Absence of Differences Between Male and Female Adolescents With Prior Sport Concussion

Sex and gender differences in mild traumatic brain injury/concussion

The high incidence of concussions/mild traumatic brain injury and the significant number of people with persisting concussion symptoms as well as the concern for delayed, neurodegenerative effects of concussions makes them a major public health concern. There is much to learn on concussions with respect to pathophysiology as well as vulnerability and resiliency factors. The heterogeneity in outcome after a concussion warrants a more personalized approach to better understand the biological and psychosocial factors that may affect outcome. In this chapter we address biological sex and gender as they impact different aspects of concussion including incidence, risk factors and outcome. As well, this chapter will provide a more fulsome overview of intimate partner violence, an often-overlooked cause of concussion in women. Applying the sex and gender lens to concussion/mild traumatic brain injury is imperative for discovery of its pathophysiology and moving closer to treatments.

Sex-related differences in visuomotor skill recovery following concussion in working-aged adults

BACKGROUND

The ability to perform visually-guided motor tasks requires the transformation of visual information into programmed motor outputs. When the guiding visual information does not align spatially with the motor output, the brain processes rules to integrate somatosensory information into an appropriate motor response. Performance on such rule-based, "cognitive-motor integration" tasks is affected in concussion. Here, we investigate the relationship between visuomotor skill performance, concussion history, and sex during the course of a post-concussion management program.

METHODS

Fifteen acutely concussed working-aged adults, 11 adults with a history of concussion, and 17 healthy controls all completed a recovery program over the course of 4 weeks. Prior to, mid-way, and following the program, all participants were tested on their visuomotor skills.

RESULTS

We observed an overall change in visuomotor behaviour in all groups, as participants completed the tasks faster and more accurately. Specifically, we observed significant visuomotor skill improvement between the first and final sessions in participants with a concussion history compared to no-concussion-history controls. Notably, we observed a stronger recovery of these skills in females.

CONCLUSIONS

Our findings indicate that (1) concussion impairs visuomotor skill performance, (2) the performance of complex, rule-based tasks showed improvement over the course of a recovery program, and (3) stronger recovery in females suggests sex-related differences in the brain networks controlling skilled performance, and the effect of injury on these networks.

Multiple Past Concussions in High School Hockey Players: Examining Cognitive Functioning and Symptom Reporting

OBJECTIVE

To investigate (1) if there are meaningful differences in baseline preseason cognitive functioning or symptom reporting between high school ice hockey players with and without prior concussions and (2) determine which health history variables predict symptom reporting.

DESIGN

Cross-sectional study.

SETTING

High schools across the state of Maine.

PARTICIPANTS

Participants were 1616 male high school ice hockey players (mean age = 15.6 years; SD = 1.5 years) who completed baseline testing between 2009 and 2015.

INDEPENDENT VARIABLES

Athletes were grouped according to their self-reported concussion history [0 (n = 1136), 1 (n = 321), 2 (n = 112), or 3+ (n = 47) previous concussions].

MAIN OUTCOME MEASURES

Cognitive functioning was measured by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery, and symptom ratings were obtained from the Post-Concussion Symptom Scale.

RESULTS

There were no statistically significant differences between groups in cognitive functioning as measured by ImPACT. The group with ≥3 prior concussions endorsed higher total symptom scores, but the effect sizes were small and not statistically significant. In a multivariate model, prior treatment for headaches (not necessarily migraines), prior treatment for a psychiatric condition, and prior treatment for substance/alcohol use all significantly predicted total symptom scores, with concussion history being the weakest independent predictor.

CONCLUSIONS

Players with a history of prior concussions performed similarly to players with no prior concussions on cognitive testing. Health history factors were more strongly associated with symptom reporting than concussion history.

Autonomic Dysregulation in Adolescent Concussion Is Sex- and Posture-Dependent

OBJECTIVE

To study autonomic responses to postural changes in concussed adolescents. The influence of sex was also studied.

DESIGN

Longitudinal cohort observational study.

PARTICIPANTS

Concussed adolescents (CONC; n = 65; 26 male adolescents; age 15 ± 1 years, range = 12-18 years) and a control (CTRL) group of nonconcussed adolescents of similar age and sport (CTRL; n = 54; 29 male adolescents; age 14 ± 1 years, range = 12-18 years).

