Symptom-based assessment of the severity of a concussion

Psychometric Properties of Computerized Cognitive Tools and Standard Neuropsychological Tests Used to Assess Sport Concussion: A Systematic Review

Athletic programs are more frequently turning to computerized cognitive tools in order to increase efficiencies in concussion assessment. However, assessment using a traditional neuropsychological test battery may provide a more comprehensive and individualized evaluation. Our goal was to inform sport clinicians of the best practices for concussion assessment through a systematic literature review describing the psychometric properties of standard neuropsychological tests and computerized tools. We conducted our search in relevant databases including Ovid Medline, Web of Science, PsycINFO, and Scopus. Journal articles were included if they evaluated psychometric properties (e.g., reliability, sensitivity) of a cognitive assessment within pure athlete samples (up to 30 days post-injury). Searches yielded 4,758 unique results. Ultimately, 103 articles met inclusion criteria, all of which focused on adolescent or young adult participants. Test-retest reliability estimates ranged from .14 to .93 for computerized tools and .02 to .95 for standard neuropsychological tests, with strongest correlations on processing speed tasks for both modalities, although processing speed tasks were most susceptible to practice effects. Reliability was improved with a 2-factor model (processing speed and memory) and by aggregating multiple baseline exams, yet remained below acceptable limits for some studies. Sensitivity to decreased cognitive performance within 72 h of injury ranged from 45%-93% for computerized tools and 18%-80% for standard neuropsychological test batteries. The method for classifying cognitive decline (normative comparison, reliable change indices, regression-based methods) affected sensitivity estimates. Combining computerized tools and standard neuropsychological tests with the strongest psychometric performance provides the greatest value in clinical assessment. To this end, future studies should evaluate the efficacy of hybrid test batteries comprised of top-performing measures from both modalities.

Examining Whether Loss of Consciousness Is Associated With Worse Performance on the SCAT5 and Slower Clinical Recovery After Concussion in Professional Athletes

Video surveillance has almost universally been employed by professional sports to identify signs of concussion during competition. This study examined associations between video-identified possible loss of consciousness (LOC), acute concussion evaluation findings, and recovery time in concussed professional rugby league players. Medical personnel and sideline video operators identified head impact events sustained during three seasons of National Rugby League (NRL) matches to determine the need for further medical evaluation. If a concussion was suspected, players were removed from play and underwent a Head Injury Assessment, including the Sports Concussion Assessment Tool, Fifth Edition (SCAT5). Video footage was later examined to identify signs of possible LOC (i.e., observed LOC, no protective action in the fall, and unresponsiveness or lying motionless). Possible LOC was identified in 99 of the 1706 head impact events (5.8%). The median duration of apparent unresponsiveness was 4.2 sec (M = 7.4, standard deviation [SD] = 12.8, interquartile range [IQR] = 2.5-6.6). In the 661 athletes for whom SCAT5 data were available, those with possible LOC endorsed more SCAT5 symptoms and performed worse on Maddocks questions, Standardized Assessment of Concussion (SAC) total scores, orientation, immediate recall, concentration, and delayed recall. For the 255 players with medically diagnosed concussions, SCAT5 data were available for 245. Concussed players with possible LOC performed significantly worse on Maddocks questions. However, there were no group differences in SCAT5 symptom endorsement, SAC total scores, orientation, immediate recall, concentration, delayed recall, or the modified version of the Balance Error Scoring System (mBESS) total errors. Further, the presence or absence of possible LOC was not associated with number of games missed or time to medical clearance for match play. The duration of possible LOC was not associated with the number of games missed or time to medical clearance for match play. According to video review in NRL players, brief LOC might be more common than previously thought. The present study reveals possible LOC is not predictive of missed games or time to recover following concussion.

Acute effects of concussion among adolescents with attention-deficit/hyperactivity disorder

Adolescents with ADHD have a greater lifetime history of concussion and experience concussion-like symptoms in the absence of a concussion, complicating concussion assessment and management. It is well established that individuals who experience greater acute symptoms following concussion are at risk for slower recovery and persistent symptoms. We examined whether youth with ADHD experience worse acute effects, within the first 72 h following concussion, compared to youth without ADHD. We hypothesized that youth with ADHD would perform worse on neurocognitive testing and endorse more severe symptoms acutely following injury, but the magnitude of change from pre injury to post injury would be similar for both groups, and thus comparable to baseline group differences. The sample included 852 adolescents with pre-injury and post-injury ImPACT results (within 72 h); we also conducted supplementary case-control analyses on a subset of youth with and without ADHD matched on demographics and pre-injury health history. For both samples, there were significant interaction effects for the Verbal Memory and Visual Motor Speed composites (p < 0.01, η²=.01-.07, small-medium effect), such that youth with ADHD showed a greater magnitude of diminished cognitive functioning from pre-injury to post-injury testing. There were no significant differences in the magnitudes of changes from pre injury to post injury with regard to overall symptom reporting (i.e., total symptom severity scores, total number of symptoms endorsed); however, there were group differences in endorsement rates for several individual symptoms. Further research is needed to determine whether such differential acute effects are associated with recovery time in youth with ADHD.

Using a Likelihood Heuristic to Summarize Conflicting Literature on Predictors of Clinical Outcome Following Sport-Related Concussion

OBJECTIVE

To introduce a new methodology for summarizing the results from systematic reviews-a likelihood heuristic-to the field of sport-related concussion.

DATA SOURCES

We applied the likelihood heuristic to the results of a systematic review published by Iverson et al (2017), containing 101 studies, on the predictors of worse clinical outcome following sport-related concussion.

STUDY SELECTION

We re-examined 5 individual prognostic factors that are of clinical interest and for which there is conflicting literature (female sex = 44 studies, prior concussion history = 41 studies, loss of consciousness = 31 studies, post-traumatic amnesia = 25 studies, and retrograde amnesia = 10 studies).

DATA EXTRACTION

For each prognostic factor, likelihood ratios were generated using the (1) number of significant and nonsignificant studies, (2) study power, (3) alpha level, and (4) prior probability that the alternative hypothesis was true.

DATA SYNTHESIS

Assuming each study had 80% power and an alpha level of 5%, observing the reported number of conflicting studies for female sex, prior concussion history, and retrograde amnesia is substantially more likely if each prognostic factor is associated with worse clinical outcome following sport-related concussion. For loss of consciousness, the observed number of conflicting studies is more likely if loss of consciousness is not associated with worse clinical outcome following sport-related concussion. A secondary analysis incorporating potentially more realistic study parameters of statistical power (45%) and alpha level (25%) generates weaker likelihood evidence that the observed numbers of studies for each prognostic factor are associated with worse clinical outcome following sport-related concussion than they are not.

CONCLUSIONS

Using a likelihood heuristic with 80% power and 5% alpha level, there is very strong likelihood evidence that female sex, prior concussion history, and retrograde amnesia are associated with worse clinical outcome following sport-related concussion. The strength of likelihood evidence that prognostic factors are associated with worse clinical outcome reduces when statistical power is lower and alpha level is inflated.

Acute Effects of Concussion in Youth With Pre-existing Migraines

OBJECTIVE

To examine associations between pre-existing migraines and postconcussion symptoms and cognitive performance acutely (within 72 hours) after a suspected concussion.

DESIGN

Nested case-control study.

SETTING

High schools in Maine, USA.

PARTICIPANTS

From a sample of 39 161 adolescent athletes who underwent baseline preseason testing, 633 were assessed within 3 days of a suspected concussion. Of these, 59 reported a history of treatment for migraines at baseline (9.3%). These athletes were individually matched to 2 athletes who had a suspected concussion but denied preinjury migraines (total N = 177; age: M = 15.8, SD = 1.3).

ASSESSMENT OF RISK FACTORS

Self-reported history of treatment for migraines by a physician.

MAIN OUTCOME MEASURES

Post-Concussion Symptom Scale total score, ImPACT composite scores, and individual symptom endorsement.

