardised, reliable, efficient and evidence-based protocol for concussion diagnosis and management that can be applied in this professional sport during practice and game day. In this article, the end-of-season version of the 2017–18 NFL Concussion Diagnosis and Management Protocol is described along with its clinical rationale. Immediate actions for concussion programme enhancement and research are reviewed. It is the Committee’s expectation that the protocol will undergo refinement and revision over time as the science and clinical practice related to concussion in sports crystallise
IMPORTANCE: Approximately one-third of children who experience a concussion develop
prolonged concussion symptoms. To our knowledge, there are currently no objective or easily
administered tests for predicting prolonged concussion symptoms. Several studies have
identified alterations in epigenetic molecules known as microRNAs (miRNAs) following
traumatic brain injury. No studies have examined whether miRNA expression can detect
prolonged concussion symptoms.
OBJECTIVE: To evaluate the efficacy of salivary miRNAs for identifying children with
concussion who are at risk for prolonged symptoms.
DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study at the Penn State Medical
Center observed 52 patients aged 7 to 21 years presenting for evaluation of concussion within
14 days of initial head injury, with follow-up at 4 and 8 weeks.
EXPOSURES All patients had a clinical diagnosis of concussion.
MAIN OUTCOMES AND MEASURES: Salivary miRNA expressionwas measured at the time of
initial clinical presentation in all patients. Patients with a Sport Concussion Assessment Tool
(SCAT3) symptom score of 5 or greater on self-report or parent report 4 weeks after injury
were designated as having prolonged symptoms.
RESULTS: Of the 52 included participants, 22 (42%) were female, and the mean (SD) age was
14 (3) years. Participants were split into the prolonged symptom group (n = 30) and acute
symptom group (n = 22). Concentrations of 15 salivary miRNAs spatially differentiated
prolonged and acute symptom groups on partial least squares discriminant analysis and
demonstrated functional relationships with neuronal regulatory pathways. Levels of 5
miRNAs (miR-320c-1, miR-133a-5p, miR-769-5p, let-7a-3p, and miR-1307-3p) accurately
identified patients with prolonged symptoms on logistic regression (area under the curve,
0.856; 95%CI, 0.822-0.890). This accuracy exceeded accuracy of symptom burden on child
(area under the curve, 0.649; 95%CI, 0.388-0.887) or parent (area under the curve, 0.562;
95%CI, 0.219-0.734) SCAT3 score. Levels of 3 miRNAs were associated with specific
symptoms 4 weeks after injury; miR-320c-1 was associated with memory difficulty (R, 0.55;
false detection rate, 0.02), miR-629 was associated with headaches (R, 0.47; false detection
rate, 0.04), and let-7b-5p was associated with fatigue (R, 0.45; false detection rate, 0.04).
CONCLUSIONS AND RELEVANCE: Salivary miRNA levels may identify the duration and character
of concussion symptoms. This could reduce parental anxiety and improve care by providing a
tool for concussion management. Further validation of this approach is needed.
Currently, only presumptive diagnosis of chronic traumatic encephalopathy (CTE) can be made in living patients. We present a modality that may be instrumental to the definitive diagnosis of CTE in living patients based on brain autopsy confirmation of [F-18]FDDNP-PET findings in an American football player with CTE. [F-18]FDDNP-PET imaging was performed 52 mo before the subject's death. Relative distribution volume parametric images and binding values were determined for cortical and subcortical regions of interest. Upon death, the brain was examined to identify the topographic distribution of neurodegenerative changes. Correlation between neuropathology and [F-18]FDDNP-PET binding patterns was performed using Spearman rank-order correlation. Mood, behavioral, motor, and cognitive changes were consistent with chronic traumatic myeloencephalopathy with a 22-yr lifetime risk exposure to American football. There were tau, amyloid, and TDP-43 neuropathological substrates in the brain with a differential topographically selective distribution. [F-18]FDDNP-PET binding levels correlated with brain tau deposition (rs = 0.59, P = .02), with highest relative distribution volumes in the parasagittal and paraventricular regions of the brain and the brain stem. No correlation with amyloid or TDP-43 deposition was observed. [F-18]FDDNP-PET signals may be consistent with neuropathological patterns of tau deposition in CTE, involving areas that receive the maximal shearing, angular-rotational acceleration-deceleration forces in American football players, consistent with distinctive and differential topographic vulnerability and selectivity of CTE beyond brain cortices, also involving midbrain and limbic areas. Future studies are warranted to determine whether differential and selective [F-18]FDDNP-PET may be useful in establishing a diagnosis of CTE in at-risk patients.