INTERVENTIONS

Concussed participants were monitored through 6 weekly visits throughout usual physician care. Control participants underwent 2 visits separated by at least 1 week to account for intrapersonal variation in testing measures.

MAIN OUTCOME MEASURES

Heart rate variability as the root mean square of successive differences in R-R intervals (RMSSD), heart rate (HR), and blood pressure [mean arterial pressure (MAP) and diastolic blood pressure (DBP)] were measured in supine, sitting, and standing postures.

RESULTS

A mixed analysis of variance revealed a group × sex × posture interaction (P = 0.04) where seated values of RMSSD were less in concussed female participants versus control female participants (42 ± 4 vs 61 ± 7 ms; P = 0.01; Mann-Whitney rank test). Compared with CTRL, CONC exhibited increased pretesting seated DBP (69 ± 1 vs 74 ± 1 mm Hg; P < 0.01), MAP (83 ± 1 vs 86 ± 1 mm Hg; P = 0.02), and baseline seated HR (72 ± 1 vs 77 ± 2 bpm; P = 0.03). Values of DBP (P = 0.03) and MAP (P < 0.01) improved at clinical discharge, whereas the RMSSD in female participants did not (P > 0.5). Data are mean ± SEM.

CONCLUSIONS

A modest reduction in female cardiac autonomic regulation was observed during seated postures. Alterations in seated concussed DBP and MAP, but not RMSSD, resolved at clinical discharge (median = 37 days). The results indicate that, in adolescents, concussion may impair cardiovagal function in a sex- and posture-dependent manner. The findings also suggest that BP metrics, but not RMSSD, are associated with clinical concussion recovery.

Neurocognitive performance and mental health of retired female football players compared to non-contact sport athletes

Background

Adverse long-term effects of playing football due to repetitive head impact exposure on neurocognition and mental health are controversial. To date, no studies have evaluated such effects in women.

Aims

To (1) compare neurocognitive performance, cognitive symptoms and mental health in retired elite female football players (FB) with retired elite female non-contact sport athletes (CON), and to (2) assess whether findings are related to history of concussion and/or heading exposure in FB.

Methods

Neurocognitive performance, mental health and cognitive symptoms were assessed using computerised tests (CNS-vital signs), paper pen tests (Category fluency, Trail-Making Test, Digit Span, Paced Auditory Serial Addition Test), questionnaires (Hospital Anxiety and Depression Scale, SF-36v2 Health Survey) and a symptom checklist. Heading exposure and concussion history were self-reported in an online survey and in a clinical interview, respectively. Linear regression was used to analyse the effect of football, concussion and heading exposure on outcomes adjusted for confounders.

Results

FB (n=66) performed similar to CON (n=45) on neurocognitive tests, except for significantly lower scores on verbal memory (mean difference (MD)=−7.038, 95% CI −12.98 to –0.08, p=0.038) and verbal fluency tests (MD=−7.534, 95% CI –13.75 to –0.46, p=0.016). Among FB weaker verbal fluency performance was significantly associated with ≥2 concussions (MD=−10.36, 95% CI –18.48 to –2.83, p=0.017), and weaker verbal memory performance with frequent heading (MD=−9.166, 95% CI –17.59 to –0.123, p=0.041). The depression score differed significantly between study populations, and was significantly associated with frequent heading but not with history of concussion in FB.

Conclusion

Further studies should investigate the clinical relevance of our findings and whether the observed associations point to a causal link between repetitive head impacts and verbal memory/fluency or mental health.

Beyond Binary: Influence of Sex and Gender on Outcome after Traumatic Brain Injury

Traumatic brain injury (TBI) affects millions of individuals each year and is a leading cause of death and disability worldwide. TBI is heterogeneous and outcome is influenced by a combination of factors that include injury location, severity, genetics, and environmental factors. More recently, sex as a biological variable has been incorporated into TBI research, although there is conflicting literature regarding clinical outcomes in males versus females after TBI. We review the current clinical literature investigating sex differences after TBI. We focus our discussion on differences within contemporary gender categories to suggest that binary categories of male and female are not sufficient to guide clinical decisions for neurotrauma. Some studies have considered physiological variables that influence sex such as hormone cycles and stages in males and females pre- and post-TBI. These data suggest that there are phasic differences within male populations and within female populations that influence an individual's outcome after TBI. Finally, we discuss the impact of gender identity and expression on outcome after TBI and highlight the lack of neurotrauma research that includes non-binary individuals. Social constructs regarding gender impact an individual's vulnerability to violence and consequent TBI, including the successful reintegration to society after TBI. We call for incorporation of gender beyond the binary in TBI education, research, and clinical care. Precision medicine necessarily must progress beyond the binary to treat individuals after TBI.

