Long-term consequences: effects on normal development profile after concussion

Ability of Head Impact Measurements to Predict Sports Concussions: A Review

BACKGROUND AND OBJECTIVES

Provide a review of the current landscape of motion sensor-based analyses of mild traumatic brain injury (concussion) and shed light on avenues for further investigation.

METHODS

A review of the literature on motion sensor-based concussion studies was conducted using search terms "concussion prediction sensor," "concussion prediction motion," "concussion diagnosis sensor," and "concussion diagnosis motion" in PubMed (between January 2000 and March 2024). In total, 207 publications were initially identified. However, only 14 studies were ultimately included, due to lack of requisite measurement variables, focus on different outcomes, or participant overlap with included studies. Consolidation of mean and standard deviation of measurement variables was performed using the application of Cochrane formula.

RESULTS

Across 14 studies, most used head impact data from football (85.7%) and the Head Impact Telemetry system for data acquisition (92.9%). Most of the studies used data sets from collegiate athletes (71.4%). A minority of studies included female athletes (14.3%). On average, male athletes experienced higher linear and rotational accelerations during concussive vs nonconcussive impacts (97.6 ± 33.8 g and 4614.9 ± 2568.7 rad/s2 vs 24.4 ± 16.2 g and 1641.9 ± 1216.6 rad/s2). Moreover, male athletes experienced higher linear accelerations, but similar rotational accelerations, compared with female athletes specifically during concussive impacts (97.6 ± 33.8 g and 4614.9 ± 2568.7 rad/s2 vs 43.0 ± 11.5 g and 4030 ± 1435 rad/s2). Notably, studies that predicted concussion probability using multivariate regression methods (26.7%) demonstrated challenges with accuracy due to low positive predictive values (ranging from 0.3%-0.9%) and high false-positive rates (up to 39.4%).

CONCLUSION

Despite the statistical differences in head impact measurements between concussive and nonconcussive impacts, they have limited clinical utility as a stand-alone concussion identification tool. Head impact measurements may be most useful when used as an adjunct to other clinical and physiological markers.

Association Between Follow-Up Visit Timing After A Concussion and Subsequent Care Seeking in Children and Youth: A Population-Based Study in British Columbia

OBJECTIVE

To assess the relationship between follow-up visit timing and occurrence of the first subsequent health care seeking visit.

SETTING

The province of British Columbia, Canada.

PARTICIPANTS

A total of 21 029 children and youth who were diagnosed with an initial concussion from January 1, 2016, to December 31, 2017. These data were obtained from Population Data BC.

DESIGN

A retrospective, descriptive correlational study.

MAIN MEASURES

Follow-up timing was measured categorically as timely (4 weeks), delayed (1-3 months), or no follow-up; the occurrence of a subsequent health care visit beyond 3 months postinjury was measured up to 12 months at 3-month intervals (ie, 4-6, 7-9, and 10-12 months). These variables were measured using diagnostic codes for concussion, post-concussion syndrome, and the 17 concussion symptoms.

RESULTS

After controlling for sociodemographic characteristics, having a delayed follow-up, relative to timely follow-up, was associated with higher odds of a subsequent health care seeking visit at 4 to 6 months (odds ratio [OR] = 2.68; confidence interval [CI], 2.08-3.47), 7 to 9 months (OR = 1.71; CI, 1.21-2.40), and 10 to 12 months (OR = 1.67; CI, 1.13-2.48). In contrast to having a delayed follow-up, having no follow-up, relative to timely follow-up, was associated with not having a subsequent health care seeking visit at 4 to 6 months (OR = 0.57; CI, 0.48-0.67) and 7 to 9 months (OR = 0.79; CI, 0.66-0.96), respectively.

CONCLUSIONS

Follow-up visit timing after a concussion in children and youth is associated with subsequent health care seeking. Greater efforts are needed to investigate the importance of initial follow-up visit timing, as they may play an integral role in injury prevention and symptom management following injury.

The Incidence of Sports-Related Concussion in Children and Adolescents: A Systematic Review and Meta-Analysis

BACKGROUND

Sport-related concussions (SRC) are a concern for young athletes due to the potential for long-term health problems. This systematic review and meta-analysis aimed to provide a comprehensive overview of the literature exploring SRC incidence in youth sports to understand the associated risks.

METHODS

Medline, Embase, SPORTDiscus, PsycINFO, and Web of Science databases were searched without language restrictions up to September 2024. Studies were included if they (i) reported data for calculation of SRC incidence, (ii) were a prospective cohort study, and (iii) included a sample aged ≤ 18 years. Studies that reported Athlete Exposure (AE) or Player Hours (PH) as SRC incidence data measures were included in a multi-level random-effects meta-analysis. Additional analysis explored SRC incidence based on age, sex, country, year of data collection, setting, and level of contact.

RESULTS

Of the 6474 studies reviewed for eligibility, 116 studies were accepted for a systematic review and 99 in the meta-analysis. A total of 3,025,911 participants were included in the review (59% male, 41% female); however, 41% of studies did not report sample size. The pooled incidence rate of SRC per 1000 AE was found to be 1.41 across 21 sports, and 4.36 per 1000 PH across 7 sports. The highest incidence per 1000 AE were in taekwondo, rugby union, and ice hockey, and the highest incidence per 1000 PH were in rugby 7s, rugby league, and rugby union.

CONCLUSIONS

This systematic review and meta-analysis can serve as an updated baseline for risk of concussion among youth athletes across various sports.

TRIAL REGISTRATION

This systematic review was registered on OSF Registries ( https://osf.io/v298s ).

Animal Models of Traumatic Brain Injury and Their Relevance in Clinical Settings

BACKGROUND

Traumatic brain injury (TBI) is a significant concern that often goes overlooked, resulting from various factors such as traffic accidents, violence, military services, and medical conditions. It is a major health issue affecting people of all age groups across the world, causing significant morbidity and mortality. TBI is a highly intricate disease process that causes both structural damage and functional deficits. These effects result from a combination of primary and secondary injury mechanisms. It is responsible for causing a range of negative effects, such as impairments in cognitive function, changes in social and behavioural patterns, difficulties with motor skills, feelings of anxiety, and symptoms of depression.

METHODS

TBI associated various animal models were reviewed in databases including PubMed, Web of Science, and Google scholar etc. The current study provides a comprehensive overview of commonly utilized animal models for TBI and examines their potential usefulness in a clinical context.

RESULTS

Despite the notable advancements in TBI outcomes over the past two decades, there remain challenges in evaluating, treating, and addressing the long-term effects and prevention of this condition. Utilizing experimental animal models is crucial for gaining insight into the development and progression of TBI, as it allows us to examine the biochemical impacts of TBI on brain mechanisms.

CONCLUSION

This exploration can assist scientists in unraveling the intricate mechanisms involved in TBI and ultimately contribute to the advancement of successful treatments and interventions aimed at enhancing outcomes for TBI patients.

Variability in youth coach concussion education requirements across states

BACKGROUND

Youth sports coaches play a critical role in proper concussion recognition and management, reinforcing the need for coach concussion education. As of 2021, most states have statutory and policy measures mandating concussion education for coaches. In practice, these mandates have been enacted through state legislatures and their respective youth sport governing bodies. Prior studies have found significant variations in the contents of state-level concussion risk reduction policies and have raised questions about their specificity.

OBJECTIVE

To expand on previous analyses to provide an overview of youth sports coach concussion education, highlighting variations in state policies and discrepancies between state mandates and youth sport governing bodies.

METHODS

This report utilized qualitative content analysis to characterize and compare U.S. state and governing body concussion education requirements for youth sport coaches. State concussion statutes were identified via the National Conference of State Legislatures and Open States databases, and governing body handbooks/bylaws were obtained via their websites. Two researchers independently coded the policies, and discrepancies were resolved through consensus meetings with additional youth traumatic brain injury experts.

RESULTS

We found significant variability in educational requirements and their implementation. A majority (68%; n = 34) of states require the completion of concussion education training for coaches. Notably, many states designate responsibility for enforcement and implementation of provisions to another party but just four state statutes delineate explicit consequences for noncompliance. Additionally, only 12 state statutes extend mandates to noninterscholastic sports, limiting their reach. In most cases, independent sanctioning authorities implement more stringent policies than the minimum acceptable standard established by state law.

CONCLUSION

Our findings provide a coded data set of youth coach concussion laws and independent sanctioning authority guidelines that can be used in future research efforts. Further research investigating a relationship between the strength of coach concussion education policies and relevant youth and adolescent concussion-related metrics is required.

Functional network disruptions in youth with concussion using the Adolescent Brain Cognitive Development study

OBJECTIVE

This study aimed to compare psychosocial outcomes and functional neuroimaging among youth with concussion, youth with anxiety, and age- and sex-matched controls.

METHODS

Using archival data from the Adolescent Brain Cognitive DevelopmentSM Study, we analyzed between-group differences in psychosocial outcomes measured by the Child Behavior Checklist's internalizing and externalizing problem scales, and assessed brain function using resting-state fMRI network-region connectivity (specifically frontoparietal network (FPN) and default mode network (DMN) connectivity with the amygdala).

RESULTS

Significant differences in psychosocial outcomes were found across all groups, with the anxiety group reporting the most internalizing problems, followed by the concussion group which significantly differed from controls. Additionally, FPN-amygdala connectivity was significantly reduced in the concussion group only; this reduced connectivity did not predict psychosocial outcomes across groups.

