A systematic review of potential long-term effects of sport-related concussion

Women, older age, faster cycling speed and increased wind speeds are independent risk factors for acute injury-related medical encounters during a 109 km mass community-based participation cycling event: a 3-year study in 102251 race starters—SAFER XII

Background

There are limited data on acute injury-related medical encounters (injuries) in endurance cycling events.

Objective

To determine the risk factors for injuries during a mass community-based endurance cycling event.

Design

Retrospective, cross-sectional study.

Setting

Cape Town Cycle Tour (109 km), South Africa.

Participants

102 251 race starters.

Methods

All injuries for 3 years were recorded by race medical doctors and nurses. Injuries were grouped into main anatomical area of injury, and a Poisson regression model was used to determine the risk factors associated with injuries.

Results

The four injury risk factors associated with all injuries during an endurance cycling event were sex (women vs men, p<0.0001), older age (p=0.0005), faster cycling speed (p<0.0001) and higher average individualised Wind Speed (aiWindSpeed, p<0.0001). The only risk factor for serious/life-threatening injuries was women (p=0.0413). For specific main anatomical areas: head/neck (women), upper limb (women, older age, faster cyclists), trunk (women, higher aiWindSpeed), and lower limb (higher aiWindSpeed).

Conclusion

Women, older age, faster cycling speed and higher aiWindSpeed were all risk factors for acute injuries during a mass community-based endurance cycling event. These risk factors should help inform race organisers and medical teams on race day to ensure the best medical care is given, and effective acute injury prevention programmes are disseminated.

Delayed Sequelae Related to Mild Traumatic Brain Injury in Children

Delayed sequelae from mild traumatic brain injury (Glasgow Coma Score at admission >13, TBI) has been documented in case reports however larger studies of these effects are sparse. We undertook a telephone based survey to assess the long term sequelae of TBI. We tracked 100 pediatric TBI patients via our trauma registry for demographic data including age, injury severity, and mechanism of injury. Then we proceeded to contact these patient’s parents via telephone. We asked regarding residual symptoms and signs of concussive injury.

Duration out from initial concussive injury ranged from 4 to 68 months. The parents of 66 boys and 34 girls were surveyed. The age of the patients at the time of mild TBI ranged from 1 to 14 years. The injury severity score ranged from 1 to 21. One being the most common Injury severity score. Thirty-three percent of patients had residual effects of concussion at the time of telephone survey. Fourteen percent had memory loss issues, 21% had anxiety/depression issues, 20% had learning disability issues, and 15% had sleep disturbance issues. Duration of time post concussive injury, mechanism, and age did not influence incidence of sequelae. Mild traumatic brain injury has significant long term sequelae. Better identifying characteristics are needed to characterize patients susceptible to long term residual effects of concussion.

Consent, capacity and compliance in concussion management: cave ergo medicus (let the doctor beware)

While the acute effects of concussion and mild traumatic brain injury (TBI) are well understood, the certainty in the medical literature regarding the long-term outcomes of sports-related concussion is limited. Long-term deficits that may result from single, repeated concussions, and possibly subconcussive impacts, include cognitive dysfunction, depression and executive dysfunction. Perhaps most troublingly, repetitive head impacts have been linked to neurodegenerative diseases, including chronic traumatic encephalopathy (CTE), although the precise risk of long-term consequences remains unknown. CTE represents a distinct tauopathy with an unknown incidence in athletic populations; however, a cause and effect relationship has not yet been demonstrated between CTE and concussions or between CTE and exposure to contact sports, as no prospective longitudinal studies have been performed to address that question. Studies of high-school sports exposure and long-term outcomes have not demonstrated consistent findings.Medical advice regarding return to play and the risk of acute and/or long-term consequences is therefore problematic. It is important that the individual's right to make their own choices regarding their health is respected. Team, coach, parental, peer or financial pressures should not influence this decision. The choice to return to play after a concussion or mild TBI injury is the athlete's decision once they have (1) recovered from their injury and have the legal capacity to make an informed decision; (2) been medically assessed and (3) been informed of any possible long-term risks in a language that they can understand.Given the current lack of certainty in relation to long-term outcomes from concussion, is it possible to provide a framework to inform players of current evidence, as part of a consent process, even if the information upon which the decision to return to sport is based remains uncertain and evolving?

Quality of life of ice hockey players after retirement due to concussions

Background:

Sports-related concussion (SRC) is increasingly recognized as a potential health problem in ice hockey. Quality of life (QoL) in players retiring due to SRC has not been thoroughly addressed.

Materials & methods:

QoL using the Sports Concussion Assessment Tool 5th Edition, Impact of Event Scale-Revised and Short Form Health Survey was measured in Swedish ice hockey players who retired due to persistence of postconcussion symptoms or fear of attaining additional SRC.

Results:

A total of 76 players were assessed, on average of 5 years after their most recent SRC. Overall, retired players had a high burden of postconcussion symptoms and reduced QoL.

Conclusion:

Retired concussed ice hockey players have a reduced QoL, particularly those retiring due to postconcussion symptoms. Symptom burden should be continuously evaluated and guide the decision to retire.

Concussions sustained while playing ice hockey are increasingly recognized as a potential health problem. Long-term consequences for players retiring due to concussions have not been fully investigated. Therefore, we evaluated symptoms, quality of life and post-traumatic stress in former Swedish ice hockey players who retired due to postconcussion symptoms or to a fear of attaining additional concussions. We found that retired ice hockey players with a history of concussions had a low quality of life and high post-traumatic stress, particularly in players with a high symptom burden. We recommend that symptom burden should be continuously evaluated and guide the decision to retire.

Plasma Biomarker Concentrations Associated With Return to Sport Following Sport-Related Concussion in Collegiate Athletes-A Concussion Assessment, Research, and Education (CARE) Consortium Study

IMPORTANCE

Identifying plasma biomarkers associated with the amount of time an athlete may need before they return to sport (RTS) following a sport-related concussion (SRC) is important because it may help to improve the health and safety of athletes.

OBJECTIVE

To examine whether plasma biomarkers can differentiate collegiate athletes who RTS in less than 14 days or 14 days or more following SRC.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter prospective diagnostic study, conducted by the National Collegiate Athletics Association-Department of Defense Concussion Assessment, Research, and Education Consortium, included 127 male and female athletes who had sustained an SRC while enrolled at 6 Concussion Assessment, Research, and Education Consortium Advanced Research Core sites as well as 2 partial-Advanced Research Core military service academies. Data were collected between February 2015 and May 2018. Athletes with SRC completed clinical testing and blood collection at preseason (baseline), postinjury (0-21 hours), 24 to 48 hours postinjury, time of symptom resolution, and 7 days after unrestricted RTS.

MAIN OUTCOMES AND MEASURES

A total of 3 plasma biomarkers (ie, total tau protein, glial fibrillary acidic protein [GFAP], and neurofilament light chain protein [Nf-L]) were measured using an ultrasensitive single molecule array technology and were included in the final analysis. RTS was examined between athletes who took less than 14 days vs those who took 14 days or more to RTS following SRC. Linear mixed models were used to identify significant interactions between period by RTS group. Area under the receiver operating characteristic curve analyses were conducted to examine whether these plasma biomarkers could discriminate between RTS groups.

RESULTS

The 127 participants had a mean (SD) age of 18.9 (1.3) years, and 97 (76.4%) were men; 65 (51.2%) took less than 14 days to RTS, and 62 (48.8%) took 14 days or more to RTS. Linear mixed models identified significant associations for both mean (SE) plasma total tau (24-48 hours postinjury, <14 days RTS vs ≥14 days RTS: -0.65 [0.12] pg/mL vs -0.14 [0.14] pg/mL; P = .008) and GFAP (postinjury, 14 days RTS vs ≥14 days RTS: 4.72 [0.12] pg/mL vs 4.39 [0.11] pg/mL; P = .04). Total tau at the time of symptom resolution had acceptable discrimination power (area under the receiver operating characteristic curve, 0.75; 95% CI, 0.63-0.86; P < .001). We also examined a combined plasma biomarker panel that incorporated Nf-L, GFAP, and total tau at each period to discriminate RTS groups. Although the analyses did reach significance at each time period when combined, results indicated that they were poor at distinguishing the groups (area under the receiver operating characteristic curve, <0.7).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that measures of total tau and GFAP may identify athletes who will require more time to RTS. However, further research is needed to improve our ability to determine recovery following an SRC.