Background:
Despite a focus on the incidence and effects of concussion, nondisclosure of sports-related concussions among retired players from the National Football League (NFL) has yet to be examined.
Purpose:
Examine the prevalence of and factors associated with nondisclosure of sports-related concussions in former NFL athletes.
Study design:
Cross-sectional study; Level of evidence, 3.
Methods:
A sample of 829 former NFL players completed a general health survey. This historical cohort included players who had played before World War II to 2001. Respondents retrospectively recalled sports-related concussions that they sustained during their professional careers and whether at least one of these sports-related concussions was not reported to medical staff. We computed the prevalence of nondisclosure among those recalling sport-related concussions during their professional careers. Multivariable binomial regression estimated adjusted prevalence ratios (PR) with 95% confidence intervals (CIs) controlling for race/ethnicity, number of years played, primary position played, professional career concussion history, and playing era. Playing era was categorized by whether the majority of a player's career was before or after a 1976 rule change to limit contact ("spearing").
Results:
Overall, 417 (50.3%) respondents reported they had sustained a concussion and did not inform medical staff at least once during their professional playing career. Nonwhite respondents had a higher prevalence of nondisclosure than white/non-Hispanic respondents (adjusted PR = 1.19; 95% CI, 1.02-1.38). An interaction between professional career concussion history and playing era was also found ( P = .08). Compared with those in the pre-spearing rule change group with 1 or 2 concussions, all other groups had larger prevalences of nondisclosure (increases ranging from 41% to 153% in multivariable models). Across concussion strata, nondisclosure prevalence was generally higher in the post-spearing rule change group than the pre-spearing rule change group, with the largest differences found among those with 1 or 2 concussions or those with 3 or 4 concussions.
Conclusion:
A large proportion of former NFL players in this historical cohort reported at least one instance of not disclosing sports-related concussions to medical staff. Future research on concussion nondisclosure needs to identify mechanisms to improve football players' intentions to disclose concussion-related symptoms to health care providers and to equip health care providers with more effective strategies for timely identification of concussion.
Importance
Scientific and lay interest in negative outcomes associated with exposure to repetitive brain trauma (RBT) continues to strengthen. Concerns about the association between RBT and dementia began more than a century ago, but have resurfaced in the last decade with the more recently described chronic traumatic encephalopathy (CTE). Chronic traumatic encephalopathy is a tauopathy associated with RBT that has become inextricably linked to conversations about sport-related concussion and mild traumatic brain injury. Accordingly, specific populations such as collision sport athletes and certain military personnel are of particular interest owing to their unique exposure to RBT. The gaps and controversies in our understanding of the epidemiologic factors, mechanism, and clinicopathological correlates of CTE reflect the current reliance on postmortem case series investigations. This review discusses the state of the science of CTE and raises considerations for researching and interpreting cognitive changes in members of at-risk populations.
Observations
The recent development of pathological diagnostic criteria for CTE represented an important step for differentiating CTE from other neurodegenerative diseases. By comparison, defining the clinical syndrome(s) associated with CTE and the necessary and sufficient symptoms needed for its diagnosis lags behind. The absence of validated in vivo biomarkers of pathological characteristics of CTE and longitudinal tracking with neuropsychological evaluation remains a significant hurdle. Attribution of candidate symptoms in retired athletes to CTE is complicated by the presence of multiple premorbid and comorbid factors affecting cognitive reserve that influence normal or expected cognitive functioning. This is a critical issue in appropriately defining reference groups for normative comparisons.
Conclusions and Relevance
Available data, while limited and complicated by selection bias, indicate that exposure to RBT represents the greatest risk factor for CTE pathological features, although clinicopathological correlates and the nature of onset and progression of symptoms are largely unknown. Considering aspects of cognitive reserve is likely essential for both interpreting cognitive outcomes associated with CTE and for developing preventive treatment programs. Research on CTE would benefit greatly from incorporating principles established within other areas of neurodegenerative disease and the nuances of clinicopathological considerations.
