Sex differences in outcome following sports-related concussion

Demographics and treatment of adolescent posttraumatic headache in a regional concussion clinic

OBJECTIVE

Mild traumatic brain injury affects over one million pediatric patients annually. Minimal data and no guidelines exist regarding treatment of posttraumatic headache (PTH). The current study investigated treatment and outcomes in patients with posttraumatic headache.

METHODS

Medical records of all patients (age 13-18 years of age) seen at a regional concussion program from 2006 to 2011 were reviewed. Statistical analysis using SAS 9.2 was conducted to determine the effectiveness of treatment as well as the association of gender, concussion history, and football participation on the duration of posttraumatic headache.

RESULTS

Four hundred subjects met the inclusion criteria. Females were more likely to report posttraumatic headache than males (90% vs. 79%, P = 0.004), more likely to be prescribed amitriptyline (24% vs. 13%, P = 0.004), and had a significantly longer recovery time (median, 80 days versus 34 days, P < 0.001). Seventeen percent of subjects were prescribed amitriptyline for treatment of posttraumatic headache, of which 82% reported a beneficial effect. There was no difference in the percentage of posttraumatic headache or recovery time in football players versus other male athletes from other sport mechanisms.

CONCLUSION

Females are more likely to report posttraumatic headache than males and also take longer to recover. Amitriptyline appears to be well-tolerated and an effective treatment strategy for patients with posttraumatic headache. Among pediatric patients evaluated in a concussion clinic, there is no difference in the proportion of football players reporting headaches compared with male players of other sports.

Injuries in recreational curling include head injuries and may be prevented by using proper footwear

INTRODUCTION

Our study examines a recreational curling population to describe patterns of injury occurrence, estimate risk of injury and to gauge attitudes towards equipment-based prevention strategies.

METHODS

In a retrospective case series, we queried the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP), a national injury surveillance database, for curling injuries entered between 1993 and 2011. Kingston General Hospital and Hotel Dieu Hospital provide the two Kingston, Ontario, sites for emergency department (ED) care and participate in CHIRPP. Each retrieved entry underwent a chart review. A secondary survey was mailed to select individuals who had experienced curling injuries to solicit details on their injury and attitudes towards equipment to prevent injury. We used descriptive statistics for rates and proportions.

RESULTS

Over 90% of acute curling injuries resulted from a fall, and 31.7% were head impacts. We found that acute injuries requiring ED presentation occur at a rate of approximately 0.17 per 1000 athlete-exposures (95% CI: 0.12-0.22). The secondary survey was completed by 54% of potential respondents. Of survey respondents, 41.3% attributed their fall to a lack of proper footwear and 73.5% of respondents agreed with mandatory sport-specific footwear as a prevention strategy, but only 8% agreed with mandatory helmet wear.

CONCLUSION

Although curling injuries requiring medical care are not common, head injuries make up a large proportion. Mandated use of appropriate footwear appears to be the most effective prevention strategy, as well as the measure deemed most acceptable by players.

Biomechanics of head impacts associated with diagnosed concussion in female collegiate ice hockey players

Epidemiological evidence suggests that female athletes may be at a greater risk of concussion than their male counterparts. The purpose of this study was to examine the biomechanics of head impacts associated with diagnosed concussions in a cohort of female collegiate ice hockey players. Instrumented helmets were worn by 58 female ice hockey players from 2 NCAA programs over a three year period. Kinematic measures of single impacts associated with diagnosed concussion and head impact exposure on days with and without diagnosed concussion were evaluated. Nine concussions were diagnosed. Head impact exposure was greater in frequency and magnitude on days of diagnosed concussions than on days without diagnosed concussion for individual athletes. Peak linear accelerations of head impacts associated with diagnosed concussion in this study are substantially lower than those previously reported in male athletes, while peak rotational accelerations are comparable. Further research is warranted to determine the extent to which female athletes' biomechanical tolerance to concussion injuries differs from males.

Aging, neurodegenerative disease, and traumatic brain injury: the role of neuroimaging

Traumatic brain injury (TBI) is a highly prevalent condition with significant effects on cognition and behavior. While the acute and sub-acute effects of TBI recover over time, relatively little is known about the long-term effects of TBI in relation to neurodegenerative disease. This issue has recently garnered a great deal of attention due to publicity surrounding chronic traumatic encephalopathy (CTE) in professional athletes, although CTE is but one of several neurodegenerative disorders associated with a history of TBI. Here, we review the literative on neurodegenerative disorders linked to remote TBI. We also review the evidence for neuroimaging changes associated with unhealthy brain aging in the context of remote TBI. We conclude that neuroimaging biomarkers have significant potential to increase understanding of the mechanisms of unhealthy brain aging and neurodegeneration following TBI, with potential for identifying those at risk for unhealthy brain aging prior to the clinical manifestation of neurodegenerative disease.

Protracted recovery from a concussion: a focus on gender and treatment interventions in an adolescent population

Background:

Several studies have demonstrated that age and sex may influence concussion recovery time frames, with female athletes and adolescents being potentially more susceptible to a protracted recovery course. Currently, limited work has examined the influence sex may have on concussion management strategies and treatment interventions, especially for younger individuals suffering persistent concussion symptoms and cognitive dysfunctions.

Hypothesis:

Female athletes are prescribed more treatment interventions than male athletes during a protracted recovery from a concussion.

Study Design:

Descriptive epidemiology study.

Level of Evidence:

Level 4.

Methods:

Data were retrospectively collected for adolescent athletes presenting to a sports medicine concussion clinic between September 2010 and September 2011.

Results:

A total of 266 adolescent athletes were evaluated and treated for concussion. Female athletes had a longer recovery course (P = 0.002) and required more treatment interventions (P < 0.001) for their symptoms and dysfunction. Female athletes were more likely to require academic accommodations (P < 0.001), vestibular therapy (P < 0.001), or medication (P < 0.001).

Conclusion:

Medical providers should be aware that during the recovery course, adolescent female athletes may require a management plan that will most likely include additional treatment interventions beyond the standard cognitive and physical rest.

Clinical Relevance:

Treatment interventions are more commonly prescribed for adolescent female athletes than for adolescent male athletes during a protracted recovery from a concussion. This highlights the need for identifying evidence-based clinical management guidelines that focus on sex, especially when dealing with persistent concussion symptoms and cognitive dysfunctions.