Traumatic Brain Injury-Induced Sex-Dependent Changes in Late-Onset Sensory Hypersensitivity and Glutamate Neurotransmission

Women approximate one-third of the annual 2.8 million people in the United States who sustain traumatic brain injury (TBI). Several clinical reports support or refute that menstrual cycle-dependent fluctuations in sex hormones are associated with severity of persisting post-TBI symptoms. Previously, we reported late-onset sensory hypersensitivity to whisker stimulation that corresponded with changes in glutamate neurotransmission at 1-month following diffuse TBI in male rats. Here, we incorporated intact age-matched naturally cycling females into the experimental design while monitoring daily estrous cycle. We hypothesized that sex would not influence late-onset sensory hypersensitivity and associated in vivo amperometric extracellular recordings of glutamate neurotransmission within the behaviorally relevant thalamocortical circuit. At 28 days following midline fluid percussion injury (FPI) or sham surgery, young adult Sprague-Dawley rats were tested for hypersensitivity to whisker stimulation using the whisker nuisance task (WNT). As predicted, both male and female rats showed significantly increased sensory hypersensitivity to whisker stimulation after FPI, with females having an overall decrease in whisker nuisance scores (sex effect), but no injury and sex interaction. In males, FPI increased potassium chloride (KCl)-evoked glutamate overflow in primary somatosensory barrel cortex (S1BF) and ventral posteromedial nucleus of the thalamus (VPM), while in females the FPI effect was discernible only within the VPM. Similar to our previous report, we found the glutamate clearance parameters were not influenced by FPI, while a sex-specific effect was evident with female rats showing a lower uptake rate constant both in S1BF and VPM and longer clearance time (in S1BF) in comparison to male rats. Fluctuations in estrous cycle were evident among brain-injured females with longer diestrus (low circulating hormone) phase of the cycle over 28 days post-TBI. Together, these findings add to growing evidence indicating both similarities and differences between sexes in a chronic response to TBI. A better understanding of the influence of gonadal hormones on behavior, neurotransmission, secondary injury and repair processes after TBI is needed both clinically and translationally, with potential impact on acute treatment, rehabilitation, and symptom management.

Sex-Related Differences in the Effects of Sports-Related Concussion: A Review

Sports-related concussion is a serious health challenge, and females are at higher risk of sustaining a sports-related concussion compared to males. Although there are many studies that investigate outcomes following concussion, females remain an understudied population, despite representing a large proportion of the organized sports community. In this review, we provide a summary of studies that investigate sex-related differences in outcome following sports-related concussion. Moreover, we provide an introduction to the methods used to study sex-related differences after sports-related concussion, including common clinical and cognitive measures, neuroimaging techniques, as well as biomarkers. A literature search inclusive of articles published to March 2020 was performed using PubMed. The studies were reviewed and discussed with regard to the methods used. Findings from these studies remain mixed with regard to the effect of sex on clinical symptoms, concussion-related alterations in brain structure and function, and recovery trajectories. Nonetheless, there is initial evidence to suggest that sex-related differences following concussion are important to consider in efforts to develop objective biomarkers for the diagnosis and prognosis of concussion. Additional studies on this topic are, however, clearly needed to improve our understanding of sex-related differences following concussion, as well as to understand their neurobiological underpinnings. Such studies will help pave the way toward more personalized clinical management and treatment of sports-related concussion.

Functional magnetic resonance imaging study of working memory several years after pediatric concussion

PRIMARY OBJECTIVE

The neurophysiological effects of pediatric concussion several years after injury remain inadequately characterized. The objective of this study was to determine if a history of concussion was associated with BOLD response differences during an n-back working memory task in youth.

RESEARCH DESIGN

Observational, cross-sectional.

METHODS AND PROCEDURES

Participants include 52 children and adolescents (M = 15.1 years, 95%CI = 14.4-15.8, range = 9-19) with past concussion (n = 33) or orthopedic injury (OI; n = 19). Mean time since injury was 2.5 years (95%CI = 2.0-3.0). Measures included postconcussion symptom ratings, neuropsychological testing, and blood-oxygen-dependent-level (BOLD) functional magnetic resonance imaging (fMRI) during an n-back working memory task.

