Recommendations for grading of concussion in athletes

Neuromechanical Models of Mild Traumatic Brain Injury Conditioned on Reaction Time: A Systematic Review and Meta-Analysis

The accurate, repeatable, and cost-effective quantitative characterization of mild traumatic brain injuries (mTBIs) is crucial for safeguarding the long-term health and performance of high-risk groups, including athletes, emergency responders, and military personnel. However, gaps remain in optimizing mTBI assessment methods, especially regarding the integration of neuromechanical metrics such as reaction time (RT) in predictive models. Background/Objectives: This review synthesizes existing research on the use of neuromechanical probabilistic models as tools for assessing mTBI, with an emphasis on RT's role in predictive diagnostics. Methods: We examined 57 published studies on recent sensing technologies such as advanced electromyographic (EMG) systems that contribute data for probabilistic neural imaging, and we also consider measurement models for real-time RT tracking as a diagnostic measure. Results: The analysis identifies three primary contributions: (1) a comprehensive survey of probabilistic approaches for mTBI characterization based on RT, (2) a technical examination of these probabilistic algorithms in terms of reliability and clinical utility, and (3) a detailed outline of experimental requirements for using RT-based metrics in psychomotor tasks to advance mTBI diagnostics. Conclusions: This review provides insights into implementing RT-based neuromechanical metrics within experimental frameworks for mTBI diagnosis, suggesting that such metrics may enhance the sensitivity and utility of assessment and rehabilitation protocols. Further validation studies are recommended to refine RT-based probabilistic models for mTBI applications.

Detection of mild traumatic brain injury in pediatric populations using BrainCheck, a tablet-based cognitive testing software: a preliminary study

Aim: Despite its high frequency of occurrence, mild traumatic brain injury (mTBI), or concussion, is difficult to recognize and diagnose, particularly in pediatric populations. Conventional methods to diagnose mTBI primarily rely on clinical questionnaires and sometimes include neuroimaging or pencil and paper neuropsychological testing. However, these methods are time consuming, require administration/interpretation from health professionals, and lack adequate test sensitivity and specificity. This study explores the use of BrainCheck Sport, a computerized neurocognitive test that is available on iPad, iPhone, or computer desktop, for mTBI assessment. The BrainCheck Sport Battery consists of 6 gamified traditional neurocognitive tests that assess areas of cognition vulnerable to mTBI such as attention, processing speed, executing functioning, and coordination. Methods: We administered BrainCheck Sport to 10 participants diagnosed with mTBI at the emergency department of Children’s hospital or local high school within 96 hours of injury, and 115 normal controls at a local high school. Statistical analysis included Mann-Whitney U test, chi-square tests, and Hochberg tests to examine differences between the mTBI group and control group on each assessment in the battery. Significant metrics from these assessments were used to build a logistic regression model that distinguishes mTBI from control participants. Results: BrainCheck Sport was able to detect significant differences in Coordination, Stroop, Immediate/Delayed Recognition between normal controls and mTBI patients. Receiver operating characteristic (ROC) analysis of our logistic regression model found a sensitivity of 84% and specificity of 81%, with an area under the curve of 0.884. Conclusions: BrainCheck Sport has potential in distinguishing mTBI from control participants, by providing a shorter, gamified test battery to assess cognitive function after brain injury, while also providing a method for tracking recovery with the opportunity to do so remotely from a patient’s home.

Assessment of Long-Term Effects of Sports-Related Concussions: Biological Mechanisms and Exosomal Biomarkers

Concussion or mild traumatic brain injury (mTBI) in athletes can cause persistent symptoms, known as post-concussion syndrome (PCS), and repeated injuries may increase the long-term risk for an athlete to develop neurodegenerative diseases such as chronic traumatic encephalopathy (CTE), and Alzheimer's disease (AD). The Center for Disease Control estimates that up to 3.8 million sport-related mTBI are reported each year in the United States. Despite the magnitude of the phenomenon, there is a current lack of comprehensive prognostic indicators and research has shown that available monitoring tools are moderately sensitive to short-term concussion effects but less sensitive to long-term consequences. The overall aim of this review is to discuss novel, quantitative, and objective measurements that can predict long-term outcomes following repeated sports-related mTBIs. The specific objectives were (1) to provide an overview of the current clinical and biomechanical tools available to health practitioners to ensure recovery after mTBIs, (2) to synthesize potential biological mechanisms in animal models underlying the long-term adverse consequences of mTBIs, (3) to discuss the possible link between repeated mTBI and neurodegenerative diseases, and (4) to discuss the current knowledge about fluid biomarkers for mTBIs with a focus on novel exosomal biomarkers. The conclusions from this review are that current post-concussion clinical tests are not sufficiently sensitive to injury and do not accurately quantify post-concussion alterations associated with repeated mTBIs. In the current review, it is proposed that current practices should be amended to include a repeated symptom inventory, a cognitive assessment of executive function and impulse control, an instrumented assessment of balance, vestibulo-ocular assessments, and an improved panel of blood or exosome biomarkers.

The Influence of Psychological Factors on the Incidence and Severity of Sports-Related Concussions: A Systematic Review

BACKGROUND

An athlete's preexisting psychological factors may influence the incidence and/or severity of sports-related concussions (SRCs).

PURPOSE

To determine if emotional states, personality traits, temperament, life stressors, and explanatory styles (optimism vs pessimism) influence the incidence and severity of SRCs in athletes.

STUDY DESIGN

Systematic review.

METHODS

A systematic literature search of multiple major medical reference databases was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included that evaluated the effect of preexisting psychological factors on the incidence and severity of SRCs in male and female athletes participating in all sports.

RESULTS

The initial search identified 1195 articles. Ten studies met our inclusion criteria and were included in our analysis. Factors such as meanness, aggression, and psychoticism were associated with an increased incidence of SRCs. Baseline traits of irritability, sadness, nervousness, and depressive symptoms were associated with worse symptomatology after SRCs. In young athletes, preexisting psychiatric illnesses, family history of psychiatric illness, and significant life stressors were associated with an increased risk of developing postconcussion syndrome after SRCs.