Examining Neurocognitive Function in Previously Concussed Interscholastic Female Soccer Players

Awareness of sport-related concussions in soccer has gained recent attention in the medical community. Interestingly, purposeful heading-a unique yet strategic and inherent part of soccer-involves repeated subconcussive blows to the head. We divided 210 female interscholastic soccer players into control (CON [never concussed]) and experimental (EXP [previously concussed]) groups. We assessed neurocognitive performance using the Automated Neuropsychological Assessment Metrics computer program before and after the players' competitive season. Headers were recorded at all sanctioned matches. Data were analyzed using a series of one-way analyses of covariance and t tests. Both groups essentially played in the same number of games (EXP = 16.1 vs. CON = 16.1) and had an equal number of total headers (EXP = 24.9 vs. CON = 24.3). Additionally, headers per game were surprisingly low in both groups (1.4 in EXP vs. 1.3 in CON). Unexpectedly, there were no significant differences between the EXP and CON groups across all dependent variables measured (p > .05). This study suggests that although previously concussed players involve themselves in purposeful heading (i.e., subconcussive insults) throughout a competitive season, there appear to be no negative consequences on neuropsychological test performance or concussion-related symptoms. Additional research is needed to determine what may result during the course of a playing career.

Premorbid predictors of postconcussion symptoms in collegiate athletes

INTRODUCTION

In recent years, the sports community has been faced with the challenge of determining when it is safe to return concussed athletes to play. Given that return-to-play decisions are partially dependent upon athletes' endorsement of symptoms, better understanding what factors contribute to the presence of symptoms following concussion is crucial. The purpose of the present study was to better characterize the symptoms that athletes endorse at baseline and to determine what impact various premorbid (or preinjury) characteristics have on the presence and severity of postconcussion symptoms in the acute injury period following concussion.

METHOD

Two groups of participants with similar ages and levels of education were examined: athletes at baseline (N = 702) and postconcussion (N = 55). Athletes were administered a comprehensive battery of neuropsychological tests, consisting of neurocognitive and neurobehavioral measures, at both time periods. The main outcome measure was the Post-Concussion Symptoms Scale (PCSS). A factor analysis was conducted on the participants' baseline PCSS data to determine the factor structure of the PCSS, and separate logistic regression analyses were conducted that examined the baseline PCSS symptom clusters (derived from the factor analysis), demographic variables, and baseline neurocognitive variables as predictors of dichotomized postconcussion PCSS total scores (i.e., low versus high symptom reporting following concussion).

RESULTS

Four distinct clusters emerged from the factor analysis measuring cognitive, physical, affective, and sleep symptoms. Logistic regression results indicated that the physical and affective symptom clusters at baseline reliably predicted athletes' postconcussion symptom group, as did sex and the neurocognitive composite score.

CONCLUSIONS

These findings show that certain baseline characteristics of athletes confer risk for greater symptomatology postconcussion. Knowledge of these risk factors can assist the management and treatment of sports-related concussion.

Gender- and sex-specific sports-related injury research in emergency medicine: a consensus on future research direction and focused application

Title IX, the commercialization of sports, the social change in sports participation, and the response to the obesity epidemic have contributed to the rapid proliferation of participation in both competitive organized sports and nontraditional athletic events. As a consequence, emergency physicians are regularly involved in the acute diagnosis, management, disposition, and counseling of a broad range of sports-related pathology. Three important and highly publicized mechanisms of injury in sports relevant to emergency medicine (EM) include concussion, heat illness, and sudden cardiac death. In conjunction with the 2014 Academic Emergency Medicine consensus conference "Gender-specific Research in Emergency Care: Investigate, Understand, and Translate How Gender Affects Patient Outcomes," a consensus group consisting of experts in EM, emergency neurology, sports medicine, and public health convened to deliberate and develop research questions that could ultimately advance the field of sports medicine and allow for meaningful application in the emergency department (ED) clinical setting. Sex differences in injury risk, diagnosis, ED treatment, and counseling are identified in each of these themes. This article presents the consensus-based priority research agenda.

Predictors of outcome after treatment of mild traumatic brain injury: a pilot study

OBJECTIVE

To determine factors affecting outcome of comprehensive outpatient rehabilitation of individuals who sustained a mild traumatic brain injury.

PARTICIPANTS

From a 4-year series of referrals, 49 nonconsecutive participants met criteria for mild traumatic brain injury (ie, loss of consciousness <30 minutes, Glasgow Coma Scale score >12).

SETTING

Outpatient, community-based postconcussion clinic at a rehabilitation hospital.

MAIN MEASURES

Participants and therapy staff completed the Mayo-Portland Adaptability Inventory-Fourth Edition (MPAI-4) at the initiation and conclusion of treatment. Participants were also administered the Trail Making Test at the start of treatment.

RESULTS

Participants generally gave poorer adaptability ratings than staff at the beginning and discharge of treatment. Regression analyses revealed that after controlling for baseline ratings, psychiatric history was associated with worse participant-rated MPAI-4 Adjustment scores at treatment discharge, whereas better Trail Making Test Part B performance at initiation of treatment predicted better participant-rated MPAI-4 Ability at treatment discharge.

CONCLUSIONS

Premorbid demographic and baseline neurocognitive factors should be taken into account prior to comprehensive treatment of mild traumatic brain injury, as they can influence long-term outcomes. Adaptability ratings from both staff and participants can be useful in gaining different perspectives and assessing factors affecting recovery.

Advanced topics in neuropsychological assessment following sport-related concussion

OBJECTIVE

This study examined seven topics relating to neuropsychological assessment following sport-related concussion: (i) traditional vs. computerized tests; (ii) the value of baseline, pre-season testing; (iii) invalid baseline scores and poor effort; (iv) when to assess following injury; (v) the reliability of neuropsychological tests; (vi) reliable change methodology; and (vii) new methods for identifying cognitive impairment.