MAIN OUTCOMES AND RESULTS

Groups did not differ on accuracy or speed during the three n-back conditions. They also did not differ in BOLD signal change for the 1- vs. 0-back or 2- vs. 0-back contrasts (controlling for task performance).

CONCLUSIONS

This study does not support group differences in BOLD response during an n-back working memory task in youth who are on average 2.5 years post-concussion. The findings are encouraging from the perspective of understanding recovery after pediatric concussion.

Sex Differences in Traumatic Brain Injury: What We Know and What We Should Know

There is growing recognition of the problem of male bias in neuroscience research, including in the field of traumatic brain injury (TBI) where fewer women than men are recruited to clinical trials and male rodents have predominantly been used as an experimental injury model. Despite TBI being a leading cause of mortality and disability worldwide, sex differences in pathophysiology and recovery are poorly understood, limiting clinical care and successful drug development. Given growing interest in sex as a biological variable affecting injury outcomes and treatment efficacy, there is a clear need to summarize sex differences in TBI. This scoping review presents an overview of current knowledge of sex differences in TBI and a comparison of human and animal studies. We found that overall, human studies report worse outcomes in women than men, whereas animal studies report better outcomes in females than males. However, closer examination shows that multiple factors including injury severity, sample size, and experimental injury model may differentially interact with sex to affect TBI outcomes. Additionally, we explore how sex differences in mitochondrial structure and function might contribute to possible sex differences in TBI outcomes. We propose recommendations for future investigations of sex differences in TBI, which we hope will lead to improved patient management, prognosis, and translation of therapies from bench to bedside.

Risk Factors for Prolonged Symptoms of Mild Traumatic Brain Injury: A Pediatric Sports Concussion Clinic Cohort

OBJECTIVE

To examine predictors of prolonged symptom duration from mild traumatic brain injury (mTBI) in a pediatric sports medicine specialty clinic cohort as these predictors may be distinct in this population.

DESIGN

Retrospective chart review.

SETTING

Outpatient specialty clinic.

PATIENTS

Charts of 549 patients (age range: 10-18 years) with concussions were reviewed in an outpatient clinic that predominantly managed sports-related injuries (77.3%). Patients (n = 431) included in the final analysis met the criteria for mTBI and were symptomatic at their first visit.

ASSESSMENT OF RISK FACTORS

Patient history, injury, and recovery variables were evaluated.

MAIN OUTCOME MEASURES

Predictors of prolonged time to reach self-reported symptom recovery were evaluated using Cox proportional hazards.

RESULTS

Median time to symptom recovery of the 431 patients who presented to clinic with symptoms was 40 days (full clinic sample median = 34 days). Analyses identified 3 unique predictors of symptom recovery: loss of consciousness (LOC) [hazard ratio (HR) = 0.56, P < 0.0001], female sex (HR = 0.57, P < 0.0001), and concussion symptom score at first clinic visit (HR = 0.76, P < 0.0001).

CONCLUSIONS

Prolonged duration of mTBI symptoms in patients who present to a pediatric sports-based concussion clinic is related to initial symptom severity, female sex, and LOC.

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.

Investigating Effects of Sex Differences and Prior Concussions on Symptom Reporting and Cognition Among Adolescent Soccer Players

BACKGROUND

There has been increasing concern regarding the possible effect of multiple concussions on the developing brain, especially for adolescent females. Hypothesis/Purpose: The objectives were to determine if there are differences in cognitive functioning, symptom reporting, and/or sex effects from prior concussions. In a very large sample of youth soccer players, it was hypothesized that (1) there would be no differences in cognitive test performance between those with and without prior concussions, (2) baseline preseason symptoms would be better predicted by noninjury factors than concussion history, and (3) males and females with prior concussions would not have differences in cognition or symptoms.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Participants included 9314 youth soccer players (mean = 14.8 years, SD = 1.2) who completed preseason baseline cognitive testing, symptom reporting, and a health/injury history questionnaire from the ImPACT battery (Immediate Post-concussion Assessment and Cognitive Testing). On the basis of injury history, athletes were grouped by number of prior concussions: 0 (boys, n = 4012; girls, n = 3963), 1 (boys, n = 527; girls, n = 457), 2 (boys, n = 130; girls, n = 97), or ≥3 (boys, n = 73; girls, n = 55). The primary measures were the 4 primary cognitive scores and the total symptom ratings from ImPACT. Primary outcomes were assessed across injury groups, controlling for age, sex, learning disability, attention-deficit/hyperactivity disorder (ADHD), treatment for headaches/migraines, substance abuse, and mental health problems.