CONCLUSION

This systematic review demonstrated a potential relationship between an athlete's preexisting psychological factors and the incidence and severity of SRCs. These associations are not entirely clear owing to the heterogeneity across included studies and the low-to-moderate certainty of evidence. Future studies should attempt to evaluate men and women independently, use well-validated psychological questionnaires, and limit the usage of self-reported SRCs, when possible. Furthermore, the potential efficacy of baseline psychological factor and/or symptom reports on the prevention and management of SRCs should be explored.

The Diagnosis of Concussion in Pediatric Emergency Departments: A Prospective Multicenter Study

BACKGROUND

The accurate identification of children with a concussion by emergency physicians is important to initiate appropriate anticipatory guidance and management.

OBJECTIVES

We compared the frequency of persistent concussion symptoms in children who were provided the diagnosis of concussion by an emergency physician versus those who met Berlin/Zurich international criteria for this diagnosis. We also determined the clinical variables independently associated with a physician-diagnosed concussion.

METHODS

This was a planned secondary analysis of a prospective, multicenter cohort study. Participants were 5-17 years of age and met the Zurich/Berlin International Consensus Statement criteria for concussion.

RESULTS

There were 2946 enrolled children. In those with physician-diagnosed concussion vs. no concussion, the frequency of persistent symptoms was 62.5% vs. 38.8% (p < 0.0001) at 1 week, 46.3% vs. 25.8% (p < 0.0001) at 2 weeks, and 33.0% vs. 23.0% (p < 0.0001) at 4 weeks. Of those meeting international criteria, 2340 (79.4%) were diagnosed with a concussion by an emergency physician and 12 variables were associated with this diagnosis. Five had an odds ratio (OR) > 1.5: older age (13-17 vs. 5-7 years, OR 2.9), longer time to presentation (≥16 vs. <16 h, OR 2.1), nausea (OR 1.7), sport mechanism (OR 1.7), and amnesia (OR 1.6).

CONCLUSIONS

Relative to international criteria, the more selective assignment of concussion by emergency physicians was associated with a greater frequency of persistent concussion symptoms. In addition, while most children meeting international criteria for concussion were also provided this diagnosis for concussion by an emergency physician, the presence of 5 specific variables made this diagnosis more likely.

Do Mild Traumatic Brain Injury Severity Sub-classification Systems Help to Identify People Who Go on to Experience Long-Term Symptoms?

Objective: To identify the systems available to sub-classify mild traumatic brain injury (TBI) and to determine their utility in predicting 1-year outcome.

Methods: A systematic review to identify mild-TBI sub-classification systems was conducted until March 2016. The identified systems were applied to a cohort ofN= 290 adults who had experienced a mild-TBI, and who had been assessed for post-concussion symptoms 1-year post injury. ANOVAs and regression models were used to determine whether each sub-classification system could distinguish between outcomes and to explore their contribution to explaining variance in post-concussion symptoms 1-year post injury.

Results: Nineteen sub-classification systems for mild-TBI met the inclusion criteria for this review. The Saal (1991) classification system significantly differentiated the experience of post-concussion symptoms in our cohort 1-year post injury (F= 2.39,p= 0.05). However, the findings did not remain significant following correction for multiple comparisons and inclusion of socio-demographic and contextual factors in the regression model.

Conclusions: Current sub-classification systems fail to explain much of the variance in post-concussion symptoms 1 year following mild-TBI. Further research is needed to identify the factors (including socio-demographic and contextual factors) to determine, who may be at risk of developing persistent post-concussion symptoms.

Mechanosensory Stimulation Evokes Acute Concussion-Like Behavior by Activating GIRKs Coupled to Muscarinic Receptors in a Simple Vertebrate

Most vertebrates show concussion responses when their heads are hit suddenly by heavy objects. Previous studies have focused on the direct physical injuries to the neural tissue caused by the concussive blow. We study a similar behavior in a simple vertebrate, the Xenopus laevis tadpole. We find that concussion-like behavior can be reliably induced by the mechanosensory stimulation of the head skin without direct physical impacts on the brain. Head skin stimulation activates a cholinergic pathway which then opens G protein-coupled inward-rectifying potassium channels (GIRKs) via postsynaptic M2 muscarinic receptors to inhibit brainstem neurons critical for the initiation and maintenance of swimming for up to minutes and can explain many features commonly observed immediately after concussion. We propose that some acute symptoms of concussion in vertebrates can be explained by the opening of GIRKs following mechanosensory stimulation to the head.

Mining standardized neurological signs and symptoms data for concussion identification

The Centers for Disease Control estimate that 1.6 to 3.8 million concussions occur in sports and recreational activities annually. Studies have shown that concussions increase the risk of future injuries and mild cognitive disorders. Despite extensive research on sports related concussion risk factors, the factors which are most predictive of concussion outcome and recovery time course remain unknown. In order to overcome the issue of physician bias and to identify the factors which can best predict concussion diagnosis, we propose a multi-variate logistic regression based analysis. We demonstrate our results on a dataset with 126 subjects (ages 12-31). Our results indicate that among 322 features, our model selected 27-29 features which included a history of playing sports, history of a previous concussion, drowsiness, nausea, trouble focusing as measured by a common symptom list, and oculomotor function. The features picked using our model were found to be highly predictive of concussions and gave a prediction performance accuracy greater than 90%, Matthews correlation coefficient greater than 0.8 and the area under the curve greater than 0.95.

Concussion in Hockey: Compliance with Return to Play Advice and Follow-up Status

Objectives:

To determine the compliance rate among hockey players with concussion or other head injuries who were advised by a physician about return to play. To assess compliance of hockey players with return to play advice and to assess the incidence of long-term post-concussion symptoms.

Methods:

A retrospective chart review, telephone questionnaire and follow-up analysis of income, level of education and professional aspirations. The study examined 40 hockey players with concussion or other head injury treated at a neurosurgical ambulatory clinic, who had initial visits between 1995 and 2003, and had been seen at least two years prior to completing the questionnaire.