MAIN RESULTS

Baseline testing can be helpful for quantifying cognitive deficits following injury and for assessing recovery. At present, however, there is insufficient evidence to conclude that having baseline test results is clearly superior to not having baseline test results. Although invalid baseline test performance can be detected in some athletes, validity indicators cannot determine the extent to which the results were due to deliberately poor performance, confusion or misunderstanding regarding some aspect of the test, distractions in group testing environments or some combination of factors. When interpreting baseline and post-injury data, sophisticated psychometric methods (e.g. reliable change, multivariate base rates) are available to assist with more accurate identification of cognitive impairment and the serial monitoring of recovery.

CONCLUSIONS

The value of neuropsychological assessment in the management of sport-related concussion has a strong empirical foundation. Additional research is needed, however, to refine its use.

Diet, age, and prior injury status differentially alter behavioral outcomes following concussion in rats

Mild traumatic brain injury (mTBI) or concussion affects a large portion of the population and although many of these individuals recover completely, a small subset of people experience lingering symptomology and poor outcomes. Little is known about the factors that affect individual susceptibility or resilience to poor outcomes after mTBI and there are currently no biomarkers to delineate mTBI diagnosis or prognosis. Based upon the growing literature associated with caloric intake and altered neurological aging and the ambiguous link between repetitive mTBI and progressive neurodegeneration, the current study was designed to examine the effect of a high fat diet (HFD), developmental age, and repetitive mTBI on behavioral outcomes following a mTBI. In addition, telomere length was examined before and after experimental mTBI. Sprague Dawley rats were maintained on a HFD or standard rat chow throughout life (including the prenatal period) and then experienced an mTBI/concussion at P30, P30 and P60, or only at P60. Behavioral outcomes were examined using a test battery that was administered between P61-P80 and included; beam-walking, open field, elevated plus maze, novel context mismatch, Morris water task, and forced swim task. Animals with a P30 mTBI often demonstrated lingering symptomology that was still present during testing at P80. Injuries at P30 and P60 rarely produced cumulative effects, and in some tests (i.e., beam walking), the first injury may have protected the brain from the second injury. Exposure to the high fat diet exacerbated many of the behavioral deficits associated with concussion. Finally, telomere length was shortened following mTBI and was influenced by the animal's dietary intake. Diet, age at the time of injury, and the number of prior concussion incidents differentially contribute to behavioral deficits and may help explain individual variations in susceptibility and resilience to poor outcomes following an mTBI.

Subarachnoid hemorrhage and the female sex: analysis of risk factors, aneurysm characteristics, and outcomes

OBJECT

The pathophysiology of aneurysmal subarachnoid hemorrhage (aSAH) is unclear. Sex may play a role in the outcome of patients with aSAH.

METHODS

The authors retrospectively identified 617 patients with aSAH (April 2005 to February 2010) and analyzed sex differences in risk factors (age, hypertension, smoking, alcohol consumption, and family history), admission-related factors (World Federation of Neurosurgical Societies grade and admission delay), aneurysm characteristics (site, side, location, and multiplicity), and outcomes (treatment modalities [coiling/clipping/both/conservative], complications [vasospasm and hydrocephalus], length of stay, and modified Rankin Scale score at 3 months).

RESULTS

The female patients with aSAH were older than the male patients (mean age 56.6 vs 51.9 years, respectively, p < 0.001), and more women than men were ≥ 55 years old (56.2% vs 40.4%, respectively, p < 0.001). Women exhibited higher rates of bilateral (6.8% vs 2.6%, respectively, p < 0.05), multiple (11.5% vs 5.2%, respectively, p < 0.05), and internal carotid artery (ICA) (36.9% vs 17.5%, respectively, p < 0.001) aneurysms and a lower rate of anterior cerebral artery aneurysms (26.3% vs 44.8%, respectively, p < 0.001) than the men, but no side differences were noted. There were no sex differences in risk factors, admission-related factors, or outcome measures. For both sexes, outcomes varied according to aneurysm location, with odds ratios for a poor outcome of 1.62 (95% CI 0.91-2.86, p = 0.1) for middle cerebral artery, 2.41 (95% CI 1.29-4.51, p = 0.01) for ICA, and 2.41 (95% CI 1.29-4.51, p = 0.006) for posterior circulation aneurysms compared with those for anterior cerebral artery aneurysms. The odds ratio for poor outcome (modified Rankin Scale score of 4-6) in women compared with men after adjusting for significant prognostic factors was 0.71 (95% CI 0.45-1.11, p > 0.05).

CONCLUSIONS

The overall outcomes after aSAH between women and men are similar.

Why women see differently from the way men see? A review of sex differences in cognition and sports

The differences of learning and memory between males and females have been well documented and confirmed by both human and animal studies. The sex differences in cognition started from early stage of neuronal development and last through entire life span. The major biological basis of the gender-dependent cognitive activity includes two major components: sex hormone and sex-related characteristics, such as sex-determining region of the Y chromosome (SRY) protein. However, the knowledge of how much biology of sex contributes to normal cognitive function and elite athletes in various sports are still pretty limited. In this review, we will be focusing on sex differences in spatial learning and memory - especially the role of male- and female-type cognitive behaviors in sports.

Washington State's Lystedt law in concussion documentation in Seattle public high schools

CONTEXT

The Lystedt law requires high school athletes who have sustained a concussion to be removed from practice and play and not to be allowed to return until cleared by a medical professional.

OBJECTIVE

To determine the effect of the Lystedt law on injury and concussion documentation in the Seattle public high schools.

DESIGN

Cross-sectional study.

SETTING

Seattle public high schools.

PATIENTS OR OTHER PARTICIPANTS

The numbers of students, aged 13 to 19 years in the 2008-2009, 2009-2010, and 2010-2011 school years, were 4348, 4925, and 4806, respectively.

MAIN OUTCOME MEASURE(S)

All injuries documented in SportsWare by athletic trainers in Seattle public high schools. We evaluated all injuries, including concussions recorded during the 2008-2009 school year, before the Lystedt law, and during the 2 school years after the law took effect (2009-2010 and 2010-2011). Incidence rates before and after the law were estimated and compared.