RESULTS

Cognitive test performance was not associated with concussion history but was associated with sex, age, learning disability, ADHD, and prior mental health problems. Greater symptom reporting was more strongly associated with psychiatric problems, older age, learning disability, substance abuse, headaches, being female, and ADHD than with a history of multiple concussions. Boys and girls did not differ on cognitive scores or symptom reporting based on a history of concussion.

CONCLUSION

In this very large sample of youth soccer players with prior concussion, there was no evidence of negative effects on cognition, very weak evidence of negative effects on symptom reporting, and no evidence of sex × concussion differences in cognition or symptom reporting.

Sex differences in sport-related concussion long-term outcomes

Approximately 1.6 to 3.8 million recreational and sports-related concussions (SRC) occur each year in the Unites States. Research suggest that female athletes are at a greater risk for a SRC compared to male athletes competing in comparable sports (i.e., soccer, basketball). Moreover, female athletes have reported more total symptoms and greater neurocognitive impairments following a SRC. Female athletes have been found to report greater symptom provocation as measured by the Vestibular/Ocular Motor Screening (VOMS), and increased brain activation compared to males. There is a scarcity of research on long-term effects of SRC in male and female athletes. Therefore, the aim of this review article is to summarize the existing literature on sex differences in acute and sub-acute SRC outcomes.

Evidence of a conservative gait strategy in athletes with a history of concussions

BACKGROUND

A history of 3 or more concussions is frequently associated with numerous short- and long-term neuropathologies. Impairments in postural control are a known acute consequence of concussion; however, limited evidence exists on the effects of multiple concussions on gait. The purpose of this study was to assess gait stepping characteristics in collegiate aged student-athletes based on concussion history.

METHODS

There were 63 participants divided into 3 even groups based on concussion history: ≥3 concussions, 1-2 concussions, and 0 concussion. All participants completed 10 trials of gait on a 4.9 m instrumented walkway. The dependent variables of interest included both gait stepping characteristics (step velocity, length, and width, double support time, and the percentage of the gait cycle in stance) and coefficient of variability (CoV) measures (step length, time, and width). The gait stepping characteristics were compared first with a MANOVA with follow-up 1-way ANOVAs and Tukey post hoc tests as appropriate. The CoV measures were compared with 1-way ANOVAs and Tukey post hoc tests.

RESULTS

There were main effects for group for step velocity, length, width, and double support time. Overall, the 0 concussion group displayed typical healthy young gait parameters and performed significantly better than either concussion group. The 0 concussion group had a significantly greater step length CoV, but there were no differences in the step time or width CoV.

CONCLUSION

This finding provides evidence of subtle impairments in postural control during gait among individuals with prior history of concussion which could be an early indicator of future neurological deficiencies. The limited difference in the variability measures is consistent with prior static stance studies and could suggest the individuals constrain their motor systems to reduce variability. Taken together, these findings suggest a conservative gait strategy which is adopted by individuals with a history of concussions.

Multiple Past Concussions in High School Football Players: Are There Differences in Cognitive Functioning and Symptom Reporting?

BACKGROUND

There is increasing concern about the possible long-term effects of multiple concussions, particularly on the developing adolescent brain. Whether the effect of multiple concussions is detectable in high school football players has not been well studied, although the public health implications are great in this population.

PURPOSE

To determine if there are measureable differences in cognitive functioning or symptom reporting in high school football players with a history of multiple concussions.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Participants included 5232 male adolescent football players (mean [±SD] age, 15.5 ± 1.2 years) who completed baseline testing between 2009 and 2014. On the basis of injury history, athletes were grouped into 0 (n = 4183), 1 (n = 733), 2 (n = 216), 3 (n = 67), or ≥4 (n = 33) prior concussions. Cognitive functioning was measured by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery, and symptom ratings were obtained from the Post-Concussion Symptom Scale.