Cognitive Ageing in Top-Level Female Soccer Players Compared to a Normative Sample from the General Population: A Cross-sectional Study

OBJECTIVE

There is an ongoing debate on the potential negative effect of contact sport participation on long-term neurocognitive performance due to inherent exposure to concussive and subconcussive head impacts. The aim of the present study was to investigate whether cognitive ageing is exacerbated in elite soccer players compared to the general population.

METHOD

Neurocognitive performance in 6 domains was compared between 240 elite soccer players and a normative sample from the general population (n = 585) using the computerised test battery CNS Vital Signs. We used two-way factorial ANOVA to analyse the interaction between age groups (15-19, 20-29, 30-39, 40-49 years) and study population (female soccer players vs. norm sample) in their effects on neurocognitive performance.

RESULTS

We found no significant interaction effect of age group and study population in five of six test domains. For processing speed, the effect of age was more pronounced in female soccer players (F = 16.89, p = .002). Further, there was a clear main effect of study population on neurocognitive performance with generally better scores in soccer players.

CONCLUSIONS

Elite female soccer players generally performed better than the norm sample on tests of cognitive function, and further, cognitive ageing effects were similar in elite soccer players and controls in all but one domain. A lifespan approach may facilitate insightful future research regarding questions related to long-term neurocognitive health in contact sport athletes.

Association Between Concussion History and Factors Relating to Cognitive, Behavioral, and Emotional Health Among American High School Athletes: A Cross-sectional Analysis

BACKGROUND

The cognitive, behavioral, and emotional deficits that may be associated with sports-related concussions among adolescents are unclear.

PURPOSE

To examine the association between reported concussion history and factors relating to cognitive, behavioral, and emotional health among a population-based sample of US high school-aged adolescents.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Participants included a representative sample of US high school student-athletes who reported a concussion history (in the past 12 months) and relevant behaviors/outcomes within 3 domains: cognitive (academics, difficulty concentrating), behavioral (drinking and driving, carrying a weapon, physically fighting, tobacco use, marijuana use, binge drinking), and emotional (symptoms of depression, suicidal thoughts/actions). The adjusted relative odds of experiencing 0 and at least 1, 2, 3, or ≥4 concussions were modeled while mutually adjusting for the behaviors of interest in addition to age, race/ethnicity, and sleep problems. Data were reported in sex stratum.

RESULTS

A total of 13,268 participants were included in the unweighted data set. Overall, 14.5% (95% CI, 12.9%-16.2%) of female and 18.1% (95% CI, 16.4%-19.8%) of male student-athletes had at least 1 concussion in the past 12 months. As compared with those who reported not engaging in any of the behaviors deleterious to health or having had any of the negative health outcomes (composite score of 0), female athletes with composite scores of 1 to 4, 5 to 7, and 8 to 11 were 1.94 (95% CI, 1.55-2.43), 3.13 (95% CI, 2.30-4.33), and 6.05 (95% CI, 3.75-9.75) times more likely to have a recent history of concussions after accounting for relevant factors. As compared with those having a composite score of 0, male athletes with composite scores of 1 to 4, 5 to 7, and 8 to 11 were 2.03 (95% CI, 1.58-2.59), 3.80 (95% CI, 2.71-5.34), and 8.23 (95% CI, 4.91-13.77) times more likely to have a recent history of concussions after accounting for relevant factors.

CONCLUSION

Self-reported concussions among US high school athletes is related to several deleterious health behaviors and outcomes. These associations should be confirmed in longitudinal analyses.

Assessment of Long-Term Effects of Sports-Related Concussions: Biological Mechanisms and Exosomal Biomarkers

Concussion or mild traumatic brain injury (mTBI) in athletes can cause persistent symptoms, known as post-concussion syndrome (PCS), and repeated injuries may increase the long-term risk for an athlete to develop neurodegenerative diseases such as chronic traumatic encephalopathy (CTE), and Alzheimer's disease (AD). The Center for Disease Control estimates that up to 3.8 million sport-related mTBI are reported each year in the United States. Despite the magnitude of the phenomenon, there is a current lack of comprehensive prognostic indicators and research has shown that available monitoring tools are moderately sensitive to short-term concussion effects but less sensitive to long-term consequences. The overall aim of this review is to discuss novel, quantitative, and objective measurements that can predict long-term outcomes following repeated sports-related mTBIs. The specific objectives were (1) to provide an overview of the current clinical and biomechanical tools available to health practitioners to ensure recovery after mTBIs, (2) to synthesize potential biological mechanisms in animal models underlying the long-term adverse consequences of mTBIs, (3) to discuss the possible link between repeated mTBI and neurodegenerative diseases, and (4) to discuss the current knowledge about fluid biomarkers for mTBIs with a focus on novel exosomal biomarkers. The conclusions from this review are that current post-concussion clinical tests are not sufficiently sensitive to injury and do not accurately quantify post-concussion alterations associated with repeated mTBIs. In the current review, it is proposed that current practices should be amended to include a repeated symptom inventory, a cognitive assessment of executive function and impulse control, an instrumented assessment of balance, vestibulo-ocular assessments, and an improved panel of blood or exosome biomarkers.

Knowledge, attitudes, and behavior toward concussion in adult cyclists

OBJECTIVE

To determine knowledge, attitudes, and behavior toward concussion in cyclists and to identify predictors of concussion knowledge.

METHODS

Cycling organizations sent members a web link to online information about the study and a questionnaire. Anyone aged >16 years, living in New Zealand and engaged in a cycling activity was invited to participate. The 36-item questionnaire included sociodemographics, knowledge about concussion, helmet use, and personal concussion history. Data were collected between 15/05/19 and 30/06/19. A multiple linear regression model identified factors associated with levels of concussion knowledge.

RESULTS

The questionnaire was completed by 672 participants aged between 16 and 82 years (x̄ = 48.6 years). Knowledge of concussion was high. However, knowledge that helmets are not able to prevent concussion was low and time to return to sport after injury was variable. Knowledge did not always translate to seeking of medical attention or replacement of helmet behavior. Younger age and having sustained at least one prior concussion were associated with higher levels of concussion knowledge F(df = 3) = 8.81, p < .001.

CONCLUSIONS

Knowledge and attitudes toward concussion were positive. However, knowledge gaps and discrepancies between attitudes and behavior were identified. Consistent, clear messages are needed around return to sport timeframes.

The Neuropathological and Clinical Diagnostic Criteria of Chronic Traumatic Encephalopathy: A Critical Examination in Relation to Other Neurodegenerative Diseases

This work critically reviews chronic traumatic encephalopathy (CTE), with a specific focus on the single criterion necessary and sufficient for diagnosis. Herein, CTE is compared to other well-established neurodegenerative entities including Alzheimer's disease and dementia with Lewy bodies. Each neurodegenerative disorder is reviewed in five pertinent areas: 1) historical perspective, 2) guideline formation process, 3) clinical diagnostic criteria, 4) pathological diagnostic criteria, and 5) validation of previously described diagnostic criteria (e.g., sensitivity and specificity). These comparisons indicate that CTE is a disease in the earliest stages of formation and has yet to undergo rigorous development and refinement similar to other neurodegenerative diseases. Suggested future revisions to the diagnostic criterion of CTE include establishing a lower threshold for accumulation of pathology, as well as accounting for the presence of concomitant neuropathology and comorbid neurodegenerative disorders. Currently, while initial efforts have been attempted, agreed upon antemortem clinical criteria do not exist. As has been the scientific standard with similar neurodegenerative disorders, antemortem diagnostic guidelines should first be refined through subcommittees of neuroscientists from diverse institutional backgrounds with a subclassification of levels of diagnostic certainty (possible, probably, and definite). Validation studies should then assess the predictive value and accuracy of proposed antemortem diagnostic criteria in relation to potential pathological criteria.

