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

Sport-Related Concussion and Mental Health Outcomes in Elite Athletes: A Systematic Review

Background

Elite athletes can experience a diverse range of symptoms following post-concussive injury. The impact of sport-related concussion on specific mental health outcomes is unclear in this population.

Objective

The aim was to appraise the evidence base regarding the association between sport-related concussion and mental health outcomes in athletes competing at elite and professional levels.

Methods

A systematic search of PubMed, EMBASE, SPORTDiscus, PsycINFO, Cochrane, and Cinahl databases was conducted.

Results

A total of 27 studies met inclusion criteria for review. Most of the included studies (67%, n = 18) were published in 2014 or later. Study methodology and reporting varied markedly. The extant research has been conducted predominantly in North America (USA, n = 23 studies; Canada, n = 3), often in male only (44.4%, n = 12) and college (70.4%, n = 19) samples. Depression is the most commonly studied mental health outcome (70.4%, n = 19 studies). Cross-sectional retrospective studies and studies including a control comparison tend to support an association between concussion exposure and depression symptoms, although several studies report that these symptoms resolved in the medium term (i.e. 1 month) post-concussion. Evidence for anxiety is mixed. There are insufficient studies to draw conclusions for other mental health domains.

Conclusion

Consistent with current recommendations to assess mood disturbance in post-concussive examinations, current evidence suggests a link between sports-related concussion and depression symptoms in elite athletes. Causation cannot be determined at this stage of enquiry because of the lack of well-designed, prospective studies. More research is required that considers a range of mental health outcomes in diverse samples of elite athletes/sports.

Electronic supplementary material

The online version of this article (10.1007/s40279-017-0810-3) contains supplementary material, which is available to authorized users.

Economic evaluations of strategies to prevent sports and recreational injury among children and adolescents: a systematic review

Objective

To identify, summarise and critically assess studies reporting costs and consequences of sport and recreation injury prevention strategies among children and adolescents.

Design

Systematic review.

Methods and data sources

We searched MEDLINE (Ovid), EMBASE, CINAHL, Pubmed, Econlit and SPORTDiscus and PEDE. Included studies were peer reviewed full economic evaluations or cost analyses of sport/recreation injury prevention among children and adolescents≤18 years of age. The Pediatric Quality Appraisal Questionnaire was used for quality assessment.

Results

The initial search yielded 1896 unique records; eight studies met inclusion criteria. Six studies were related to injury prevention in the context of recreation, two were related to sports. For recreation studies in cycling and swimming: costs per head injury averted was US$3109 to $228 197; costs per hospitalisation avoided was US$3526 to 872 794; cost per life saved/death avoided was US$3531 to $103 518 154. Sport interventions in hockey and soccer were cost saving (fewer injuries and lower costs). Global quality assessments ranged from poor to good. Important limitations included short time horizons and intermediate outcome measures.

Conclusions

Few rigorous economic evaluations related to sport and recreation injury prevention have been conducted. The range of estimates and variation in outcomes used preclude specific conclusions; however, where strategies both improve health and are cost saving, implementation should be prioritised. Future economic evaluations should incorporate time horizons sufficient to capture changes in long-term health and use utility-based outcome measures in order to capture individual preferences for changes in health states and facilitate comparison across intervention types.

Injuries in karate: systematic review

OBJECTIVES

to identify all studies of Karate injuries and assess injury rates, types, location, and causes.

METHODS

Six electronic and four grey literature databases were searched. Two reviewers independently assessed titles/abstracts, abstracted data and assessed risk-of-bias with the Newcastle-Ottawa scale. Average injury rates/1000AE (AE = athletic-encounter) and/1000minutesAE, injury location and type weighted by study size were calculated.

RESULTS

In competitions rates of injury/1000AE and/1000 minutesAE were similar for males (111.4/1000AE, 75.4/1000 minAE) and females (105.8/1000AE, 72.8/1000 minAE). Location of injury rates/1000AE for males were 44.0 for head/neck, 11.9 lower extremities, 8.1 torso and 5.4 upper extremities and were similar for females: 41.2 head/neck, 12.4 lower extremities, 9.1 torso and 6.3 upper extremities. Injury rates varied widely by study. Rates/1000AE for type of injury were contusions/abrasions/lacerations/bruises/tooth avulsion for males (68.1) and females (30.4); hematomas/bleeding/epistaxis males (11.4) and females (12.1); strains/sprains males (3.5) and females (0.1); dislocations males (2.9) and females (0.9); concussions males (2.5) and females (3.9); and fractures males (2.9) and females (1.4). Punches were a more common mechanism of injury for males (59.8) than females (40.8) and kicks similar (males 19.7, females 21.7). Weighted averages were not calculated for weight class or belt colour because there were too few studies. Nineteen injury surveys reported annual injury rates from 30% to rates ten times higher but used different reporting methods. Studies provided no data to explain wide rate ranges.