RESULTS

Individuals with a pre-existing migraine disorder endorsed greater symptom severity (M = 8.4, SD = 9.9) compared with controls (M = 4.5, SD = 6.5; Cohen's d = 0.47) at preinjury baseline and acutely after suspected injury (migraine: M = 26.0, SD = 25.5; controls: M = 16.7, SD = 15.4; d = 0.44). Acutely after a suspected concussion, greater proportions of athletes with migraine disorders reported mental fogginess (49.2% vs 33.9%) and memory problems (39.0% vs 24.6%; P < 0.05). Baseline ImPACT composite scores were similar between migraine and control groups (d = 0.04-0.13). Adolescents with pre-existing migraine disorders performed worse after a suspected concussion compared with the control participants on verbal memory (F = 4.32, P = 0.041) and visual memory (F = 3.95, P = 0.049).

CONCLUSIONS

Individuals with pre-existing migraine disorders may be at higher risk for worse outcomes, including greater overall burden of symptoms and worse cognitive functioning in the memory domain, in the first 72 hours after concussion.

Photophobia Associated with Traumatic Brain Injury: A Systematic Review and Meta-analysis

SIGNIFICANCE

This study reports the prevalence and relative risk of photophobia in patients with traumatic brain injury (TBI).

OBJECTIVES

This study aimed to conduct a systematic review and meta-analysis to determine the prevalence and relative risk of photophobia in patients with TBI.

DATA SOURCES

Three databases were used for literature search: PubMed, EMBASE, and Cochrane Library.

STUDY APPRAISAL AND SYNTHESIS METHODS

Publications reporting the prevalence of photophobia after TBI in patients of any age were included. A series of meta-regression analyses based on a generalized linear mixed model was performed to identify potential sources of heterogeneity in the prevalence estimates.

RESULTS

Seventy-five eligible publications were identified. The prevalence of photophobia was 30.46% (95% confidence interval [CI], 20.05 to 40.88%) at 1 week after the injury. Prevalence decreased to 19.34% (95% CI, 10.40 to 28.27%) between 1 week and 1 month after TBI and to 13.51% (95% CI, 5.77 to 21.24%) between 1 and 3 months after the injury. The rapid decrease in the prevalence of photophobia in the first 3 months after a TBI injury was significant (P < .001). Three months post-TBI, the prevalence of photophobia leveled off to a near plateau with nonsignificant variability, increasing between 3 and 6 months (17.68%; 95% CI, 9.05 to 26.32%) and decreasing between 6 and 12 months since TBI (14.85%; 95% CI, 6.80 to 22.90%). Subgroup analysis of 14 publications that contained control data showed that the estimated risk ratio for photophobia was significantly higher in the TBI than in the control group during the entire 12 months after TBI.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

This study demonstrates that photophobia is a frequent complaint after TBI, which largely resolves for many individuals within 3 months after the injury. For some patients, however, photophobia can last up to 12 months and possibly longer. Developing an objective quantitative methodology for measuring photophobia, validating a dedicated photophobia questionnaire, and having a specific photophobia International Classification of Diseases, Tenth Revision code would greatly improve data gathering and analysis.

Association of Concussion Symptoms With Testosterone Levels and Erectile Dysfunction in Former Professional US-Style Football Players

Question

Are professional US-style football players with a history of multiple concussion symptoms more likely to report indicators of low testosterone levels or erectile dysfunction (ED)?

Findings

In this cross-sectional study of 3409 former players, a monotonically increasing association was found between the number of concussion symptoms and the odds of reporting an indicator of low testosterone level and ED.

Meaning

Concussion symptoms among former football players were associated with low testosterone levels and ED indicators, suggesting that men with a history of head injury may benefit from discussions with their health care clinicians regarding these treatable outcomes.

Importance

Small studies suggest that head trauma in men may be associated with low testosterone levels and sexual dysfunction through mechanisms that likely include hypopituitarism secondary to ischemic injury and pituitary axonal tract damage. Athletes in contact sports may be at risk for pituitary insufficiencies or erectile dysfunction (ED) because of the high number of head traumas experienced during their careers. Whether multiple symptomatic concussive events are associated with later indicators of low testosterone levels and ED is unknown.

Objective

To explore the associations between concussion symptom history and participant-reported indicators of low testosterone levels and ED.

Design, Setting, and Participants

This cross-sectional study of former professional US-style football players was conducted in Boston, Massachusetts, from January 2015 to March 2017. Surveys on past football exposures, demographic factors, and current health conditions were sent via electronic and postal mail to participants within and outside of the United States. Analyses were conducted in Boston, Massachusetts; the data analysis began in March 2018 and additional analyses were performed through June 2019. Of the 13 720 male former players eligible to enroll who were contacted, 3506 (25.6%) responded.

Exposures

Concussion symptom score was calculated by summing the frequency with which participants reported 10 symptoms, such as loss of consciousness, disorientation, nausea, memory problems, and dizziness, at the time of football-related head injury.

Main Outcomes and Measures

Self-reported recommendations or prescriptions for low testosterone or ED medication served as indicators for testosterone insufficiency and ED.

Results

In 3409 former players (mean [SD] age, 52.5 [14.1] years), the prevalence of indicators of low testosterone levels and ED was 18.3% and 22.7%, respectively. The odds of reporting low testosterone levels or ED indicators were elevated for previously established risk factors (eg, diabetes, sleep apnea, and mood disorders). Models adjusted for demographic characteristics, football exposures, and current health factors showed a significant monotonically increasing association of concussion symptom score with the odds of reporting the low testosterone indicator (highest vs lowest quartile, odds ratio, 2.39; 95% CI, 1.79-3.19; P < .001). The ED indicator showed a similar association (highest quartile vs lowest, odds ratio, 1.72; 95% CI, 1.30-2.27; P < .001).

Conclusions and Relevance

Concussion symptoms at the time of injury among former football players were associated with current participant-reported low testosterone levels and ED indicators. These findings suggest that men with a history of head injury may benefit from discussions with their health care clinicians regarding testosterone deficiency and sexual dysfunction.

Examining Criteria for Defining Persistent Post-concussion Symptoms in Children and Adolescents

Researchers operationalize persistent post-concussion symptoms in children and adolescents using varied definitions. Many pre-existing conditions, personal characteristics, and current health issues can affect symptom endorsement rates in the absence of, or in combination with, a recent concussion, and the use of varied definitions can lead to differences in conclusions about persistent symptoms and recovery across studies. This study examined how endorsement rates varied by 14 different operational definitions of persistent post-concussion symptoms for uninjured boys and girls with and without pre-existing or current health problems. This cross-sectional study included a large sample (age range: 11–18) of girls (n = 21,923) and boys (n = 26,556) without a recent concussion who completed the Post-Concussion Symptom Scale at preseason baseline. Endorsements rates varied substantially by definition, health history, and current health issues. The most lenient definition (i.e., a single mild symptom) was endorsed by most participants (54.5% of boys/65.3% of girls). A large portion of participants with pre-existing mental health problems (42.7% of boys/51.5% of girls), current moderate psychological distress (70.9% of boys/72.4% of girls), and insufficient sleep prior to testing (33.4% of boys/47.6% of girls) endorsed symptoms consistent with mild ICD-10 postconcussional syndrome; whereas participants with no current or prior health problems rarely met this definition (1.6% of boys/1.6% of girls). The results illustrate the tremendous variability in the case definitions of persistent symptoms and the importance of harmonizing definitions across future studies.

Investigating cannabis use and associated symptoms among university students with and without a history of concussion

Recently, there has been a growing interest in the use of cannabis after traumatic brain injury (TBI); however, little is known about the long-term effects of cannabis on milder injuries and post-concussive symptoms. Further, substance use often increases post-TBI and, thus, individuals who chronically use cannabis may unknowingly be exceeding safe or therapeutic doses. The current cross-sectional study explores the prevalence of cannabis use among university students with and without a history of concussion and examines the relationship between concussion and post-concussive symptoms as a function of cannabis use. Eighty-four undergraduates (n = 51 without a prior concussion; n = 33 with a prior concussion) completed a series of questionnaires, capturing their head injury history, current and past substance use, and post-concussive symptomatology. Results indicated that those with a history of concussion were more likely to use cannabis and had higher cannabis use severity scores compared to those without a previous concussion. Further, among cannabis users only, concussion severity demonstrated a significant positive association with post-concussive symptom (e.g., headaches, memory problems) severity (i.e., frequency, intensity, duration). Taken together, the long-term use of cannabis may be detrimental to individuals with a history of concussion, exacerbating, rather than mitigating, post-concussive symptoms.