The influence of education in decision making concerning athlete’s return to sport following a concussion injury: A systematic review

Objectives

Concussions have emerged as one of the most prevalent and controversial injuries sustained within the sporting context. The objective of this review was to determine the influence that education has on decision making concerning athlete’s return to sport following a concussion injury and if the risk is worth it in the eyes of the athletes.

Study design

Systematic review.

Methods

A rapid literature review was performed in PubMed, CINAHL, SPORTDiscus, Embase and Web of Science looking for articles that discussed concussions and any three of the four following search terms: (a) decision making, (b) education/knowledge, (c) sport/return to sport and (d) risk.

Results

Sixteen of 1243 articles were included in this review based on eligibility criteria. Ten were cohort studies, four were cross-sectional studies and two were qualitative research. There was a good agreement between the authors for all studies when determining risk of bias, presenting a Cohen’s κ of 0.901 (95% CI, 0.834, 0.968), p <  0.001.

Conclusion

Education can make a difference in athlete’s decision making process to return to sport; however, their awareness of the health risks that they put themselves in by returning to sport too soon is clouded by other external and internal factors. What is not fully understood is why do they put themselves at this risk? Further studies should explore athletes’ risk aversion behaviour and how it impacts their decision to return to sport following a concussion.

Extracellular Vesicle Proteins and MicroRNAs as Biomarkers for Traumatic Brain Injury

Traumatic brain injury (TBI) is a heterogeneous condition, associated with diverse etiologies, clinical presentations and degrees of severity, and may result in chronic neurobehavioral sequelae. The field of TBI biomarkers is rapidly evolving to address the many facets of TBI pathology and improve its clinical management. Recent years have witnessed a marked increase in the number of publications and interest in the role of extracellular vesicles (EVs), which include exosomes, cell signaling, immune responses, and as biomarkers in a number of pathologies. Exosomes have a well-defined lipid bilayer with surface markers that reflect the cell of origin and an aqueous core that contains a variety of biological material including proteins (e.g., cytokines and growth factors) and nucleic acids (e.g., microRNAs). The presence of proteins associated with neurodegenerative changes such as amyloid-β, α-synuclein and phosphorylated tau in exosomes suggests a role in the initiation and propagation of neurological diseases. However, mechanisms of cell communication involving exosomes in the brain and their role in TBI pathology are poorly understood. Exosomes are promising TBI biomarkers as they can cross the blood-brain barrier and can be isolated from peripheral fluids, including serum, saliva, sweat, and urine. Exosomal content is protected from enzymatic degradation by exosome membranes and reflects the internal environment of their cell of origin, offering insights into tissue-specific pathological processes. Challenges in the clinical use of exosomal cargo as biomarkers include difficulty in isolating pure exosomes, variable yields of the isolation processes, quantification of vesicles, and lack of specificity of exosomal markers. Moreover, there is no consensus regarding nomenclature and characteristics of EV subtypes. In this review, we discuss current technical limitations and challenges of using exosomes and other EVs as blood-based biomarkers, highlighting their potential as diagnostic and prognostic tools in TBI.

Soccer heading and subclinical neuropsychiatric symptomatology in professional soccer players

Objectives

To evaluate the association between postconcussive symptomatology and heading in professional soccer players, overcoming the bias of self-reported exposure, we evaluated several clinical neuropsychiatric symptoms using questionnaires after a thorough objective follow-up of players’ heading exposure throughout an entire season.

Methods

We collected heading data for all Israeli Premier League players for an entire season using a web-based platform for performance analysis, which enabled us to quantify the exact number of headers per player. Players filled out questionnaires regarding postconcussion symptoms, depression, anxiety, and sleep disorders. We tested the association between the number of headers and each outcome using a negative binomial regression corrected for the hours played.

Results

A total of 159 players were included, of whom 79 were considered in the high heading exposure group (49%), defined as more than median number of headings (1.34 per game hour). Among players without any past head injury, those with higher heading exposure were less likely to have postconcussion symptoms compared with players with low heading exposure (relative risk [RR] per heading per hour 0.94, 95% confidence interval [CI] 0.912–0.963). Players with high heading exposure had fewer depression symptoms (RR 0.98, 95% CI 0.961–0.997), anxiety (RR 0.98, 95% CI 0.958–0.997), and sleep disorders (RR 0.98, 95% CI 0.961–0.996).

Conclusion

Professional soccer players with high heading rate do not display higher postconcussive symptomatology severity. Symptoms among players with low heading exposure might be explained by low resilience, possibly associated with an inferior heading technique. Alternatively, it can reflect heading-avoidant behavior.

Magnetic Resonance Spectroscopy following Mild Traumatic Brain Injury: A Systematic Review and Meta-Analysis on the Potential to Detect Posttraumatic Neurodegeneration

INTRODUCTION

Traumatic brain injury (TBI) is the most relevant external risk factor for dementia and a major global health burden. Mild TBI (mTBI) contributes to up to 90% of all TBIs, and the classification "mild" often misrepresents the patient's burden who suffer from neuropsychiatric long-term sequelae. Magnetic resonance spectroscopy (MRS) allows in vivo detection of compromised brain metabolism although it is not routinely used after TBI.

OBJECTIVE

Thus, we performed a systematic review and meta-analysis to elucidate if MRS has the potential to identify changes in brain metabolism in adult patients after a single mTBI with a negative routine brain scan (CCT and/or MRI scan) compared to aged- and sex-matched healthy controls (HC) during the acute or subacute postinjury phase (≤90 days after mTBI).

METHODS

A comprehensive literature search was conducted from the first edition of electronic databases until January 31, 2020. Group analyses were performed per metabolite using a random-effects model.

RESULTS

Four and 2 out of 5,417 articles met the inclusion criteria for the meta-analysis and systematic review, respectively. For the meta-analysis, 50 mTBI patients and 51 HC with a mean age of 31 and 30 years, respectively, were scanned using N-acetyl-aspartate (NAA), a marker for neuronal integrity. Glutamate (Glu), a marker for disturbed brain metabolism, choline (Cho), a marker for increased cell membrane turnover, and creatine (Cr) were used in 2 out of the 4 included articles. Regions of interests were the frontal lobe, the white matter around 1 cm above the lateral ventricles, or the whole brain. NAA was decreased in patients compared to HC with an effect size (ES) of -0.49 (95% CI -1.08 to 0.09), primarily measured in the frontal lobe. Glu was increased in the white matter in 22 mTBI patients compared to 22 HC (ES 0.79; 95% CI 0.17-1.41). Cho was decreased in 31 mTBI patients compared to 31 HC (ES -0.31; 95% CI -0.81 to 0.19). Cr was contradictory and, therefore, potentially not suitable as a reference marker after mTBI.

CONCLUSIONS

MRS pinpoints changes in posttraumatic brain metabolism that correlate with cognitive dysfunction and, thus, might possibly help to detect mTBI patients at risk for unfavorable outcome or posttraumatic neurodegeneration early.

Late contributions of repetitive head impacts and TBI to depression symptoms and cognition

OBJECTIVE

To test the hypothesis that repetitive head impacts (RHIs), like those from contact sport play and traumatic brain injury (TBI) have long-term neuropsychiatric and cognitive consequences, we compared middle-age and older adult participants who reported a history of RHI and/or TBI with those without this history on measures of depression and cognition.