There is a pressing need to identify objective biomarkers for the assessment of sport-related concussion to reduce the reliance on clinical judgment for the management of these injuries. The goal of the current study was to prospectively establish the acute effects of sport-related concussion (SRC) on serum levels of S100B, GFAP, and UCH-L1. Collegiate and high school football players were enrolled and provided blood at preseason. Injured athletes participated in follow-up visits at approximately 6 and 24-48 hours following documented SRC (N=32). Non-injured football players participated in similar follow-up visits and served as controls (N=29). The median time between injury and blood collection was 2 hours (6-hour visit) and 22.5 hours (24-48-hour visit) in concussed athletes. Concussed athletes had significantly elevated UCH-L1 levels at the 6-hour visit relative to preseason levels (Z=2.22, p=0.03) and levels in control athletes (Z=3.02, p=0.003). Concussed athletes also had elevated S100B at 6 hours relative to preseason (Z=2.07, p=0.04) and controls (Z=2.75, p=0.006). Both markers showed fair discrimination between concussed and control athletes (UCH-L1 AUC[95% confidence internal]=0.74 [0.61-0.88], S100B AUC=0.72 [0.58-0.87]). Percent-change of UCH-L1 and S100B at 6 hours relative to preseason also showed fair discrimination (AUC=0.79[0.66-0.92] and AUC=0.77[0.64-0.90]). GFAP levels did not differ between groups or in concussed athletes relative to preseason. This study provides prospective evidence of significant increases in serum levels of UCH-L1 and S100B during the early acute period following SRC and lays the foundation for future studies examining the clinical potential for blood-based biomarkers in the early detection of concussion.
Objective:
To conduct a systematic review of published literature on advanced neuroimaging, fluid biomarkers and genetic testing in the assessment of sport-related concussion (SRC).
Data sources:
Computerised searches of Medline, PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, Scopus and Cochrane Library from 1 January 2000 to 31 December 2016 were done. There were 3222 articles identified.
Study selection:
In addition to medical subject heading terms, a study was included if (1) published in English, (2) represented original research, (3) involved human research, (4) pertained to SRC and (5) involved data from neuroimaging, fluid biomarkers or genetic testing collected within 6 months of injury. Ninety-eight studies qualified for review (76 neuroimaging, 16 biomarkers and 6 genetic testing).
Data extraction:
Separate reviews were conducted for neuroimaging, biomarkers and genetic testing. A standardised data extraction tool was used to document study design, population, tests employed and key findings. Reviewers used a modified quality assessment of studies of diagnostic accuracy studies (QUADAS-2) tool to rate the risk of bias, and a modified Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to rate the overall level of evidence for each search.
Data synthesis:
Results from the three respective reviews are compiled in separate tables and an interpretive summary of the findings is provided.
Conclusions:
Advanced neuroimaging, fluid biomarkers and genetic testing are important research tools, but require further validation to determine their ultimate clinical utility in the evaluation of SRC. Future research efforts should address current gaps that limit clinical translation. Ultimately, research on neurobiological and genetic aspects of SRC is predicted to have major translational significance to evidence-based approaches to clinical management of SRC, much like applied clinical research has had over the past 20 years.
Aim or objective:
The aim of this study is to consolidate studies of physiological measures following sport-related concussion (SRC) to determine if a time course of postinjury altered neurobiology can be outlined. This biological time course was considered with respect to clinically relevant outcomes such as vulnerability to repeat injury and safe timing of return to physical contact risk.
Design:
Systematic review.
Data sources:
PubMed, CINAHL, Cochrane Central, PsychINFO.
Eligibility criteria for selecting studies:
Studies were included if they reported original research on physiological or neurobiological changes after SRC. Excluded were cases series <5 subjects, reviews, meta-analyses, editorials, animal research and research not pertaining to SRC.
Results:
A total of 5834 articles were identified, of which 80 were included for full-text data extraction and review. Relatively few longitudinal studies exist that follow both physiological dysfunction and clinical measures to recovery.
Summary/conclusions:
Modalities of measuring physiological change after SRC were categorised into the following: functional MRI, diffusion tensor imaging, magnetic resonance spectroscopy, cerebral blood flow, electrophysiology, heart rate, exercise, fluid biomarkers and transcranial magnetic stimulation. Due to differences in modalities, time course, study design and outcomes, it is not possible to define a single 'physiological time window' for SRC recovery. Multiple studies suggest physiological dysfunction may outlast current clinical measures of recovery, supporting a buffer zone of gradually increasing activity before full contact risk. Future studies need to use generalisable populations, longitudinal designs following to physiological and clinical recovery and careful correlation of neurobiological modalities with clinical measures.