CONCLUSIONS

Studies need to adopt one injury definition, one data-collection form, and collect comprehensive data for each study for both training and competitions. More data are needed to measure the effect of weight, age and experience on injuries, rates and types of injury during training, and for competitors with high injury rates. RCTs are needed of interventions such as training and feedback of performance data to reduce injury rates.

Advanced biomarkers of pediatric mild traumatic brain injury: Progress and perils

There is growing public concern about neurodegenerative changes (e.g., Chronic Traumatic Encephalopathy) that may occur chronically following clinically apparent and clinically silent (i.e., sub-concussive blows) pediatric mild traumatic brain injury (pmTBI). However, there are currently no biomarkers that clinicians can use to objectively diagnose patients or predict those who may struggle to recover. Non-invasive neuroimaging, electrophysiological and neuromodulation biomarkers have promise for providing evidence of the so-called "invisible wounds" of pmTBI. Our systematic review, however, belies that notion, identifying a relative paucity of high-quality, clinically impactful, diagnostic or prognostic biomarker studies in the sub-acute injury phase (36 studies on unique samples in 28 years), with the majority focusing on adolescent pmTBI. Ultimately, well-powered longitudinal studies with appropriate control groups, as well as standardized and clearly-defined inclusion criteria (time post-injury, injury severity and past history) are needed to truly understand the complex pathophysiology that is hypothesized (i.e., still needs to be determined) to exist during the acute and sub-acute stages of pmTBI and may underlie post-concussive symptoms.

Strides Toward Better Understanding of Post-Traumatic Headache Pathophysiology Using Animal Models

PURPOSE OF REVIEW

In recent years, the awareness of the detrimental impact of concussion and mild traumatic brain injuries (mTBI) is becoming more apparent. Concussive head trauma results in a constellation of cognitive and somatic symptoms of which post-traumatic headache is the most common. Our understanding of post-traumatic headache is limited by the paucity of well validated, characterized, and clinically relevant animal models with strong predictive validity. In this review, we aim to summarize and discuss current animal models of concussion/mTBI and related data that start to shed light on the pathophysiology of post-traumatic headache.

RECENT FINDINGS

Each of the models will be discussed in terms of their face, construct, and predictive validity as well as overall translational relevance to concussion, mTBI, and post-traumatic headache. Significant contributions to the pathophysiology of PTH garnered from these models are discussed as well as potential contributors to the development of chronic post-traumatic headache. Although post-traumatic headache is one of the most common symptoms following mild head trauma, there remains a disconnect between the study of mild traumatic brain injury and headache in the pre-clinical literature. A greater understanding of the relationship between these phenomena is currently needed to provide more insight into the increasing frequency of this debilitating condition in both military and civilian populations.

Personal subjectivity in clinician discussion about retirement from sport post-concussion

BACKGROUND

There is increasing focus on the number of concussions after which an athlete should discontinue participating in contact or collision sports. This is a clinically subjective and, in some cases, a preference-sensitive decision.

PURPOSE

Our goal was to assess whether there is personal subjectivity in when athletic trainers (ATs) discuss the possibility of sport retirement post-concussion with athletes.

METHODS

A national sample of ATs who provide clinical care to college athletes completed a questionnaire (n = 677, 34% response rate). Structural equation modeling was used to assess the association between risk perceptions, risk tolerance, social influences (beliefs about athlete, coach and parent preferences), expectancies about athlete success (on and off field), and the number of concussions after which retirement would be discussed.

RESULTS

There was a significant direct effect of AT risk tolerance on the number of concussions after which sport retirement would be discussed, among both male and female ATs (male B = 0.54, p < 0.001; female B = 0.31, p < 0.001). ATs who more strongly prioritized athletes' on-field achievements indicated that they would discuss sport retirement after a larger number of concussions compared to their peers who less strongly valued athletic achievement.