RESULTS

There were no statistically significant differences between groups (based on the number of reported concussions) regarding cognitive functioning. Athletes with ≥3 prior concussions reported more symptoms than did athletes with 0 or 1 prior injury. In multivariate analyses, concussion history was independently related to symptom reporting but less so than developmental problems (eg, attention or learning problems) or other health problems (eg, past treatment for psychiatric problems, headaches, or migraines).

CONCLUSION

In the largest study to date, high school football players with multiple past concussions performed the same on cognitive testing as those with no prior concussions. Concussion history was one of several factors that were independently related to symptom reporting.

Cognition in the Emergency Department as a Predictor of Recovery after Pediatric Mild Traumatic Brain Injury

Cognitive abilities can be acutely disrupted in children and adolescents who sustain a mild traumatic brain injury (mTBI), with the potential that these disruptions may be predictive of recovery. The objective of this study was to determine if cognitive abilities in the emergency department (ED) can differentiate and predict poor symptom recovery following a pediatric mTBI. Participants included 77 male and female youth with a mTBI (mean age=13.6; SD=2.6). All participants completed computerized cognitive testing (four subtests from the CNS Vital Signs) when they presented to the ED. Symptom measurement occurred in the ED (for pre-injury), at 7-10 days, 1 month, 2 months, and 3 months post-mTBI using the post-concussion symptom inventory (PCSI). Recovery was determined using reliable change scores for symptom ratings from 28 orthopedic injury controls (mean age=13.9 years; SD=2.1). Significantly worse Reaction Time scores (i.e., rapid information processing) in the ED were found in those who remained symptomatic at 1 month. Performances on the Reaction Time and Cognitive Flexibility domain scores were predictive of symptom outcome at 1 month for youth (above and beyond sex and baseline symptom burden). Youth with low scores on Reaction Time and/or Cognitive Flexibility were nearly 15 times (95% CI=1.8-323.5) more likely to remain symptomatic at 1 month post-mTBI. No significant group differences were found at 7-10 days, 2 months, or 3 months post-injury. Rapid computerized cognitive testing in the ED following a mTBI may help clinicians predict which youth may or may not remain symptomatic at follow-up.

Sports-Related Concussion

Sports-related concussions (SRC) are common in all ages and occur in all sports. The diagnosis based on clinical suspicion after more serious injury is ruled out. Symptoms of concussion are due to a temporary and reversible neurometabolic cascade resulting in blood flow changes, neuronal excitotoxicity, ionic shifts, and mitochondrial changes. Symptoms are nonspecific, and commonly include headache, cognitive complaints, photophobia, and phonophobia. Loss of consciousness is rare in SRC and has limited influence on recovery and prognosis. Imaging has a limited role in the management of concussion and should be used to evaluate for more serious intracranial pathology. Treatment is based on symptoms and an understanding of the typical, rapid (7-10 days) recovery. No athlete should return to play until their symptoms have resolved and they have completed a supervised, step-wise return to play protocol. The article covers the most recent literature on the diagnosis and management of SRC, including evidence-based recommendations and expert-based consensus opinion. The article will also discuss issues regarding medical retirement, legislation, and future concepts in concussion diagnosis and management.

Sex-Based Differences as a Predictor of Recovery Trajectories in Young Athletes After a Sports-Related Concussion

BACKGROUND

To date, few studies have delineated clear sex-based differences in symptom resolution after a sports-related concussion (SRC), and equivocal results have been identified in sex-based differences on baseline assessments.

PURPOSE

To assess whether female athletes displayed prolonged recovery and more symptoms at baseline and after an SRC compared with male athletes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The current study assessed 135 male and 41 female athletes (10-18 years old) who participated in high-impact sports in metropolitan Atlanta middle and high schools. All athletes completed a baseline assessment and at least 1 postconcussion assessment from the Immediate Post-Concussion Assessment and Cognitive Testing battery. Longitudinal hierarchical linear modeling was employed to examine individual-level variables and their associations with adolescents' rates of recovery in concussive symptoms after controlling for age and number of prior concussions.

RESULTS

Aggregate symptoms were rated as higher in female athletes compared with male athletes at baseline (mean ± SD: females, 13.49 ± 11.20; males, 4.88 ± 8.74; F(1,175) = 10.59, P < .001) and immediately after a concussion (females: 16.75 ± 18.08; males: 10.58 ± 14.21; F(1,175) = 3.99, P = .05). There were no group differences in the slope of recovery between male and female athletes, indicating generally similar trajectories of change for both groups. Post hoc analyses revealed higher baseline levels of migraine and neuropsychological symptoms in female athletes.