This paper presents the Sport Concussion Assessment Tool 5th Edition (SCAT5), which is the most recent revision of a sport concussion evaluation tool for use by healthcare professionals in the acute evaluation of suspected concussion. The revision of the SCAT3 (first published in 2013) culminated in the SCAT5. The revision was based on a systematic review and synthesis of current research, public input and expert panel review as part of the 5th International Consensus Conference on Concussion in Sport held in Berlin in 2016. The SCAT5 is intended for use in those who are 13 years of age or older. The Child SCAT5 is a tool for those aged 5-12 years, which is discussed elsewhere.
Aim or objective
The objective of this systematic review was to evaluate the evidence regarding rest and active treatment/rehabilitation following sport-related concussion (SRC).
Design
Systematic review.
Data sources
MEDLINE (OVID), CINAHL (EbscoHost), PsycInfo (OVID), Cochrane Central Register of Controlled Trials (OVID), SPORTDiscus (EbscoHost), EMBASE (OVID) and Proquest DissertationsandTheses Global (Proquest) were searched systematically.
Eligibility criteria for selecting studies
Studies were included if they met the following criteria: (1) original research; (2) reported SRC as the diagnosis; and (3) evaluated the effect of rest or active treatment/rehabilitation. Review articles were excluded.
Results
Twenty-eight studies met the inclusion criteria (9 regarding the effects of rest and 19 evaluating active treatment). The methodological quality of the literature was limited; only five randomised controlled trials (RCTs) met the eligibility criteria. Those RCTs included rest, cervical and vestibular rehabilitation, subsymptom threshold aerobic exercise and multifaceted collaborative care.
Summary/conclusions
A brief period (24–48 hours) of cognitive and physical rest is appropriate for most patients. Following this, patients should be encouraged to gradually increase activity. The exact amount and duration of rest are not yet well defined and require further investigation. The data support interventions including cervical and vestibular rehabilitation and multifaceted collaborative care. Closely monitored subsymptom threshold, submaximal exercise may be of benefit.
Systematic review registration
PROSPERO 2016:CRD42016039570
Objective
Non-concussed individuals may report a variety of concussion-like symptoms even in the absence of a diagnosed brain injury. Previous studies described concussion-like symptom reporting in adolescent athletes. This study provides complementary data on concussion-like symptoms in collegiate athletes.
Methods
We analyzed baseline symptom scales from 738 collegiate athletes (452 men and 286 women) who completed either the Sport Concussion Assessment Tool, 3 Symptom Evaluation (S3SE; n = 377) or the Post-Concussion Scale (PCS; n = 361) and determined if subjects met criteria for diagnosis of International Classification of Diseases 10th Revision (ICD-10) postconcussional syndrome. Symptoms were grouped as somatic, cognitive, emotional, or sleep-related. We analyzed associations with medical history factors using chi-square analyses, and examined recovery time of a subset of concussed athletes based on baseline symptomatology (n = 117) with independent samples t-test.
Results
Across all athletes, 120 (16.3%) reported baseline symptoms meeting criteria for ICD-10 postconcussional syndrome. Women were 1.7 times more likely to meet these criteria (21.7% vs. 12.8%, p = .002). Athletes completing the S3SE were 1.5 times more likely to meet criteria than those completing the PCS (p = .011). Previously diagnosed psychiatric disorder was significantly associated with emotional domain symptom reporting, and attention deficit-hyperactivity disorder diagnosis was associated with cognitive domain symptom reporting. On average, athletes meeting ICD-10 postconcussional syndrome criteria at baseline experienced longer recovery from concussion (t[115] = 2.35, p = .020).
Conclusions
Non-concussed collegiate athletes report concussion-like symptoms at a clinically significant rate. Pre-injury medical history and reporting rates of concussion-like symptoms may explain variance in post-concussion symptom expression. Measured incidence of baseline postconcussional syndrome may, in part, depend on the symptom report measure that is used.
Purpose: To characterize on-field features (location, player position, and time during game) and biomechanical features (anticipation status, closing distance, impact location and type) associated with concussions in NFL games over a 4-season period (2010-2011 to 2013-2014).
Study Design: Descriptive epidemiology study
Methods: We analyzed video of a subset of reported, in-game concussions for the 2010-2011 to 2013-2014 seasons. These videos represented a sample of injuries that were diagnosed and reported on the same day and that could be clearly associated with an in-game collision as captured on video. We determined anticipation status, closing distance, impact location on the injured player’s helmet, and impact type (helmet-to-helmet, helmet-to-body, or helmet-to-ground). Associations between these variables were analyzed by use of descriptive statistics and tests of association.