METHODS

This cross-sectional study included 13,323 individuals (mean age, 61.95; 72.5% female) from the Brain Health Registry who completed online assessments, including the Ohio State University TBI Identification Method, the Geriatric Depression Scale (GDS-15), and the CogState Brief Battery and Lumos Labs NeuroCognitive Performance Tests. Inverse propensity-weighted linear regressions accounting for age, sex, race/ethnicity, and education tested the effects of RHI and TBI compared to a non-RHI/TBI group.

RESULTS

A total of 725 participants reported RHI exposure (mostly contact sport play and abuse) and 7,277 reported TBI (n = 2,604 with loss of consciousness [LOC]). RHI (β, 1.24; 95% CI, 0.36-2.12), TBI without LOC (β, 0.43; 95% CI, 0.31-0.54), and TBI with LOC (β, 0.75; 95% CI, 0.59-0.91) corresponded to higher GDS-15 scores. While TBI with LOC had the most neuropsychological associations, TBI without LOC had a negative effect on CogState Identification (β, 0.004; 95% CI, 0.001-0.01) and CogState One Back Test (β, 0.004; 95% CI, 0.0002-0.01). RHI predicted worse CogState One Back Test scores (β, 0.02; 95% CI, -0.01 to 0.05). There were RHI × TBI interaction effects on several neuropsychological subtests, and participants who had a history of both RHI and TBI with LOC had the greatest depression symptoms and worse cognition.

CONCLUSIONS

RHI and TBI independently contributed to worse mid- to later-life neuropsychiatric and cognitive functioning.

Exosomal neurofilament light: A prognostic biomarker for remote symptoms after mild traumatic brain injury?

OBJECTIVE

To measure exosomal and plasma levels of candidate blood biomarkers in veterans with history of mild traumatic brain injury (mTBI) and test their relationship with chronic symptoms.

METHODS

Exosomal and plasma levels of neurofilament light (NfL) chain, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and vascular endothelial growth factor (VEGF) were measured using an ultrasensitive assay in a cohort of 195 veterans, enrolled in the Chronic Effects of Neurotrauma Consortium Longitudinal Study. We examined relationships between candidate biomarkers and symptoms of postconcussive syndrome (PCS), posttraumatic stress disorder (PTSD), and depression. Biomarker levels were compared among those with no traumatic brain injury (TBI) (controls), 1-2 mTBIs, and repetitive (3 or more) mTBIs.

RESULTS

Elevated exosomal and plasma levels of NfL were associated with repetitive mTBIs and with chronic PCS, PTSD, and depression symptoms. Plasma TNF-α levels correlated with PCS and PTSD symptoms. The total number of mTBIs correlated with exosomal and plasma NfL levels and plasma IL-6. Increased number of years since the most recent TBI correlated with higher exosomal NfL and lower plasma IL-6 levels, while increased number of years since first TBI correlated with higher levels of exosomal and plasma NfL, as well as plasma TNF-α and VEGF.

CONCLUSION

Repetitive mTBIs are associated with elevated exosomal and plasma levels of NfL, even years following these injuries, with the greatest elevations in those with chronic PCS, PTSD, and depression symptoms. Our results suggest a possible neuroinflammatory and axonal disruptive basis for symptoms that persist years after mTBI, especially repetitive.

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

PRIMARY OBJECTIVE

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

RESEARCH DESIGN

Observational, cross-sectional.

METHODS AND PROCEDURES

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

MAIN OUTCOMES AND RESULTS

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

CONCLUSIONS

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

White Matter Abnormalities in Retired Professional Rugby League Players with a History of Concussion

The topic of potential long-term neurological consequences from having multiple concussions during a career in collision sports is controversial. We sought to investigate white matter microstructure using diffusion tensor imaging (DTI) in retired professional Australian National Rugby League (NRL) players (n = 11) with a history of multiple self-reported concussions compared with age- and education-matched controls (n = 13) who have had no history of brain trauma. Diffusion-weighted images were acquired with a Siemens 3T scanner. All participants completed a clinical interview. There were no significant differences between groups on measures of depression, anxiety, stress, or post-concussion symptoms; however, NRL players scored significantly higher on the alcohol use disorder identification test (AUDIT). Voxelwise analyses of DTI measures were performed using tract-based spatial statistics (TBSS) with age and AUDIT scores included as covariates. TBSS revealed significantly reduced fractional anisotropy (FA), and increased radial diffusivity (RD), axial diffusivity (AD), and trace (TR) in white matter regions of recently retired NRL players compared with controls. FA was significantly reduced in the right superior longitudinal fasciculus and right corticospinal tract while TR, RD, and AD were increased in these regions, as well as the corpus callosum, forceps major, right uncinate fasciculus, and left corticospinal tract. In summary, DTI in a small cohort of recently retired professional NRL players with a history of multiple concussions showed differences in white matter microstructure compared with age- and education-matched controls with no history of brain trauma.

Radiographic and neurobehavioral profile of sports-related concussion associated with scholastic wrestling: a case report

Sports-related concussions (SRCs) are typically characterized by transient neurologic deficits due to physiologic and metabolic brain injury. However, following an SRC, subsequent insults may lead to severe and permanent injury in the affected brain cells. We present the case of a 15-year-old female scholastic wrestler who developed acute encephalopathy, macroscopic white matter injury on imaging, and chronic behavioral changes from inadequate neuro-recovery after a documented SRC. We also compare her case with established SRC data, demonstrating that wrestling-related concussions and repetitive head impacts can produce similar degrees of diffuse neuroinflammation, myelinated axonopathy, blood-brain barrier disruption, and post-concussive symptoms.

Characterizing the Risk of Depression Following Mild Traumatic Brain Injury: A Meta-Analysis of the Literature Comparing Chronic mTBI to Non-mTBI Populations

Objective: Mild traumatic brain injury (mTBI) is associated with depressed mood acutely post-injury, but there is little evidence regarding long-term depression. The aim of this study was to determine the odds ratio (OR) of depression chronically following mTBI.

Methods: We searched Medline (PubMed), ProQuest, and Web of Science from date of database creation to January 23, 2019, for eligible studies examining depression at least 6 months post-injury in adult subjects with mTBI of any etiology, including civilians and military. Three authors independently reviewed titles and abstracts for study eligibility. Data were extracted and collated by two investigators. Risk of bias was assessed with the SIGN methodology. Study data were pooled using random-effects meta-analysis. The primary exposure was mTBI, and the primary outcome was depression. Secondary exploratory variables were time of assessment, age at injury, age at assessment, sex, and etiology.

Results: We included 47 cross-sectional studies (n = 25,103 mTBI and 29,982 control), 26 cohort studies (n = 70,119 mTBI, 262,034 control), four prospective observational studies (n = 1,058 mTBI and 733 control), two prospective longitudinal studies (n = 119 mTBI, 81 control), two case-control studies (n = 56 mTBI, 56 control), and one randomized controlled trial (n = 252 mTBI, 3,214 control). mTBI was associated with a 3.29-fold increased risk of depression (OR 3.29, 95% CI 2.68–4.03, I² = 96%). The OR for depression did not change when subjects were assessed at 6–12 months (OR 2.43, 1.45–4.07), years 1–2 (OR 4.12, 2.10–8.07); 2–10 (OR 3.28, 2.42–4.46), or 10+ (OR 3.42, 1.51–7.77). Similar risk of depression was sustained across different age at injury (<25: OR 2.26, 1.82–2.81; 25–35: OR 4.67, 3.06–7.14; >35: OR 2.69, 1.42–5.10) and different age at assessment (<40 years: OR 3.14, 2.48–3.99; >40 years: OR 4.57, 2.54–8.24). Female sex had a non-significant increase in OR (OR 19.97, 2.39–166.93) compared to male (OR 3.0, 2.33–3.86). mTBI etiology had no impact on depression.

Conclusions: Those experiencing mTBI are more than three times more likely to experience depression compared to those without a history of mTBI, and this risk remains decades beyond the mTBI event. Future longitudinal studies are needed to identify and mitigate this risk.