CONCLUSION

This study provided preliminary findings that brain connectivity is reduced exclusively in individuals with concussion. Although disruptions were observed in the concussion group, further investigation is warranted to understand how disruptions may be associated with concussion symptoms. Studies that utilize well-defined control and study groups, and comprehensive cognitive and mental health measures will offer a deeper understanding of the relationship between brain function and psychosocial outcomes.

Correlation of King-Devick Test and Helmet Impact Exposures Over a Youth Football Season

BACKGROUND

The cumulative effect of repetitive subconcussive head impacts on neurocognitive function during youth contact sports remains largely unknown. There is a paucity of literature evaluating cumulative helmet forces over a season and their correlation with preseason and postseason cognitive performance tasks such as the King-Devick test (KDT).

HYPOTHESIS

Higher helmet forces recorded throughout a 10-week, 10-game youth football season would correlate with slower performance on postseason KDT.

STUDY DESIGN

Prospective cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A cohort of 58 youth football players (ages 9-13 years) underwent pre- and postseason KDT. Players wore SpeedFlex helmets (Riddell) fitted with InSite Impact Response System helmet accelerometers (Riddell) which recorded impacts of ≥15g. Head impacts were tallied over a season and assigned a score of 1, 2, or 3 based on magnitude of g forces. Suspected concussions were correlated with KDT times and recorded instances of head impact. Pre- and postseason KDT scores were compared.

RESULTS

During the season, 2013 head impacts were recorded. Median (range) total cumulative force score was 24 (5-476); 6 players sustained head impacts concerning for concussion, and 4 were clinically diagnosed with concussions. Overall, postseason KDT times improved compared with preseason, with a median (range) change of -4.8 seconds (-7.6, -1.1). Analysis showed no correlation between changes in KDT time and total cumulative force score over the season.

CONCLUSION

KDT times in youth football players did not change significantly based on head impact exposure over a single youth football season; most players' KDT times improved from preseason to postseason.

CLINICAL RELEVANCE

Although our study did not show significant cognitive impact as measured by KDT over a single youth football season, the long-term effects of concussion on the immature brain and how it can impact cognitive development remains largely unknown and should be an area of ongoing study.

Alterations of cerebrovascular reactivity following pediatric mild traumatic brain injury are independent of neurodevelopmental changes

Cerebrovascular dysfunction following mild traumatic brain injury (mTBI) is understudied relative to other microstructural injuries, especially during neurodevelopment. The blood-oxygen level dependent response was used to investigate cerebrovascular reactivity (CVR) in response to hypercapnia following pediatric mTBI (pmTBI; ages 8-18 years), as well as pseudocontinuous arterial spin labeling to measure cerebral blood flow (CBF). Data were collected ∼1-week (N = 107) and 4 months (N = 73) post-injury. Sex- and age-matched healthy controls (HC) underwent identical examinations at comparable time points (N = 110 and N = 91). Subtle clinical and cognitive deficits existed at ∼1 week that resolved for some, but not all domains at 4 months post-injury. At both visits, pmTBI showed an increased maximal fit between end-tidal CO2 regressor and the cerebrovascular response across multiple regions (primarily fronto-temporal), as well as increased latency to maximal fit in independent regions (primarily posterior). Hypoperfusion was also noted within the bilateral cerebellum. A biphasic relationship existed between CVR amplitude and age (i.e., positive until 14.5 years, negative thereafter) in both gray and white matter, but these neurodevelopment effects did not moderate injury effects. CVR metrics were not associated with post-concussive symptoms or cognitive deficits. In conclusion, cerebrovascular dysfunction may persist for up to four months following pmTBI.

The importance of language in describing concussions: A qualitative analysis

BACKGROUND

Concussions are mild traumatic brain injuries that are often undiagnosed due to difficulties in identifying symptoms. To minimize the negative sequelae associated with undiagnosed concussion, efforts have targeted improving concussion reporting. However, knowing more about concussions does not indicate how likely an athlete is to report their concussion. Alternatively, the attitudes and beliefs of athletes and surrounding stakeholders have shown to be a better indication of whether an athlete intends to report their concussion. Prior research has shown that athletes report concussions less often when the injury is described using language that minimizes their severity, such as when it is referred to as a "ding." This study evaluated whether describing concussions using the word "brain" was associated with individuals' underlying attitudes and beliefs about the injury's severity.

OBJECTIVE

To measure the relationship between perceived concussion severity and the language used to describe concussions, specifically whether participants used the word "brain" in describing the injury.

METHODS

One-on-one semi-structured telephone interviews were conducted, and a cross sectional secondary qualitative analysis was performed to assess participants' perceived concussion severity and their use of the word "brain" to describe concussions.

DESIGN

Cross-sectional secondary qualitative analysis.

SETTING

One-on-one semistructured telephone interviews.

PARTICIPANTS

In 2017, 94 individuals involved in high school sports, including athletes, coaches, educators, parents of athletes, and athletic directors were recruited via convenience sampling.

MAIN OUTCOME MEASURES

Respondents' perceived severity of concussions.

RESULTS

Individuals who used a brain phrase to describe concussion also perceived concussions as more severe (p < .001). Specifically, those who described concussions with maximum severity had higher odds of using brain phrases than those who described concussions as having minimum (odds ratio [OR] = 0.05, 95% confidence interval [CI] = 0.002-0.299, p < .001) or moderate severity (OR = 0.24, 95% CI = 0.086-0.647, p = .003), with the most significant relationship found among coaches.

CONCLUSIONS

These findings demonstrate the relationship between medical terminology and perceived severity of concussions. This relationship may play a role in concussion reporting behavior for coaches, athletes, and parents. Education programs using similar medical terminology may promote concussion reporting behaviors.

Symptom Recovery in Children Aged 5 to 12 Years With Sport-Related and Non-Sport-Related Concussion

Importance

There is limited research on clinical features and symptom recovery from sport-related concussion (SRC) and non-SRC in younger children.

Objective

To investigate the trajectory of symptom recovery in children aged 5 to 7 years and 8 to 12 years with SRC and non-SRC at 1, 2, 4, 8, and 12 weeks postinjury.

Design, Setting, and Participants

This secondary analysis of a prospective multicenter cohort study (Predicting and Preventing Postconcussive Problems in Pediatrics) included participants aged 5 to 12 years with acute concussion who presented to 9 pediatric emergency departments within the Pediatric Emergency Research Canada network between August 2013 and June 2015. Analyses were conducted from September 2023 to May 2024.

Exposure

Participants had a concussion consistent with the Zurich consensus diagnostic criteria and 85% completeness of the Post-Concussion Symptom Inventory (PCSI) at each time point.

Main Outcomes and Measures

The primary outcome was symptom change, defined as current minus preinjury ratings 1, 2, 4, 8, and 12 weeks postinjury, measured using the PCSI. Symptoms were self-rated for children aged 8 to 12 years and child- and parent-rated for children aged 5 to 7 years. Mixed-effect models were conducted using total PCSI score adjusting for random effects; fixed-effect indicators included injury setting (SRC and non-SRC), time, injury setting × time, and other variables associated with recovery.

Results

A total of 1747 children, including 513 aged 5 to 7 years (mean [SD] age, 6.57 [0.85] years; 320 male [62.4%]) and 1234 aged 8 to 12 years (mean [SD] age, 10.68 [1.40] years; 806 male [65.3%]) were recruited, of whom 477 aged 5 to 7 years and 1157 aged 8 to 12 years were included in the analysis. Of those included in the analysis, 207 aged 5 to 7 years (43.4%; mean [SD] age, 6.68 [0.84] years; 142 male [68.6%]) and 790 aged 8 to 12 years (67.2%; mean [SD] age, 10.77 [1.40] years; 547 male [69.2%]) sustained an SRC. No significant differences in recovery curves across time postinjury were found between those with SRC and non-SRC (5-7 years: β = -0.09; 95% CI, -1.10 to 0.92; 8-12 years: β = 0.11; 95%CI, -1.50 to 1.70).

Conclusions and Relevance

In this cohort study of children aged 5 to 12 years with an acute SRC or non-SRC, symptom recovery trajectories over time were similar in both groups. This finding suggests similar management protocols can be used for sport and nonsport mechanisms of injury (excluding assault and motor vehicle crash) in the younger population.

Simultaneous Measurement of GABA, Glutathione, and Glutamate-Glutamine in the Thalamus using Edited MR Spectroscopy: Feasibility and Applications in Traumatic Brain Injury

BACKGROUND

MR spectroscopy (MRS) is a noninvasive tool for evaluating biochemical alterations, such as glutamate (Glu)/gamma-aminobutyric acid (GABA) imbalance and depletion of antioxidative glutathione (GSH) after traumatic brain injury (TBI). Thalamus, a critical and vulnerable region post-TBI, is challenging for MRS acquisitions, necessitating optimization to simultaneously measure GABA/Glu and GSH.

PURPOSE

To assess the feasibility and optimize acquisition and processing approaches for simultaneously measuring GABA, Glx (Glu + glutamine (Gln)), and GSH in the thalamus, employing Hadamard encoding and reconstruction of MEscher-GArwood (MEGA)-edited spectroscopy (HERMES).

STUDY TYPE

Prospective.

SUBJECTS

28 control subjects (age: 35.9 ± 15.1 years), and 17 mild TBI (mTBI) patients (age: 32.4 ± 11.3 years).