Soccer-Related Concussions Among Swedish Elite Soccer Players: A Descriptive Study of 1,030 Players

Objective: There are growing concerns about the short- and long-term consequences of sports-related concussion, which account for about 5–9% of all sports injuries. We hypothesized there may be sex differences in concussion history and concussion-related symptoms, evaluated among elite soccer players in Sweden.

Design: Retrospective survey study.

Participants and Setting: Soccer players (n = 1,030) from 55 Swedish elite soccer teams. Questionnaires were completed prior to the start of the 2017 season.

Assessment of Risk Factors: Player history of soccer-related concussion (SoRC), symptoms and management following a SoRC were evaluated.

Main Outcome Measures: Before the start of the season the players completed a baseline questionnaire assessing previous concussions. The Sports Concussion Assessment Tool 3 was included with regard to symptom evaluation.

Results: Out of 993 responding players 334 (34.6%) reported a previous SoRC and 103 players (10.4%) reported a SoRC during the past year. After sustaining a SoRC, 114 players (34.2%) reported that they continued their ongoing activity without a period of rest, more commonly female (44.9%) than male players (27.7%; P = 0.002). Symptom resolution time was 1 week or less for 61.3% of the players that reported having persisting symptoms. A positive correlation was observed between number of previous concussions and prevalence of three persisting symptoms: fatigue (P < 0.001), concentration/memory issues (P = 0.002) and headache (P = 0.047).

Conclusion: About 35% of male and female elite soccer players in Sweden have experienced a previous SoRC, and about 10% experienced a SoRC during the last year. Female players continued to play after a SoRC, without a period of rest, more often than males. A higher risk of persisting symptoms was observed in players with a history of multiple concussions.

Attention-Deficit/Hyperactivity Disorder and Outcome After Concussion: A Systematic Review

OBJECTIVE

To synthesize the literature and conduct a gap analysis on the association between attention-deficit/hyperactivity disorder (ADHD) and clinical outcome from sport-related concussion.

METHOD

The electronic search for this systematic review (PROSPERO ID: CRD42019128281) was conducted in February 2019 using terms related to concussion, sports/athletics, and predictors/modifiers of outcome to search the PubMed, PsycINFO, MEDLINE, CINAHL, Cochrane Library, EMBASE, SPORTDiscus, Scopus, and Web of Science databases. Eligible studies evaluated the association between ADHD and outcome from sport-related concussion. Of 4014 studies screened, 359 full-text articles were reviewed, with 14 studies ultimately included, involving 3623 participants (n = 359 [9.9%] with ADHD).

RESULTS

Study samples were primarily from specialty medical clinics (57.1%) and high school or college athletic groups (28.6%). Only 2 studies reported a statistically significant association between ADHD and worse clinical outcome. Of these, 1 included 13 participants with ADHD and the other included only 8 participants with ADHD. Only 1 previous study in this review was designed specifically to examine ADHD and prolonged concussion recovery, and that study did not report a statistically significant association.

CONCLUSION

There is not a clear association between ADHD and worse clinical outcome from concussion. However, eligible studies had limitations in research design, and nearly all studies were underpowered and evaluated the association between ADHD and concussion outcome as a secondary focus rather than the primary research question, precluding definitive conclusions. The association between ADHD and clinical outcomes remains unclear, and future research specifically examining ADHD and concussion recovery is needed.

Assessing the predictive value of primary evaluation with the Immediate Post-Concussion Assessment and Cognitive Test following head injury

OBJECTIVE

Concussions are a major public health concern, especially for high school and college student athletes. However, there are few prognostic metrics that can accurately quantify concussion severity in order to anticipate recovery time and symptom regression. The Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) is a widely used neurocognitive assessment that can diagnose and track recovery from concussions. This study assesses whether initial ImPACT scores, collected within 48 hours of the injury, can predict persistence of concussion at follow-up.

METHODS

Results from 6912 ImPACT tests were compiled in 2161 unique student athletes, ages 12-22 years. The authors defined a novel metric, the Severity Index (SI), which is a summation of the number of standard deviations from baseline at the 80% CI for each of the 5 composite scores reported by ImPACT. Patients were binned into groups based on SI (0-3.99, 4-7.99, 8-11.99, 12+) and the relationships between SI groups, composite scores, symptom profiles, and recovery time were characterized using 1-way and 2-way ANOVAs and Kaplan-Meier plots. A logistic regression assessed the value of SI for predicting concussion at follow-up.

RESULTS

Patients with a higher SI at diagnosis were more likely to still be concussed at their first follow-up (F3,2300 = 93.06; p < 0.0001). Groups with a higher SI also displayed consistently slower recovery over a 42-day period and were more likely to report symptoms in all 4 symptom clusters (Migraine, Cognition, Sleep, and Neuropsychiatric). When controlling for sex, age, number of previous concussions, days between assessments, and location, SI significantly increased the odds of being concussed at follow-up (OR 1.122, 95% CI 1.088-1.142; p < 0.001). This model showed good discrimination with an area under the curve of 0.74.

CONCLUSIONS

SI is a useful prognostic tool for assessing head injury severity. Concussions with higher initial SI tend to last longer and have broader symptomatic profiles. These findings can help patients and providers estimate recovery based on similar ImPACT score profiles.

Clinical predictors of symptom resolution for children and adolescents with sport-related concussion

OBJECTIVE

The goal of this study was to determine which variables assessed during an initial clinical evaluation for concussion are independently associated with time until symptom resolution among pediatric patients.

METHODS

Data collected from a prospective clinical registry of pediatric patients with concussion were analyzed. The primary outcome variable was time from injury until symptom resolution. Predictor variables assessed within 10 days after injury included preinjury factors, Health and Behavior Inventory scores, headache severity, and balance, vestibular, and oculomotor test performances. The researchers used univariate Cox proportional models to identify potential predictors of symptom resolution time and constructed a multivariate Cox proportional hazards model in which total duration of concussion symptoms remained the outcome variable.

RESULTS

The sample consisted of 351 patients (33% female, mean age 14.6 ± 2.2 years, evaluated 5.6 ± 2.6 days after concussion). Univariate Cox proportional hazards models indicated that several variables were associated with a longer duration of symptoms, including headache severity (hazard ratio [HR] 0.90 [95% CI 0.85-0.96]), headache frequency (HR 0.83 [95% CI 0.71-0.96]), confusion (HR 0.79 [95% CI 0.69-0.92]), forgetfulness (HR 0.79 [95% CI 0.68-0.92]), attention difficulties (HR 0.83 [95% CI 0.72-0.96]), trouble remembering (HR 0.84 [95% CI 0.72-0.98]), getting tired often (HR 0.86 [95% CI 0.76-0.97]), getting tired easily (HR 0.86 [95% CI 0.76-0.98]), dizziness (HR 0.86 [95% CI 0.75-0.99]), and abnormal performance on the Romberg test (HR 0.59 [95% CI 0.40-0.85]). A multivariate Cox proportional hazards model indicated that an abnormal performance on the Romberg test was independently associated with a longer duration of symptoms (HR 0.65 [95% CI 0.44-0.98]; p = 0.038).

CONCLUSIONS

For children and adolescents evaluated within 10 days after receiving a concussion, abnormal performance on the Romberg test was independently associated with a longer duration of symptoms during recovery. In line with findings of other recent studies investigating predictors of symptom resolution, postural stability tests may provide useful prognostic information for sports medicine clinicians.