If Not Now, When? An Absence of Neurocognitive and Postural Stability Deficits in Collegiate Athletes with One or More Concussions

A history of concussion has been associated with decreased neurocognitive function and postural control. The purpose of our study was to compare neurocognitive function and postural control in collegiate athletes with and without varying histories of concussion. Collegiate athletes were divided into groups based on 0 (n = 129), 1 (n = 91), 2 (n = 52), and 3+ (n = 34) prior concussions. Participants in each group were carefully matched by sport, sex, height, weight, and age. Athletes were administered the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT™) and the Sensory Organization Test (SOT) as part of a standard of care pre-season assessment. Group ImPACT (Verbal and Visual Memory, Visual Motor Speed, and Reaction Time) and SOT (Equilibrium Score and Somatosensory, Visual, and Vestibular sensory ratios) outcome scores were compared using one-way analyses of variance (ANOVAs). Coefficients of variation (CVs) were also calculated for each outcome score and were compared using two-sample tests with 95% confidence intervals (CIs). Participants with and without a history of concussion were not significantly different for any ImPACT or SOT outcome score (p's > 0.10). Groups (0, 1, 2, and 3+ previous concussions) were not different from each other for any ImPACT or SOT outcome score (p's ≥ 0.11). Likewise, the CVs associated with each ImPACT and SOT outcome score did not vary significantly between outcome scores for any group comparison (p ≥ 0.09). Our findings suggest that a history of one or more concussions does not influence neurocognitive performance or postural stability in collegiate athletes at their pre-season baseline assessment.

Concussion and long-term cognitive impairment among professional or elite sport-persons: a systematic review

INTRODUCTION

Understanding whether concussion in sport is associated with worsening cognitive function in later life will likely have immediate repercussion on sports concussion prevention and management policy and sporting rules and regulations. This systematic review aims to summarise the evidence on the association between concussion sustained by professional/elite athletes and long-term cognitive impairment.

METHODS

Embase, PubMed and Web of Science were used to search for eligible studies. Studies including professional/elite athletes from any sport were considered. Three comparison groups were considered: internal comparison (concussed vs non-concussed athletes within the same sample); between-sport comparison (contact sport athletes vs non-contact sports ones); external comparison (athletes vs samples of the general population or population norms).

RESULTS

14 studies were included (rugby, American football, ice hockey players, boxers and marital art fighters). The general quality of the evidence was poor. The overall evidence, weighted for type of comparison and study quality, points towards an association between sustaining a sport-related concussion and poorer cognitive function later in life in rugby, American football and boxing, although it is unclear to what extent this is clinically relevant. Data on ice hockey and martial arts were too sparse to allow conclusions to be drawn.

CONCLUSION

High-quality, appropriately designed and powered epidemiological studies are urgently needed to assess the association between sustaining a sport-related concussion and cognitive impairment later in life. Particular emphasis should be put on the clinical translational value of findings.

Functional Connectivity Changes in Retired Rugby League Players: A Data-Driven Functional Magnetic Resonance Imaging Study

There is considerable interest in the long-term brain health of retired contact and collision sport athletes; however, little is known about possible underlying changes in functional brain connectivity in this group. We evaluated whole-brain functional connectivity patterns using multi-voxel pattern analysis (MVPA) to determine whether alterations in functional connectivity distinguish retired professional athletes from a matched group of healthy community control subjects. Thirty-two retired athletes with a history of multiple self-reported sport-related concussions and 36 healthy community control subjects who were similar in age and education, completed functional magnetic resonance imaging. We identified brain regions with abnormal functional connectivity patterns using whole-brain MVPA as implemented in the Conn toolbox. First-level MVPA was performed using 64 principal component analysis (PCA) components. Second-level F test was performed using the first three MVPA components for retired athletes > controls group contrast. Post hoc seed-to-voxel analyses using the MVPA cluster results as seeds were performed to characterize functional connectivity abnormalities from brain regions identified by MVPA. MVPA revealed one cluster of abnormal functional connectivity located in cerebellar lobule V. This region of lobule V corresponded to the ventral attention network. Post hoc seed-to-voxel analysis using the cerebellar MVPA cluster as a seed revealed multiple areas of cerebral cortical hyper-connectivity and hypo-connectivity in retired athletes when compared with controls. This initial report suggests that cerebellar dysfunction might be present and clinically important in some retired athletes.

Concussion History and Career Status Influence Performance on Baseline Assessments in Elite Football Players

OBJECTIVE

To determine if concussion history and career status is associated with neurocognitive performance in elite football players.

METHODS

The study design was a cross-sectional single assessment. Fifty-seven elite football players (age 29.39 ± 7.49 years) categorized as draft prospects, active professional players, and retired professional players were assessed on the Sport Concussion Assessment Tool - third edition (SCAT-3), in an outpatient therapy setting.

RESULTS

Common symptoms were the following: fatigue (45.6%), trouble falling asleep (35.1%), difficulty remembering (33.3%) and irritability (22.8%); 36.8% reported no symptoms. The low concussion (0-1) group reported fewer symptoms (U = 608.50, p < .001), less symptom severity (U = 598.00, p = -.001), and produced greater scores on the Standardized Assessment of Concussion (SAC) total scores compared to the multiple concussion (2+) group (U = 253.00, p = .024), but no differences were observed on modified Balance Error Scoring System (m-BESS) scores (U = 501.50, p = .066) on the Mann-Whitney U test. The Kruskal-Wallis test and post-hoc analysis indicated retired players were significantly different from draft prospects and current professional players for total symptom scores (p < .001), total symptom severity (p < .001), SAC total scores (p = .030), and m-BESS (p < .001).

CONCLUSIONS

Concussion history and career status appear associated with total symptoms, symptom severity, performance on the SAC, and the m-BESS in elite football players. With this in mind, future research is recommended to determine longitudinal impact for elite football players.

Physical Therapy Evaluation and Treatment After Concussion/Mild Traumatic Brain Injury

Over the last decade, numerous concussion evidence-based clinical practice guidelines (CPGs), consensus statements, and clinical guidance documents have been published. These documents have typically focused on the diagnosis of concussion and medical management of individuals post concussion, but provide little specific guidance for physical therapy management of concussion and its associated impairments. Further, many of these guidance documents have targeted specific populations in specific care contexts. The primary purpose of this CPG is to provide a set of evidence-based recommendations for physical therapist management of the wide spectrum of patients who have experienced a concussive event. J Orthop Sports Phys Ther 2020;50(4):CPG1-CPG73. doi:10.2519/jospt.2020.0301.

Exercise, redox system and neurodegenerative diseases

Regular exercise induces a wide range of redox system-associated molecular adaptive responses to the nervous system. The intermittent induction of reactive oxygen species (ROS) during acute exercise sessions and the related upregulation of antioxidant/repair and housekeeping systems are associated with improved physiological function. Exercise-induced proliferation and differentiation of neuronal stem cells are ROS dependent processes. The increased production of brain derived neurotrophic factor (BDNF) and the regulation by regular exercise are dependent upon redox sensitive pathways. ROS are causative and associative factors of neurodegenerative diseases and regular exercise provides significant neuroprotective effects against Alzheimer's disease, Parkinson's disease, and hypoxia/reperfusion related disorders. Regular exercise regulates redox homeostasis in the brain with complex multi-level molecular pathways.

Patterns of head impact exposure in men's and women's collegiate club water polo

OBJECTIVES

Recent reports have demonstrated a risk of concussion and subconcussive head impacts in collegiate varsity and international elite water polo. We sought to characterize patterns of head impact exposure at the collegiate club level of water polo.

DESIGN

Prospective cohort study.

METHODS

Head impact sensors (SIM-G, Triax Technologies) were worn by men's (n=16) and women's (n=15) collegiate club water polo players during 11 games. Peak linear acceleration (PLA) and peak rotational acceleration (PRA) of head impacts were recorded by the sensors. Two streams of competition video were used to verify and describe the nature of head impacts.