Results:

There was a 58% (23 of 40) participation rate in the study. Fifteen (65%) of the 23 participants were advised to never return to play, and 5 (33%) were non-compliant and returned to play. Four (80%) of the five non-compliant players continued to suffer from post concussion symptoms. Overall, 15 (65%) of the 23 players participating in the study continued to suffer post concussion symptoms at least two years after the clinic visit.

Conclusions:

Five (33%) of 15 hockey players advised to never return to play were non-compliant and returned to play, and four continued to suffer from post concussion symptoms two or more years later. After repeated concussions, 65% of hockey players had long-term sequelae that prevented return to play and produced long-term post-concussion symptoms.

Head and neck injuries in football (soccer)

The incidence for concussions in football (soccer) is equivalent to other contact sports such as American football and ice hockey. The risk of concussion is increased in goalkeepers, females and perhaps young players. Head to head contact between athletes is the most common mechanism for concussion, while heading does not appear to be a frequent cause. Research is providing evidence that neck muscle development and protective headgear may play a role in the prevention of concussions. The presence and pathophysiology of a chronic encephalopathy secondary to a cumulative subconcussive blows obtained in football is still controversial. Neck injuries are not as common as head injuries and are not frequently reported in the literature. The biomechanics of neck injuries are different between children and adults which may account for the different types of injuries in these populations. Spinal cord injuries are rarely seen in football and are usually associated with major fractures/dislocations.

Inadequate Helmet Fit Increases Concussion Severity in American High School Football Players

Background:

There is limited information on the relationship between football helmet fit and concussion severity.

Hypothesis:

Poor helmet fit may predispose football players to a more severe concussion.

Study Design:

Descriptive epidemiology study.

Level of Evidence:

Level 3.

Methods:

Data from concussion injury reports were obtained from the National High School Sports-Related Injury Surveillance System over a 9-year period. Symptoms, duration, and helmet parameters (fit, interior padding) were analyzed for all first-time concussions.

Results:

Data from 4580 concussions were analyzed. Patients who suffered concussions with a helmet that did not fit properly (3.22%), as determined by an athletic trainer, had higher rates of drowsiness (RR, 1.46; P = 0.005), hyperexcitability (RR, 2.38; P = 0.047), and sensitivity to noise (RR, 1.88; P < 0.001); had more symptoms (5.34 vs 4.54, P = 0.004); and had longer symptom duration (P = 0.04). Athletes with helmets lined with an air bladder had greater rates of sensitivity to light (RR, 1.13; P = 0.02), sensitivity to noise (RR, 1.25; P = 0.009), and longer symptom duration (P = 0.004) compared with foam or gel liners.

Conclusion:

An improperly fitted football helmet is a risk factor for a concussion with more symptoms and of longer duration. Concussions of longer duration are also more common in players with an air bladder–lined helmet. Current high school football rules should mandate supervision and maintenance of helmet fit throughout the season, prior to impact.

Clinical Relevance:

Team physicians, athletic trainers, coaches, and high school officials should ensure proper oversight of helmet fit in high school athletes to decrease concussion severity and duration.

The long-term effects of repetitive mild head injuries in sports

At least 300 000 sports-related concussions occur in the United States annually. With millions of American athletes, the long-term effects of repeated concussion or mild traumatic brain injury are an important topic. Unfortunately, there is a lack of strong data on the causality or prevalence of long-term effects among athletes. Chronic traumatic encephalopathy (CTE), a progressive neurodegenerative tauopathy, with associated clinical, behavioral, and neuropathological findings, is an important clinical entity in need of further study. Diffusion tensor imaging can elucidate trauma-induced white matter damage, but the diagnosis of CTE cannot be proven until postmortem neuropathology shows characteristic neurofibrillary and astrocytic tangles. Concern exists that athletes subject to repeated concussive and even subconcussive blows may be at risk of CTE, but no definitive data exist due to the difficulty in diagnosis. Animal models suggest that mild traumatic brain injuries lead to primarily a metabolic derangement with increased excitotoxic neurotransmitter release, extracellular potassium, and intracellular calcium. Further understanding of the underlying pathophysiology may eventually lead to better therapeutic and diagnostic options for the treating clinician.

The diagnosis of concussion in a pediatric emergency department

OBJECTIVES

To compare the proportion of children diagnosed with a concussion by pediatric emergency physicians vs the proportion who met criteria for this injury as recommended by Zurich Fourth International Conference on Concussion consensus statement and to determine clinical variables associated with a physician diagnosis of a concussion.

STUDY DESIGN

This was a prospective, cross-sectional study conducted at a tertiary care pediatric emergency department. We enrolled children ages 5 through 17 who presented with a head injury and collected data on demographics, mechanism of injury, head injury-related symptoms/signs, physician diagnosis, and discharge advice.

RESULTS

We identified 495 children whose mean age was 10.1 years (SD 3.4 years); 308 (62.2%) were male. Emergency physicians diagnosed concussion in 200 (40.4%; 95% CI 36.1, 44.7) children, and 443 (89.5%; 95% CI 86.8, 92.2) met criteria for concussion in accordance with the Zurich consensus statement (P<.0001). Age≥10 years (OR 1.8), presentation≥1 day after injury (OR 2.4), injury from collision sports (OR 5.6), and symptoms of headache (OR 2.2) or amnesia (OR 3.4) were the variables significantly associated with an emergency physician's diagnosis of concussion.

CONCLUSIONS

Pediatric emergency physicians diagnosed concussion less often relative to international consensus-based guidelines and used a limited number of variables to make this diagnosis compared with current recommendations. Thus, pediatric emergency physicians may be missing cases of concussion and the corresponding opportunity to provide critical advice for cognitive and physical management.

Why university athletes choose not to reveal their concussion symptoms during a practice or game

OBJECTIVE

To determine why athletes decide not to seek medical attention during a game or practice when they believe they have suffered a concussion.

DESIGN

A retrospective survey.

SETTING

University Sport Medicine Clinic.