RESULTS

The concussion rate was -1.09% in 2008-2009, 2.26% in 2009-2010, and 2.26% in 2010-2011. A comparison of relative risks showed that the incidence rates of concussions were different before and 1 year after the Lystedt law (relative risk = 2.10; 95% confidence interval [CI] = 1.50, 2.93) and 2 years after the law (relative risk = 2.10; 95% CI = 1.49, 2.93). Overall, the mean number of days out of play after 2008-2009 was almost 7 days greater after the law took effect (difference = 6.9 days; 95% CI = 0.70, 13.1). For females, the mean number of days out of play after 2008-2009 was more than 17 days in 2009-2010 (difference = 17.2 days; 95% CI = 4.81, 29.5) and was more than 6 days in 2010-2011 (difference = 6.3 days; 95% CI = 1.62, 11.0).

CONCLUSIONS

The number of documented concussions more than doubled after the institution of the Lystedt law, which may be attributed to heightened awareness and closer monitoring.

Chronic traumatic encephalopathy: where are we and where are we going?

Chronic traumatic encephalopathy (CTE, previously called punch drunk and dementia pugilistica) has a rich history in the medical literature in association with boxing, but has only recently been recognized with other contact sports, such as football and ice hockey, as well as with military blast injuries. CTE is thought to be a neurodegenerative disease associated with repeated concussive and subconcussive blows to the head. There is characteristic gross and microscopic pathology found in the brain, including frontal and temporal atrophy, axonal degeneration, and hyperphosphorylated tau and TAR DNA-binding protein 43 pathology. Clinically, there are characteristic progressive deficits in cognition (memory, executive dysfunction), behavior (explosivity, aggression), mood (depression, suicidality), and motor function (parkinsonism), which correlate with the anatomic distribution of brain pathology. While CTE shares clinical and neuropathological traits with other neurodegenerative diseases, the clinical syndrome and the neuropathology as a whole are distinct from other neurodegenerative diseases. Here we review the CTE literature to date. We also draw on the literature from mild traumatic brain injury and other neurodegenerative dementias, particularly when these studies provide guidance for future CTE research. We conclude by suggesting seven essential areas for future CTE research.

Sex differences in white matter abnormalities after mild traumatic brain injury: localization and correlation with outcome

PURPOSE

To evaluate sex differences in diffusion-tensor imaging (DTI) white matter abnormalities after mild traumatic brain injury (mTBI) using tract-based spatial statistics (TBSS) and to compare associated clinical outcomes.

MATERIALS AND METHODS

The institutional review board approved this study, with waiver of informed consent. DTI in 69 patients with mTBI (47 male and 22 female patients) and 21 control subjects (10 male and 11 female subjects) with normal conventional magnetic resonance (MR) images were retrospectively reviewed. Fractional anisotropy (FA) maps were generated as a measure of white matter integrity. Patients with mTBI underwent serial neurocognitive testing with Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). Correlation between sex, white matter FA values, ImPACT scores, and time to symptom resolution (TSR) were analyzed with multivariate analysis and TBSS.

RESULTS

No significant difference in age was seen between males and females (control subjects, P = .3; patients with mTBI, P = .34). No significant difference was seen in initial ImPACT symptom scores (P = .33) between male and female patients with mTBI. Male patients with mTBI had significantly decreased FA values in the uncinate fasciculus (UF) bilaterally (mean FA, 0.425; 95% confidence interval: 0.375, 0.476) compared with female patients with mTBI and control subjects (P < .05), with a significantly longer TSR (P = .04). Multivariate analysis showed sex and UF FA values independently correlated with TSR longer than 3 months (adjusted odds ratios, 2.27 and 2.38; P = .04 and P < .001, respectively), but initial symptom severity did not (adjusted odds ratio, 1.15; P = .35).

CONCLUSION

Relative sparing of the UF is seen in female compared with male patients after mTBI, with sex and UF FA values as stronger predictors of TSR than initial symptom severity.

Neurometabolic and microstructural alterations following a sports-related concussion in female athletes

BACKGROUND

Sports-related concussions are a major public health concern affecting millions of individuals annually. Neurometabolic and microstructural alterations have been reported in the chronic phase following a concussion in male athletes, while no study has investigated these alterations in female athletes.

METHODS

Neurometabolic and microstructural alterations following a concussion were investigated by comparing 10 female athletes with a concussion and 10 control female athletes, using magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI). Athletes with concussion were scanned at least 7 months post-concussion (mean = 18.9 months).

RESULTS

MRS revealed a significant lower level of myo-inositol in the hippocampus and the primary motor cortices (M1) bilaterally. DTI analysis using Tract-Based Spatial Statistics (TBSS) showed no difference in fractional anisotropy (FA) while higher level of mean diffusivity (MD) in athletes with concussion was detected in large white matter tracts including the forceps minors, inferior/superior longitudinal fasciculi, inferior fronto-occipital fasciculus, cingulum, uncinate fasciculus, anterior thalamic radiations and corticospinal tract. Moreover, a region of interest approach for the corpus callosum revealed a significant lower level of FA in the segment containing fibres projecting to M1.

CONCLUSIONS

This study demonstrates persistent neurometabolic and microstructural alterations in female athletes suffering a sports-related concussion.

Baseline neurocognitive testing in sports-related concussions: the importance of a prior night's sleep

BACKGROUND

The management of sports-related concussions (SRCs) utilizes serial neurocognitive assessments and self-reported symptom inventories to assess recovery and safety for return to play (RTP). Because postconcussive RTP goals include symptom resolution and a return to neurocognitive baseline levels, clinical decisions rest in part on understanding modifiers of this baseline. Several studies have reported age and sex to influence baseline neurocognitive performance, but few have assessed the potential effect of sleep. We chose to investigate the effect of reported sleep duration on baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) performance and the number of patient-reported symptoms.

HYPOTHESIS

We hypothesized that athletes receiving less sleep before baseline testing would perform worse on neurocognitive metrics and report more symptoms.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We retrospectively reviewed 3686 nonconcussed athletes (2371 male, 1315 female; 3305 high school, 381 college) with baseline symptom and ImPACT neurocognitive scores. Patients were stratified into 3 groups based on self-reported sleep duration the night before testing: (1) short, <7 hours; (2) intermediate, 7-9 hours; and (3) long, ≥9 hours. A multivariate analysis of covariance (MANCOVA) with an α level of .05 was used to assess the influence of sleep duration on baseline ImPACT performance. A univariate ANCOVA was performed to investigate the influence of sleep on total self-reported symptoms.