CONCLUSIONS

The results suggest the potential utility of standardized approaches to communicating concussion risk consistently to athletes. This can help ensure that all athletes are uniformly able to make informed decisions about continued exposure to concussion risk that are based on their values and preferences.

Affective, neurocognitive and psychosocial disorders associated with traumatic brain injury and post-traumatic epilepsy

Survivors of traumatic brain injury (TBI) often develop chronic neurological, neurocognitive, psychological, and psychosocial deficits that can have a profound impact on an individual's wellbeing and quality of life. TBI is also a common cause of acquired epilepsy, which is itself associated with significant behavioral morbidity. This review considers the clinical and preclinical evidence that post-traumatic epilepsy (PTE) acts as a 'second-hit' insult to worsen chronic behavioral outcomes for brain-injured patients, across the domains of emotional, cognitive, and psychosocial functioning. Surprisingly, few well-designed studies have specifically examined the relationship between seizures and behavioral outcomes after TBI. The complex mechanisms underlying these comorbidities remain incompletely understood, although many of the biological processes that precipitate seizure occurrence and epileptogenesis may also contribute to the development of chronic behavioral deficits. Further, the relationship between PTE and behavioral dysfunction is increasingly recognized to be a bidirectional one, whereby premorbid conditions are a risk factor for PTE. Clinical studies in this arena are often challenged by the confounding effects of anti-seizure medications, while preclinical studies have rarely examined an adequately extended time course to fully capture the time course of epilepsy development after a TBI. To drive the field forward towards improved treatment strategies, it is imperative that both seizures and neurobehavioral outcomes are assessed in parallel after TBI, both in patient populations and preclinical models.

Elevated markers of brain injury as a result of clinically asymptomatic high-acceleration head impacts in high-school football athletes

OBJECTIVE

This prospective observational cohort study of high-school football athletes was performed to determine if high-acceleration head impacts (HHIs) that do not result in clinically diagnosed concussion still lead to increases in serum levels of biomarkers indicating traumatic brain injury (TBI) in asymptomatic athletes and to determine the longitudinal profile of these biomarkers over the course of the football season.

METHODS

Sixteen varsity high-school football athletes underwent baseline neurocognitive testing and blood sampling for the biomarkers tau, ubiquitin C-terminal hydrolase L1 (UCH-L1), neurofilament light protein (NF-L), glial fibrillary acidic protein (GFAP), and spectrin breakdown products (SBDPs). All athletes wore helmet-based accelerometers to measure and record head impact data during all practices and games. At various time points during the season, 6 of these athletes met the criteria for HHI (linear acceleration > 95g and rotational acceleration > 3760 rad/sec2); in these athletes a second blood sample was drawn at the end of the athletic event during which the HHI occurred. Five athletes who did not meet the criteria for HHI underwent repeat blood sampling following the final game of the season. In a separate analysis, all athletes who did not receive a diagnosis of concussion during the season (n = 12) underwent repeat neurocognitive testing and blood sampling after the end of the season.

RESULTS

Total tau levels increased 492.6% ± 109.8% from baseline to postsession values in athletes who received an HHI, compared with 164% ± 35% in athletes who did not receive an HHI (p = 0.03). Similarly, UCH-L1 levels increased 738.2% ± 163.3% in athletes following an HHI, compared with 237.7% ± 71.9% in athletes in whom there was no HHI (p = 0.03). At the end of the season, researchers found that tau levels had increased 0.6 ± 0.2 pg/ml (p = 0.003) and UCH-L1 levels had increased 144.3 ± 56 pg/ml (p = 0.002). No significant elevations in serum NF-L, GFAP, or SBDPs were seen between baseline and end-of-athletic event or end-of-season sampling (for all, p > 0.05).

CONCLUSIONS

In this pilot study on asymptomatic football athletes, an HHI was associated with increased markers of neuronal (UCH-L1) and axonal (tau) injury when compared with values in control athletes. These same markers were also increased in nonconcussed athletes following the football season.

Concussion

Concussions are a common injury for which patients often present first to primary care physicians. They can affect the day-to-day function of patients in school and work, as well as in sports and recreational activities. Recognizing common physical signs and symptoms after injury facilitates timely diagnosis and treatment, permitting initiation of an active management approach to recovery while preventing secondary injury. For persons with persistent symptoms, active rehabilitation may be utilized, with the goal of returning patients to full function.