Results: A total of 871 diagnosed concussions were reported as occurring during NFL preseason, regular season, and postseason games for the 2010-2011, 2011-2012, 2012-2013, and 2013-2014 seasons. A total of 1324 games were played during this period, giving a concussion incidence rate of 0.658 per game (95% CI, 0.61-0.70). From the video-reviewed subset (n = 429; 49.3%), the majority of injurious impacts occurred with good anticipation (57.3%) and <10 yards of closing distance (59.0%). An association was found between anticipation status and play type (χ2 = 27.398, P < .001), largely because injuries occurring on pass plays were more likely to be poorly anticipated than injuries during run plays (43.0% vs 21.4%; χ2 = 14.78, P < .001). Kick returns had the greatest proportion of well-anticipated impacts (78%) and the greatest proportion of impacts with ≥10 yards of closing distance (80%). The type of impact was approximately equally divided between helmet-to-helmet, helmet-to-body, and helmet-to-ground types. The impact location was broadly distributed over the helmet of the injured player.
Conclusion: In-game concussions in the NFL occurred through a diverse variety of mechanisms, surprisingly tended to be well-anticipated, and, also surprisingly, occurred with <10 yards of closing distance. The impacts causing concussion were broadly distributed over the helmet. More concussions occurred during the second half of game play, but we do not have evidence to explain this finding.
An estimated 1.1 million high school and 75,000 college athletes participate in tackle football annually in the United States. Football is a collision sport; traumatic injuries are frequent (1,2), and can be fatal (3). This report updates the incidence and characteristics of deaths caused by traumatic brain injury and spinal cord injury (4) in high school and college football and presents illustrative case descriptions. Information was analyzed from the National Center for Catastrophic Sport Injury Research (NCCSIR). During 2005-2014, a total of 28 deaths (2.8 deaths per year) from traumatic brain and spinal cord injuries occurred among high school (24 deaths) and college football players (four deaths) combined. Most deaths occurred during competitions and resulted from tackling or being tackled. All four of the college deaths and 14 (58%) of the 24 high school deaths occurred during the last 5 years (2010-2014) of the 10-year study period. These findings support the need for continued surveillance and safety efforts (particularly during competition) to ensure proper tackling techniques, emergency planning for severe injuries, availability of medical care onsite during competitions, and assessment that it is safe to return to play following a concussion.
: The clinical and computed tomographic (CT) findings in a series of 161 consecutive patients operated upon for postraumatic extradural hematoma are analyzed. Thirteen (8%) patients had delayed epidural hematoma formation. The overall mortality for the series was 12%, significantly lower than that observed during the prior "angiographic" period at the same unit (30%). Because all but 1 of the deaths occurred among the 66 patients unconscious at the time of operation (27% mortality in this subgroup), the authors sought differential factors between comatose and noncomatose patients at operation. There were no significant differences between these groups in age, sex, mechanism of injury, preoperative course of consciousness (lucid interval or not), or epidural hematoma location and shape. In contrast, significant differences were seen between the two subgroups in trauma-to-operation interval, hematoma volume, CT hematoma density (mixed low-high CT density vs. homogeneous hyperdensity), midline displacement, severity of associated intracranial lesions, and postoperative intracranial pressure (ICP). Patients comatose at operation usually evidenced a more rapid clinical deterioration (a shorter trauma-to-operation interval) and tended to have a large hematoma volume, a higher incidence of mixed CT density clot (hyperacute bleeding), more marked shift of midline structures, more severe associated lesions, and higher postoperative ICP levels. (Neurosurgery 23:44-51, 1988)
Copyright (C) by the Congress of Neurological Surgeons
Post-concussion impairments may result in unsafe driving performance, but little research is available to guide consensus on when concussed individuals should return to driving. The purpose of this study was to compare driving performance between individuals with and without a concussion and to explore relationships between neuropsychological and driving performance. Fourteen participants with concussion (Age:20.2±0.9yo) and 14 non-concussed age and driving experience matched controls (Age:20.4±1.1yo) completed a graded symptom checklist, a brief neuropsychological exam, and a 20.5km driving simulation task. Participants with a concussion completed driving simulation within 48 hours of becoming asymptomatic (15.9±9.0 days post-concussion). One-way ANOVAs were used to compare total number of crashes, tickets, lane excursions; as well as standard deviation of lateral position (SDLP), and standard deviation of speed. Pearson's correlations were conducted to explore the relationship between the neuropsychological and driving performance separately by group (±=0.05). Participants with a concussion committed more frequent lane excursions (concussed:10.9±4.5; controls:7.4±2.4; p=0.017) and exhibited greater SDLP compared to controls during the first (concussed:45.7±21.3cm, controls:27.4±6.1cm; p=0.030) and final curve (concussed:39.6±24.4cm; controls:33.5±21.3cm; p=0.036). Poorer performance on symbol digit modalities (r=-0.54), Rey Osterrieth Complex Figure (r=-0.53), verbal memory (r=-0.77), and motor speed (r=-0.54) were correlated with more frequent lane excursions among the concussed group, but not the control group. Despite being asymptomatic, concussed participants exhibited poorer vehicle control, especially when navigating curves. Driving impairments may persist beyond when individuals with a concussion have returned to driving. Our study provides preliminary guidance regarding which neuropsychological functions may best indicate driving impairment following concussion.