FIELD STRENGTH/SEQUENCE

3T/T1-weighted magnetization-prepared rapid gradient-echo (MP-RAGE), HERMES.

ASSESSMENT

We evaluated the impact of acquisition with spatial saturation bands and post-processing with spectral alignment on HERMES performance in the thalamus among controls. Within-subject variability was examined in five controls through repeated scans within a week. The HERMES spectra in the posterior cingulate cortex (PCC) of controls were used as a reference for assessing HERMES performance in a reliable target. Furthermore, we compared metabolite levels and fitting quality in the thalamus between mTBI patients and controls.

STATISTICAL TESTS

Unpaired t-tests and within-subject coefficient-of-variation (CV). A P-value <0.05 was deemed significant.

RESULTS

HERMES spectra, acquired with saturation bands and processed with spectral alignment, yielded reliable metabolite measurements in the thalamus. The mean within-subject CV for GABA, Glx, and GSH levels were 18%, 10%, and 16% in the thalamus (7%, 9%, and 16% in the PCC). GABA (3.20 ± 0.60 vs 2.51 ± 0.55, P < 0.01) and Glx (8.69 ± 1.23 vs 7.72 ± 1.19, P = 0.03) levels in the thalamus were significantly higher in mTBI patients than in controls, with GSH (1.27 ± 0.35 vs 1.22 ± 0.28, P = 0.65) levels showing no significant difference.

DATA CONCLUSION

Simultaneous measuring GABA/Glx and GSH using HERMES is feasible in the thalamus, providing valuable insight into TBI.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Visual Evoked Potential Effects on Magnocellular and Parvocellular Pathways from Athletes After Mild Traumatic Brain Injuries

Background

The objective of this study is to examine magnocellular and parvocellular pathways differentiation based on checkerboard spatial frequency stimulation between normal and visually impaired individuals from athletes with mild traumatic brain injury.

Purpose

Athletes who exhibited photophobia, and blurriness were subjected to 5 spatial frequency stimuli presented to the left and right eye, and both eyes simultaneously to determine the type of receptive field loss deprecation based on sports-related brain trauma.

Methods

Checkerboard stimulation enables the measurement between 2 visual processing pathways and enables the determination of the integrity of visual processing through visual evoked potentials (VEPs).

Conclusion

The principal results reflect P1 responses demonstrated distinct changes in amplitude from mTBI (>5 µV) from normal cohorts concluding higher P1 amplitude of the VEP in mTBI cohorts had increased after injury. Latency in P1 was not as distinct as amplitude changes. Our major conclusion is that most of the mTBI cohort exhibited receptive field loss across all the patients appears to be magnocellular process deprecation due to frequent instances of 8 × 8 and 16 × 16 spatial frequencies input as it relates to amplitude and latency output.

Return to Play Guidelines in Pediatric Concussion: A Systematic Review of Current Literature

INTRODUCTION

Pediatric concussions, particularly in youth sports, are a significant public health concern, with up to 18% of children experiencing one by age 17. Return-to-play (RTP) guidelines aim to protect athletes from the adverse effects of repeated injuries, but these protocols vary widely based on factors such as age, sport, and geography. This review synthesizes current literature on RTP guidelines for pediatric concussions to provide evidence-based recommendations.

METHODS

A systematic search of PubMed was conducted using Medical Subject Headings (MeSH) terms "return to play," "pediatric concussion," and "mild traumatic brain injury." Studies published between January 2000 and December 2023 were included if they focused on RTP protocols for children aged 5 to 17. After screening 60 articles, 45 were selected for review. Study quality was assessed using the Newcastle-Ottawa Scale and Cochrane Risk of Bias Tool.

RESULTS

RTP protocols showed significant variability influenced by age, gender, and sport type. Common themes included initial rest followed by a gradual return to activity. Female athletes generally required longer recovery periods. Multidisciplinary care and early therapeutic interventions, such as vestibular therapy, were associated with better outcomes and faster recovery.

CONCLUSIONS

There is a need for standardized, evidence-based RTP guidelines to address inconsistencies in concussion management. Future research should focus on creating universally applicable protocols, with attention to gender, sport-specific factors, and early intervention to improve recovery outcomes for young athletes.

Role of nonpharmacological concussion management in children: systematic review of randomized controlled trials

Concussion is a global public health problem that affects many children worldwide. Most patients present with postconcussion syndrome and normal brain imaging findings. Despite the high incidence of concussion in children, published research on nonpharmacological management is lacking and much more often concerns pharmacological interventions. This systematic review aimed to evaluate the role of nonpharmacological interventions in managing concussion based on randomized controlled trials. The PubMed, Scopus, Web of Science, and Cochrane databases were extensively searched for articles published between January 2013 and July 2023. A modified patient intervention, comparison, and outcome framework was used to construct the search strategy and eligibility criteria. Risk of bias was assessed using the Risk of Bias-2 tool. A total of 16 studies conducted between January 2013 and July 2023 were analyzed. Three studies were conducted in an acute care setting (<24-hour postinjury) involving rest, computer time, and doing nothing, while the other 13 studies were conducted in a chronic care setting (>24-hour postinjury) and included aerobic exercise, collaborative care intervention, cervical spine rehabilitation, education by physiotherapists, a hyperbaric oxygen therapy protocol, family intervention therapy, virtual reality, traditional occupational therapy, virtual rehabilitation, oculomotor control exercises, vestibular rehabilitation, coordination exercises, and balance exercises. This systematic review highlights the importance of nonpharmacological therapy in pediatric concussion cases. Active rehabilitation may yield promising outcomes. Another interesting approach may be useful in pediatric concussion management. However, this systematic review shows a lack of high-quality literature supporting nonpharmacological pediatric concussion treatments.

Spontaneous Headshake after a Kinematic Event (SHAAKE): Evaluating the Utility of a Potential New Sign in the Diagnosis of Concussion

Background/Objectives: Diagnosing concussions is problematic, in part due to the invisible nature of concussion symptoms, in addition to personal and interpersonal factors that influence symptom reporting. As a result, observable signs of concussion can ensure concussions are identified and appropriately treated. Here, we define a potential novel sign, the spontaneous headshake after a kinematic event (SHAAKE) and evaluate its utility in the diagnosis of concussion. Methods: A cross-sectional survey study of 347 athletes (age 27, IQR: 25-29; 47.6% female; highest level of play: college-46.1%, high school-41.2%) identified whether SHAAKE occurred, the reasons underlying SHAAKEs, and its utility for self-reported concussion. Sensitivity and positive predictive value were calculated across all sports and these parameters, as well as estimates for specificity and negative predictive value leveraging published helmet sensor data, were calculated for football players. Results: The median number of times participants reported SHAAKE was 5 (IQR: 3-10), with 4 (IQR: 2-7) associated with a self-reported concussion. Overall, 84.9% of participants reported concussion symptoms as the most common reason for their SHAAKEs. Across all sports, SHAAKE had a sensitivity of 49.6% and positive predictive value 72.4% for diagnosing concussion. In football players, SHAAKE had a sensitivity of 52.3%, estimated specificity of 99.9%, positive predictive value of 91.9%, and estimated negative predictive value of 99.5% for diagnosing self-reported concussion. Conclusions: These results demonstrate that nearly three-quarters of athletes reported a SHAAKE associated with a self-reported concussion, which supports the potential for SHAAKE to be used as a concussion screening tool.

Associations between concussion and more severe TBIs, mild cognitive impairment, and early-onset dementia among military retirees over 40 years

Background and objectives

As the population of U.S. service members (SMs) who have sustained concussions and more severe traumatic brain injuries (TBIs) during military service ages, understanding the long-term outcomes associated with such injuries will provide critical information that may promote long-term assessment, support, and rehabilitation following military service. The objective of this research was to examine whether concussion and more severe TBIs are associated with greater risk of precursors to dementia (i.e., mild cognitive impairment, memory loss), early-onset dementia, and any dementia.

Methods

This study used a retrospective cohort design wherein archival medical and career records from 1980 to 2020 identified U.S. military personnel who retired from military service and their corresponding Tricare-reimbursable medical encounters in inpatient and/or outpatient settings in military treatment facilities and/or purchased care settings both before and after retirement. All military personnel who served on active duty between 1980 and 2020 and were at least 45 years of age by 2020 were eligible for inclusion (N = 6,092,432). Those who were discharged from military service with a retirement designation, and were thus eligible for Tricare for Life, were included in the analytic sample (N = 1,211,972). Diagnoses of concussion and more severe TBI during active duty service recorded in inpatient settings between 1980 and 2020 and in outpatient settings from 2001 to 2020 were identified. Focal outcomes of interest included memory loss, mild cognitive impairment, Alzheimer's, Lewy Body dementia, frontotemporal dementia, and vascular dementia. Dementia diagnoses before age 65 were labeled early-onset.

Results

Those with (vs. without) concussion diagnoses during military service were significantly more likely to be diagnosed with memory loss and mild cognitive impairment and any of the dementias examined. However, they were not at greater risk of being diagnosed with early-onset dementia.

Discussion

Military SMs diagnosed with concussion may be at elevated risk for long-term neurodegenerative outcomes including memory loss, mild cognitive impairment, and dementia. As the population of SMs who sustained TBI during the Global War on Terror continue to age, the prevalence of dementia will increase and may bring a unique burden to the VHA.