PARTICIPANTS

A total of 469 male and female university athletes from several varsity team sports were participated in the study.

MAIN OUTCOME MEASURES

Athletes were surveyed about the previous 12 months to identify specific reasons why those athletes who believed they had suffered a concussion during a game or practice decided not to seek attention at that time, how often these reasons occurred, and how important these reasons were in the decision process.

RESULTS

Ninety-two of the 469 athletes (19.6%) believed they had suffered a concussion within the previous 12 months while playing their respective sport, and 72 of these 92 athletes (78.3%) did not seek medical attention during the game or practice at least once during that time. Sports in which athletes were more likely to not reveal their concussion symptoms were football and ice hockey. The reason "Did not feel the concussion was serious/severe and felt you could still continue to play with little danger to yourself," was listed most commonly (55/92) as a cause for not seeking medical attention for a presumed concussion.

CONCLUSIONS

A significant percentage of university athletes who believed they had suffered a concussion chose not to seek medical attention at the time of injury. Improved education of players, parents, and coaches about the dangers of continuing to play with concussion symptoms may help improve reporting.

CLINICAL RELEVANCE

Medical staff should be aware that university athletes who believe they have suffered a concussion may choose not to volunteer their symptoms during a game or practice for a variety of personal and athletic reasons.

Canadian Minor Hockey Participants’ Knowledge about Concussion

Background and Objectives:

In Canada and the USA, ice hockey is a cause of traumatic brain injury. Post-concussive symptoms are the most important feature of the diagnosis of concussion in sports and it is recommended that athletes not return to play while still symptomatic. Lack of knowledge of concussions could therefore be one of the main detriments to concussion prevention in hockey. The purpose of this research is to describe what minor league hockey players, coaches, parents and trainers know about concussion and its management.

Methods:

A questionnaire to assess concussion knowledge and return to play guidelines was developed and administered to players at different competitive levels (n = 267), coaches, trainers and parents (total adults n = 142) from the Greater Toronto Area.

Results:

Although a majority of adults and players could identify mechanisms responsible for concussion, about one-quarter of adults and about a quarter to a half of children could not recall any symptoms or recalled only one symptom of a concussion. A significant number of players and some adults did not know what a concussion was or how it occurred. Almost half of the players and a fifth of the adults incorrectly stated that concussion was treated with medication or physical therapy. Nearly one quarter of all players did not know if an athlete experiencing symptoms of concussion should continue playing.

Conclusions:

This study demonstrated that a significant number of people held misconceptions about concussion in hockey which could lead to serious health consequences and creates a need for better preventive and educational strategies.

Acute concussion symptom severity and delayed symptom resolution

BACKGROUND AND OBJECTIVES

Up to 30% of children who have concussion initially evaluated in the emergency department (ED) display delayed symptom resolution (DSR). Greater initial symptom severity may be an easily quantifiable predictor of DSR. We hypothesized that greater symptom severity immediately after injury increases the risk for DSR.

METHODS

We conducted a prospective longitudinal cohort study of children 8 to 18 years old presenting to the ED with concussion. Acute symptom severity was assessed using a graded symptom inventory. Presence of DSR was assessed 1 month later. Graded symptom inventory scores were tested for association with DSR by sensitivity analysis. We conducted a similar analysis for post-concussion syndrome (PCS) as defined by the International Statistical Classification of Diseases and Related Health Problems, 10th revision. Potential symptoms characteristic of DSR were explored by using hierarchical cluster analysis.

RESULTS

We enrolled 234 subjects; 179 (76%) completed follow-up. Thirty-eight subjects (21%) experienced DSR. Initial symptom severity was not significantly associated with DSR 1 month after concussion. A total of 22 subjects (12%) had PCS. Scores >10 (possible range, 0-28) were associated with an increased risk for PCS (RR, 3.1; 95% confidence interval 1.2-8.0). Three of 6 of the most characteristic symptoms of DSR were also most characteristic of early symptom resolution. However, cognitive symptoms were more characteristic of subjects reporting DSR.

CONCLUSIONS

Greater symptom severity measured at ED presentation does not predict DSR but is associated with PCS. Risk stratification therefore depends on how the persistent symptoms are defined. Cognitive symptoms may warrant particular attention in future study. Follow-up is recommended for all patients after ED evaluation of concussion to monitor for DSR.

Mild traumatic brain injury: is diffusion imaging ready for primetime in forensic medicine?

Mild traumatic brain injury (MTBI) is difficult to accurately assess with conventional imaging because such approaches usually fail to detect any evidence of brain damage. Recent studies of MTBI patients using diffusion-weighted imaging and diffusion tensor imaging suggest that these techniques have the potential to help grade tissue damage severity, track its development, and provide prognostic markers for clinical outcome. Although these results are promising and indicate that the forensic diagnosis of MTBI might eventually benefit from the use of diffusion-weighted imaging and diffusion tensor imaging, healthy skepticism and caution should be exercised with regard to interpreting their meaning because there is no consensus about which methods of data analysis to use and very few investigations have been conducted, of which most have been small in sample size and examined patients at only one time point after injury.

Trauma and impaired consciousness

This article discusses brain trauma and impaired consciousness. It reviews the various states of impaired consciousness related to trauma, with an historical and current literature viewpoint. The causes and pathophysiology of impaired consciousness in concussion, diffuse axonal injury, and focal brain lesions are discussed and management options evaluated.

Detailed concussion symptom analysis in a paediatric ED population

PRIMARY OBJECTIVE

To examine the frequency of acute mild traumatic brain injury (mTBI) symptoms in children using a concussion symptom inventory and to identify which symptoms are most useful in identifying mTBI. It was hypothesized that symptoms associated with mTBI are more common in children with head injury than orthopaedic injury and certain symptoms are more useful than others in identifying mTBI.

RESEARCH DESIGN

Prospective case-control study conducted in a paediatric trauma centre emergency department.

METHODS AND PROCEDURES

Children of 6-18 years old with head injury or a minor extremity injury were enrolled. Symptoms were assessed using a graded symptom checklist. Symptom frequency was compared using a chi-square test. The association between individual symptoms with AMS was evaluated with logistic regression analysis.