Biomechanical comparison of concussions with and without a loss of consciousness in elite American football: implications for prevention

Loss of consciousness (LOC) associated with concussion is no longer considered an indicator of severity of injury in concussion management protocols. Studies investigating the association between LOC and recovery time or neurophysiological performance have reported ambiguous findings and resulted in a limited understanding of the severity of LOC-inducing head impacts. Concussive injuries with and without LOC from helmet-to-helmet and shoulder collisions and falls in elite American football were reconstructed in laboratory using a hybrid III headform and finite element model to obtain peak linear and rotational acceleration and brain tissue deformation metrics in the cerebral cortex, the cerebral white matter, the corpus callosum, the thalamus and the brainstem. Impact velocity, peak linear and rotational acceleration were significantly greater in the LOC group than the no LOC group. The brain tissue deformation metrics were greater in the LOC group than the no LOC group. The best overall predictor for LOC was impact velocity. Concussions with LOC are characterised by greater magnitudes of brain tissue deformation. This was mainly the result of higher impact velocities in the LOC group providing league decision-makers with an understanding of the importance of managing impact velocity through athlete education and rule enforcement or change.

A preliminary report of cerebral white matter microstructural changes associated with adolescent sports concussion acutely and subacutely using diffusion tensor imaging

Diffusion tensor imaging (DTI) has demonstrated its utility in detecting microscopic post-concussion cerebral white matter structural changes, which are not routinely evident on conventional neuroimaging modalities. In this study, we compared 10 adolescents with sports concussion (SC) to 12 orthopedically-injured (OI) individuals within 96 h and three months post injury to 12 typically-developing (TD) participants using DTI and volumetric analyses. In terms of volume, no group differences were noted between SC, OI and TD groups at both 96 h and three months post concussion. Results did not show significant differences between SC, OI, and TD groups for both fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in all regions of interest within 96 h post concussion. However, at three months post-injury, the SC group exhibited significantly lower FA than the TD group in various regions of interest. In terms of ADC, significant group differences between SC and TD groups were found in some regions, with SC group having higher ADC than TD. No group differences for FA and ADC were noted between SC and OI groups at three months post-injury. However, several moderate effect sizes on between-group analyses were noted such that FA was lower and ADC was higher in SC relative to OI. Longitudinally, the SC group demonstrated decreased FA and increased ADC in some areas. The findings highlight the fact that the brain continues to change during the post-injury recovery period, and raises the possibility that adverse changes may result from the neurometabolic cascade that purportedly ensues following SC. DTI may potentially be used to characterize the nature of brain changes that occur following sports-related concussions.

Sport-Related Concussion in Children and Adolescents

Sport-related concussion is an important topic in nearly all sports and at all levels of sport for children and adolescents. Concussion knowledge and approaches to management have progressed since the American Academy of Pediatrics published its first clinical report on the subject in 2010. Concussion's definition, signs, and symptoms must be understood to diagnose it and rule out more severe intracranial injury. Pediatric health care providers should have a good understanding of diagnostic evaluation and initial management strategies. Effective management can aid recovery and potentially reduce the risk of long-term symptoms and complications. Because concussion symptoms often interfere with school, social life, family relationships, and athletics, a concussion may affect the emotional well-being of the injured athlete. Because every concussion has its own unique spectrum and severity of symptoms, individualized management is appropriate. The reduction, not necessarily elimination, of physical and cognitive activity is the mainstay of treatment. A full return to activity and/or sport is accomplished by using a stepwise program while evaluating for a return of symptoms. An understanding of prolonged symptoms and complications will help the pediatric health care provider know when to refer to a specialist. Additional research is needed in nearly all aspects of concussion in the young athlete. This report provides education on the current state of sport-related concussion knowledge, diagnosis, and management in children and adolescents.

Clinical Findings in a Multicenter MRI Study of Mild TBI

Background: Uncertainty continues to surround mild traumatic brain injury (mTBI) diagnosis, symptoms, prognosis, and outcome due in part to a lack of objective biomarkers of injury and recovery. As mTBI gains recognition as a serious public health epidemic, there is need to identify risk factors, diagnostic tools, and imaging biomarkers to help guide diagnosis and management. Methods: One hundred and eleven patients (15-50 years old) were enrolled acutely after mTBI and followed with up to four standardized serial assessments over 3 months. Each encounter included a clinical exam, neuropsychological assessment, and magnetic resonance imaging (MRI). Chi-square and linear mixed models were used to assess changes over time and determine potential biomarkers of mTBI severity and outcome. Results: The symptoms most frequently endorsed after mTBI were headache (91%), not feeling right (89%), fatigue (86%), and feeling slowed down (84%). Of the 104 mTBI patients with a processed MRI scan, 28 (27%) subjects had white matter changes which were deemed unrelated to age, and 26 of these findings were deemed unrelated to acute trauma. Of the neuropsychological assessments tested, 5- and 6-Digit Backward Recall, the modified Balance Error Scoring System (BESS), and Immediate 5-Word Recall significantly improved longitudinally in mTBI subjects and differentiated between mTBI subjects and controls. Female sex was found to increase symptom severity scores (SSS) at every time point. Age ≥ 25 years was correlated with increased SSS. Subjects aged ≥ 25 also did not improve longitudinally on 5-Digit Backward Recall, Immediate 5-Word Recall, or Single-Leg Stance of the BESS, whereas subjects < 25 years improved significantly. Patients who reported personal history of depression, anxiety, or other psychiatric disorder had higher SSS at each time point. Conclusions: The results of this study show that 5- and 6-Digit Backward Recall, the modified BESS, and Immediate 5-Word Recall should be considered useful in demonstrating cognitive and vestibular improvement during the mTBI recovery process. Clinicians should take female sex, older age, and history of psychiatric disorder into account when managing mTBI patients. Further study is necessary to determine the true prevalence of white matter changes in people with mTBI.

Toxic tau: The TAU gene polymorphisms associate with concussion history in rugby union players

OBJECTIVES

Concussion is a brain injury that occurs when biomechanical forces are transmitted to the head region resulting in neurological deficits. The accumulation of tau protein in autopsies of athletes with multiple concussions implicates tau in concussion-associated neurodegeneration. The TAU rs2435211 (C>T) and rs2435200 (G>A) polymorphisms are involved in pathological tau expression and neurodegenerative disease risk. The aims of this study were to investigate the associations of TAU (rs2435211, rs2435200) polymorphisms with concussion history and sustaining multiple concussions in rugby.

DESIGN

In total, 140 non-concussed controls and 163 previously concussed participants (all cases group, N=163; clinically diagnosed, N=140; multiple concussed, N=87) were recruited from high school (N=135, junior), club and professional rugby teams (N=166, senior).

METHODS

Participants were genotyped for TAU rs2435211 and rs2435200 polymorphisms.

RESULTS

In seniors, the rs2435200 AA genotype was significantly over-represented in the control group compared to the multiple concussed subgroup (P=0.033, control: 25%, N=16, multiple concussed: 11%, N=6; OR: 0.34, 95% CI 0.12-0.96). While the AG genotype was significantly under-represented in the control compared to multiple concussed (P=0.024, control: 45%, N=29, multiple concussed: 63%, N=36; OR: 2.34, 95% CI 1.11-4.95). The inferred TAU (rs2435211 C>T-rs2435200 G>A) T-G haplotype was significantly under-represented in the control (19%, N=12) compared to the all cases group (30%, N=28, P=0.031).

CONCLUSIONS

The TAU-associated neurodegenerative pathway was implicated as a potential pathophysiological mechanism underlying concussion in seniors. In future, the identification of TAU polymorphisms associated with concussion risk may assist clinical management and reduce risk of severe complications.

A review of sideline assessment measures for identifying sports-related concussion

Currently, there is a lack of clear, “gold standard” guidelines for the identification and management of sports-related concussion. This is of concern considering the importance of preventing further injury during game-play. Moreover, a number of assessment measures and tools aim to detect concussion in athletes and help inform return to play decisions, including the assessment of posture and balance, eye-saccades, memory, attention, orientation and post-concussive symptomatology. However, they have often not been widely disseminated for validity studies, and their utility or sensitivity in detecting concussion is limited due to a number of factors. As such, this review will examine current guidelines and sideline assessments measures which aim to inform decisions about return to play following sports-related concussion.

