Traumatic brain injury (TBI) is a condition that occurs commonly in children from infancy through adolescence and is a global health concern. Pediatric TBI presents with a bimodal age distribution, with very young children (0-4 years) and adolescents (15-19 years) more commonly injured. Because children\'s brains are still developing, there is increased vulnerability to the effects of head trauma, which results in entirely different patterns of injury than in adults. Pediatric TBI has a profound and lasting impact on a child\'s development and quality of life, resulting in long-lasting consequences to physical, cognitive, and emotional development. Chronic issues like learning disabilities, behavioral problems, and emotional disturbances can develop. Early intervention and ongoing support are critical for minimizing these long-term deficits. Many animal models of TBI exist, and each varies significantly, displaying different characteristics of clinical TBI. The neurodevelopment differs in the rodent from the human in timing and effect, so TBI outcomes in the juvenile rodent can thus vary from the human child. The current review compares findings from preclinical TBI work in juvenile and adult rodents to clinical TBI research in pediatric and adult humans. We focus on the four brain regions most affected by TBI: the prefrontal cortex, corpus callosum, hippocampus, and hypothalamus. Each has its unique developmental projections and thus is impacted by TBI differently. This review aims to compare the healthy neurodevelopment of these four brain regions in humans to the developmental processes in rodents.

Objective: This study investigated influence of biological sex on postconcussive symptoms (PCS) following concussion using the Federal Interagency Traumatic Brain Injury Research (FITBIR) database. Method: All studies with publicly released data as of 4/7/21 that included both males and females, enough information to determine severity of injury consistent with concussion, a measure of PCS, and objective measures of neurocognitive functioning were used. This resulted in 6 studies with a total of 9890 participants (3206 females, 6684 males); 815 participants completed the Neurobehavioral Symptom Inventory (NSI), 471 completed the Rivermead Post-Concussion Symptoms Questionnaire (RPSQ), and 8604 completed the Sport Concussion Assessment Tool-3rd Edition (SCAT 3). Questionnaires were harmonized and the following symptom composite scores were computed: total score, somatic, cognitive, and affective. Data were analyzed using linear mixed-effects models. Results: Females endorsed higher total symptoms relative to males and that military personnel endorsed higher symptoms relative to civilians. Additionally, there was a small but significant interaction effect, such that female military personnel endorsed even higher symptoms than would be predicted by the main effects. Similar patterns were observed for somatic, cognitive, and affective symptom domains. Conclusions: Further understanding sex differences in PCS reporting is key to informing the most appropriate treatment options. Future work will need to examine whether sex differences in symptom reporting is due to sex differences in endorsement styles or genuine differences in symptom presentation, as well as the relationship between study population (e.g., military, civilian, sport) and sex on objective cognitive functioning and other functional outcomes.

OBJECTIVE: Prior studies have investigated associations between gender, symptom resolution, and time to return to play following sport-related concussion (SRC). However, there is a notable gap in research regarding the association between gender and return to learn (RTL) in adolescents. Therefore, this study 1) compared the patterns of RTL between boys and girls who are high school student athletes, and 2) evaluated the possible association between gender and time to RTL after adjusting for covariates.
METHODS: A retrospective cohort study of a prospective surveillance program that monitored concussion recovery of athletes in high schools throughout the state of Maine between February 2015 and January 2023 was performed. The primary independent variable was gender, dichotomized as boys and girls. The primary outcome was time to RTL, defined by the number of days for an athlete to return to school without accommodations. Mann-Whitney U-tests were used to compare RTL between the boys and girls. Each athlete\'s RTL status was dichotomized (i.e., returned vs had not returned) at several time points following injury (i.e., 1, 2, 3, and 4 weeks), and chi-square tests were performed to compare the proportions who achieved RTL between groups. Multivariable linear regression analyses were performed to evaluate the predictive value of gender on RTL. Covariates included age, number of previous concussions, history of learning disability or attention-deficit disorder or attention-deficit/hyperactivity disorder, history of a psychological condition, history of headaches or migraines, initial Sport Concussion Assessment Tool (SCAT3/SCAT5) score, and days to evaluation.
RESULTS: Of 895 high school athletes, 488 (54.5%) were boys and 407 (45.5%) were girls. There was no statistically significant difference in median [IQR] days to RTL between genders (6.0 [3.0-11.0] vs 6.0 [3.0-12.0] days; U = 84,365.00, p < 0.375). A greater proportion of boys successfully returned to learn without accommodations by 3 weeks following concussion (93.5% vs 89.4%; χ2 = 4.68, p = 0.030), but no differences were found at 1, 2, or 4 weeks. A multivariable model predicting days to RTL showed that gender was not a significant predictor of RTL (p > 0.05). Longer days to evaluation (β = 0.10, p = 0.021) and higher initial SCAT3/SCAT5 scores (β = 0.15, p < 0.001) predicted longer RTL.
CONCLUSIONS: In a cohort of high school athletes, RTL did not differ between boys and girls following SRC. Gender was not a significant predictor of RTL. Longer days to evaluation and higher initial symptom scores were associated with longer RTL.