MAIN OUTCOMES AND RESULTS

Children with head injury displayed more frequent symptoms than controls. Head-injured cases with altered mental status (AMS) demonstrated the most frequent and severe symptoms (median symptom scores: control = 1, cases without AMS = 5, cases with AMS = 10; p < 0.001). Headache, nausea, dizziness, blurred/double vision and not feeling 'sharp' were associated with AMS.

CONCLUSIONS

Symptoms associated with mTBI are more frequent in children with head injury. AMS magnifies this effect. A symptom inventory is integral to the evaluation of mTBI in children; a smaller set of dichotomized symptoms may be as useful as and more easily administered than lengthier symptom scales.

Identifying neurocognitive deficits in adolescents following concussion

OBJECTIVES

This study of concussed adolescents sought to determine if a computer-based neurocognitive assessment (Immediate Postconcussion Assessment and Cognitive Test [ImPACT]) performed on patients who present to the emergency department (ED) immediately following head injury would correlate with assessments performed 3 to 10 days postinjury and if ED neurocognitive testing would detect differences in concussion severity that clinical grading scales could not.

METHODS

A prospective cohort sample of patients 11 to 17 years of age presenting to the ED within 12 hours of a head injury were evaluated using two traditional concussion grading scales and neurocognitive testing. ED neurocognitive scores were compared to follow-up scores obtained at least 3 days postinjury. Postconcussive symptoms, outcomes, and complications were assessed via telephone follow-up for all subjects.

RESULTS

Sixty patients completed phone follow-up. Thirty-six patients (60%) completed follow-up testing a median of 6 days postinjury. Traditional concussion grading did not correlate with neurocognitive deficits detected in the ED or at follow-up. For the neurocognitive domains of verbal memory, processing speed, and reaction time, there was a significant correlation between ED and follow-up scores trending toward clinical improvement. By 2 weeks postinjury, 23 patients (41%) had not returned to normal activity. At 6 weeks, six patients (10%) still had not returned to normal activity.

CONCLUSIONS

Immediate assessment in the ED can predict neurocognitive deficits seen in follow-up and may be potentially useful to individualize management or test therapeutic interventions. Neurocognitive assessment in the ED detected deficits that clinical grading could not and correlated with deficits at follow-up.

Diffusion tensor imaging of mild traumatic brain injury

Mild traumatic brain injury (mTBI) remains a challenge to accurately assess with conventional neuroimaging. Recent research holds out the promise that diffusion tensor imaging (DTI) can be used to predict recovery in mTBI patients. Unlike computed tomography or conventional magnetic resonance imaging, DTI is sensitive to microstructural axonal injury, the neuropathology that is thought to be most responsible for the persistent cognitive and behavioral impairments that often occur after mTBI. Through the use of newer DTI analysis techniques such as automated region of interest analysis, tract-based voxel-wise analysis, and quantitative tractography, researchers have shown that frontal and temporal association white matter pathways are most frequently damaged in mTBI and that the microstructural integrity of these tracts correlates with behavioral and cognitive measures. Future longitudinal DTI studies are needed to elucidate how symptoms and the microstructural pathology evolve over time. Moving forward, large-scale investigations will ascertain whether DTI can serve as a predictive imaging biomarker for long-term neurocognitive deficits after mTBI that would be of value for triaging patients to clinical trials of experimental cognitive enhancement therapies and rehabilitation methods, as well as for monitoring their response to these interventions.

Evaluation of the standardized assessment of concussion in a pediatric emergency department

OBJECTIVE

The Standardized Assessment of Concussion (SAC) is a validated tool for identifying the effects of mild traumatic brain injury (mTBI). Previous research focused on sport-related sideline evaluation of adolescents and adults. Our goal was to evaluate performance of the SAC among subjects with and without head injury in a pediatric emergency department (ED).

METHODS

This was an observational study of children 6 to 18 years of age who presented to an ED with blunt head injury (case-patients) or minor extremity injury (controls). SAC and graded-symptom-checklist scores were compared. American Academy of Neurology concussion grades, presence of loss of consciousness and posttraumatic amnesia were also compared with SAC and graded-symptom-checklist scores among case-patients.

RESULTS

Three hundred forty-eight children were enrolled. SAC scores trended lower (greater cognitive deficits) for case-patients compared with controls but did not reach significance. Graded-symptom-checklist scores were significantly higher among case-patients. Presence of altered mental status magnified this effect. There was no correlation between SAC scores and other indicators of mTBI. There was a positive correlation between graded-symptom-checklist scores and posttraumatic amnesia and American Academy of Neurology concussion grade.

CONCLUSIONS

The graded symptom checklist reliably identified mTBI symptoms for all children aged 6 years and older. SAC scores tended to be lower for case-patients compared with controls but did not reach significance. Patients with altered mental status at the time of injury manifest an increased number and severity of symptoms. Additional research into strategies to identify cognitive deficits related to mTBI and classify mTBI severity in children is needed.

Natural history of concussion in sport: markers of severity and implications for management

BACKGROUND

Evidence-based clinical data are required for safe return to play after concussion in sport.

PURPOSE

The objective of this study was to describe the natural history of concussion in sport and identify clinical features associated with more severe concussive injury, using return-to-sport decisions as a surrogate measure of injury severity.

STUDY DESIGN

Cohort study (prognosis); Level of evidence, 3.

METHODS

Male elite senior, elite junior, and community-based Australian Rules football players had preseason baseline cognitive testing (Digit Symbol Substitution Test, Trail-Making Test-Part B, and CogSport computerized test battery). Players were recruited into the study after a concussive injury sustained while playing football. Concussed players were tested serially until all clinical features of their injury had resolved.