RESULTS

When controlling for age and sex as covariates, the MANCOVA revealed significant group differences on ImPACT reaction time, verbal memory, and visual memory scores but not visual-motor (processing) speed scores. An ANCOVA also revealed significant group differences in total reported symptoms. For baseline symptoms and ImPACT scores, subsequent pairwise comparisons revealed these associations to be most significant when comparing the short and intermediate sleep groups.

CONCLUSION

Our results indicate that athletes sleeping fewer than 7 hours before baseline testing perform worse on 3 of 4 ImPACT scores and report more symptoms. Because SRC management and RTP decisions hinge on the comparison with a reliable baseline evaluation, clinicians should consider sleep duration before baseline neurocognitive testing as a potential factor in the assessment of athletes' recovery.

Neuroprotective strategies for traumatic brain injury: improving clinical translation

Traumatic brain injury (TBI) induces secondary biochemical changes that contribute to delayed neuroinflammation, neuronal cell death, and neurological dysfunction. Attenuating such secondary injury has provided the conceptual basis for neuroprotective treatments. Despite strong experimental data, more than 30 clinical trials of neuroprotection in TBI patients have failed. In part, these failures likely reflect methodological differences between the clinical and animal studies, as well as inadequate pre-clinical evaluation and/or trial design problems. However, recent changes in experimental approach and advances in clinical trial methodology have raised the potential for successful clinical translation. Here we critically analyze the current limitations and translational opportunities for developing successful neuroprotective therapies for TBI.

Risk modifiers for concussion and prolonged recovery

Context:

Currently, no consensus exists for grading the severity of concussions. Identification of risk factors that may affect concussion risk and the likelihood of prolonged recovery can be of value to providers who manage concussion.

Evidence Acquisition:

Relevant studies were identified through MEDLINE (1996-2011) using the keywords concussion, postconcussive syndrome, and risk or risk factor. Targeted searches for specific risk factors were conducted with additional keywords, such as gender and migraine. Manual review of reference lists was also performed to identify pertinent literature.

Results:

For risk factors of concussion, history of prior concussion and female sex have the most supporting evidence. Sports with consistently high risk for sustaining a concussion include football, men’s ice hockey, and women’s soccer. Younger athletes appear to be more susceptible to concussion, but data are limited and inconsistent. Protective equipment does not definitively alter concussion risk, though it protects against other injuries. Symptoms such as long headaches, migraines, amnesia, and multiple symptoms appear to be associated with prolonged recovery. Younger age may also increase the risk of prolonged concussion.

Conclusion:

High-quality evidence for risk modifiers in concussion remains sparse. Prior concussion, collision sports, female sex, and women’s soccer are the strongest known risk factors. Evidence for most other factors is inconclusive.

Effect of sex on symptoms and return to baseline in sport-related concussion

OBJECT

Sport-related concussions (SRCs) among youth athletes represent a significant public health concern. Prior research suggests that females fare worse symptomatically after an SRC. The authors aimed to assess sex differences in number, severity, and resolution of postconcussive symptoms using reliable change index (RCI) methodology applied to days to return to symptom baseline.

METHODS

Between 2009 and 2011, 740 youth athletes completed valid neurocognitive and symptom testing before and after an SRC using Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). A total of 122 female and 122 male athletes were matched on number of prior concussions, age, and number of days to first postconcussion test. At baseline and postconcussion, the authors compared each of the individual 22 symptoms on ImPACT to calculate individual symptom severity and aggregate symptom severity, or the Total Symptom Score (TSS). When comparing individual symptoms, the significance level for the comparison of each symptom was set at 0.05/22 = 0.0023. When comparing aggregate symptom severity, or TSS, a single value was compared, requiring an alpha set to 0.05. The number of days to return to baseline TSS was compared using RCI methods set at the 80% confidence interval, equal to a raw score point value of 9.18 on the TSS.

RESULTS

At baseline, females reported a greater severity for the symptom, "sleeping less than usual," compared with males (0.88 ± 1.49 vs 0.31 ± 0.86, p < 0.001). However, no other individual symptom severity differences were noted before or after SRC. At baseline, females exhibited a statistically significant greater aggregate symptom severity than males (7.24 ± 10.22 vs 4.10 ± 6.52, p = 0.005). Greater aggregate symptom severity for females was also found postconcussion (21.38 ± 19.02 vs 16.80 ± 17.07, p = 0.049). Females took longer to return to baseline TSS (9.1 ± 7.1 days vs 7.0 ± 5.1 days, p = 0.013).

CONCLUSIONS

The results of this retrospective study indicate that females endorse a greater severity of symptoms at baseline and postconcussion than males without significantly different symptom profiles. Furthermore, after suffering an SRC, females take longer to return to their baseline symptom level.

Athletes' age, sex, and years of education moderate the acute neuropsychological impact of sports-related concussion: a meta-analysis

The objective of this study is to determine which pre-existing athlete characteristics, if any, are associated with greater deficits in functioning following sports-related concussion, after controlling for factors previously shown to moderate this effect (e.g., time since injury). Ninety-one independent samples of concussion were included in a fixed+systematic effects meta-analysis (n = 3,801 concussed athletes; 5,631 controls). Moderating variables were assessed using analogue-to-ANOVA and meta-regression analyses. Post-injury assessments first conducted 1-10 days following sports-related concussion revealed significant neuropsychological dysfunction, postural instability and post-concussion symptom reporting (d = -0.54, -1.10, and -1.14, respectively). During this interval, females (d = -0.87), adolescent athletes competing in high school competitions (d = -0.60), and those with 10 years of education (d = -1.32) demonstrated larger post-concussion neuropsychological deficits than males (d = -0.42), adults (d = -0.25), athletes competing at other levels of competition (d = -0.43 to -0.41), or those with 16 years of education (d = -0.15), respectively. However, these sub-groups' differential impairment/recovery beyond 10 days could not be reliably quantified from available literature. Pre-existing athlete characteristics, particularly age, sex and education, were demonstrated to be significant modifiers of neuropsychological outcomes within 10 days of a sports-related concussion. Implications for return-to-play decision-making and future research directions are discussed.