RESULTS

Men's players sustained 52 verified head impacts of magnitude 39.7±16.3g PLA and 5.2±3.2 krad/s² PRA, and women's players sustained 43 verified head impacts of magnitude 33.7±12.6g PLA and 4.0±2.8krad/s² PRA. Impacts sustained by men had greater PLA than those sustained by women (p=.045). Athletes were impacted most frequently at the offensive center position, to the back of the head, and by an opponent's torso or limb.

CONCLUSIONS

Our cohort of male and female athletes sustained relatively infrequent head impacts during water polo competitions played at the collegiate club level. The amount of head impact exposure in our cohort was dependent on player position, with offensive centers prone to sustaining the most impacts. Head impact sensors are subject to large amounts of false positives and should be used in conjunction with video recordings to verify the validity of impact data.

Estimated Age of First Exposure to American Football and Neurocognitive Performance Amongst NCAA Male Student-Athletes: A Cohort Study

BACKGROUND

Repetitive head impacts in young athletes are potentially detrimental to later life (e.g., age 50 + years) neurological function; however, it is unknown what the short-term effects (e.g., age 20 years) are in collegiate student-athletes.

OBJECTIVE

The purpose of this study was to determine the effect of the estimated age of first exposure to American tackle football participation on neurocognitive performance and symptom severity scores in collegiate student-athletes.

METHODS

We used a cohort study in which neurocognitive performance was assessed using the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) test in 4376 male athletes (age 19.3 ± 1.5 years, mass 96.3 ± 20.3 kg, height 185.0 ± 7.4 cm). Athletes were grouped by sport participation [American football (n = 3462) or non-contact (n = 914)] and estimated age of first exposure [< 12 years (n = 3022) or ≥ 12 years (n = 1354)]. The outcome measures were the four primary cognitive scores and the symptom severity score from ImPACT. We assessed primary outcomes across groups, controlling for age, learning accommodations, and concussion history.

RESULTS

Neurocognitive performance was not associated with the estimated age of first exposure-by-group interaction.

CONCLUSION

Our findings indicate that participation in American tackle football before age 12 years does not result in neurocognitive deficits in college. Therefore, we suggest the following: the consequences of early exposure to repetitive head impacts do not manifest by college, the ImPACT test was not sensitive enough to identify the effects of an earlier estimated age of first exposure, or there is no association between an earlier estimated age of first exposure and neurocognitive functioning. Future longitudinal studies are warranted.

Sports-related concussions and subconcussive impacts in athletes: incidence, diagnosis, and the emerging role of EPA and DHA

Sports-related concussions (SRC) are traumatic brain injuries induced as the result of a biomechanical force to the body that temporarily impair neurological functions. Not all traumatic impacts reach the threshold necessary to produce concussive symptoms; however, the culmination of these events is known as a subconcussive impact (SCI). Athletes who have been diagnosed with a SRC or those who accumulate multiple SCI have exhibited structural damage to the brain, impairments to learning and memory, and an increase in depressive symptoms. This area is rapidly evolving, and current clinical definitions of injury, diagnosis, and treatment of SRC and SCI are reviewed. In tandem, there is also growing research examining the role of nutrition in brain injuries, focusing primarily on n-3 polyunsaturated fatty acids (PUFA). The potential role of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in reducing inflammation and promoting recovery following brain injury are also reviewed. Overall, advancements in the evaluation of SRC and SCI coupled with n-3 PUFA supplementation show promise in the management of brain injuries, leading to better long-term health outcomes for athletes. Novelty SRC have garnered widespread attention due to the growing body of reported prevalence in youth and professional sports. Current definitions and protocol(s) for diagnosing SRC and SCI have improved, but still require further evaluation. n-3, EPA and DHA, reduce inflammation and promote recovery following brain injuries in experimental models.

Match Situations Leading to Head Injuries in Professional Male Football (Soccer)-A Video-Based Analysis Over 12 Years

OBJECTIVE

To identify risk situations promoting head injuries in professional male football (soccer) and to investigate the impact of a rule change in 2006 punishing elbow-head contacts.

DESIGN

Analysis of video sequences of head events leading to head injury.

PARTICIPANTS

Professional football players of the first male German Bundesliga.

MAIN OUTCOME MEASURES

Observational criteria of head impacts on video recordings (players' actions preceding head injuries, foul play-referee's decision and assessment of rater, ball possession, on-pitch medical treatment, and consequences of head impact).

RESULTS

Three hundred thirty-four head injuries were reported in kicker Sportmagazin corresponding to an incidence rate of 2.25 (95% confidence interval 2.01-2.51) per 1000 player match hours. The injured player predominantly jumped (60%), headed the ball (36%), or ran forwards (20%); the noninjured players mainly jumped (64%), headed the ball (27%), or raised the elbow to the head (23%). Free ball situations (2 players challenge for the ball) caused most of the head injuries (81%). The players' action "raising the elbow" during a head injury seemed to be lower after the rule change.

CONCLUSIONS

Jumping for the ball with the intention of heading is the predominant action associated with head injury risk. Head injuries occur most often when players challenge for the ball in a header duel. As head injuries bear the potential risk of long-term health sequelae, the identification of situational circumstances is essential to develop preventative means in the future.

Retinal nerve fibre changes in sports-related repetitive traumatic brain injury

IMPORTANCE

There is limited literature on the use of optical coherence tomography in the assessment of retinal nerve fibre layer (RNFL) thickness in sports-related repetitive mild traumatic brain injury.

BACKGROUND

To evaluate RNFL thickness in professional rugby league players. RNFL thinning may serve as a proxy for wider white matter degeneration.

DESIGN

Cross-sectional observational study.

PARTICIPANTS

Thirteen retired Australian professional rugby league players were recruited.

METHODS

Participants underwent binocular optical coherence tomography to measure RNFL thickness. Each participant underwent a complete ophthalmic assessment to exclude concurrent disease.

MAIN OUTCOME MEASURES

RNFL thickness of each eye were compared with a normative database.

RESULTS

Participants had played professional Rugby League for 18 years on average and reported sustaining 15 sports-related concussions throughout their career. The RNFL in participants was four micrometres thinner than that of matched normative data. Cohort average RNFL thickness was reduced in 12 out of 14 optical coherence testing parameters. These findings were statistically significant in the left inferonasal [P = .013] and left nasal [P = .006] sectors. There was no statistically significant relationship between RNFL thickness and other visual measures.

CONCLUSIONS AND RELEVANCE

This study is the first to demonstrate RNFL thinning in a cohort of retired Australian professional Rugby League players. RNFL changes have been shown to correlate with cerebral white matter loss and neurodegeneration. Optical coherence tomography may serve as a safe and economical means of screening for repetitive traumatic brain injury related neurodegeneration in contact sport athletes.

POINT/COUNTER-POINT-Links between traumatic brain injury and dementia remain poorly defined

There has been considerable public interest in the topic of traumatic brain injury (TBI) as a risk factor for development of late-life dementia. A review was performed on empirical studies examining the relationship between these two conditions. Although results from a number of studies clearly demonstrate that TBI is a positive risk factor for developing dementia, there are an equivalent number of studies that obtain inconclusive or negative findings. Inconsistencies across studies are often the result of methodological findings including the nature of the investigational design, choice of comparison groups, and criteria used to define cases. In many studies, the diagnosis of TBI is obtained retrospectively in a manner that is subject to bias. Accurate identification of dementia cases is often compromised by the use of inappropriately brief follow-up periods and variations in diagnostic methods. There remains no universally accepted neurobiological mechanism to explain the transition from acute TBI to the chronic effects of dementia. Studies of specialty populations, including athletes and military personnel are beset by secular and cohort effects, raising questions about the applicability of findings to the general population. No existing studies have been able to exclude the possible effects of confounding medical or lifestyle factors in facilitating the onset of dementia following TBI. Although the research findings suggest a general association between TBI and dementia, the specifics of the relationship remain poorly defined.