RESULTS

Of 1015 players, 88 concussions were observed in 78 players. Concussion-associated symptoms lasted an average of 48.6 hours (95% confidence interval, 39.5-57.7 hours) with delayed return to sport correlated with > or = 4 symptoms, headache lasting > or = 60 hours, or self-reported "fatigue/fogginess." Cognitive deficits using the Digit Symbol Substitution Test and Trail-Making Test-part B recovered concomitantly with symptoms, but computerized test results recovered 2 to 3 days later and remained impaired in 35% of concussed players after symptom resolution.

CONCLUSION

Delayed return to sport was associated with initially greater symptom load, prolonged headache, or subjective concentration deficits. Cognitive testing recovery varied, taking 2 to 3 days longer for computerized tests, suggesting greater sensitivity to impairment. Therefore, symptom assessment alone may be predictive of but may underestimate time to complete recovery, which may be better estimated with computerized cognitive testing.

Online training in sports concussion for youth sports coaches

The purpose of this study was to evaluate ACTive: Athletic Concussion Training using Interactive Video Education, an interactive e-learning program designed to train community coaches of youth ages 10-18 in effective sports concussion prevention and management practices. Seventy-five youth sports coaches from across the country completed the study over the Internet. Results of a randomized control trial demonstrated significant differences between treatment and control participants on measures of (a) knowledge about sports concussion, management, and prevention; (b) attitudes about the importance of preventing sports concussion; and (c) intention and self-efficacy in sports concussion management and prevention. The results suggest that ACTive is an effective method of training youth sports coaches who are in an important position to reduce risks associated with sports concussion.

"My child doesn't have a brain injury, he only has a concussion"

OBJECTIVE

The term "concussion" is frequently used in clinical records to describe a traumatic head injury; however, there are no standard definitions of this term, particularly in how it is used with children. The goals of this study were to examine the clinical correlates of the concussion diagnosis and to identify the factors that lead to the use of this term in a regional pediatric center.

METHODS

Medical data were prospectively collected from 434 children with traumatic brain injury who were admitted to a Canadian children's hospital. A proportional hazards regression was used to examine the association of the concussion diagnosis and the times until discharge and school return. A classification-tree analysis modeled the clinical correlates of patients who received a concussion diagnosis.

RESULTS

The concussion label was significantly more likely to be applied to children with mild Glasgow Coma Scale scores of 13 to 15 (P = .03). The concussion label was strongly predictive of earlier hospital discharge (odds ratio [OR]: 1.5; 95% confidence interval [CI]: 1.2-1.9; P = .003) and earlier return to school (OR: 2.4 [95% CI: 1.6-3.7]; P < .001). A diagnosis of a concussion was significantly more likely when the computed-tomography results were normal and the child had lost consciousness.

CONCLUSIONS

Children with mild traumatic brain injuries have an increased frequency of receiving the concussion label, although the label may also be applied to children with more-severe injuries. The concussion diagnosis is associated with important clinical outcomes. Its typical use in hospital settings likely refers to an impact-related mild brain injury, in the absence of indicators other than a loss of consciousness. Clinicians may use the concussion label because it is less alarming to parents than the term mild brain injury, with the intent of implying that the injury is transient with no significant long-term health consequences.

Neurologic injuries in hockey

Ice hockey is a fast contact sport played on an ice surface enclosed by rigid boards. There is an intrinsic risk for injury in hockey, with many injuries potentially affecting the nervous system. This article provides an overview of neurologic injuries occurring in hockey as reported in the scientific literature. Among all injuries, a small but real risk for catastrophic cervical spinal cord injury and a high incidence of concussion emerge as the two most important neurologic issues.

Neuropsychology and clinical neuroscience of persistent post-concussive syndrome

On the mild end of the acquired brain injury spectrum, the terms concussion and mild traumatic brain injury (mTBI) have been used interchangeably, where persistent post-concussive syndrome (PPCS) has been a label given when symptoms persist for more than three months post-concussion. Whereas a brief history of concussion research is overviewed, the focus of this review is on the current status of PPCS as a clinical entity from the perspective of recent advances in the biomechanical modeling of concussion in human and animal studies, particularly directed at a better understanding of the neuropathology associated with concussion. These studies implicate common regions of injury, including the upper brainstem, base of the frontal lobe, hypothalamic-pituitary axis, medial temporal lobe, fornix, and corpus callosum. Limitations of current neuropsychological techniques for the clinical assessment of memory and executive function are explored and recommendations for improved research designs offered, that may enhance the study of long-term neuropsychological sequelae of concussion.

Mechanisms of injury for concussions in university football, ice hockey, and soccer: a pilot study

OBJECTIVE

To examine the mechanisms of injury for concussions in university football, ice hockey, and soccer.

DESIGN

Prospective analysis.

SETTING

McGill University.

PATIENTS

All athletes participating in varsity football, ice hockey, and soccer.

MAIN OUTCOME MEASURES

Athletes participating in university varsity football, ice hockey, and soccer were followed prospectively to determine the mechanisms of injury for concussions, whether certain mechanisms of injury causing concussions were more common in any of the three sports, whether different areas of the body seem to be more vulnerable to a concussion after contact, and whether these areas might be predisposed to higher grades of concussion after contact.

RESULTS

There were 69 concussions in 60 athletes over a 3-year period. Being hit in the head or helmet was the most common mechanism of injury for all 3 sports. The side/temporal area of the head or helmet was the most probable area to be struck, resulting in concussion for both football and soccer. When examining the body part or object delivering the concussive blow, contact with another player's helmet was the most probable mechanism in football.

CONCLUSION

The mechanisms of injury for concussions in football are similar to previously published research on professional football players. The mechanisms of injury for concussions in soccer are similar to past research on Australian rules football and rugby.

Concussive head injury in children and adolescents related to sports and other leisure physical activities

OBJECTIVE

To compare the characteristics of children and adolescents with concussive head injury (CHI) sustained during organised sports or other leisure physical activity.

METHODS

This was a case series study reviewing the medical records retrospectively over a four year period of children 6-16 years presenting to the emergency department with a CHI after participating in sport and/or recreation activity.