A follow-up study of neurometabolic alterations in female concussed athletes

Athletes who sustain a concussion demonstrate a variety of symptoms and neuropsychological alterations that could be brought on by neurometabolic abnormalities. However, no study has yet investigated these aspects in female athletes using magnetic resonance spectroscopy. The present study investigated the neurometabolic and -psychological effects of a concussion in the acute (7-10 days postinjury) and chronic (6 months postinjury) phases after injury. Eleven female concussed athletes and 10 female control athletes were scanned at both time points in a 3T magnetic resonance imaging scanner. Neuropsychological and symptomatic evaluations were completed at each time point. Neuropsychological alterations and a higher severity of symptoms were found in the acute phase in concussed athletes, relative to controls, but showed recovery in the chronic phase. Concussed athletes showed neurometabolic impairment in prefrontal and motor cortices characterized by a pathological increase of glutamine/glutamate and creatine (Cr) only in the chronic phase. Also, a significant decrease in N-acetyl-aspartate/Cr ratio was observed in control athletes at the second time point. Concussed female athletes showed acute cognitive alterations and higher severity of symptoms that do not appear to be underlied by neurometabolic abnormalities, which are only present in the chronic postinjury phase.

Relative risk for concussions in young female soccer players

The objective of this study was to determine the relative risk and reported symptoms of concussions in 11- to 13-year-old, female soccer players. For this, a survey to compare the reported incidence of concussion in age-matched female soccer players to nonsoccer players was performed. The survey included 342 girls between the ages of 11 and 13: 195 were involved in an organized soccer team and 147 were not involved in organized soccer but were allowed to participate in any other sport or activity. A total of 94 of the 195 soccer players, or 48%, reported at least one symptom consistent with a concussion. The most prevalent symptom for these girls was headache (84%). A total of 34 of the 147 nonsoccer players, or 23%, reported at least one symptom consistent with a concussion in the previous six months. These results determined that the relative risk of probable concussions among 11- to 13-year-old, female soccer players is 2.09 (p < .001, α = .05, CI = 95%). This demonstrates that the relative risk of probable concussions in young female soccer players is significantly higher than in a control group of nonsoccer players of the same sex and age.

Are there differences in neurocognitive function and symptoms between male and female soccer players after concussions?

BACKGROUND

Researchers have suggested that there are sex differences in outcomes after sport-related concussions. Factors such as sport type/rules, age, and body mass index (BMI) may influence these differences. Hypotheses/

PURPOSE

The purposes of this study were (1) to examine neurocognitive performance after concussions between male and female soccer players and (2) to compare concussion symptoms between male and female soccer players. We hypothesized that female concussed soccer players would report more concussion symptoms and worse cognitive performance compared with male concussed soccer players.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 39 male (mean BMI, 22.21 ± 2.34 kg/m(2); mean age, 17.69 ± 2.10 years) and 56 female (mean BMI, 23.47 ± 2.66 kg/m(2); mean age, 17.78 ± 2.30 years) concussed soccer players participated in this study. Participants were similar in age, history of concussion, sport, and time since injury. Participants completed computerized neurocognitive tests and symptom reports at baseline and 8 days after injury. Body mass index served as a covariate in all analyses.

RESULTS

After adjusting for BMI, results from a repeated-measures analysis of covariance (ANCOVA) revealed a group by time interaction for visual memory (F1,82 = 5.50; P = .021). Specifically, female concussed soccer players (mean score, 68.7 ± 15.2) performed worse at 8 days after a concussion compared with male concussed athletes (mean score, 77.2 ± 8.9). Results of another ANCOVA for total concussion symptoms indicated an interaction for group by time (F1,82 = 4.26; P = .04). Specifically, female concussed soccer players (mean score, 11.9 ± 15.7) reported more total concussion symptoms at 8 days compared with male concussed athletes (mean score, 5.3 ± 7.4). There were significant main effects for sex on verbal (F1,82 = 5.98; P = .017) and visual (F1,82 = 4.65; P = .034) memory, with female athletes reporting lower scores than male athletes. Female athletes also reported more symptoms on the migraine-cognitive-fatigue (F1,82 = 10.8; P = .001) and sleep (F1,82 = 9.2; P = .003) clusters than male athletes.

CONCLUSION

In contrast to recent studies, after controlling for BMI, female athletes exhibited lower performance on visual memory composite scores and higher scores on total symptoms than male athletes after concussions.

Acute clinical recovery from sport-related concussion

Concussion is a highly prevalent injury in contact and collision sports that has historically been poorly understood. An influx of sport-concussion research in recent years has led to a dramatic improvement in our understanding of the injury's defining characteristics and natural history of recovery. In this review, we discuss the current state of knowledge regarding the characteristic features of concussion and typical acute course of recovery, with an emphasis on the aspects of functioning most commonly assessed by clinicians and researchers (e.g., symptoms, cognitive deficits, postural stability). While prototypical clinical recovery is becoming better understood, questions remain regarding what factors (e.g., injury severity, demographic variables, history of prior concussions, psychological factors) may explain individual variability in recovery. Although research concerning individual differences in response to concussion is relatively new, and in many cases limited methodologically, we discuss the evidence about several potential moderators of concussion recovery and point out areas for future research. Finally, we describe how increased knowledge about the negative effects of and recovery following concussion has been translated into clinical guidelines for managing concussed athletes.

Mean girls: sex differences in the effects of mild traumatic brain injury on the social dynamics of juvenile rat play behaviour

Clinical studies indicate that children who experience a traumatic brain injury (TBI) are often the victim of peer rejection, have very few mutual friends, and are at risk for long-term behavioural and social impairments. Owing to the fact that peer play is critical for healthy development, it is possible that the long-term impairments are associated not only with the TBI, but also altered play during this critical period of brain development. This study was designed to determine if social dynamics and juvenile play are altered in rats that experience a mild TBI (mTBI) early in life. Play-fighting behaviours were recorded and analyzed for young male and female Sprague Dawley rats that were given either an mTBI or a sham injury. The study found that the presence of an mTBI altered the play fighting relationship, and the nature of the alterations were dependent upon the sex of the pairing and the injury status of their peers. Sham rats were significantly less likely to initiate play with an mTBI rat, and were more likely to respond to a play initiation from an mTBI rat with an avoidant strategy. This effect was significantly more pronounced in female rats, whereby it appeared that female rats with an mTBI were particularly rejected and most often excluded from play experiences. Male rats with an mTBI learned normal play strategies from their sham peers (when housed in mixed cages), whereas female rats with an mTBI show heightened impairment in these conditions. Play therapy may need to be incorporated into treatment strategies for children with TBI.