OBJECTIVE: Postconcussive symptom questionnaires (PCSQs) are often used in concussion patient assessment, yet there is a lack of knowledge as to whether symptom subtype prevalence is dependent on the mechanism of injury (MOI). These subtypes can be defined as cognitive, atlanto-occipital/cervical spine, autonomic, balance, low energy/fatigue/sleep, emotional changes, eyes, and somatic. Using an institutional PCSQ that quantitatively addressed these subtypes, this retrospective study aimed to provide insight into differences in subtype symptomatology between sports-related (SR) and non-sports-related (NSR) injuries.
METHODS: Consecutive concussion patients with Glasgow Coma Scale (GCS) score ≥ 13 and ≥ 16 years of age who were treated at a concussion clinic affiliated with an academic level I trauma center in the United States between December 2009 and January 2020 were eligible for inclusion. The authors extracted data on MOI, comorbidities, habits, prior injuries, and PCSQ results. Multivariate analysis of covariance was then conducted to determine the correlations between subtype scores and MOI while considering covariates.
RESULTS: Of the 194 patients remaining after applying inclusion and exclusion criteria, analysis included 91 patients in the SR group consisting of 54 (59%) males with mean ± SD (range) age of 20.9 ± 7.3 (16-58) years and 103 patients in the NSR group consisting of 38 (37%) males with mean age of 39.2 ± 14.8 (17-71) years. Demographic characteristics differed significantly between groups. Estimated marginal mean scores were significantly lower in the SR injury group compared to the NSR injury group (with comparing main effects) for the cognitive (p < 0.001), autonomic (p < 0.000), balance (p < 0.025), energy (p < 0.006), emotional (p < 0.000), and total score (p < 0.001) subtypes. Multivariate tests identified three comorbidities that contributed to differences in subtype scores between groups: migraines (p < 0.012), vertigo (p < 0.004), and anxiety (p < 0.038). No significant results were found for the remaining comorbidities of (but not limited to) depression, neuropsychiatric disorders, seizures, syncope, sleep disorder, or none.
CONCLUSIONS: The findings indicate that patients who sustain a concussion via an NSR injury present with more severe symptoms but similar concussion subtype frequency as those presenting with SR concussion. This suggests that the MOI may correlate more closely to symptom severity than concussion subtype composition, although larger patient populations with more definitive control of MOI are needed to further elucidate these claims.

The history behind the biological, mechanistic, and clinical insights into concussion provides awareness of the current understanding and future areas for study. Although the initial description of concussion appeared in the 10th century, the potential long-term structural consequences were first defined by Harrison Martland, M.D., who performed a postmortem study of former boxers in 1928. He found evidence of perivascular microhemorrhage that he believed eventually evolved into a \"replacement gliosis\" underlying a clinical syndrome that he named \"punch drunk,\" which was characterized by acute confusion with chronic cognitive and physical symptoms developing in those with prolonged exposure. Further research into the potential long-term consequences of repetitive concussions, particularly in athletics and the military, led to an understanding of chronic traumatic encephalopathy. To ameliorate possible long-term risks, research has been focused on preventative and therapeutic measures for concussion. In this review article, the authors present the history of concussion and the long-term sequelae of repeated head injury. Specifically, they consider how the understanding of concussion has evolved from antiquity into the modern era, and how this change in understanding of head injury has led to an appreciation of the fact that its long-term implications sometimes manifest as the clinical and histopathological entity of chronic traumatic encephalopathy.