Assessment of the Behaviors of an In Vitro Brain Model On-Chip under Shockwave Impacts

Herein we report the assessment of the effects of shockwave (SW) impacts on adult rat hippocampal progenitor cell (AHPC) neurospheres (NSs), which are used as in vitro brain models, for enhancing our understanding of the mechanisms of traumatic brain injury (TBI). The assessment has been achieved by using culture dishes and a new microchip. The microchip allows the chemicals released from the brain models cultured inside the cell culture chamber under SW impacts to diffuse to the nanosensors in adjacent sensor chambers through built-in diffusion barriers, which are used to prevent the cells from entering the sensor chambers, thereby mitigating the biofouling issues of the sensor surface. Experiments showed the negative impact of the SW on the viability, proliferation, and differentiation of the cells within the NSs. A qPCR gene expression analysis was performed and appeared to confirm some of the immunocytochemistry (ICC) results. Finally, we demonstrated that the microchip can be used to monitor lactate dehydrogenase (LDH) released from the AHPC-NSs subjected to SW impacts. As expected, LDH levels changed when AHPC-NSs were injured by SW impacts, verifying this chip can be used for assessing the degrees of injuries to AHPC-NSs by monitoring LDH levels. Taken together, these results suggest the feasibility of using the chip to better understand the interactions between SW impacts and in vitro brain models, paving the way for potentially establishing in vitro TBI models on a chip.

Youth with Low Pre-injury Mental Health Symptoms Are at a Higher Risk for Symptoms Following Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is a growing public health concern, and it is a common injury amongst children and adolescents. Existing evidence suggests that mTBI in youth may be related to both externalizing and internalizing symptoms. However, many existing studies fail to control for pre-injury symptoms or consider the potential interaction between mTBI and pre-injury symptom levels. The current study employed data from a longitudinal sample (N = 1,803) of youth from the Project on Human Development in Chicago Neighborhoods to assess the interaction between pre-injury externalizing and internalizing symptoms and outcomes following mTBI in youth. The results showed, contrary to our expectations, that participants with lower pre-injury symptoms were at a greater risk for increased psychopathology following mTBI, compared to participants with higher pre-injury symptoms and non-injured participants. Potential explanations for the results and implications are discussed.

Lateral fluid percussion injury: A rat model of experimental traumatic brain injury

Traumatic brain injury (TBI) represents one of the leading causes of disability and death worldwide. The annual economic impact of TBI-including direct and indirect costs-is high, particularly impacting low- and middle-income countries. Despite extensive research, a comprehensive understanding of the primary and secondary TBI pathophysiology, followed by the development of promising therapeutic approaches, remains limited. These fundamental caveats in knowledge have motivated the development of various experimental models to explore the molecular mechanisms underpinning the pathogenesis of TBI. In this context, the Lateral Fluid Percussion Injury (LFPI) model produces a brain injury that mimics most of the neurological and systemic aspects observed in human TBI. Moreover, its high reproducibility makes the LFPI model one of the most widely used rodent-based TBI models. In this chapter, we provide a detailed surgical protocol of the LFPI model used to induce TBI in adult Wistar rats. We further highlight the neuroscore test as a valuable tool for the evaluation of TBI-induced sensorimotor consequences and their severity in rats. Lastly, we briefly summarize the current knowledge on the pathological aspects and functional outcomes observed in the LFPI-induced TBI model in rodents.

X as a proxy for tackle safety culture? Sentiment analysis of social media posts on red-carded and yellow-carded tackles during the 2019 Rugby World Cup

Objectives

This study analysed the overall sentiment of attitudes, opinions, views and emotions expressed in posts on X related to red-carded and yellow-carded tackles during the 2019 Rugby World Cup (RWC).

Methods

Sentiment analysis was conducted on posts on X about red or yellow cards issued at the 2019 RWC. Posts were classified as 'agree', 'disagree' and 'neutral'. The frequency of posts, red cards, yellow cards, all injuries, tackle injuries and total number of tackles per match were also synced to the 45-match playing schedule.

Results

Five tackle-related red cards were issued during the 2019 RWC, and 15 tackle-related yellow cards, with 337 and 302 posts identified for each card decision, respectively. For red cards, 42% of posts (n=158/377) agreed with the referee's decision, 19% (n=71/377) disagreed and 40% were neutral. For yellow cards, 24% (n=73/302) agreed with the referee's decision, 33% (n=99/302) disagreed and 43% were neutral.

Conclusions

For red cards, posts were 2.2 times more likely to agree with the referee's decision than disagree. Posts that agreed with a red card decision were also more likely to be shared (reposted) than posts that disagreed with a red card decision. In contrast, sentiments expressed for yellow card decisions were mixed. This may be related to interpreting the degree of danger and whether mitigation is applied. Within the ecosystem of rugby, sharing sentiments on social media plays a powerful role in creating a positive player welfare narrative.

Hard-Headed Decisions: Intrapersonal Factors Underlying Concussion Reporting in University Athletes

Most of the research investigating sports concussion (SC) disclosure has been conducted using questionnaires with a pre-determined set of questions. Hence, significant gaps remain in our understanding of which factors weight in the decision-making process underlying SC disclosure and how they contribute to it. This present study aims to fill some of these gaps using qualitative methods to identify intrapersonal determinants of SC disclosure and describe their influence on an athlete's decision-making process. Our results are based on in-depth, semistructured interviews (range, 56-79 min; total = 587 min) with 9 university athletes (5 females, 4 males) from three team sports (soccer, rugby, and cheerleading). Using constant comparative analysis guided by Straussian grounded theory, we identified 13 concepts, across three major intrapersonal categories (i.e., attitudes and behaviors; concussion knowledge; and subjective evaluation of the concussion), contributing to SC disclosure, including novel determinants such as prioritization of athletic versus intellectual activities and maturity level. Our results suggest that a comparison between experiential knowledge and severity of the injury plays a major role in determining an athlete's disclosure behaviors. Athletes with a history of concussion seem to adopt a non-disclosure default strategy and are inclined to disclose their concussion symptoms only if they judge their current concussion to be worse than their previous most severe injury. Other concepts identified appear to contribute to the decisional process by modulating the adoption of this non-disclosure default strategy. Our work highlights the benefits and necessity of using qualitative methods to study the decision-making process underlying concussion disclosure.

A review of brain regions and associated post-concussion symptoms

The human brain is an exceptionally complex organ that is comprised of billions of neurons. Therefore, when a traumatic event such as a concussion occurs, somatic, cognitive, behavioral, and sleep impairments are the common outcome. Each concussion is unique in the sense that the magnitude of biomechanical forces and the direction, rotation, and source of those forces are different for each concussive event. This helps to explain the unpredictable nature of post-concussion symptoms that can arise and resolve. The purpose of this narrative review is to connect the anatomical location, healthy function, and associated post-concussion symptoms of some major cerebral gray and white matter brain regions and the cerebellum. As a non-exhaustive description of post-concussion symptoms nor comprehensive inclusion of all brain regions, we have aimed to amalgamate the research performed for specific brain regions into a single article to clarify and enhance clinical and research concussion assessment. The current status of concussion diagnosis is highly subjective and primarily based on self-report of symptoms, so this review may be able to provide a connection between brain anatomy and the clinical presentation of concussions to enhance medical imaging assessments. By explaining anatomical relevance in terms of clinical concussion symptom presentation, an increased understanding of concussions may also be achieved to improve concussion recognition and diagnosis.

Mild traumatic brain injury as a pathological process

Traumatic brain injury (TBI) is defined as dysfunction or other evidence of brain pathology caused by external physical force. More than 69 million new cases of TBI are registered worldwide each year, 80% of them - mild TBI. Based on the physical mechanism of induced trauma, we can separate its pathophysiology into primary and secondary injuries. Many literature sources have confirmed that mechanically induced brain injury initiates ionic, metabolic, inflammatory, and neurovascular changes in the CNS, which can lead to acute, subacute, and chronic neurological consequences. Despite the global nature of the disease, its high heterogeneity, lack of a unified classification system, rapid fluctuation of epidemiological trends, and variability of long-term consequences significantly complicate research and the development of new therapeutic strategies. In this review paper, we systematize current knowledge of biomechanical and molecular mechanisms of mild TBI and provide general information on the classification and epidemiology of this complex disorder.

Return to the Emergency Department Within 3 Months Following Pediatric Acute Concussion

OBJECTIVE

To determine the proportion of concussed children returning to the emergency department (ED) for a concussion-related reason within 3 months of initial presentation and to determine which clinical composite score (5P or Post-Concussion Symptom Inventory) best predicts a return visit.

SETTING, DESIGN, AND PARTICIPANTS

We combined a secondary analysis of data from the prospectively collected 5P study with a retrospective medical record review of children aged 5 to 18 years who returned to the Children's Hospital of Eastern Ontario (CHEO) ED for a concussion-related reason within 3 months of an acutely diagnosed concussion. Among 770 eligible participants, 632 children (median age: 11.8 [interquartile range (IQR), 9.0-14.5] years; 58.9% male) were included in the study.

MAIN MEASURES

The primary outcome was the number of patients who returned to CHEO ED for a concussion-related reason within 3 months of an acute concussion diagnosed at CHEO ED. The secondary outcome was number of patients who returned within 14 days.