Self-reported history of concussions is associated with risk factors for suicide completion among high school students

BACKGROUND

Suicide is the third leading cause of death among adolescents. While research has found concussions to be a risk factor for suicide in adults, this relationship is not well studied in nationally representative samples of youth. This study examines the relationship between self-reported history of sports-related concussion and five risk factors for suicide completion.

METHODS

Data were obtained from the 2017 Youth Risk Behavior Surveillance Survey (n=13,353). Multivariate logistic regression models assessed the relationship between self-reported, sports-related concussion and five risk factors for suicide completion. Analyses controlled for sex, race/ethnicity, grade, bullying victimization, and sexual orientation. Subsample analyses were conducted stratified by sex. Interaction models examined biological sex as a possible effect modifier.

RESULTS

Overall, 15.0% of high school students reported a sports-related concussion in the past 12-months. Self-reported, sports-related concussion was significantly associated with greater odds of feeling sad/hopeless (Adj OR: 1.20; 95% CI:1.02-1.42), suicidal ideations (Adj OR: 1.25; 95% CI:1.02-1.55), suicide attempt (Adj OR: 1.60; 95% CI:1.31-1.96), and suicide attempt treated by a doctor/nurse (Adj OR: 2.35; 95% CI:1.68-3.29), adjusting for covariates. Stratified analyses demonstrated differences by sex, however, no direct evidence of effect modification was observed in interaction models.

LIMITATIONS

Data are cross-sectional, prohibiting causal inferences. Measures were assessed via self-report. No pre-concussion measures of mental health.

CONCLUSION

Self-reported sports-related concussion was associated with risk factors for suicide completion. No direct evidence of effect modification was observed but stratified analyses suggest biological sex may impact the observed relationship.

A Clinicopathological Report of a 93-Year-Old Former Street Boxer With Coexistence of Chronic Traumatic Encephalopathy, Alzheimer's Disease, Dementia With Lewy Bodies, and Hippocampal Sclerosis With TDP-43 Pathology

Chronic traumatic encephalopathy (CTE) was recently recognized as a new tauopathy in which multifocal perivascular phosphorylated tau aggregates accumulate in neurons, astrocytes, and neurites at the depths of the cortical sulci. Traumatic brain injury (TBI) in early or mid-life is known to be associated with an increased risk of dementia in late life. This case report describes a 93-year-old former street boxer with a premortem diagnosis of severe dementia, who showed pathological evidence of the coexistence of Alzheimer's disease, CTE, dementia with Lewy bodies, and hippocampal sclerosis with TDP-43 pathology. These findings suggest that TBI may trigger a variety of misfolded proteins leading to dementia. Currently, clear clinical diagnostic criteria for CTE have not been established. Therefore, clinicians should be aware that TBI is a risk factor for dementia and that CTE can overlap with other neurodegenerative diseases.

Integrated Stress Response Inhibitor Reverses Sex-Dependent Behavioral and Cell-Specific Deficits after Mild Repetitive Head Trauma

Mild repetitive traumatic brain injury (rTBI) induces chronic behavioral and cognitive alterations and increases the risk for dementia. Currently, there are no therapeutic strategies to prevent or mitigate chronic deficits associated with rTBI. Previously we developed an animal model of rTBI that recapitulates the cognitive and behavioral deficits observed in humans. We now report that rTBI results in an increase in risk-taking behavior in male but not female mice. This behavioral phenotype is associated with chronic activation of the integrated stress response and cell-specific synaptic alterations in the type A subtype of layer V pyramidal neurons in the medial prefrontal cortex. Strikingly, by briefly treating animals weeks after injury with ISRIB, a selective inhibitor of the integrated stress response (ISR), we (1) relieve ISR activation, (2) reverse the increased risk-taking behavioral phenotype and maintain this reversal, and (3) restore cell-specific synaptic function in the affected mice. Our results indicate that targeting the ISR even at late time points after injury can permanently reverse behavioral changes. As such, pharmacological inhibition of the ISR emerges as a promising avenue to combat rTBI-induced behavioral dysfunction.

Sports career-related concussion and mental health symptoms in former elite athletes

BACKGROUND

In elite sports, concussion is common and recurrent, especially in high-speed contact or collision sports such as american and australian football, ice hockey and rugby. Mental health symptoms (e.g., anxiety, depression, sleep disturbance) are often reported by former elite athletes, with prevalence ranging from 16% for distress to 26% for anxiety/depression. This article focuses on the potential relationship between sports career-related concussion and mental health symptoms in former elite athletes.

METHOD

A narrative mini-review was based on the scientific literature.

RESULTS

Some literature based on cross-sectional data suggests that sports career-related concussion might lead in the long term to mental health symptoms in former elite athletes. Retired professional American football players reporting three or more previous concussions were found to be three times more likely to be diagnosed with depression than those with no history of concussion. Former professional athletes from football, ice hockey and rugby who reported a history of six or more concussions were approximately up to five times more likely to report mental health symptoms.

CONCLUSIONS

While longitudinal evidence about any causal relationship is lacking, the suggested relationship between sports career-related concussion and mental health symptoms in former elite athletes warrants the development of support measures for elite athletes transitioning out of sport, especially for those with a history of concussion.

History of Sport-Related Concussion and Long-Term Clinical Cognitive Health Outcomes in Retired Athletes: A Systematic Review

BACKGROUND

Sport-related concussions (SRCs) are known to have short-term effects on cognitive processes, which can result in diverse clinical presentations. The long-term effects of SRC and repeated exposure to head impacts that do not result in SRC on specific cognitive health outcomes remain unclear.

OBJECTIVES

To synthesize and appraise the evidence base regarding cognitive health in living retired athletes with a history of head-impact exposure or SRC.

DATA SOURCES

A systematic search of the EMBASE, PsycINFO, MEDLINE/PubMed, CINAHL, Cochrane Central Register of Controlled Trials, and Web of Science databases was conducted from inception to April 2018 using common key words and medical subject headings related to 3 components: (1) the participant (eg, retired athlete), (2) the primary outcome measure (eg, cognitive test used), and (3) the secondary outcome measure (eg, history of sport concussion).

STUDY SELECTION

Cross-sectional studies of living retired male or female athletes in which at least 1 cognitive test was used as an outcome measure were included. Two reviewers independently screened studies.

DATA EXTRACTION

Data extraction was performed using Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Methodologic quality was assessed independently by 2 reviewers using the Downs and Black tool.

DATA SYNTHESIS

The search yielded 46 cross-sectional observational studies that were included in a qualitative synthesis. Most included studies (80%, n = 37) were published in the 5 years before our review. A large proportion of these studies (n = 20) included retired American National Football League players. The other research investigated professional, university, high school, and amateur retired athletes participating in sports such as American and Australian football, boxing, field and ice hockey, rugby, and soccer. The total sample consisted of 13 975 participants: 7387 collision-sport athletes, 662 contact-sport athletes, 3346 noncontact-sport athletes, and 2580 participants classified as controls. Compared with control participants or normative data, retired athletes displayed worse performance in 17 of 31 studies (55%) of memory, 6 of 11 studies (55%) of executive function, and 4 of 6 studies (67%) of psychomotor function and increased subjective concerns about cognitive function in 11 of 14 studies (79%). The authors of 13 of 46 investigations (28%) reported a frequency-response relationship, with poorer cognitive outcomes in athletes who had greater levels of exposure to head impacts or concussions. However, these results must be interpreted in light of the lack of methodologic rigor and moderate quality assessment of the included studies.