Utility of a multimodal neurophysiologic assessment tool in distinguishing between individuals with and without a history of mild traumatic brain injury

This was a preliminary validation study of a multimodal concussion assessment battery incorporating eye-tracking, balance, and neurocognitive tests on a new hardware platform, the Computerized Brain Injury Assessment System. Using receiver-operating characteristics analyses, (1) we identified a subset of the most discriminating neurophysiological assessment tests involving smooth pursuit eye movement tracking errors, corrective saccade counts, a balance score ratio sensitive to vestibular balance performance, and two neurocognitive tests of response speed and memory/incidental learning; (2) we demonstrated the enhancement in discriminatory capability of detecting concussion-related deficits through the combination of the identified subset of assessments; and (3) we demonstrated the effectiveness of a robust and readily implemented global scoring approach was demonstrated for both eye track and balance assessment tests. These results are significant in introducing a comprehensive solution for concussion assessment that incorporates an economical, compact, and mobile hardware system and an assessment battery that is multimodal and time efficient and whose efficacy has been demonstrated on a preliminary basis. This represents a significant step toward the goal of a system capable of making a dependable return-to-play/duty determination based on concussion likelihood.

Inflammatory and apoptotic signalling pathways and concussion severity: a genetic association study

The objective was to investigate the relationship between IL-1B rs16944, IL-6 rs1800795, and CASP8 rs3834129 genetic polymorphisms and concussion severity. Rugby players from high school, senior amateur, and professional teams completed a concussion severity questionnaire and donated a DNA sample. Participants (n = 163) were split into symptom severity groups around the median number and duration of symptoms. The frequency of participants with high symptom counts (more than five symptoms) increased across the IL-1B (C/C: 35%; C/T: 51%; T/T: 56%; P = 0.047) and the IL-6 (C/C: 31%; C/G: 44%; G/G: 58%; P = 0.027) genotypes. The C-C inferred interleukin allele construct frequency, created from combining the IL-1B and IL-6 genotype data, was lower in participants reporting a high symptom count (18%), compared to those with a low symptom count (fewer than six symptoms, 36%, P = 0.002). Similarly, the C-C inferred interleukin allele construct frequency was lower in those reporting prolonged symptom duration (more than one week, 16%), as opposed to short symptom duration (less than one week, 34%, P = 0.015). This study provides evidence of novel inflammatory pathway genetic associations with concussion severity, which supports the hypothesis implicating neuroinflammation in the development of concussion symptoms.

Investigating the Variability in Mild Traumatic Brain Injury Definitions: A Prospective Cohort Study

OBJECTIVE

To prospectively compare the proportion of traumatic brain injuries (TBIs) that would be classified as mild by applying different published definitions of mild TBI to a large prospectively collected dataset, and to examine the variability in the proportions included by various definitions.

DESIGN

Prospective observational study.

SETTING

Hospital emergency departments.

PARTICIPANTS

Children (N=11,907) aged 3 to 16 years (mean age, 8.2±3.9y). Of the participants, 3868 (32.5%) were girls, and 7374 (61.9%) of the TBIs were the result of a fall. Median Glasgow Coma Scale score was 15.

MAIN OUTCOME MEASURES

We applied 17 different definitions of mild TBI, identified through a published systematic review, to children aged 3 to 16 years. Adjustments and clarifications were made to some definitions. The number and percentage identified for each definition is presented.

RESULTS

Adjustments had to be made to the 17 definitions to apply to the dataset: none in 7, minor to substantial in 10. The percentage classified as mild TBI across definitions varied from 7.1% (n=841) to 98.7% (n=11,756) and varied by age group.

CONCLUSIONS

When applying the 17 definitions of mild TBI to a large prospective multicenter dataset of TBI, there was wide variability in the number of cases classified. Clinicians and researchers need to be aware of this variability when examining literature concerning children with mild TBI.

Sex-specific Outcomes and Predictors of Concussion Recovery

INTRODUCTION

Sports-related concussion (SRC) is a substantial concern in collegiate athletics. Some studies of SRC that make comparisons by sex are limited by sample size, follow-up duration, or referral bias. Sex-specific predictors of occurrence and recovery are uncertain.

METHODS

A 15-year retrospective cohort study identified 1,200 Columbia University varsity athletes (822 male [68.5%], 378 female [31.5%]) at risk of collegiate SRC.

RESULTS

A total of 228 athletes experienced at least one collegiate concussion, including 88 female athletes (23.3% of female athletes) and 140 male athletes (17.0% of male athletes) (P = 0.01); follow-up data were available on 97.8% of these athletes. Postconcussion symptoms were similar by sex, with the exception of sleep disturbance (29.3% of male athletes versus 42.0% of female athletes; P = 0.048) and memory impairment (43.6% of male athletes versus 30.7% of female athletes; P = 0.052), although the latter difference was not statistically significant. Risk factors for collegiate concussion included female sex (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.1 to 2.0) or precollegiate concussion (OR, 2.9; 95% CI, 2.2 to 3.9). Prolonged recovery was predicted by the presence of eight or more postconcussion symptoms for all athletes (OR, 3.77; 95% CI, 1.68 to 8.46) and for female athletes only (OR, 8.24; 95% CI, 1.58 to 43.0); this finding was not statistically significant for male athletes.

DISCUSSION

Female athletes were more likely than male athletes to experience concussion. Increasing numbers of prior concussions predicted recurrence. Although most postconcussion symptoms were highly intercorrelated, the total number of symptoms predicted a prolonged recovery period.

CONCLUSION

This study confirms sex-based differences in SRCs. Longitudinal studies of collegiate cohorts should attempt to limit follow-up bias and offer opportunities to clarify determinants of SRC.

Evidence of Concussion Signs in National Rugby League Match Play: a Video Review and Validation Study

BACKGROUND

Many professional sports have introduced sideline video review to help recognise concussions. The reliability and validity of identifying clinical and observable signs of concussion using video analysis has not been extensively explored. This study examined the reliability and validity of clinical signs of concussion using video analysis in the National Rugby League (NRL).

METHODS

All 201 professional NRL matches from the 2014 season were reviewed to document six signs of possible concussion (unresponsiveness, slow to get up, clutching/shaking head, gait ataxia, vacant stare, and seizure).

RESULTS

A total of 127,062 tackles were reviewed. Getting up slowly was the most common observable sign (2240 times in the season, 1.8% of all tackles) but only 223 times where it appeared to be a possible concussion (0.2% of all tackles and 10.0% of the times it occurred). Additionally, clutching/shaking the head occurred 361 times (on 212 occasions this sign appeared to be due to a possible concussion), gait ataxia was observed 102 times, a vacant stare was noted 98 times, unresponsiveness 52 times, and a possible seizure 4 times. On 383 occasions, one or more of the observable signs were identified and deemed associated with a possible concussion. There were 175 incidences in which a player appeared to demonstrate two or more concussion signs, and 54 incidences where a player appeared to demonstrate three or more concussion signs. A total of 60 diagnosed concussions occurred, and the concussion interchange rule was activated 167 times. Intra-rater reliability (κ = 0.65-1.00) was moderate to perfect for all six video signs; however, the inter-rater reliability was not as strong (κ = 0.22-0.76). Most of the signs had relatively low sensitivity (0.18-0.75), but high specificity (0.85-1.00).

CONCLUSIONS

Using video replay, observable signs of concussion appear to be sensitive to concussion diagnoses when reviewing known injuries among professional rugby league players. When reviewing an entire season, however, certain signs occur very commonly and did not identify concussion. Thus, the implementation of video review in the NRL is challenging, but can provide a useful addition to sideline concussion identification and removal from play decisions.