RESULTS

Forty-seven children (7.4%; 95% confidence interval [CI]: 5.6-9.7) had a concussion-related return to the ED within 3 months, the majority of which occurred in the first 14 days (29/47; 61.7%; 95% CI: 47.4-74.2). History of migraines (21.3% vs 9.7%; P = .03) were more common in those with a return visit. Headache was the most frequently reported symptom (87.2%) on revisit. Females aged 13 to 18 years had the highest return rate (survival rate: 85.8% [95% CI: 79.8-92.3]) compared with males and younger age groups. In multivariable Cox hazards regression modeling, inclusion of risk scores improved prognostication (pseudo R2 = 8%). The difference in pseudo R2 between 5P and Post-Concussion Symptom Inventory is small.

CONCLUSION

Most children and adolescents do not return to the ED following an acute concussion. Female youth with medium to high 5P scores at the index concussion visit may benefit from early referral to interdisciplinary specialty concussion care to guide treatment in anticipation of prolonged symptoms. By identifying these risk factors at the initial ED visit, healthcare and patient burden may be reduced.

Cranial Bone Changes Induced by Mild Traumatic Brain Injuries: A Neglected Player in Concussion Outcomes?

Mild traumatic brain injuries (TBIs), particularly when repetitive in nature, are increasingly recognized to have a range of significant negative implications for brain health. Much of the ongoing research in the field is focused on the neurological consequences of these injuries and the relationship between TBIs and long-term neurodegenerative conditions such as chronic traumatic encephalopathy and Alzheimer's disease. However, our understanding of the complex relationship between applied mechanical force at impact, brain pathophysiology, and neurological function remains incomplete. Past research has shown that mild TBIs, even below the threshold that results in cranial fracture, induce changes in cranial bone structure and morphology. These structural and physiological changes likely have implications for the transmission of mechanical force into the underlying brain parenchyma. Here, we review this evidence in the context of the current understanding of bone mechanosensitivity and the consequences of TBIs or concussions. We postulate that heterogeneity of the calvarium, including differing bone thickness attributable to past impacts, age, or individual variability, may be a modulator of outcomes after subsequent TBIs. We advocate for greater consideration of cranial responses to TBI in both experimental and computer modeling of impact biomechanics, and raise the hypothesis that calvarial bone thickness represents a novel biomarker of brain injury vulnerability post-TBI.

Mild Traumatic Brain Injury and Behavior and Sleep Among 9- and 10-Year Old Children: Initial Findings From the Adolescent Brain Cognitive Development (ABCD) Study

There has been concern about the potential sequelae of mild traumatic brain injury (mTBI) in children. This study used data from the Adolescent Brain Cognitive DevelopmentSM (ABCD) study to investigate associations between mTBI and behavior and sleep in school-aged children. Generalized additive mixed models were run to examine the association between TBI and parent-reported Child Behavior Checklist and Sleep Disturbance Scale for Children scores. mTBI with or without loss of consciousness (LOC) in 9- and 10-year old children was associated with 1) higher internalizing, externalizing and total problems and 2) greater sleep disturbance scores on the CBCL. The study also demonstrated a higher incidence of mTBI with and without LOC in boys compared to girls. This study shows a statistically significant but modest association between mTBI and behavioral and sleep changes, suggesting that in a non-clinical, sociodemographically diverse community sample of school-aged children mTBI does not result in clinically significant behavioral or psychological sequelae.

Multidimensional Frailty and Traumatic Brain Injury among Older Adults: A Literature Review

Background

Numerous health conditions in the older adult population can be attributed to falls, including traumatic brain injury (TBI), which can lead to devastating short and long-term sequelae. Older adults are also more likely to experience frailty, which encompasses physical, psychological, and social deficits that may lead to adverse health outcomes. Our literature review synthesizes current evidence for understanding frailty in the context of TBI among older adults using the Integral Model of Frailty as a framework.

Content Synthesis

A total of 32 articles were identified, and 9 articles were included. The results of this review indicate that outcomes resulting from TBI are closely linked to the physical, psychological, and social domains of frailty.

Conclusions

A small amount of literature currently examines frailty in the context of TBI among older adults. Using the Integral Model of Frailty to understand frailty in the context of TBI can help clinicians anticipate patient outcomes and improve care plans. We emphasize the need for a greater understanding of TBI concerning frailty to improve health outcomes among older adult patients.

Measuring anxiety-like behavior in a mouse model of mTBI: Assessment in standard and home cage assays

Traumatic brain injury (TBI) is a primary global health concern and one of the most common causes of neurological impairments in people under 50. Mild TBI (mTBI) accounts for the majority of TBI cases. Anxiety is the most common complaint after mTBI in humans. This study aims to evaluate behavioral tests designed to assess anxiety-like phenotypes in a mice model of mTBI. ICR mice underwent mTBI using the weight-drop model. Seven days post-injury, mice were subjected to one of five different behavioral tests: Elevated Plus Maze (EPM), Open Field apparatus (OF), Marble Burying test (MBT), Light Dark Box (LDB), and the Light Spot test within the PhenoTyper home cage (LS). In the EPM and OF tests, there were no significant differences between the groups. During the 30-min test period of the MBT, mTBI mice buried significantly more marbles than control mice. In the LDB, mTBI mice spent significantly less time on the far side of the arena than control mice. In addition, the time it took for mTBI mice to get to the far side of the arena was significantly longer compared to controls. Results of LS show significant within-group mean differences for total distance traveled for mTBI mice but not for the control. Furthermore, injured mice moved significantly more than control mice. According to the results, the anxiety traits exhibited by mTBI mice depend upon the time of exposure to the aversive stimulus, the apparatus, and the properties of the stressors used. Therefore, the characterization of anxiety-like behavior in mTBI mice is more complicated than was initially suggested. Based on our findings, we recommend incorporating a variety of stressors and test session lengths when assessing anxiety-like behavior in experimental models of mTBI.

A Pilot Investigation of Visual Pathways in Patients with Mild Traumatic Brain Injury

In this study, we examined visual processing within primary visual areas (V1) in normal and visually impaired individuals who exhibit significant visual symptomology due to sports-related mild traumatic brain injury (mTBI). Five spatial frequency stimuli were applied to the right, left and both eyes in order to assess the visual processing of patients with sports-related mild traumatic brain injuries who exhibited visual abnormalities, i.e., photophobia, blurriness, etc., and controls. The measurement of the left/right eye and binocular integration was accomplished via the quantification of the spectral power and visual event-related potentials. The principal results have shown that the power spectral density (PSD) measurements display a distinct loss in the alpha band-width range, which corresponded to more instances of medium-sized receptive field loss. Medium-size receptive field loss may correspond to parvocellular (p-cell) processing deprecation. Our major conclusion provides a new measurement, using PSD analysis to assess mTBI conditions from primary V1 areas. The statistical analysis demonstrated significant differences between the mTBI and control cohort in the Visual Evoked Potentials (VEP) amplitude responses and PSD measurements. Additionally, the PSD measurements were able to assess the improvement in the mTBI primary visual areas over time through rehabilitation.

Injuries among Canadian children and youth: an analysis using the 2019 Canadian Health Survey on Children and Youth

This work provides an overview of injury patterns in Canadian children and youth aged 1 to 17 years. Self-reported data from the 2019 Canadian Health Survey on Children and Youth were used to calculate estimates for the percentage of Canadian children and youth who experienced a head injury or concussion, broken bone or fracture, or serious cut or puncture within the last 12 months, overall and by sex and age group. Head injuries and concussions (4.0%) were the most commonly reported, but the least likely to be seen by a medical professional. Injuries most frequently occurred while engaging in sports, physical activity or playing.

Hippocampal vulnerability to hyperhomocysteinemia worsens pathological outcomes of mild traumatic brain injury in rats

Background

Mild traumatic brain injury (mTBI) generally resolves within weeks. However, 15-30% of patients present persistent pathological and neurobehavioral sequelae that negatively affect their quality of life. Hyperhomocysteinemia (HHCY) is a neurotoxic condition derived from homocysteine accumulation above 15 μM. HHCY can occur in diverse stressful situations, including those sustained by U.S. active-duty service members on the battlefield or during routine combat practice. Mild-TBI accounts for more than 80% of all TBI cases, and HHCY exists in 5-7% of the general population. We recently reported that moderate HHCY exacerbates mTBI-induced cortical injury pathophysiology, including increased oxidative stress. Several studies have demonstrated hippocampus vulnerability to oxidative stress and its downstream effects on inflammation and cell death.

Objective

This study aimed to assess the deleterious impact of HHCY on mTBI-associated hippocampal pathological changes. We tested the hypothesis that moderate HHCY aggravates mTBI-induced hippocampal pathological changes.

Methods

HHCY was induced in adult male Sprague-Dawley rats with a high methionine dose. Rats were then subjected to mTBI by controlled cortical impact under sustained HHCY. Blood plasma was assessed for homocysteine levels and brain tissue for markers of oxidative stress, blood-brain barrier integrity, and cell death. Endothelial cell ultrastructure was assessed by Electron Microscopy and working memory performance using the Y maze test.

Results

HHCY increased the hippocampal expression of nitrotyrosine in astroglial cells and decreased tight junction protein occludin levels associated with the enlargement of the endothelial cell nucleus. Furthermore, HHCY altered the expression of apoptosis-regulating proteins α-ii spectrin hydrolysis, ERK1/2, and AKT phosphorylation, mirrored by exacerbated mTBI-related hippocampal neuronal loss and working memory deficits.