Acute death resulting from head trauma is a rare but catastrophic occurrence in contact sports, especially American football. Of concern is that there is no governmental or other central reporting entity tracking these events... Copyright AANS, 2016 Language: en
Objective:
The primary goals of this study were (1) to report rates of concussion-like symptoms in healthy adolescent student athletes assessed using the Sport Concussion Assessment Tool, 3rd edition (SCAT3) at baseline, (2) to examine rates of psychiatric diagnoses in this population, and (3) to evaluate effects of baseline symptoms on SCAT3 cognitive and balance performance.
Methods:
349 adolescent student athletes (245 male) were administered the SCAT3 during pre-participation physical examinations. We described the prevalence rate of student athletes meeting criteria for International Classification of Diseases, 10th revision, post-concussional syndrome (ICD-10 PCS) diagnosis at baseline, and evaluated associations between symptom reporting and demographic/medical history factors using chi-square tests. Rates of self-reported psychiatric diagnosis were compared to general population estimates with one-sample binomial tests. We also compared SCAT3 cognitive and balance performance between adolescents with and without baseline ICD-10 PCS symptoms.
Results:
Overall, 20.3% of participants met ICD-10 PCS criteria at baseline. Rates were similar across sexes and age groups. We found no statistical association with medical history factors. The proportion of student athletes reporting a history of psychiatric diagnosis (5.2%) was significantly lower than general population estimates (14.0%; p < .001), and this effect was consistent across sexes and age groups. SCAT3 cognitive and balance performance did not differ based on baseline symptom reporting.
Conclusions:
Healthy adolescent student athletes frequently report concussion-like symptoms at baseline. Clinicians should factor pre-injury symptomatology and medical history into concussion management when determining symptom etiology throughout the course of recovery.
Background:
Alzheimer's disease (AD) and chronic traumatic encephalopathy (CTE) have long been recognized as sharing some similar neuropathological features, mainly the presence of neurofibrilary tangles and hyperphosphorylated tau, but have generally been described as distinct entities. Evidence indicates that neurotrauma increases the risk of developing dementia and accelerates the progression of disease. Findings are emerging that CTE and AD may be present in the same patients.
Clinical presentation:
This study presents a series of previously unpublished cases, with one case demonstrating possible neurotrauma-related AD, one pure CTE, and an example of a case exhibiting features of both AD and CTE. The future significance of this work lies not only in the confirmation of AD-CTE co-existence, but, more importantly, ways of generating a hypothesis about the possibility that CTE may accelerate AD development. Understanding the relationship between neurotrauma and neurodegenerative disease will help elucidate how distinct disease entities can co-exist in the same patient. It will ultimately require the use of pre-clinical animal models and repeat injury paradigms to investigate clinically relevant injury mechanisms. These models should produce a CTE-like phenotype that must be both neuropathologically and behaviourally similar to human disease.
Conclusion:
This case series and review of the literature presents a discussion of AD and CTE in the context of neurotrauma. It highlights recent work from repetitive neurotrauma models with an emphasis on those exhibiting a CTE-like phenotype. Potential mechanisms of interest shared amongst AD and CTE are briefly addressed and future experiments are advocated for to enhance understanding of CTE pathophysiology and the relationship between CTE and AD.