CONCLUSIONS

Evidence of poorer cognitive health among retired athletes with a history of concussion and head-impact exposure is evolving. Our results suggest that a history of SRC may more greatly affect the cognitive domains of memory, executive function, and psychomotor function. Retired athletes appeared to have increased self-reported cognitive difficulties, but the paucity of high-quality, prospective studies limited the conclusions that could be drawn regarding a cause-and-effect relationship between concussion and long-term health outcomes. Future researchers should consider a range of cognitive health outcomes, as well as premorbid ability, in diverse samples of athletes with or without a history of concussion or head-impact exposure to delineate the long-term effects of sport participation on cognitive functioning.

Cerebral white matter lacerations in children caused by repetitive head trauma

It has been known that infants less than 1 year develop cerebral white matter (WM) lacerations associated with head trauma, however, there has been no report of similar WM lesions over 1 year. We report three teenage boys (11, 12, and 18 years at final MRI studies) with acquired WM lacerations associated with recurrent head trauma who developed neurologic symptoms such as spastic paralysis, afebrile convulsions, and cognitive impairment. Two of them (patients 1 and 2) were given a diagnosis of autism spectrum disorder and had a history of repeated severe self-inflicted head trauma from preschool age. Patient 3, who practiced karate and boxing from preschool age, showed gradual declining intellectual ability. Brain MRI of the three patients revealed severe lacerations in the bilateral cerebral WM. Previous neuroimaging showed no WM lacerations at 4 and 5 years in patients 1 and 2, or mild WM lacerations at 17 years in patient 3, indicating the WM lacerations could have been acquired in childhood. It is suggested that repetition of head trauma in children can cause cerebral WM lacerations and brain dysfunction.

Characterizing the Link Between Glial Activation and Changed Functional Connectivity in National Football League Players Using Multimodal Neuroimaging

OBJECTIVE

The primary objective of this preliminary study was to examine the impact of NFL play on interregional functional connectivity between two brain regions, the supramarginal gyrus (SMG) and the thalamus, identified as having higher binding of [¹¹C]DPA-713 in NFL players. The authors' secondary objective was to examine the effect of years since play on the interregional connectivity.

METHODS

Resting-state functional MRI was used to examine functional brain changes between regions with evidence of past injury in active or recently retired NFL players (defined as ≤12 years since NFL play) and distantly retired players (defined as >12 years since NFL play). Age-comparable individuals without a history of concussion or participation in collegiate or professional collision sports were included as a control group.

RESULTS

Compared with healthy control subjects, NFL players showed a loss of anticorrelation between the left SMG and bilateral thalami (mean z score=-2.434, p=0.015). No difference was observed when examining right SMG connectivity. The pattern of connectivity in active and recently retired players mimicked the pattern observed in distantly retired players and older control subjects.

CONCLUSIONS

Further study of the clinical significance of this altered pattern of interregional connectivity in active and recently retired NFL players is needed.

Exploring Traumatic Brain Injuries and Aggressive Antisocial Behaviors in Young Male Violent Offenders

Background: Traumatic brain injury (TBI) is a major cause of disabilities and mortality worldwide, with higher prevalence in offender populations than in the general population. Previous research has strongly advocated increased awareness of TBI in offender populations. The aim of this study was to explore the prevalence and characteristics of TBI, and to investigate associations and interactions between TBI, aggressive antisocial behaviors, general intellectual functioning, and substance use disorders (SUD) in a well-characterized group of young violent offenders. Methods: The study investigated a cohort (n = 269) of 18 to 25-year-old male violent offenders in Sweden. Data on TBI (files + self-report), aggressive antisocial behaviors (Life History of Aggression), SUD (clinical interviews), and general intellectual functioning (General Ability Index, Wechsler Adult Intelligence Scales Third Edition) were collected between 2010 and 2012. Parametric (Student's t-test) and non-parametric (Mann-Whitney U-test, Spearman's rho, χ², Kruskal Wallis test) inferential statistics were applied and effect sizes reported. Results: TBI, both with and without loss of consciousness, was common, with 77.5% of the offenders reporting having suffered at least one TBI during their lifetime. TBI was associated with an increased occurrence of aggressive antisocial behaviors and SUD, and offenders with both TBI and SUD evidenced the largest amount of aggressive antisocial behaviors. No clinically meaningful associations were found between TBI and general intelligence. Effect sizes were in the small to medium range. Conclusions: Our study confirms an increased prevalence of TBI among young violent offenders compared to the general population, as well as associations between TBI, aggressive antisocial behaviors, and SUD. However, it provides no information on the severity of the TBI, nor on the causality of the demonstrated associations. Nevertheless, TBI, and possible related deficits, need to be considered in the assessment and treatment of young violent offenders.

The Effect of Sport-Related Concussion Injuries on Concussion Symptoms and Health-Related Quality of Life in Male and Female Adolescent Athletes: A Prospective Study

BACKGROUND

Sport-related concussions (SRCs) are associated with short-term disablement, characterized as increased concussion symptoms and lower health-related quality of life (HRQoL). However, there are limited longitudinal data detailing how an SRC affects disablement beyond short-term injury recovery.

PURPOSE

To longitudinally assess the effect of SRCs on symptoms and HRQoL in high school athletes through the 12 months after injury.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The 125 participants included high school athletes who sustained an SRC (female patients, 36%; mean ± SD age, 15.9 ± 1.1 years). The Post-concussion Symptom Scale (PCSS) from the Sport Concussion Assessment Tool-3 and the Pediatric Quality of Life Inventory 4.0 (PedsQL) were completed at enrollment and repeated at 24 to 72 hours (onset) and at 7 days (D7) after the SRC; on the date of return to play (RTP); and at 3, 6, and 12 months (M12) after the SRC. Scores at each time point were compared with the athletes' own baseline via linear mixed models for repeated measures, controlling for age, sex, and history of previous SRC and with patient as a random effect.

RESULTS

Relative to baseline, female patients reported higher PCSS symptom and severity scores at onset (P < .001) and D7 (P < .001), while scores were not higher (P > .05) for RTP through M12. As compared with baseline, male patients reported higher PCSS scores at onset (P < .001) and D7 (P = .003) and severity scores at onset (P < .001) and D7 (P = .016), while the symptom and severity scores were not higher (P > .05) at RTP through M12. Female participants reported lower PedsQL physical scores at onset (P = .006), while scores were not lower (P > .05) from D7 through M12. Female psychosocial scores were not lower (P > .05) at any time after the SRC, while the total PedsQL score was lower at onset (P = .05) but not from D7 through M12. Male physical scores were lower at onset (P < .001) and D7 (P = .001) but not lower (P > .05) from RTP through M12. Male psychosocial and PedsQL scores were unchanged (P > .05) from baseline at onset through M12.

CONCLUSION

After an SRC, high school athletes reported initial disablement (increased symptoms and lower HRQoL) through their RTP. However, after RTP, no similar disablement was detected through 12 months after injury.

Surfing-related head injuries presenting to United States emergency departments

This study examined the incidence and trends of surfing-related and mild traumatic brain injuries that presented to United States emergency departments between 2001 and 2016. Subjects with surging-related head injuries were retrieved from the National Electronic Injury Surveillance System. A weighted total of 34,337 surfing-related head injuries were identified. The annual incidence of surfing-related head injuries insignificantly decreased from 2001 to 2016 (R² = .119; p = .19). Most common injuries included lacerations (50.4%), blunt head injuries (25.7%), and mild traumatic brain injuries (16.1%). Mild traumatic brain injury incidence and annual percentage increased significantly during the study period (R² = .251; p = .05 and R² = .346; p = .02, respectively).

Sports Medicine Update: Concussion

A systematic approach is required for patients with a suspected concussion. Although standardized tools can aid in assessment, the diagnosis of concussion remains a clinical one. At the time of diagnosis, patients should be given both verbal and written review of the common symptoms of concussion, expected course of recovery, as well as strategies to manage symptoms. Most patients benefit from a brief period of rest, followed by a gradual reintroduction of activities, and a graduated return-to-sport protocol. Patients with prolonged recovery from a concussion may benefit from exercise, vestibular, and cognitive rehabilitation programs.