Conclusion

Our findings indicate that HHCY is an epigenetic factor that modulates mTBI pathological progression in the hippocampus and represents a putative therapeutic target for mitigating such physiological stressors that increase severity.

mTBI-DSANet: A deep self-attention model for diagnosing mild traumatic brain injury using multi-level functional connectivity networks

The main approach for analyzing resting-state functional magnetic resonance imaging (rs-fMRI) is the low-order functional connectivity network (LoFCN) based on the correlation between two brain regions. Based on LoFCN, researchers recently proposed the topographical high-order FCN (tHoFCN) and the associated high-order FCN (aHoFCN) to explore the high-order interactions among brain regions. In this work, we designed a Deep Self-Attention (DSA) framework called mTBI-DSANet to diagnose mild traumatic brain injury (mTBI) using multi-level FCNs, including LoFCN, tHoFCN, and aHoFCN. The multilayer perceptron and self-attention mechanism in mTBI-DSANet were designed to capture important features for the mTBI diagnosis. We evaluated the mTBI-DSANet's performance on the real rs-fMRI dataset, which was collected by Third Xiangya Hospital of Central South University from April 2014 to February 2021. We compared the performance of mTBI-DSANet with distinct FCNs and their combinations under 10-fold cross-validation. Based on the LoFCN+aHoFCN combination, the average performance of mTBI-DSANet achieved the best accuracy of 0.834, which is significantly better than peer methods. The experiments demonstrated the potential of the mTBI-DSANet in assisting mTBI diagnosis.

Long-term effects of multiple concussions on prefrontal cortex oxygenation during neurovascular coupling activation in retired male contact sport athletes

Purpose

This study aimed to investigate the long-term effects of multiple concussions on prefrontal cortex oxygenation during a neurovascular coupling activating task using near infrared spectroscopy (NIRS).

Methods

Self-reported physically active males who previously participated in contact team sports at various levels of competition and who previously had experienced at least 3 concussions (n = 55; mTBI) or had no history of concussions (n = 29; CTRL) were recruited. Participants completed a 5 min "Where's Waldo" object identification protocol which consisted of participants closing their eyes for 20-s followed by 40-s (repeated 5 times over 5-min) of searching a computer screen for "Waldo" hidden in a field of distractors. NIRS (μM) was used to measure right and left prefrontal cortex cerebral oxygenation. Oxygenated (O2Hb), deoxygenated (HHb), total (tHb) haemoglobin, and haemoglobin difference (HbDiff) were analysed through the change in average maximal and minimal values (ΔMAX), Z-scores, and standard deviations.

Results

There were no significant differences in the relative change in cerebral oxygenation of the right prefrontal cortex between groups. In mTBI, left prefrontal cortex HHb ΔMAX (p = 0.031) and tHb ΔMAX (p = 0.044) were significantly lower than in the CTRL group. Within-group, right vs. left prefrontal cortex differences showed significantly lower values in left HbDiff Z-scores (p = 0.019) in only the mTBI group while the CTRL group showed significantly lower values in left HbDiff SD (p = 0.045).

Conclusion

This preliminary study suggests that there are changes in prefrontal cortex oxygenation in males who had a history of experiencing multiple concussions in their past during a neurovascular coupling activating task. These changes may represent potential long-term effects in the brain's ability to adapt cerebral oxygenation during increased neural activity.

History of traumatic brain injury in relation to cognitive functioning, memory complaints and brain structure in mid-life

In this study, we investigated history of traumatic brain injury with loss of consciousness in relation to cognitive functioning, subjective memory complaints and brain structure in mid-life. This study included 2,005 participants (mean age: 47.6 years, standard deviation: 5.0, women: 65%) from the ORACLE study between 2017-2020. History of traumatic brain injury was defined as at least one life-time self-reported head injury with loss of consciousness. Associations of history of traumatic brain injury with (1) cognitive functioning (measured with the 15-Word learning test, Stroop task, Letter-digit substitution test, Word fluency test, Purdue pegboard test, and Design organization test) (2) current subjective memory complaints (present/absent, measured with a survey), and (3) brain structure (total brain volume, frontal and temporal lobes volume, gray matter volume, white matter volume, white matter hyperintensities volume, infarcts, and microbleeds, measured with brain-MRI) were assessed using linear or logistic regression models and adjusted for relevant confounders. In total, 250 of 2,005 (12%) participants reported a history of traumatic brain injury. Of those who reported the time post-injury (n=173), most participants (n=151, 87%) reported that it occurred more than 10 years ago. We found no associations between history of traumatic brain injury and any of the cognitive tests. We did find that a history of traumatic brain injury was associated with having mid-life subjective memory complaints (odds ratio (OR): 1.87, 95% confidence interval (CI): 1.35; 2.58). This association was also present when investigating only those who reported an injury more than 10 years ago (OR:1.69, 95% CI: 1.15; 2.50). Additionally, the association was stronger in those with more than 30 minutes loss of consciousness (OR: 3.57, 95%CI: 1.48; 8.59) than in those with less than 30 minutes loss of consciousness (OR: 1.85, 95%CI: 1.25; 2.74), when compared to those without history of traumatic brain injury. Lastly, we found no associations between history of traumatic brain injury and any of the structural brain-MRI outcomes. In conclusion, our study suggests that at least one life-time traumatic brain injury with loss of consciousness in mid-life is associated with long-term subjective memory complaints, but not with cognitive functioning or brain structure.

Assessing Cognitive Behavioral Therapy for Insomnia to Improve Sleep Outcomes in Individuals With a Concussion: Protocol for a Delayed Randomized Controlled Trial

BACKGROUND

Sleep disturbances post concussion have been associated with more frequent and severe concussion symptoms and may contribute to poorer recovery. Cognitive behavioral therapy for insomnia (CBT-I) is an effective treatment for insomnia; however, it remains unclear if this treatment method is effective in improving sleep outcomes and reducing concomitant postconcussion symptoms.

OBJECTIVE

The hypotheses for this study are that (1) CBT-I will improve sleep outcomes and (2) CBT-I will improve concomitant postconcussion symptoms.

METHODS

In total, 40 individuals who are within ≥4 weeks of postconcussion injury and have insomnia symptoms will be enrolled in this randomized controlled trial. Participants will be randomized into either a group that starts a 6-week CBT-I program immediately after baseline or a waitlist control group that starts CBT-I following a 6-week waiting period. All participants will be reassessed 6, 12, and 18 weeks after baseline. Standardized assessments measuring sleep outcomes, postconcussion symptoms, and mood will be used. Linear regression and t tests will be used for statistical analyses.

RESULTS

Enrollment of 40 participants was completed July 2022, data collection will be completed in November 2022, and publication of main findings is anticipated in May 2023. It is anticipated that participants experience reduced insomnia symptoms and postconcussion symptoms following CBT-I and these improvements will be retained for at least 12 weeks. Additionally, we expect to observe a positive correlation between sleep and postconcussion symptom improvement.

CONCLUSIONS

Successful completion of this pilot study will allow for a better understanding of the treatment of insomnia and postconcussion symptoms in individuals following a concussion.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04885205; https://clinicaltrials.gov/ct2/show/NCT04885205.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/38608.

Long-term effects of multiple concussions on prefrontal cortex oxygenation during repeated squat-stands in retired contact sport athletes

BACKGROUND

This study investigated the long-term effects of multiple concussions on prefrontal cortex oxygenation using near-infrared spectroscopy (NIRS) during a squat-stand maneuver that activated dynamic cerebral autoregulation.

METHODS

Active male retired contact sport athletes with a history of 3+ concussions (mTBI; n = 55), and active retired athletes with no concussion history (CTRL; n = 29) were recruited. Participants completed a 5-min squat-stand maneuve (10-s squat, 10-s stand, 0.05 Hz; 15 times). Oxygenated (O₂Hb), deoxygenated (HHb), total (tHb) hemoglobin, and hemoglobin difference (HbDiff) were analyzed through the change in maximal and minimal values during the test (∆MAX), Z-scores, and standard deviations.

RESULTS

mTBI group showed left prefrontal cortex O₂Hb ∆MAX (p = 0.046) and HbDiff ∆MAX (p = 0.018) were significantly higher. Within-group analyses showed significantly higher left HHb ∆MAX (p = 0.003) and lower left HbDiff Z-scores (p = 0.010) only in the mTBI group. The CTRL group demonstrated significantly lower left HbDiff SD (p = 0.039), tHb Z-scores (p = 0.030), and HbDiff ∆MAX (p = 0.037) compared to right prefrontal cortex response.

CONCLUSION

These preliminary results suggest changes in prefrontal cortex oxygenation potentially affecting the brain's ability to adapt to changing cerebral perfusion pressure after multiple previous concussions.

Applying the Bradford Hill Criteria for Causation to Repetitive Head Impacts and Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with a history of repetitive head impacts (RHI). CTE was described in boxers as early as the 1920s and by the 1950s it was widely accepted that hits to the head caused some boxers to become "punch drunk." However, the recent discovery of CTE in American and Australian-rules football, soccer, rugby, ice hockey, and other sports has resulted in renewed debate on whether the relationship between RHI and CTE is causal. Identifying the strength of the evidential relationship between CTE and RHI has implications for public health and medico-legal issues. From a public health perspective, environmentally caused diseases can be mitigated or prevented. Medico-legally, millions of children are exposed to RHI through sports participation; this demographic is too young to legally consent to any potential long-term risks associated with this exposure. To better understand the strength of evidence underlying the possible causal relationship between RHI and CTE, we examined the medical literature through the Bradford Hill criteria for causation. The Bradford Hill criteria, first proposed in 1965 by Sir Austin Bradford Hill, provide a framework to determine if one can justifiably move from an observed association to a verdict of causation. The Bradford Hill criteria include nine viewpoints by which to evaluate human epidemiologic evidence to determine if causation can be deduced: strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment, and analogy. We explored the question of causation by evaluating studies on CTE as it relates to RHI exposure. Through this lens, we found convincing evidence of a causal relationship between RHI and CTE, as well as an absence of evidence-based alternative explanations. By organizing the CTE literature through this framework, we hope to advance the global conversation on CTE mitigation efforts.