Chronic Traumatic Encephalopathy in Professional American Football Players: Where Are We Now?

Repetitive head trauma provides a favorable milieu for the onset of inflammatory and neurodegenerative processes. The result of long-lasting head trauma is chronic traumatic encephalopathy (CTE), a disease process well-recognized in boxers, military personnel, and more recently, in American football players. CTE is a chronic neurodegenerative disease with hallmarks of hyperphosphorylated tau (p-tau) aggregates and intercellular lesions of neurofibrillary tangles. The criteria for CTE diagnosis requires at least 1-2 focal perivascular lesions of p-tau in the cerebral cortex, at the depth of the sulci. These pathognomonic lesions aggregate within neurons and glial cells such as astrocytes, and cell processes within the vicinity of small blood vessels. CTE presents in a distinct topographical distribution pattern compared to other tauopathies such as AD and other age-related astrogliopathies. CTE also has an insidious onset, years after repetitive head trauma. The disease course of CTE is characterized by cognitive dysfunction, behavioral changes, and can progress to altered motor function with parkinsonian-like manifestations in later stages. This short review aims to summarize CTE in professional football, epidemiology, diagnosis based on neuroanatomical abnormalities, cognitive degeneration, and adverse mental health effects, as well as gaps in the literature and future directions in diagnostics, therapeutics, and preventive measures.

Prevalence and Correlates of Psychological Distress among Retired Elite Athletes: A Systematic Review

This article presents results of a systematic review of the literature (2000-2017) examining the prevalence and correlates of psychological distress among retired elite athletes. Forty articles were selected and included. Our review suggests the prevalence of psychological distress among retired athletes is similar to that found in the general population. However, subgroups reporting medical comorbidities, significant pain, a greater number of concussions, less social support, and adverse psychosocial factors were at greater risk for psychological distress. Additionally, athletes experiencing psychological distress in retirement often do not seek treatment for their distress. Based on the existing literature, there is a need for greater standardization and use of reliable measures, as well as use of diagnostic interviews in order to assess the most accurate prevalence of psychological distress among these athletes. Longitudinal designs, matched control groups, more heterogeneous samples, and use of multivariate analyses would also help to more accurately determine the prevalence and risk factors of psychological distress in this population. This review suggests a number of different clinical implications and highlights directions for future research to enhance our understanding of the long-term psychological health of former elite athletes.

Return-to-play after concussion: state of knowledge, frequency of use and application barriers of guidelines among decision-makers in rugby

Validated strategies and guidelines for a safe and individualized diagnosis and return-to-play (RTP) after concussion in rugby are needed. Little is known about the state of knowledge, frequency of use and application barriers of state-of-the-art guidelines among decision-makers in professional or semi-professional rugby teams. Participants (n = 195) from the coaching team (head coach, assistance coach, athletic coach), the medical team (physiotherapist, physician, rehabilitation therapist, neuropsychologist), or from the officials of a professional or semi-professional rugby team (top three major leagues in Germany), filled in a questionnaire on their knowledge, frequency of use and application barriers of evidence-based guidelines (Graduated RTP protocol and The 5R). Depending on their function in the team and on the league of play, the state of knowledge and application of the diagnostic tools and the RTP guidelines differ. A considerable number are aware of one or both guidelines, but do not apply these guidelines (up to 27% of respondants). The main reasons for the non-usage were not my decision (59%), use of concurrent guidelines (54%), each player must decide by his own (36%), never experienced a concussion in my players (30%), other (19%), the guideline is useless (18%) and a player may play despite a concussion (14%). Raising awareness of the state-of-the-art guidelines is important to educate further the coaching, medical and official team members in identifying symptoms and executing the RTP-process in accordance with evidence-based strategies.

Effect of Mindfulness Based Stress Reduction (MBSR) in Increasing Pain Tolerance and Improving the Mental Health of Injured Athletes