Concussion

Concussion has been recognized as a clinical entity for more than 1000 years. Throughout the 20th century it was studied extensively in boxers, but it did not pique the interest of the general population because it is the accepted goal of the boxer to inflict such an injury on their opponent. In 2002, however, the possibility that repetitive concussions could result in chronic brain damage and a progressive neurologic disorder was raised by a postmortem evaluation of a retired player in the most popular sports institution in the United States, the National Football League. Since that time concussion has been a frequent topic of conversation in homes, schools, and on television and has become a major focus of sports programs in communities and schools at all levels. Now all 50 states, the District of Columbia, and the National Collegiate Athletic Association have enacted laws and rules to protect the athlete.

Reducing concussion symptoms among teenage youth: Evaluation of a mobile health app

OBJECTIVE

To evaluate whether a mobile health application that employs elements of social game design could compliment medical care for unresolved concussion symptoms.

DESIGN

Phase I and Phase II (open-label, non-randomized, ecological momentary assessment methodology).

SETTING

Outpatient concussion clinic.

PARTICIPANTS

Youth, aged 13-18 years, with concussion symptoms 3+ weeks after injury; Phase I: n = 20; Phase II: n = 19.

INTERVENTIONS

Participants received standard of care for concussion. The experimental group also used a mobile health application as a gamified symptoms journal.

OUTCOME MEASURES

Phase I: feasibility and satisfaction with intervention (7-point Likert scale, 1 high). Phase II: change in SCAT-3 concussion symptoms (primary), depression and optimism.

RESULTS

Phase 1: A plurality of participants completed the intervention (14 of 20) with high use (110 +/- 18% play) and satisfaction (median +/- interquartile range (IQR) = 2.0+/- 0.0). Phase II: Groups were equivalent on baseline symptoms, intervention duration, gender distribution, days since injury and medication prescription. Symptoms and optimism improved more for the experimental than for the active control cohort (U = 18.5, p = 0.028, effect size r = 0.50 and U = 18.5, p = 0.028, effect size r = 0.51, respectively).

CONCLUSIONS

Mobile apps incorporating social game mechanics and a heroic narrative may promote health management among teenagers with unresolved concussion symptoms.

An association between polymorphisms within the APOE gene and concussion aetiology in rugby union players

OBJECTIVES

Concussion refers to changes in neurological function due to biomechanical forces transmitted to the head. The APOE ε4 allele is associated with brain injury severity. The objective was to determine if APOE gene variants are associated with concussion history and severity in rugby players.

DESIGN

In total, 128 non-concussed controls and 160 previously concussed participants (all cases N=160; diagnosed N=139) were recruited from high school (junior, N=121), club (N=116) and professional rugby teams (N=51).

METHODS

Participants were genotyped for rs405509 (G>T), rs429358 (T>C) and rs7412 (C>T) APOE variants. Statistical analyses were performed using the R environment.

RESULTS

The rs405509 TT genotype was over-represented in controls compared to all cases (P=0.043; control: 29%, all cases: 18%; odds ratio: 0.55, 95% confidence interval 0.31-0.98). The APOE-ε isoform frequencies were not significantly different between groups (P>0.05). Additionally, the inferred APOE (rs405509-ε2/ε3/ε4) T-ε3 haplotype was over-represented in controls (41%) compared to diagnosed (32%, P=0.042). The G-ε3 haplotype was under-represented in controls (36%) compared to all cases (44%, P=0.019) and diagnosed (44%, P=0.021). The TT genotype was significantly associated with rapid recovery (P=0.048, <1 week: 51%, N=70, ≥1 week: 36%, N=29; odds ratio: 0.55, 95% confidence interval 0.30-1.01).

CONCLUSIONS

These findings support the further elucidation of the APOE gene or closely-related genes in concussion aetiology. Although similar preliminary results were found when juniors were separately analysed, the under-powered sample size for junior subgroup requires future investigation in larger cohorts of junior-level athletes.

Predictors of clinical recovery from concussion: a systematic review

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.

Audiovestibular symptoms as predictors of prolonged sports-related concussion among NCAA athletes

OBJECTIVE

We looked to determine the rates of audiovestibular symptoms following sports-related concussions among collegiate athletes. Further, we assessed the correlation between these symptoms and the time to return to participation in athletic activity.

STUDY DESIGN

Retrospective analysis of the National Collegiate Athletic Association Injury Surveillance System (NCAA-ISS).

METHODS

The NCAA-ISS was queried from 2009 through 2014 for seven men's sports and eight women's sports across divisions 1, 2, and 3. Injuries resulting in concussions were analyzed for audiovestibular symptoms, duration of symptoms, and return to participation times.

RESULTS

From 2009 to 2014, there were 1,647 recorded sports-related concussions, with athletes reporting dizziness (68.2%), imbalance (35.8%), disorientation (31.4%), noise sensitivity (29.9%), and tinnitus (8.5%). Concussion symptoms resolved within 1 day (17.1%), within 2 to 7 days (50.0%), within 8 to 30 days (25.9%), or persisted over 1 month (7.0%). Return to participation occurred within 1 week (38.3%), within 1 month (53.0%), or over 1 month (8.7%). Using Mann-Whitney U testing, overall symptom duration and return to competition time were significantly increased when any of these symptoms were present (P < 0.05). Duration of concussion symptom correlated with dizziness (P = 0.043) and noise sensitivity (P = 0.000), whereas return to participation times correlated with imbalance (P = 0.011) and noise sensitivity (P = 0.000). Dizziness and imbalance (odds ratio: 4.15, confidence interval: 3.20-5.38, P < 0.001) were the two symptoms with the strongest association.

CONCLUSION

Audiovestibular symptoms are common complaints among collegiate athletes sustaining concussions. Dizziness and noise sensitivity correlated with the duration of concussive symptoms, whereas imbalance and noise sensitivity was correlated with prolonged return to competition time.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2850-2853, 2017.

What are the critical elements of sideline screening that can be used to establish the diagnosis of concussion? A systematic review

BACKGROUND

Sideline detection is the first and most significant step in recognising a potential concussion and removing an athlete from harm. This systematic review aims to evaluate the critical elements aiding sideline recognition of potential concussions including screening tools, technologies and integrated assessment protocols.

DATA SOURCES

Bibliographic databases, grey literature repositories and relevant websites were searched from 1 January 2000 to 30 September 2016. A total of 3562 articles were identified.

STUDY SELECTION

Original research studies evaluating a sideline tool, technology or protocol for sports-related concussion were eligible, of which 27 studies were included.

DATA EXTRACTION

A standardised form was used to record information. The QUADAS-2 and Newcastle-Ottawa tools were used to rate risk of bias. Strength of evidence was assessed using the Grades of Recommendation, Assessment, Development and Evaluation Working Group system.

DATA SYNTHESIS

Studies assessing symptoms, the King-Devick test and multimodal assessments reported high sensitivity and specificity. Evaluations of balance and cognitive tests described lower sensitivity but higher specificity. However, these studies were at high risk of bias and the overall strength of evidence examining sideline screening tools was very low. A strong body of evidence demonstrated that head impact sensors did not provide useful sideline concussion information. Low-strength evidence suggested a multimodal, multitime-based concussion evaluation process incorporating video review was important in the recognition of significant head impact events and delayed onset concussion.

CONCLUSION

In the absence of definitive evidence confirming the diagnostic accuracy of sideline screening tests, consensus-derived multimodal assessment tools, such as the Sports Concussion Assessment Tool, are recommended. Sideline video review may improve recognition and removal from play of athletes who have sustained significant head impact events. Current evidence does not support the use of impact sensor systems for real-time concussion identification.

Statements of Agreement From the Targeted Evaluation and Active Management (TEAM) Approaches to Treating Concussion Meeting Held in Pittsburgh, October 15-16, 2015

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.

Neuropsychological Outcomes in Patients with Complicated Versus Uncomplicated Mild Traumatic Brain Injury: 6-Month Follow-Up

OBJECTIVE

To compare the extent of persistent neuropsychological impairment in patients with complicated mild traumatic brain injury (mTBI) and those with uncomplicated mTBI.