Understanding athletic trainers' beliefs toward a multifacted sport-related concussion approach: application of the theory of planned behavior

CONTEXT

Practice guidelines recommend a multifaceted approach for managing concussions, but a relatively small percentage of athletic trainers (ATs) follow these recommendations. Understanding ATs' beliefs toward the recommended concussion practice guidelines is the first step in identifying interventions that could increase compliance. The theory of planned behavior (TPB) allows us to measure ATs' beliefs toward the recommended concussion practice guidelines.

OBJECTIVE

To examine the influence of ATs' beliefs toward the current recommended concussion guidelines on concussion-management practice through an application of the TPB.

DESIGN

Cross-sectional study.

SETTING

A Web link with a survey was e-mailed to 1000 randomly selected members of the National Athletic Trainers' Association (NATA).

PATIENTS OR OTHER PARTICIPANTS

A total of 221 certified ATs working in secondary school/clinic, high school, and college/university settings.

MAIN OUTCOME MEASURE(S)

A 66-item survey reflecting the current recommended concussion guidelines of the NATA and International Conference on Concussion in Sport was created to measure beliefs using the TPB constructs attitude toward the behavior (BA), subjective norms (SN), perceived behavioral control (PBC), and behavioral intention (BI) of ATs. We used a linear multiple regression to determine if the TPB constructs BA, SN, and PBC predicted BI and if PBC and BI predicted behavior according to the TPB model.

RESULTS

We found that BA, SN, and PBC predicted BI (R = 0.683, R(2) = 0.466, F3,202 = 58.78, P < .001). The BA (t202 = 5.53, P < .001) and PBC (t202 = 9.64, P < .001) contributed to the model, whereas SN (t202 = -0.84, P = .402) did not. The PBC and BI predicted behavior (R = 0.661, R(2) = 0.437, F2,203 = 78.902, P < .001).

CONCLUSIONS

In this sample, the TPB constructs predicted BI and behavior of ATs' compliance with recommended concussion-management guidelines. The BA and PBC were the most influential constructs, indicating that those with positive attitudes toward concussion-management recommendations are more likely to implement them, and ATs are less likely to implement them when they do not believe they have the power to do so. We theorize that interventions targeting ATs' attitudes and control perceptions will lead to improved compliance.

Time interval between concussions and symptom duration

OBJECTIVE

To test the hypothesis that children with a previous history of concussion have a longer duration of symptoms after a repeat concussion than those without such a history.

METHODS

Prospective cohort study of consecutive patients 11 to 22 years old presenting to the emergency department of a children's hospital with an acute concussion. The main outcome measure was time to symptom resolution, assessed by the Rivermead Post-Concussion Symptoms Questionnaire (RPSQ). Patients and providers completed a questionnaire describing mechanism of injury, associated symptoms, past medical history, examination findings, diagnostic studies, and the RPSQ. Patients were then serially administered the RPSQ for 3 months after the concussion or until all symptoms resolved.

RESULTS

A total of 280 patients were enrolled over 12 months. Patients with a history of previous concussion had a longer duration of symptoms than those without previous concussion (24 vs 12 days, P = .02). Median symptom duration was even longer for patients with multiple previous concussions (28 days, P = .03) and for those who had sustained a concussion within the previous year (35 days, P = .007) compared with patients without those risk factors. In a multivariate model, previous concussion, absence of loss of consciousness, age ≥13, and initial RPSQ score >18 were significant predictors of prolonged recovery.

CONCLUSIONS

Children with a history of a previous concussion, particularly recent or multiple concussions, are at increased risk for prolonged symptoms after concussion. These findings have direct implications on the management of patients with concussion who are at high risk for repeat injuries.

Focusing a gender lens on emergency medicine research: 2012 update

The influence of sex and gender on patient care is just being recognized in emergency medicine (EM). Providers are realizing the need to improve outcomes for both men and women by incorporating sex- and gender-specific science into clinical practice, while EM researchers are now beginning to study novel sex- and gender-specific perspectives in the areas of acute care research. This article serves as an update on the sex differences in a variety of acute clinical care topics within the field of EM and showcases opportunities for improving patient care outcomes and expanding research to advance the science of gender-specific emergency care.

Are there cognitive and neurobehavioural correlates of hormonal neuroprotection for women after TBI?

This study examined possible cognitive correlates of hormonal neuroprotection following traumatic brain injury (TBI) using archival neuropsychological findings for 1563 individuals undergoing acute TBI rehabilitation between 1989 and 2002. Presumed age of menopause was based on the STRAW (Stages of Reproductive Aging) staging system (Soules, 2005; Soules et al., 2001) and general linear model (GLM) analysis of performance on neuropsychological testing by participants across gender and age groups (25-34, 35-44, 45-54, and 55-64) was performed. Hypotheses were (1) women with TBI in the oldest age group would have lower scores on neuropsychological tests and functional outcome measures than women in the younger groups, and (2) men in the oldest age group would have higher scores than women of the same age group. Analyses revealed that oldest females had significantly worse Trails B and SDMT written and oral scores than the youngest females. In addition, oldest females had significantly better Trails B, Rey AVLT and SDMT written scores than the oldest males. Possible cohort exposure to hormone replacement therapy, unknown hormonal status at time of testing, and sample-specific injury characteristics may have contributed to these findings.

Evaluation and management of mild traumatic brain injury: an Eastern Association for the Surgery of Trauma practice management guideline

BACKGROUND

An estimated 1.1 million people sustain a mild traumatic brain injury (MTBI) annually in the United States. The natural history of MTBI remains poorly characterized, and its optimal clinical management is unclear. The Eastern Association for the Surgery of Trauma had previously published a set of practice management guidelines for MTBI in 2001. The purpose of this review was to update these guidelines to reflect the literature published since that time.

METHODS

The PubMed and Cochrane Library databases were searched for articles related to MTBI published between 1998 and 2011. Selected older references were also examined.