Literature indicates that injured athletes face both physical and psychological distress after they have been injured. In this study, a Mindfulness Based Stress Reduction (MBSR) was utilised as an intervention for use during the period of recovery with injured athletes and, to the best of our knowledge, this is the first study using MBSR as an intervention for this purpose. Objective: The aim of this research was to investigate the role of MBSR practise in reducing the perception of pain and decreasing anxiety/stress, as well as increasing pain tolerance and mindfulness. An additional aim was to increase positive mood and decrease negative mood in injured athletes. Methods: The participants comprised of twenty athletes (male = 14; female = 6; age range = 21-36 years) who had severe injuries, preventing their participation in sport for more than 3 months. Prior to their injury, the participants had trained regularly with their University teams and participated in official university championships. Both groups followed their normal physiotherapy treatment, but in addition, the intervention group practised mindfulness meditation for 8 weeks (one 90-min session/week). A Cold Pressor Test (CPT) was used to assess pain tolerance. In contrast, the perception of pain was measured using a Visual Analogue Scale. Other measurements used were the Mindful Attention Awareness Scale (MAAS), Depression Anxiety and Stress Scale (DASS), and Profile of Mood States (POMS). Results: Our results demonstrated an increase in pain tolerance for the intervention group and an increase in mindful awareness for injured athletes. Moreover, our findings observed a promising change in positive mood for both groups. Regarding the Stress/Anxiety scores, our findings showed a notable decrease across sessions; however, no significant changes were observed in other main and interaction effects in both groups. Conclusion: Injured athletes can benefit from using mindfulness as part of the sport rehabilitation process to increase their pain tolerance and awareness. Further research is required to assess whether increasing pain tolerance could help in the therapeutic process.

Implementation of the 2017 Berlin Concussion in Sport Group Consensus Statement in contact and collision sports: a joint position statement from 11 national and international sports organisations

The 2017 Berlin Concussion in Sport Group Consensus Statement provides a global summary of best practice in concussion prevention, diagnosis and management, underpinned by systematic reviews and expert consensus. Due to their different settings and rules, individual sports need to adapt concussion guidelines according to their specific regulatory environment. At the same time, consistent application of the Berlin Consensus Statement's themes across sporting codes is likely to facilitate superior and uniform diagnosis and management, improve concussion education and highlight collaborative research opportunities. This document summarises the approaches discussed by medical representatives from the governing bodies of 10 different contact and collision sports in Dublin, Ireland in July 2017. Those sports are: American football, Australian football, basketball, cricket, equestrian sports, football/soccer, ice hockey, rugby league, rugby union and skiing. This document had been endorsed by 11 sport governing bodies/national federations at the time of being published.

Influence of playing rugby on long-term brain health following retirement: a systematic review and narrative synthesis

Objectives

The aim of this review was to systematically investigate long-term brain health in retired rugby players.

Methods

Six databases were systematically searched from inception to January 2018 using Medical Subject Headings and keywords. Two reviewers independently screened studies for inclusion. Cross-sectional studies of living retired male or female rugby players in which at least one cognitive test was used as an outcome measure were included. Data extraction was performed using Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Methodological quality was assessed independently by two reviewers using the Downs and Black methodological quality tool.

Results

This review yielded six studies with an overall methodological quality of 'moderate'. A total of 672 male retired rugby players (mean ages of 38-52 years) were included in this review. Three studies investigated neuropsychological functioning in retired rugby players in comparison with controls, with no significant evidence of decreased performance in the majority of tests when compared with controls. Five out of the six studies explored self-reported measures of cognition. Three studies compared retired rugby players to controls, one of which found significantly increased subjective cognitive complaints among retired rugby players. The other two studies found that persistent postconcussion symptoms were associated with a higher number of self-reported concussions. Two studies reported decreased fine motor control in retired rugby players in comparison with controls. Neurometabolites and electrophysiological changes were explored by two studies, with minimal and non-significant findings.

Conclusions

Overall findings are mixed. Methodological biases reduce the overall study quality and limited the conclusions that can be drawn. Findings of decreased fine motor control in retired athletes may be influenced by lack of controlling for evidence of upper limb musculoskeletal injuries. While some studies show evidence of reduced cognitive function among former athletes, the results are not significantly lower than population norms. Cognitive findings from this review are inconsistent within and across study cohorts and are biased towards positive findings when self-report methods were selected. Current evidence suggests that large gaps remain in the understanding of the cause-and-effect relationships between playing rugby and long-term brain health in retired players.

Knowledge, Attitudes and Concussion Information Sources Among First Nations in Ontario

OBJECTIVE

Hockey is a popular sport played by many First Nation youth. Concussion frequently goes unrecognized and unreported in youth hockey. Unintentional injuries among Indigenous youth occur at rates three to four times the national Canadian average. The study sought to examine knowledge, attitudes and sources of concussion information among First Nations people attending a provincial hockey tournament.