METHODS

Sixty-one patients with mTBI (Glasgow Coma Scale score 13-15) were recruited prospectively, categorized according to baseline computed tomography findings, and subjected to neuropsychological assessment at initial admission (n = 61) as well as at a 6-month follow-up (n = 30). The paired t test, Cohen's d effect size calculation, and repeated-measures analysis of variance were used to establish the differences between the 2 groups in terms of neuropsychological performance.

RESULTS

A trend toward poorer neuropsychological performance among the patients with complicated mTBI was observed during admission; however, performance in this group improved over time. In contrast, the uncomplicated mTBI group showed slower recovery, especially in tasks of memory, visuospatial processing, and executive functions, at follow-up.

CONCLUSIONS

Our findings suggest that despite the broad umbrella designation of mTBI, the current classification schemes of injury severity for mild neurotrauma should be revisited. They also raise questions about the clinical relevance of both traumatic focal lesions and the absence of visible traumatic lesions on brain imaging studies in patients with milder forms of head trauma.

Sleep Disorders Associated With Traumatic Brain Injury-A Review

BACKGROUND

Sleep disorders are common are common following traumatic brain injury.

METHODS

In this article we review the spectrum and proposed mechanisms of traumatic brain injury associated sleep disorders and discuss the clinical approach to diagnosis and management of these disorders.

RESULT

Disordered sleep and wakefulness after traumatic brain injury is common. Sleep disruption contributes to morbidity, such as the development of neurocognitive and neurobehavioral deficits, and prolongs the recovery phase after injury. Early recognition and correction of these problems may limit the secondary effects of traumatic brain injury and improve patient outcomes.

CONCLUSION

Evaluating sleep disorders in traumatic brain injury should be an important component of post-traumatic brain injury assessment and management.

Relationship between the apolipoprotein E gene and headache following sports-related concussion

INTRODUCTION

Headache is one of the most commonly reported and longest lasting symptoms that concussed athletes report, yet the etiology of headache symptoms following concussion is not entirely clear. The purpose of this study was to determine whether the e4 allele of the apolipoprotein E (APOE) gene influences the presence and severity of postconcussion headache.

METHOD

Participants were composed of 45 concussed athletes and 43 healthy/nonconcussed athletes who were involved in a clinically based sports concussion management program. All athletes completed the Post-Concussion Symptom Scale (PCSS). The "headache" symptom from the PCSS was the primary outcome variable. Buccal samples were collected and analyzed to determine APOE genotype.

RESULTS

A significantly greater proportion of concussed e4+ athletes than e4- athletes endorsed headache. Furthermore, concussed e4+ athletes endorsed more severe headaches than e4- athletes. When examining the healthy/nonconcussed sample (i.e., athletes at baseline), results showed no differences between e4 allele groups with respect to the presence and severity of headache.

CONCLUSIONS

These findings show that when compared to concussed e4- athletes, e4+ athletes are more likely to (a) endorse postconcussion headache and (b) report more severe headache symptoms following concussion. Conversely, it appears that the e4 allele does not influence baseline reports of headache. Thus, results suggest that those with the e4 genotype may be at a higher risk for experiencing headache-related difficulties only after a concussion is sustained.

Preinjury somatization symptoms contribute to clinical recovery after sport-related concussion

OBJECTIVE

To determine the degree to which preinjury and acute postinjury psychosocial and injury-related variables predict symptom duration following sport-related concussion.

METHODS

A total of 2,055 high school and collegiate athletes completed preseason evaluations. Concussed athletes (n = 127) repeated assessments serially (<24 hours and days 8, 15, and 45) postinjury. Cox proportional hazard modeling was used to predict concussive symptom duration (in days). Predictors considered included demographic and history variables; baseline psychological, neurocognitive, and balance functioning; acute injury characteristics; and postinjury clinical measures.

RESULTS

Preinjury somatic symptom score (Brief Symptom Inventory-18 somatization scale) was the strongest premorbid predictor of symptom duration. Acute (24-hour) postconcussive symptom burden (Sport Concussion Assessment Tool-3 symptom severity) was the best injury-related predictor of recovery. These 2 predictors were moderately correlated (r = 0.51). Path analyses indicated that the relationship between preinjury somatization symptoms and symptom recovery was mediated by postinjury concussive symptoms.

CONCLUSIONS

Preinjury somatization symptoms contribute to reported postconcussive symptom recovery via their influence on acute postconcussive symptoms. The findings highlight the relevance of premorbid psychological factors in postconcussive recovery, even in a healthy athlete sample relatively free of psychopathology or medical comorbidities. Future research should elucidate the neurobiopsychosocial mechanisms that explain the role of this individual difference variable in outcome following concussive injury.

Sleep Disorders Associated With Mild Traumatic Brain Injury Using Sport Concussion Assessment Tool 3

BACKGROUND

Sleep problems affect 30% to 80% of patients with mild traumatic brain injury. We assessed the prevalence of sleep disorders after mild traumatic brain injury and its correlation with other symptoms.

METHODS AND MATERIALS

Individuals with mild traumatic brain injury were assessed at the New York University Concussion Center during 2013-2014 with the Sports Concussion Assessment Tool, third edition, data following mild traumatic brain injury. The relationship between sleep problems (drowsiness, difficulty falling asleep, fatigue or low energy), psychiatric symptoms (sadness, nervousness or anxiousness), headache, and dizziness were analyzed by Spearman correlation and logistic regression using moderate to severe versus none to mild categorization.

RESULTS

Ninety-three patients were retrospectively considered. The most common injury causes were falls (34.4%) and motor vehicle accidents (21.5%). There was a positive correlation between dizziness, headache, psychiatric problems (sadness, anxiety, irritability), and sleep problems (fatigue, drowsiness, and difficulty falling asleep) (P < 0.001). Logistic regression showed a significant association between moderate to severe psychiatric symptoms and moderate to severe sleep symptoms (P < 0.05). Sleep symptoms became more severe with increased time interval from mild traumatic brain injury to Sport Concussion Assessment Tool 3 administration (odds ratio = 1.005, 1.006, and 1.008, P < 0.05). There was significant correlation between motor vehicle accident and drowsiness and difficulty falling asleep (P < 0.05). Medications given in the emergency department had a positive correlation with drowsiness (P < 0.05).

CONCLUSIONS

Individuals who report moderate to severe headache, dizziness, and psychiatric symptoms have a higher likelihood of reporting moderate to severe sleep disorders following mild traumatic brain injury and should be counseled and initiated with early interventions.

Age Differences in Recovery After Sport-Related Concussion: A Comparison of High School and Collegiate Athletes

CONTEXT

Younger age has been hypothesized to be a risk factor for prolonged recovery after sport-related concussion, yet few studies have directly evaluated age differences in acute recovery.

OBJECTIVE

To compare clinical recovery patterns for high school and collegiate athletes.

DESIGN

Prospective cohort study.

SETTING

Large, multicenter prospective sample collected from 1999-2003 in a sports medicine setting.

SUBJECTS

Concussed athletes (n = 621; 545 males and 76 females) and uninjured controls (n = 150) participating in high school and collegiate contact and collision sports (79% in football, 15.7% in soccer, and the remainder in lacrosse or ice hockey).

MAIN OUTCOME MEASURE(S)

Participants underwent evaluation of symptoms (Graded Symptom Checklist), cognition (Standardized Assessment of Concussion, paper-and-pencil neuropsychological tests), and postural stability (Balance Error Scoring System). Athletes were evaluated preinjury and followed serially at several time points after concussive injury: immediately, 3 hours postinjury, and at days 1, 2, 3, 5, 7, and 45 or 90 (with neuropsychological measures administered at baseline and 3 postinjury time points).

RESULTS

Comparisons of concussed high school and collegiate athletes with uninjured controls suggested that high school athletes took 1 to 2 days longer to recover on a cognitive (Standardized Assessment of Concussion) measure. Comparisons with the control group on other measures (symptoms, balance) as well as direct comparisons between concussed high school and collegiate samples revealed no differences in the recovery courses between the high school and collegiate groups on any measure. Group-level recovery occurred at or before 7 days postinjury on all assessment metrics.