OBJECTIVE: This study aimed to determine the validity of quantitative pupillometry to predict the length of time for return to full activity/duty after a mild traumatic brain injury (mTBI) in a cohort of injured cadets at West Point.
METHODS: Each subject received baseline (T0) quantitative pupillometry, in addition to evaluation with the Balance Error Scoring System (BESS), Standardized Assessment of Concussion (SAC), and Sport Concussion Assessment Tool 5th Edition Symptom Survey (SCAT5). Repeat assessments using the same parameters were conducted within 48 hours of injury (T1), at the beginning of progressive return to activity (T2), and at the completion of progressive return to activity protocols (T3). Pupillary metrics were compared on the basis of length of time to return to full play/duty and the clinical scores.
RESULTS: The authors\' statistical analyses found correlations between pupillometry measures at T1, including end-initial diameter and maximum constriction velocity, with larger change and faster constriction predicting earlier return to play. There was also an association with maximum constriction velocity at baseline (T0), predicting faster return to play.
CONCLUSIONS: The authors conclude that that pupillometry may be a valuable tool for assessing time to return to duty from mTBI by providing a measure of baseline resiliency to mTBI and/or autonomic dysfunction in the acute phase after mTBI.

OBJECTIVE: Epidemiology provides fundamental opportunities to protect student-athlete health. The goal of this study was to describe the epidemiology of sport-related concussion (SRC) across 8 years (2015/2016-2022/2023) and compare boys\' and girls\' sports for SRC incidence and SRC mechanisms.
METHODS: This was a retrospective cohort study performed using a statewide high school head injury surveillance system of high school student-athletes (n = 2,182,128; boys, n = 1,267,389; girls, n = 914,739). Exposures of interest included study year and boys and girls in comparable sports. Clinical incidence was calculated by dividing SRC counts in each sport by the number of participants per 100 player-seasons and presented with 95% CIs. The 2019/2020 and 2020/2021 data were included in the analysis, however caution is warranted due to the COVID-19 pandemic. Clinical incidence ratios (CIRs) were estimated for sex-comparable sports, and significance was determined if 95% CIs excluded 1.00. The authors compared mechanism of injury in boys\' and girls\' comparable sports with chi-square analyses (p < 0.05).
RESULTS: Among 25,482 total SRCs, the overall clinical incidence of SRC for all boys and girls was 1.17 (95% CI 1.15-1.18) per 100 player-seasons across all years. Across all years, the overall clinical incidence in boys\' sports was 1.34 (95% CI 1.32-1.36) per 100 player-seasons, and 0.93 (95% CI 0.91-0.95) per 100 player-seasons in girls\' sports. Boys\' sports with the highest clinical incidence included football, ice hockey, and wrestling. Girls\' sports with the highest clinical incidence included basketball, soccer, lacrosse, competitive cheer, and gymnastics. Girls consistently had higher SRC rates relative to boys for baseball/softball, basketball, and soccer (CIR range 1.65 [95% CI 1.41-1.93] to 3.32 [95% CI 2.67-4.16]). Girls had lower SRC in lacrosse in 2015/2016 (CIR 0.63, 95% CI 0.40-0.97); no difference in 2016/2017-2020/2021, but had higher clinical incidence in 2021/2022 (CIR 1.69, 95% CI 1.18-2.44) relative to boys. In boys the most common mechanism of SRC occurred from person-to-person contact (n = 8752, 62.8%), whereas girls commonly sustained SRC from person-to-object contact (n = 2369, 33.4%) and from person-to-person contact (n = 2368, 33.4%). There were significant associations between boys\' versus girls\' sports and mechanism of injury within baseball/softball (χ2 = 12.71, p = 0.005); basketball (χ2 = 36.47, p < 0.001); lacrosse (χ2 = 185.15, p < 0.001); and soccer (χ2 = 122.70, p < 0.001).
CONCLUSIONS: These findings can help understand the potential impact of interventions aimed at preventing or reducing SRC. Including girls\' sports within this study extends research for a largely underrepresented group.