Biomarkers of Neuroinflammation in Traumatic Brain Injury

Traumatic brain injury (TBI) is characterized by neuroinflammation and structural damage leading to symptoms and altered brain function. Biomarkers are useful in understanding neuroinflammation and correlations with TBI sequalae. The purpose of this paper is to identify and discuss biomarkers of neuroinflammation used to study TBI and its sequalae. A systematic review was conducted using PubMed, CINAHL, Embase, and Web of Science. A total of 350 articles met criteria; 70 used biomarkers. PRISMA criteria were used for Quality Assessment. Articles included reviews (n = 17), case-control (n = 25), cross-sectional (n = 25) studies, and randomized controlled trials (n = 3). Twenty-seven biomarkers were identified, including inflammasomes, cytokines, neuropeptides, complement complexes, miRNA and exosomes, and glial cell-specific proteins. Biomarkers aid in predicting morbidity and mortality and advance our understanding of neuroinflammation in TBI. This systematic review advances our understanding of the neuroinflammatory response to better enable nurses and clinicians to provide informed care of TBI patients.

Association between Sleep Disturbances at Subacute Stage of Mild Traumatic Brain Injury and Long-Term Outcomes

Mild (mTBI) traumatic brain injury (TBI) accounts for the majority of all TBI cases. Evidence has suggested that patients with mTBI can suffer from long-lasting cognitive deficits, persistent symptoms, and decreased quality of life. Sleep disorders are commonly observed after TBI, with the prevalence rate of sleep disturbances in persons with TBI being much higher than that in the general population. Poor sleep quality can impair cognitive functions in the general population. This effect of sleep disturbances may impede the recovery processes in the population with TBI. The objective of this study is to add to our understanding of the relationship between self-reported sleep problems and other post-concussion symptoms and look at the association between early sleep problems and long-term outcomes in mTBI. Post-concussion symptoms, neurocognitive functions, level of global outcomes, and rating of satisfaction of life were assessed in 64 patients with mTBI. The results revealed that the presence of sleep disturbances co-occur with an increased level of overall post-concussion symptoms at the subacute stage of mTBI, particularly with symptoms including poor concentration, memory problems, and irritability. In addition, sleep disturbance at the subacute stage is associated with persistent poor concentration and memory problems, as well as worse neurocognitive function, slower overall recovery, and lower satisfactory of life at the long term. Our findings suggest that sleep disturbance can be a prognostic factor of long-term outcomes after mTBI. Early interventions to improve sleep quality can have potential benefits to facilitate the recovery process from mTBI.

Mental Health Outcomes Across the Lifespan in Individuals With Persistent Post-Concussion Symptoms: A Scoping Review

Objective

Concussion is a common yet heterogenous injury. Approximately 15-30% of cases present with persistent post-concussion symptoms (PPCS), continuing 4 weeks or more post-injury in children, youth, and adolescents, and 3 months or more in adults. There are known bidirectional links between PPCS and mental health outcomes. The focus of this scoping review is to explore the literature on mental health outcomes in individuals experiencing PPCS. Research objectives were to explore: (1) the mental health outcomes of individuals with PPCS and types of assessments used to identify mental health outcomes this group, and (2) how mental health outcomes compare in terms of similarities and differences among pediatric and adult populations with PPCS.

Method

Ovid MEDLINE; EMBASE; CINAHL, and PsycInfo databases were searched. After title and abstract screening of 11,920 studies, 481 articles were reviewed. Twenty-five papers met inclusion criteria. Results were organized by mental health outcomes of pediatric and adult populations, separately.

Results

There was a significantly higher number of studies devoted to adult populations. Of the 25 studies, 19 (76%) focused on adults, while six (24%) focused on adolescents. In adult populations, studies focused on symptoms of: anxiety (n = 2), depression (n = 8), and anxiety and depression (n = 9). Two studies assessed other emotional outcomes (10.5%). Within pediatric populations, an equal number of studies explored symptoms of: anxiety (n = 2), depression (n = 2), and anxiety and depression (n = 2). No studies focused on other emotional outcomes. Studies ranged greatly in methods, design, and control group. Most studies reported higher psychiatric symptoms of anxiety and/or depression in those with PPCS compared to individuals with recovered concussion or healthy controls.

Discussion

This review contributes to the understanding of mental health outcomes in those experiencing PPCS. Mental health and PPCS requires greater attention in pediatric populations, and consider strategies for those experiencing PPCS and mental health impacts. Future studies should consider including a wider range of emotional outcomes in their design, not limited to anxiety and depression. Study results may lead to improvements and research in the identification, assessment, and management of PPCS and mental health.

Factors Associated With Repeat Emergency Department Visits in a State-wide Cohort of Pediatric Patients With Mild Traumatic Brain Injury

OBJECTIVE

To describe demographic, injury, and clinical characteristics of pediatric patients treated in the ED for mild traumatic brain injury (mTBI), and to evaluate characteristics associated with mTBI-related return emergency department (ED) visit within 1 month of initial presentation.

METHODS

Retrospective cohort study from April 1, 2012, to September 30, 2017, of children 19 years or younger presenting to any Maryland ED for mTBI identified in the Maryland Health Services Cost Review Commission database using ICD-9/10 codes. Demographic, injury, and clinical characteristics of individuals were collected. The primary outcome was mTBI-related return ED visit within 4 weeks. Multiple logistic regression tested the associated of individual demographic, injury, and clinical characteristics with mTBI-related return ED visit.

RESULTS

There were 25,582 individuals who had an ED visit for mTBI, of which 717 (2.8%) returned to the ED within 4 weeks and 468 (1.8%) within 1 week with a mTBI-related diagnosis. In multivariable logistic regression analyses, public insurance (adjusted odds ratio [aOR], 1.44; 95% confidence interval [CI], 1.21-1.72) and female sex (aOR, 1.34; 95% CI, 1.15-1.56) were associated with increased odds of return to the ED within 4 weeks. Age younger than 2 years (aOR, 0.39; 95% CI, 0.21-0.72) was associated with decreased odds of return visit. There was a trend toward decreased odds of return patients receiving computed tomography head imaging (aOR, 0.86; 95% CI, 0.74-1.01).

CONCLUSIONS

Although return to the ED for mTBI-related complaints is uncommon, girls, older children, and publicly insured individuals may be at increased risk. Future targeted study may identify areas to improve access to appropriate longitudinal care and justify ED programs to better coordinate follow-up for mTBI.

Myelin Content in Mild Traumatic Brain Injury Patients with Post-Concussion Syndrome: Quantitative Assessment with a Multidynamic Multiecho Sequence

Objective

This study aimed to explore the myelin volume change in patients with mild traumatic brain injury (mTBI) with post-concussion syndrome (PCS) using a multidynamic multiecho (MDME) sequence and automatic whole-brain segmentation.

Materials and Methods

Forty-one consecutive mTBI patients with PCS and 29 controls, who had undergone MRI including the MDME sequence between October 2016 and April 2018, were included. Myelin volume fraction (MVF) maps were derived from the MDME sequence. After three dimensional T1-based brain segmentation, the average MVF was analyzed at the bilateral cerebral white matter (WM), bilateral cerebral gray matter (GM), corpus callosum, and brainstem. The Mann–Whitney U-test was performed to compare MVF and myelin volume between patients with mTBI and controls. Myelin volume was correlated with neuropsychological test scores using the Spearman rank correlation test.

Results

The average MVF at the bilateral cerebral WM was lower in mTBI patients with PCS (median [interquartile range], 25.2% [22.6%–26.4%]) than that in controls (26.8% [25.6%–27.8%]) (p = 0.004). The region-of-interest myelin volume was lower in mTBI patients with PCS than that in controls at the corpus callosum (1.87 cm³ [1.70–2.05 cm³] vs. 2.21 cm³ [1.86–3.46 cm³]; p = 0.003) and brainstem (9.98 cm³ [9.45–11.00 cm³] vs. 11.05 cm³ [10.10–11.53 cm³]; p = 0.015). The total myelin volume was lower in mTBI patients with PCS than that in controls at the corpus callosum (0.45 cm³ [0.39–0.48 cm³] vs. 0.48 cm³ [0.45–0.54 cm³]; p = 0.004) and brainstem (1.45 cm³ [1.28–1.59 cm³] vs. 1.54 cm³ [1.42–1.67 cm³]; p = 0.042). No significant correlation was observed between myelin volume parameters and neuropsychological test scores, except for the total myelin volume at the bilateral cerebral WM and verbal learning test (delayed recall) (r = 0.425; p = 0.048).

Conclusion

MVF quantified from the MDME sequence was decreased at the bilateral cerebral WM in mTBI patients with PCS. The total myelin volumes at the corpus callosum and brainstem were decreased in mTBI patients with PCS due to atrophic changes.