RESULTS

A total of 112 articles were reviewed and used to construct a series of recommendations.

CONCLUSION

The previous recommendation that brain computed tomographic (CT) should be performed on patients that present acutely with suspected brain trauma remains unchanged. A number of additional recommendations were added. Standardized criteria that may be used to determine which patients receive a brain CT in resource-limited environments are described. Patients with an MTBI and negative brain CT result may be discharged from the emergency department if they have no other injuries or issues requiring admission. Patients taking warfarin who present with an MTBI should have their international normalized ratio (INR) level determined, and those with supratherapeutic INR values should be admitted for observation. Deficits in cognition and memory usually resolve within 1 month but may persist for longer periods in 20% to 40% of cases. Routine use of magnetic resonance imaging, positron emission tomography, nuclear magnetic resonance, or biochemical markers for the clinical management of MTBI is not supported at the present time.

Sport-related concussion: "how many is too many?"

The long-term effects of multiple sport-related concussions are currently at the center of debate in the popular press and scientific community. The question, "How many concussions are too many," is frequently asked in the competitive sport environment by parents, athletes, and coaches. While research suggests that a history of concussion influences the risk and recovery from subsequent concussion, studies investigating the long-term effects of multiple concussions are less conclusive. This paper reviews the literature on multiple concussions and the potential long-term consequences of these injuries. Furthermore, this paper addresses how concussion history can inform clinical and return-to-play decisions. Recent studies incorporating novel brain imaging and electrophysiological technology for assessing residual impairment from multiple concussions are reviewed and the clinical implications of this work are discussed.

The management of sport-related concussion: considerations for male and female athletes

Sport-related concussion continues to be a centerpiece of attention in the field of sports medicine. The benefit to using neurocognitive testing when managing concussion will be documented in this review. In addition to providing critical objective information on the neurocognitive status of the concussed athlete, research data will be provided on the pre- and post-concussion neurocognitive profiles of concussed male and female athletes. Specifically, an overview of research will be presented on the epidemiology of male and female concussion rates, as well as concussion outcomes including symptoms and cognitive function post-injury. Finally, a clinician's perspective on managing sports-related concussion will be presented focusing on three factors regarding sex differences: risk factors, clinical presentation, and management.

Sport as Laboratory: Lessons Learned From Baseline and Postconcussion Assessment Research

Knowledge and awareness of sport concussion has been forwarded by research modeled on the neuropsychological testing paradigm associated with Barth’s “sport as laboratory” assessment model. The purpose of this paper is to elucidate lessons learned from that research. Key considerations for planning and implementing large-scale studies of concussion in sport while making adequate provision for the clinical needs of concussed athletes are reviewed. Toward that end, logistical, methodological, and ethical considerations are discussed within the context of research conducted in a university setting. Topics addressed include culture of sport and risk; research planning and design; communication with strategic partners; defining injury; choosing a test battery; data management, outcomes, and analyses; dissemination of results; and finally, clinical and ethical implications that may arise during the research enterprise. The paper concludes with a summary of the main lessons learned and directions for future research.

Response to acute concussive injury in soccer players: is gender a modifying factor?

OBJECT

Several studies have suggested a gender difference in response to sports-related concussion (SRC). The Concussion in Sport group did not include gender as a modifying factor in SRC, concluding that the evidence at that point was equivocal. In the present study the authors endeavored to assess acute neurocognitive and symptom responses to an SRC in equivalent cohorts of male and female soccer players. The authors hypothesized that female athletes would experience greater levels of acute symptoms and neurocognitive impairment than males.

METHODS

Baseline symptom and neurocognitive scores were determined in 40 male and 40 female soccer players by using the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) scale prior to any SRC. After sustaining an SRC, each athlete completed postconcussion ImPACT tests and was carefully matched on a wide array of biopsychosocial variables. Baseline symptom and neurocognitive test scores were compared, and their acute symptoms and neurocognitive responses to concussive injury were assessed.

RESULTS

Specific a priori hypotheses about differences between males and females at baseline and at postconcussion measurements of verbal and visual memory ImPACT scores were evaluated according to simple main effects of the gender variable and according to baseline-to-postconcussion main effect and interaction of 2 × 2 split-plot ANOVA. Neither the interaction nor the main effects nor the simple main effects for either ImPACT variable were found to be statistically significant. Exploratory ANOVAs applied to the remaining ImPACT variables of visualmotor speed, reaction time, impulse control, and symptom total scores revealed only a single statistically significant baseline-to-postconcussion main effect for the symptom total.

CONCLUSIONS

The results failed to replicate prior findings of gender-specific baseline neurocognitive differences in verbal and visual memory. The findings also indicated no differential gender-based acute response to concussion (symptoms or neurocognitive scores) among high school soccer players. The implications of these findings for the inclusion of gender as a modifying factor in this tightly matched cohort are addressed. Potential explanations for the null findings are discussed.

Subacute concussion-related symptoms and postconcussion syndrome in pediatrics

PURPOSE OF REVIEW

Millions of youth sustain concussion each year; although most fully recover following an isolated concussion, a significant minority develop prolonged symptoms and disability following concussion. This article reviews recent data regarding the epidemiology of postconcussion syndrome (PCS) and recommendations for the evaluation and management of postconcussive symptoms in pediatrics.

RECENT FINDINGS

PCS is a constellation of symptoms related to head injury including somatic symptoms, sleep dysregulation, cognitive deficits and emotional disturbance. Postconcussive symptoms affect 1.5-11% of concussed youth for more than 1 month after injury, depending on the population studied. Girls have a higher risk of postconcussive headache but it is not clear if cognitive recovery differs between the sexes. Advanced neuroimaging techniques demonstrate a correlation between postconcussive symptoms and functional neurological changes. However, pre-existing and psychosocial factors also affect risk for prolonged PCS. Current treatment strategies are based mainly on expert opinion and studies of related syndromes.

SUMMARY

Although a minority of concussed youth develop prolonged PCS, those who are affected can develop significant disability. Prolonged postconcussive symptoms are likely due to interactions between the biological injury, pre-existing risk factors and psychosocial issues. Further research is essential to improve outcomes for this vulnerable population.