OBJECTIVE: The aim of this study was to compare injury circumstances, characteristics, and clinical management of emergency department (ED) presentations for sports-related concussion (SRC) and non-SRC.
METHODS: This multicenter prospective observational study identified patients 5-17 years old who presented to EDs within 24 hours of head injury, with one or more signs or symptoms of concussion. Participants had a Glasgow Coma Scale score of 13-15 and no abnormalities on CT (if performed). Data were stratified by age: young children (5-8 years), older children (9-12 years), and adolescents (13-17 years).
RESULTS: Of 4709 patients meeting the concussion criteria, non-SRC accounted for 56.3% of overall concussions, including 80.9% of younger child, 51.1% of older child, and 37.0% of adolescent concussions. The most common mechanism of non-SRC was falls for all ages. The most common activity accounting for SRC was bike riding for younger children, and rugby for older children and adolescents. Concussions occurring in sports areas, home, and educational settings accounted for 26.2%, 21.8%, and 19.0% of overall concussions. Concussions occurring in a sports area increased with age, while occurrences in home and educational settings decreased with age. The presence of amnesia significantly differed for SRC and non-SRC for all age groups, while vomiting and disorientation differed for older children and adolescents. Adolescents with non-SRC were admitted to a ward and underwent CT at higher proportions than those with SRC.
CONCLUSIONS: Non-SRC more commonly presented to EDs overall, with SRC more common with increasing age. These data provide important information to inform public health policies, guidelines, and prevention efforts.

OBJECTIVE: Concussions are self-limited forms of mild traumatic brain injury (TBI). Gradual return to play (RTP) is crucial to minimizing the risk of second impact syndrome. Online patient educational materials (OPEM) are often used to guide decision-making. Previous literature has reported that grade-level readability of OPEM is higher than recommended by the American Medical Association and the National Institutes of Health. The authors evaluated the readability of OPEM on concussion and RTP.
METHODS: An online search engine was used to identify websites providing OPEM on concussion and RTP. Text specific to concussion and RTP was extracted from each website and readability was assessed using the following six standardized indices: Flesch Reading Ease (FRE), Flesch-Kincaid Grade Level, Gunning Fog Index, Coleman-Liau Index, Simple Measure of Gobbledygook Index, and Automated Readability Index. One-way ANOVA and Tukey\'s post hoc test were used to compare readability across sources of information.
RESULTS: There were 59 concussion and RTP articles, and readability levels exceeded the recommended 6th grade level, irrespective of the source of information. Academic institutions published OPEM at simpler readability levels (higher FRE scores). Private organizations published OPEM at more complex (higher) grade-level readability levels in comparison with academic and nonprofit institutions (p < 0.05).
CONCLUSIONS: The readability of OPEM on RTP after concussions exceeds the literacy of the average American. There is a critical need to modify the concussion and RTP OPEM to improve comprehension by a broad audience.

UNASSIGNED: Concussions are a common condition in athletes leading to symptoms including headache, dizziness, and sometimes vestibular deficits. Concussion management typically involves rest and a gradual return to activity among other interventions. This case series includes three patients who were evaluated using Mechanical Diagnosis and Therapy (MDT) after sport-related injuries involving concussion-like symptoms. MDT is a system of evaluating patients using repeated movements and sustained positions to assess symptomatic and mechanical changes.
UNASSIGNED: Patients in this case series demonstrated rapid reduction of symptoms using variations of repeated cervical movements and sustained positions, which enabled them to return to play with a lasting resolution of symptoms.
UNASSIGNED: This highlights the importance of a classification system for the appropriate treatment of these cases who did not require management using concussion protocol, as they were classified as cervical derangement.