CONCLUSIONS

The findings suggest no clinically significant age differences exist in recovery after sport-related concussion, and therefore, separate injury-management protocols are not needed for high school and collegiate athletes.

Concussion recovery time among high school and collegiate athletes: a systematic review and meta-analysis

BACKGROUND

Concussion diagnosis and management is made through the clinical exam using assessment tools that include self-report symptomatology, postural control, and cognitive evaluations. The specific timing of concussion resolution varies between individuals. However, despite a lack of research in concussion recovery, it is widely accepted that the majority of young adults will recover in 7-10 days, with youth athletes taking longer.

OBJECTIVES

The purpose of this review is to directly compare the recovery duration among high school and collegiate athletes on symptom reports and cognitive assessments following concussion.

DATA SOURCES

Data were collected from a literature search comprising high school or college athletes only. This included studies (n = 6) that reported symptom or cognitive performance recovery to the exact day.

RESULTS

High school athletes self-reported symptom recovery at 15 days compared with 6 days in collegiate athletes. Both college and high school athletes showed cognitive recovery at similar rates of 5 and 7 days.

LIMITATIONS

This review only included articles that were directly related to concussed high school or college athletes. Additionally, athletes in the high school and college setting typically receive a battery of neurocognitive tests that may not be as sensitive or as comprehensive as a full neuropsychological exam.

CONCLUSION

The review finds that neurocognitive recovery rates are similar among high school and college athletes, while symptom reporting shows longer recovery time points in high school than in college.

IMPLICATIONS OF KEY FINDINGS

An individualized and stepwise concussion management plan is important for proper concussion recovery regardless of age.

Epidemiology of Sports-Related Concussions in National Collegiate Athletic Association Athletes From 2009-2010 to 2013-2014: Symptom Prevalence, Symptom Resolution Time, and Return-to-Play Time

BACKGROUND

Limited data exist among collegiate student-athletes on the epidemiology of sports-related concussion (SRC) outcomes, such as symptoms, symptom resolution time, and return-to-play time.

PURPOSE

This study used the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) to describe the epidemiology of SRC outcomes in 25 collegiate sports.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

SRC data from the NCAA ISP during the 2009-2010 to 2013-2014 academic years were analyzed regarding symptoms, time to resolution of symptoms, and time to return to play. Findings were also stratified by sex in sex-comparable sports (ie, ice hockey, soccer, basketball, lacrosse, baseball/softball) and whether SRCs were reported as recurrent.

RESULTS

Of the 1670 concussions reported during the 2009-2010 to 2013-2014 academic years, an average (±SD) of 5.29 ± 2.94 concussion symptoms were reported, with the most common being headache (92.2%) and dizziness (68.9%). Most concussions had symptoms resolve within 1 week (60.1%); however, 6.2% had a symptom resolution time of over 4 weeks. Additionally, 8.9% of concussions required over 4 weeks before return to play. The proportion of SRCs that required at least 1 week before return to play increased from 42.7% in 2009-2010 to 70.2% in 2013-2014 (linear trend, P < .001). Within sex-comparable sports analyses, the average number of symptoms and symptom resolution time did not differ by sex. However, a larger proportion of concussions in male athletes included amnesia and disorientation; a larger proportion of concussions in female athletes included headache, excess drowsiness, and nausea/vomiting. A total of 151 SRCs (9.0%) were reported as recurrent. The average number of symptoms reported with recurrent SRCs (5.99 ± 3.43) was greater than that of nonrecurrent SRCs (5.22 ± 2.88; P = .01). A greater proportion of recurrent SRCs also resulted in a long symptom resolution time (14.6% vs 5.4%, respectively; P < .001) and long return-to-play time (21.2% vs 7.7%, respectively; P < .001) compared with nonrecurrent SRCs.

CONCLUSION

Trends in return-to-play time may indicate changing concussion management practices in which team medical staff members withhold players from participation longer to ensure symptom resolution. Concussion symptoms may differ by sex and recurrence. Future research should continue to examine the trends and discrepancies in symptom resolution time and return-to-play time.

Tackling in Youth Football

American football remains one of the most popular sports for young athletes. The injuries sustained during football, especially those to the head and neck, have been a topic of intense interest recently in both the public media and medical literature. The recognition of these injuries and the potential for long-term sequelae have led some physicians to call for a reduction in the number of contact practices, a postponement of tackling until a certain age, and even a ban on high school football. This statement reviews the literature regarding injuries in football, particularly those of the head and neck, the relationship between tackling and football-related injuries, and the potential effects of limiting or delaying tackling on injury risk.

Developmental and gender influences on executive function following concussion in youth hockey players

BACKGROUND

Concussion is the most common athletic injury in youth who are simultaneously undergoing rapid developmental changes in the brain, specifically the development of executive functions (EF). The developing brain is more vulnerable to concussive injury with a protracted and different trajectory of recovery than that of adults. Thus, there is a critical need to enhance understanding of how concussion affects EF in youth.

OBJECTIVE

To investigate the effects of age, gender and concussion history (i.e. concussion incidence, recency, severity) on EF in youth hockey players.

METHODS

This 3-year cross-sectional and longitudinal multiple cohort study examined data from 211 hockey players of 8-15 years of age. Mixed-effects modelling was used to examine the influence of age, gender and concussion on EF in youth athletes.

FINDINGS

Baseline analyses revealed significant age and gender effects on measures of EF. Multiple effects of concussion history on measures of cognitive flexibility (F = 2.48, p = 0.03) and psychomotor speed (F = 2.59, p = 0.04) were found.

IMPLICATIONS

This study highlights the impact of age, gender and concussion on EF in youth. These findings provide foundational knowledge to better manage cognitive sequelae following sports-related concussion.

Comparison of Neurocognitive Testing and the Measurement of Marinobufagenin in Mild Traumatic Brain Injury: A Preliminary Report

The evaluation of concussed athletes, including testing to determine if and when they may return to play, has become an important task of athletic trainers and team physicians. Currently, concussion protocols are in place, which depend largely upon assessments based upon neurocognitive testing (NCT). The authors have evaluated the use of a biomarker of brain trauma, marinobufagenin (MBG), and compared its application in concussed athletes with the performance of NTC. We found a disparity between these two testing procedures. In this communication, the findings of these comparative data are presented. We noted that athletes whose NCT evaluations had returned to baseline and who were allowed to again participate in play then showed a recurrence of elevated urinary MBG excretion. These observations raise concern as to the processes currently in effect with regard to the decision as to returning athletes to the full activity. They suggest a need for further evaluation.

Characterization of acute stress reaction following an IED blast-related mild traumatic brain injury

PRIMARY OBJECTIVE

To characterize an acute stress reaction (ASR) following an improvised explosive device (IED) blast-related mild traumatic brain injury (mTBI).

RESEARCH DESIGN

Participants were male, US military personnel treated in Afghanistan within 4 days following an IED-related mTBI event (n = 239).

METHODS AND PROCEDURES

Demographics, diagnosis of ASR, injury history and self-reported mTBIs, blast exposures and psychological health histories were recorded.

MAIN OUTCOMES AND RESULTS

In total, 12.5% of patients met ASR criteria. Patients with ASR were significantly younger and junior in rank (p < 0.05). Patients with ASR were more likely to experience the IED-blast while dismounted, report a loss of consciousness (LOC) and higher pain levels (p < 0.05). Adjusting for age and rank, multivariate logistic regression showed an association between mTBI history and ASR (AOR = 1.405; 95% CI = 1.105-1.786, p < 0.01). Adjusting for mechanism of injury (dismounted vs. mounted), LOC and pain, multivariate logistic regression showed an association between mTBI history and ASR (AOR = 1.453; 95% CI = 1.132-1.864, p < 0.01). Prior blast exposure and past psychological health issues were not associated with ASR.

CONCLUSIONS

A history of multiple mTBIs is associated with increased risk of ASR. Future research is warranted.