Sports- and Physical Activity-Related Concussions, Binge Drinking and Marijuana Use among Adolescents: The Mediating Role of Depression and Suicidal Ideation

BACKGROUND

Although past studies have examined the adverse impact of sports- and physical activity-related concussions (SPACs) on health and mental health outcomes, there is a dearth of research investigating the association between SPACs and binge drinking and marijuana use.

OBJECTIVE

The objective of this study is to examine the cross-sectional association between SPACs and binge drinking and marijuana use among adolescents and whether symptoms of depression and suicidal ideation mediate this association.

METHODS

Data for this study came from the 2017 and 2019 National Youth Risk Behavior Survey. An analytic sample of 17,175 adolescents aged 14-18 years (50.2% male) was analyzed using binary logistic regression.

RESULTS

Of the 17,175 adolescents, 13.7% engaged in binge drinking and 19.3% used marijuana 30 days preceding the survey date. Approximately one in seven (14.1%) adolescents had SPACs during the past year. Upon controlling for the effects of other factors, adolescents who had SPACs had 1.74 times higher odds of engaging in binge drinking (AOR = 1.74, p<.001, 95% CI = 1.47-2.06) and 1.42 times higher odds of using marijuana (AOR = 1.42, p<.001, 95% CI = 1.24-1.62) than those who did not have SPACs. Symptoms of depression and suicidal ideation explained 12% of the association between SPACs and binge drinking, and 19% of the association between SPACs and marijuana use.

CONCLUSIONS

Understanding the association between SPACs and substance use and mental health could contribute to early identification of adolescents who may engage in substance use.

"You Can't Fix Your Brain": Exploring concussion experiences of children and parents

PURPOSE

To explore the experiences, information needs and preferences of children who have had a concussion and their parents who have cared for them.

DESIGN

Qualitative description.

METHODS

Semi-structured qualitative interviews were conducted via Zoom with children who have had a concussion between ages 5 and 16 years and parents who have cared for a child with a concussion. Interviews were audio-recorded and transcribed.

RESULTS

Fourteen interviews were conducted with children and parents who have experiences with concussion. Four major themes were identified: (1) mechanism of injury and concussion symptoms experienced by children, (2) parent concerns, emotions, and health care experience with child's concussion, (3) concussions affect more than just your head and, (4) health information seeking, and preferences of parents and children related to concussion. Children and their parents have unique experiences, information needs and preferences regarding concussion.

PRACTICE IMPLICATIONS

This information offers valuable insights about developing resources about childhood concussion that parents and children will find useful and relevant. This research has direct relevance to healthcare professionals who may encounter children with concussion in their daily practice so they can ensure the needs of children and families are being met. Our findings will be used to create the content for an innovative knowledge translation tool about pediatric concussion.

Regional Topological Aberrances of White Matter- and Gray Matter-Based Functional Networks for Attention Processing May Foster Traumatic Brain Injury-Related Attention Deficits in Adults

Traumatic brain injury (TBI) is highly prevalent in adults. TBI-related functional brain alterations have been linked with common post-TBI neurobehavioral sequelae, with unknown neural substrates. This study examined the systems-level functional brain alterations in white matter (WM) and gray matter (GM) for visual sustained-attention processing, and their interactions and contributions to post-TBI attention deficits. Task-based functional MRI data were collected from 42 adults with TBI and 43 group-matched normal controls (NCs), and analyzed using the graph theoretic technique. Global and nodal topological properties were calculated and compared between the two groups. Correlation analyses were conducted between the neuroimaging measures that showed significant between-group differences and the behavioral symptom measures in attention domain in the groups of TBI and NCs, respectively. Significantly altered nodal efficiencies and/or degrees in several WM and GM nodes were reported in the TBI group, including the posterior corona radiata (PCR), posterior thalamic radiation (PTR), postcentral gyrus (PoG), and superior temporal sulcus (STS). Subjects with TBI also demonstrated abnormal systems-level functional synchronization between the PTR and STS in the right hemisphere, hypo-interaction between the PCR and PoG in the left hemisphere, as well as the involvement of systems-level functional aberrances in the PCR in TBI-related behavioral impairments in the attention domain. The findings of the current study suggest that TBI-related systems-level functional alterations associated with these two major-association WM tracts, and their anatomically connected GM regions may play critical role in TBI-related behavioral deficits in attention domains.

A Routine Electroencephalography Monitoring System for Automated Sports-Related Concussion Detection

Cases of concussions in the United States keep increasing and are now up to 2 million to 3 million incidents per year. Although concussions are recoverable and usually not life-threatening, the degree and rate of recovery may vary depending on age, severity of the injury, and past concussion history. A subsequent concussion before full recovery may lead to more-severe brain damage and poorer outcomes. Electroencephalography (EEG) recordings can identify brain dysfunctionality and abnormalities, such as after a concussion. Routine EEG monitoring can be a convenient method for reducing unreported injuries and preventing long-term damage, especially among groups with a greater risk of experiencing a concussion, such as athletes participating in contact sports. Because of the relative availability of EEG compared to other brain-imaging techniques (e.g., functional magnetic resonance imaging), the use of EEG monitoring is growing for various neurological disorders. In this longitudinal study, EEG was analyzed from 4 football athletes before their athletic season and also within 7 days of concussion. Compared to a control group of 4 additional athletes, a concussion was detected with up to 99.5% accuracy using EEG recordings in the Theta-Alpha band. Classifiers that use data from only a subset of the EEG electrodes providing reliable detection are also proposed. The most effective classifiers used EEG recordings from the Central scalp region in the Beta band and over the Temporal scalp region using the Theta-Alpha band. This proof-of-concept study and preliminary findings suggest that EEG monitoring may be used to identify a sports-related concussion occurrence with a high level of accuracy and thus reduce the chance of unreported concussion.

Ketogenic Diet as a potential treatment for traumatic brain injury in mice

Traumatic brain injury (TBI) is a brain dysfunction without present treatment. Previous studies have shown that animals fed ketogenic diet (KD) perform better in learning tasks than those fed standard diet (SD) following brain injury. The goal of this study was to examine whether KD is a neuroprotective in TBI mouse model. We utilized a closed head injury model to induce TBI in mice, followed by up to 30 days of KD/SD. Elevated levels of ketone bodies were confirmed in the blood following KD. Cognitive and behavioral performance was assessed post injury and molecular and cellular changes were assessed within the temporal cortex and hippocampus. Y-maze and Novel Object Recognition tasks indicated that mTBI mice maintained on KD displayed better cognitive abilities than mTBI mice maintained on SD. Mice maintained on SD post-injury demonstrated SIRT1 reduction when compared with uninjured and KD groups. In addition, KD management attenuated mTBI-induced astrocyte reactivity in the dentate gyrus and decreased degeneration of neurons in the dentate gyrus and in the cortex. These results support accumulating evidence that KD may be an effective approach to increase the brain’s resistance to damage and suggest a potential new therapeutic strategy for treating TBI.

Incidence of and Mortality From Amyotrophic Lateral Sclerosis in National Football League Athletes

Importance

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease; understanding ALS risk factors is a critical public health issue.

Objectives

To evaluate the incidence of and mortality from ALS in National Football League (NFL) athletes and to describe characteristics associated with ALS within this cohort.

Design, Setting, and Participants

This population-based cohort study included all 19 423 NFL athletes who debuted between 1960 and 2019 and played 1 or more professional game. It was conducted between October 3, 2020, and July 19, 2021.

Exposure

Participation in the NFL, including playing 1 or more professional games.

Main Outcomes and Measures

Cases of ALS and death information were identified based on public records from NFL statistics aggregators, news reports, obituaries, and National Death Index results. The standardized incidence ratio and the standardized mortality ratio were calculated based on data acquired from surveillance studies of ALS accounting for age, sex, and race. Secondary analyses examined the association of body mass index, NFL career duration, race, birth location, and markers of fame, using a nested case-control design, matching athletes with ALS to athletes without ALS, by NFL debut year.

Results

A total of 19 423 male former and current NFL players (age range, 23-78 years) were included in this cohort study and were followed up for a cumulative 493 168 years (mean [SD] follow-up, 30.6 [13.7] years). Thirty-eight players received a diagnosis of ALS, and 28 died during the study time frame, representing a significantly higher incidence of ALS diagnosis (standardized incidence ratio, 3.59; 95% CI, 2.58-4.93) and mortality (standardized mortality ratio, 3.94; 95% CI, 2.62-5.69) among NFL players compared with the US male population, adjusting for age and race. Among NFL athletes, nested-case-control analyses found that those who received a diagnosis of ALS had significantly longer careers (mean [SD] duration, 7.0 [3.9] years) than athletes without ALS (mean [SD] duration, 4.5 [3.6] years; odds ratio, 1.2; 95% CI, 1.1-1.3). There were no differences in ALS status based on proxies of NFL fame, body mass index, position played, birth location, or race.

Conclusions and Relevance

The age-, sex-, and race-adjusted incidence of and mortality from ALS among all NFL players who debuted between 1960 and 2019 were nearly 4 times as high as those of the general population. Athletes with a diagnosis of ALS had longer NFL careers than those without ALS, suggesting an association between NFL duration of play and ALS. The identification of these risk factors for ALS helps to inform the study of pathophysiological mechanisms responsible for this fatal neurodegenerative disease.