RESULTS

There were 592 cases of sport and recreation related concussion over the study period (2000-2003). Most of the patients (n = 424, 71.6%) were male, with half (n = 304, 51.4%) being older than 10 years of age. A total of 152 (25.7%) cases of CHI were related to playing sports. Most cases (71.2%) were mild concussion. The cause of injury was a fall (n = 322, 54.4%) or a collision. Nearly a quarter of the children (n = 143, 24.2%) were admitted to hospital, with imaging performed in 134 (22.7%). Most children were treated appropriately and no adverse events were reported.

CONCLUSIONS

A severe CHI in a child is six times more likely to have resulted from organised sport than from other leisure physical activities. Outcomes for CHI in children is excellent, although their management places a considerable burden on emergency services. The need for activity restriction and the benefits of this in reducing long term cognitive effects of CHI are uncertain.

Concussion management by primary care providers

OBJECTIVE

To assess current concussion management practices of primary care providers.

METHODS

An 11 item questionnaire was mailed to primary care providers in the state of Maine, with serial mailings to non-respondents.

RESULTS

Over 50% of the questionnaires were completed, with nearly 70% of primary care providers indicating that they routinely use published guidelines as a tool in managing patients with concussion. Nearly two thirds of providers were aware that neuropsychological tests could be used, but only 16% had access to such tests within a week of injury.

CONCLUSIONS

Primary care providers are using published concussion management guidelines with high frequency, but many are unable to access neuropsychological testing when it is required.

Management of sport-related concussion in young athletes

Sport-related head injuries are a common clinical problem. Most head injuries in young athletes are mild traumatic brain injuries or concussions. The highest number of sport-related concussions has been reported in American football. In addition to the well described physical and psychosocial growth, there is ongoing neurocognitive development of the brain during childhood and through adolescence. This developmental process has direct implications in the assessment and management of head injuries in young athletes. Research on the management and long-term outcome following brain injuries in young athletes is limited. Traditionally, the assessment of concussion has been based on clinical history and physical and neurological examination. Increasingly, neuropsychological testing, especially computerised testing, is providing objective measures for the initial assessment and follow-up of young athletes following brain injuries. Numerous guidelines have been published for grading and return to play criteria following concussion; however, none of these have been prospectively validated by research and none are specifically applicable to children and adolescents.

Recognition and characteristics of concussions in the emergency department population

An anonymous survey was conducted over a 6-month period of time using consenting Emergency Department (ED) patients in an attempt to better understand concussions occurring in the ED population. Calculations were made using the respondents' history and self-reported symptoms during the previous 12 months. Five hundred twenty-two of 700 approached patients responded to the anonymous questionnaire. Of respondents, 20.1% (105/522) answered that they had experienced symptoms of a concussion after being hit in the head during the previous 12 months. Of the 105 respondents who experienced a concussion, 88.6% (93/105) did not recognize that they had suffered a concussion. There were 28.2% (147/522) of all respondents who were actively engaging in at least one activity that was considered to be at high risk for concussions. Headache was the most common symptom for both recognized and unrecognized concussions. Respondents who experienced nausea after being hit in the head were the most likely to seek some form of medical attention, followed by people who suffered a loss of consciousness. Those patients who suffered a loss of consciousness were the most likely to visit an ED. Many patients have a poor understanding of concussions and these patients may be actively participating in high-risk activities while still suffering symptoms from a concussion. Therefore, these patients may be at risk for further concussions and Second Impact Syndrome.

Posttraumatic migraine characteristics in athletes following sports-related concussion

OBJECT

The object of this study was to compare symptom status and neurocognitive functioning in athletes with no headache (non-HA group), athletes complaining of headache (HA group), and athletes with characteristics of posttraumatic migraine (PTM group).

METHODS

Neurocognitive tests were undertaken by 261 high-school and collegiate athletes with a mean age of 16.36 +/- 2.6 years. Athletes were separated into three groups: the PTM group (74 athletes with a mean age of 16.39 +/- 3.06 years), the HA group (124 athletes with a mean age of 16.44 +/- 2.51 years), and the non-HA group (63 patients with a mean age of 16.14 +/- 2.18 years). Neurocognitive summary scores (outcome measures) for verbal and visual memory, visual motor speed, reaction time, and total symptom scores were collected using ImPACT, a computer software program designed to assess sports-related concussion. Significant differences existed among the three groups for all outcome measures. The PTM group demonstrated significantly greater neurocognitive deficits when compared with the HA and non-HA groups. The PTM group also exhibited the greatest amount of departure from baseline scores.

CONCLUSIONS

The differences among these groups can be used as a basis to argue that PTM characteristics triggered by sports-related concussion are related to increased neurocognitive dysfunction following mild traumatic brain injury. Thus, athletes suffering a concussion accompanied by PTM should be examined in a setting that includes symptom status and neurocognitive testing to address their recovery more fully. Given the increased impairments observed in the PTM group, in this population clinicians should exercise increased caution in decisions about treatment and when the athlete should be allowed to return to play.

The college athlete

Participation in sports is important to many college students. Student athletes come from different levels of previous sport experience as they enter collegiate athletics. The primary source of student medical care is the campus student health center. The health care providers at student health centers attend to many of the sports-related concerns of student athletes. Preparticipation evaluation provides an opportunity to assess the general health of the student athlete and to identify conditions that might increase the risk of further injury. Sudden cardiac death and sports-associated concussions have generated much interest and are reviewed in this article. Other areas reviewed here include use of drugs and supplements, ankle sprains, acute knee ligament injuries, back pain, and shoulder impingement syndrome.

Head injuries presenting to emergency departments in the United States from 1990 to 1999 for ice hockey, soccer, and football

STUDY OBJECTIVE

To examine the number and rates of head injuries occurring in the community as a whole for the team sports of ice hockey, soccer, and football by analyzing data from patients presenting to US emergency departments (EDs) from 1990 to 1999.

DESIGN

Retrospective analysis.

MAIN OUTCOME MEASURES

Data compiled for the US Consumer Product Safety Commission using the National Electronic Injury Surveillance System were used to generate estimates for the total number of head injuries, concussions, internal head injuries, and skull fractures occurring on a national level from the years 1990 to 1999. These data were combined with yearly participation figures to generate rates of injuries presenting to the ED for each sport.