CONCLUSION

Although female athletes in the current study reported increased symptoms, identical recovery patterns were observed in both sexes, suggesting that sex-based differences in concussion recovery are better explained by increased symptom frequency among female athletes when compared with their male counterparts.

Factors Associated With Concussion-like Symptom Reporting in High School Athletes

IMPORTANCE

Every state in the United States has passed legislation for sport-related concussion, making this health issue important for physicians and other health care professionals. Safely returning athletes to sport after concussion relies on accurately determining when their symptoms resolve.

OBJECTIVE

To evaluate baseline concussion-like symptom reporting in uninjured adolescent student athletes.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional, observational study, we studied 31 958 high school athletes from Maine with no concussion in the past 6 months who completed a preseason baseline testing program between 2009 and 2013.

RESULTS

Symptom reporting was more common in girls than boys. Most students with preexisting conditions reported one or more symptoms (60%-82% of boys and 73%-97% of girls). Nineteen percent of boys and 28% of girls reported having a symptom burden resembling an International Classification of Diseases, 10th Revision (ICD-10) diagnosis of postconcussional syndrome (PCS). Students with preexisting conditions were even more likely to endorse a symptom burden that resembled PCS (21%-47% for boys and 33%-72% for girls). Prior treatment of a psychiatric condition was the strongest independent predictor for symptom reporting in boys, followed by a history of migraines. For girls, the strongest independent predictors were prior treatment of a psychiatric condition or substance abuse and attention-deficit/hyperactivity disorder. The weakest independent predictor of symptoms for both sexes was history of prior concussions.

CONCLUSIONS AND RELEVANCE

In the absence of a recent concussion, symptom reporting is related to sex and preexisting conditions. Consideration of sex and preexisting health conditions can help prevent misinterpretation of symptoms in student athletes who sustain a concussion.

Rates and Predictors of Invalid Baseline Test Performance in High School and Collegiate Athletes for 3 Computerized Neurocognitive Tests: ANAM, Axon Sports, and ImPACT

BACKGROUND

Preseason baseline testing using computerized neurocognitive tests (CNTs) is increasingly performed on athletes. Adequate effort is critical to establish valid estimates of ability, but many users do not evaluate performance validity, and the conditions that affect validity are not well understood across the available CNTs.

PURPOSE

To examine the rates and predictors of invalid baseline performance for 3 popular CNTs: Automated Neuropsychological Assessment Metrics (ANAM), Axon Sports, and Immediate Post-Concussion and Cognitive Testing (ImPACT).

STUDY DESIGN

Controlled laboratory study.

METHODS

High school and collegiate athletes (N = 2063) completed 2 of 3 CNTs each during preseason evaluations. All possible pairings were present across the sample, and the order of administration was randomized. Examiners provided 1-on-1, scripted pretest instructions, emphasizing the importance of good effort. Profile validity was determined by the manufacturers' standard criteria.

RESULTS

The overall percentage of tests flagged as of questionable validity was lowest for ImPACT (2.7%) and higher for ANAM and Axon (10.7% and 11.3%, respectively). The majority of invalid baseline profiles were flagged as such because of failure on only 1 validity criterion. Several athlete and testing factors (eg, attention deficit hyperactivity disorder [ADHD], estimated general intellectual ability, administration order) predicted validity status for 1 or more CNTs. Considering only first CNT administrations and participants without ADHD and/or a learning disability (n = 1835) brought the rates of invalid baseline performances to 2.1%, 8.8%, and 7.0% for ImPACT, ANAM, and Axon, respectively. Invalid profiles on the Medical Symptom Validity Test (MSVT) were rare (1.8% of participants) and demonstrated poor correspondence to CNT validity outcomes.

CONCLUSION

The validity criteria for these CNTs may not identify the same causes of invalidity or be equally sensitive to effort. The validity indicators may not be equally appropriate for some athletes (eg, those with neurodevelopmental disorders).

CLINICAL RELEVANCE

The data suggest that athletes do not put forth widespread low effort or that some validity criteria are more sensitive to invalid performance than others. It is important for examiners to be aware of the conditions that maximize the quality of baseline assessments and to understand what sources of invalid performance are captured by the validity criteria that they obtain.