RESULTS

There were an estimated 17,008 head injuries from ice hockey, 86,697 from soccer, and 204,802 from football that presented to US EDs from 1990 to 1999. The total number of concussions presenting to EDs in the United States over the same period was estimated to be 4820 from ice hockey, 21,715 from soccer, and 68,861 from football. While the rates of head injuries, concussions, and combined concussions/internal head injuries/skull fractures presenting to EDs per 10,000 players were not always statistically similar for all 3 sports in each year data were available, they were usually comparable.

CONCLUSION

While the total numbers of head injuries, concussions, and combined concussions/skull fractures/internal head injuries presenting to EDs in the United States are different for ice hockey, soccer, and football for the years studied, the yearly rates for these injuries are comparable among all 3 sports.

Epidemiology of athletic head and neck injuries

In this article, we review the available data on sporting injuries to the head and neck and discuss sport-specific injury risk and prevention strategies, as well as the costs of head and neck injuries.

Evaluation of neuropsychological domain scores and postural stability following cerebral concussion in sports

CONTEXT

With increasing knowledge and research about concussion, there have been few objective studies that have used neuropsychological domain scores and postural stability to assess concussion.

OBJECTIVE

To evaluate the recovery curve of athletes who incur sport-related concussion from repeated serial testing of neuropsychological and posturography testing.

DESIGN

A prospective epidemiological model was used for the course of the study.

SETTING

Division I intercollegiate athletics.

PARTICIPANTS

Athletes participating in football, soccer, basketball, softball, and cheerleading.

MAIN OUTCOME MEASURES

Neuropsychological scores and posturography measures were obtained preseason and serially at day 1, day 2, day 3, and day 10 postconcussion. Control participants were tested at the same intervals. Neuropsychological scores were converted to standards score and then into domains of attention, learning, speed of information processing, concentration, memory, and verbal fluency. Analysis of covariance with the baseline test as the covariate was used to analyze the data with univariate post hoc tests performed.

RESULTS

Significant group differences were found for self reported symptoms (P = 0.001), speed of information processing (P = 0.005), mean stability (P = 0.002), and vestibular function (P = 0.003) between injured and control participants. A group, by day, planned comparison found that speed of information processing and composite balance measures demonstrated significant differences through day 10 postinjury, while symptoms and the vestibular ratio remained significant only through day 3.

CONCLUSIONS

The concussion recovery curve demonstrated short-term neuropsychological and posturography deficits following injury. A comprehensive approach to concussion management should be used to assess the injury and make return-to-play decisions.

Symptom-based assessment of the severity of a concussion

OBJECT

Current grading systems of concussion and return-to-play guidelines have little empirical support. The authors therefore examined the relationships of the characteristics and symptoms of concussion and the history of concussion to three indicators of concussion severity-number of immediate symptoms, number of symptoms at the initial follow-up examination, and duration of symptoms--to establish an empirical basis for grading concussions.

METHODS

Forty-seven athletes who sustained concussions were administered alternate forms of an Internet-based neurocognitive test until their performances were within normal limits relative to baseline levels. Assessments of observer-reported and self-reported symptoms at the sideline of the playing field on the day of injury, and at follow-up examinations were also obtained as part of a comprehensive concussion management protocol. Although loss of consciousness (LOC) was a useful indicator of the initial severity of the injury, it did not correlate with other indices of concussion severity, including duration of symptoms. Athletes reporting memory problems at follow-up examinations had significantly more symptoms in general, longer durations of those symptoms, and significant decreases in scores on neurocognitive tests administered approximately 48 hours postinjury. This decline of scores on neurocognitive testing was significantly associated with an increased duration of symptoms. A history of concussion was unrelated to the number and duration of symptoms.

CONCLUSIONS

This paper represents the first documentation of empirically derived indicators of the clinical course of postconcussion symptom resolution. Self-reported memory problems apparent 24 hours postconcussion were robust indicators of the severity of sports-related concussion and should be a primary consideration in determining an athlete's readiness to return to competition. A decline on neurocognitive testing was the only objective measure significantly related to the duration of symptoms. Neither a brief LOC nor a history of concussion was a useful predictor of the duration of postconcussion symptoms.

Concussions among university football and soccer players

OBJECTIVE

A study to examine the incidence and characteristics of concussions among Canadian university athletes during 1 full year of football and soccer participation.

DESIGN

Retrospective survey.

PARTICIPANTS

Three hundred eighty Canadian university football and 240 Canadian university soccer players reporting to 1999 fall training camp. Of these, 328 football and 201 soccer players returned a completed questionnaire.

MAIN OUTCOME MEASURES

Based on self-reported symptoms, calculations were made to determine the number of concussions experienced during the previous full year of football or soccer participation, the duration of symptoms, the time for return to play, and any associated risk factors for concussions.

RESULTS

Of all the athletes who returned completed questionnaires, 70.4% of the football players and 62.7% of the soccer players had experienced symptoms of a concussion during the previous year. Only 23.4% of the concussed football players and 19.8% of the concussed soccer players realized they had suffered a concussion. More than one concussion was experienced by 84.6% of the concussed football players and 81.7% of the concussed soccer players. Examining symptom duration, 27.6% of all concussed football players and 18.8% of all concussed soccer players experienced symptoms for at least 1 day or longer. Tight end and defensive lineman were the positions most commonly affected in football, while goalies were the players most commonly affected in soccer. Variables that increased the odds of suffering a concussion during the previous year for football players included a history of a traumatic loss of consciousness or a recognized concussion in the past. Variables that increased the odds of suffering a concussion during the previous year for soccer players included a past history of a recognized concussion while playing soccer and being female.

CONCLUSIONS

University football and soccer players seem to be experiencing a significant amount of concussions while participating in their respective sports. Variables that seem to increase the odds of suffering a concussion during the previous year for football and soccer players include a history of a recognized concussion. Despite being relatively common, symptoms of concussion may not be recognized by many players.