METHODS

A cross-sectional survey was undertaken. The survey by Mzazik et al. were modified to use in this study. Participants included youth (6-18 years) hockey players (n=75), parents (n=248) and coaches (n=68). The main outcome measure was total knowledge index (TKI) which consisted of the sum of correct responses to 15 multiple choice questions. Additional data gathered included demographics, concussion history, attitudes toward concussion and sources of information. Descriptive statistics included proportion comparisons. Variables were tested using χ 2 and analysis of variance.

RESULTS

Overall TKI scores (out of a total of 15) were low; players (5.9±2.8), parents (7.5±2.6) and coaches (7.9±2.6). Participants with higher knowledge scores reported more appreciation of the seriousness of concussion. Sources of information about concussion differed by study group, suggesting the need for multiple knowledge translation strategies to reach youth, parents and coaches.

CONCLUSIONS

Future initiatives are urgently needed to improve education and prevention of concussion in First Nations youth hockey. Collaborating and engaging with communities can help to ensure an Indigenous lens for culturally safe interventions.

Chronic traumatic encephalopathy in sports: a historical and narrative review

My objectives are to review: 1) a brief history of sport-related concussion (SRC) and chronic traumatic encephalopathy (CTE), 2) the evolution of CTE in American professional football, 3) the data regarding SRC/CTE as they relate to depression and suicide, 4) the data on the neurocognitive effects of subconcussion/repetitive head trauma (with emphases on heading the ball in soccer and early exposure to football), 5) the evidence related to SRC and neurodegenerative diseases, 6) the published studies of CTE, 7) the NINDS neuropathological criteria for CTE, 8) public beliefs about SRC/CTE, and 9) the scientific questions regarding CTE.

Population-based cohort study of the impacts of mild traumatic brain injury in adults four years post-injury

There is increasing evidence that some people can experience persistent symptoms for up to a year following mild TBI. However, few longitudinal studies of mild TBI exist and the longer-term impact remains unclear. The purpose of this study is to determine if there are long-term effects of mild traumatic brain injury (TBI) four-years later. Adults (aged ≥16 years) identified as part of a TBI incidence study who experienced a mild-TBI four-years ago (N = 232) were compared to age-sex matched controls (N = 232). Sociodemographic variables, prior TBI and symptoms were assessed at the time of injury. Four years post-injury participants completed the Rivermead Post-Concussion Symptom Questionnaire, Hospital Anxiety and Depression Scale, Pittsburgh Sleep Quality Index and the Participation Assessment with Recombined Tools. Analysis of covariance was used to compare differences between TBI cases four years post-injury and controls, controlling for prior TBI and depression. A multiple regression model was used to identify the predictors of increased symptoms and reduced participation. The mild-TBI sample experienced significantly increased self-reported cognitive symptoms (F = 19.90, p = <0.01) four years post-injury than controls. There were no differences between the groups for somatic (F = 0.02, p = 0.89) or emotional symptoms (F = 0.31, p = 0.58). Additionally, the mild-TBI group reported significantly poorer community participation across all three domains: productivity (F = 199.07, p = <0.00), social relations (F = 13.93, p = <0.00) and getting out and about (F = 364.69, p = <0.00) compared to controls. A regression model accounting for 41% of the variance in cognitive symptoms in TBI cases revealed a history of TBI, receiving acute medical attention and baseline cognitive symptoms, sleep quality, anxiety and depression were predictive of outcome. The results indicate that whilst somatic and emotional symptoms resolve over time, cognitive symptoms can become persistent and that mild TBI can impact longer-term community participation. Early intervention is needed to reduce the longer-term impact of cognitive symptoms and facilitate participation.

Medical retirement from sport after concussions: A practical guide for a difficult discussion

Purpose of review

In patients with a considerable history of sports-related concussion, the decision of when to discontinue participation in sports due to medical concerns including neurologic disorders has potentially life-altering consequences, especially for young athletes, and merits a comprehensive evaluation involving nuanced discussion. Few resources exist to aid the sports medicine provider.

Recent findings

In this narrative review, we describe 10 prototypical vignettes based upon the authors' collective experience in concussion management and propose an algorithm to help clinicians navigate retirement discussions. Issues for consideration include absolute and relative contraindications to return to sport, ranging from clinical or radiographic evidence of lasting neurologic injury to prolonged concussion recovery periods or reduced injury threshold to patient-centered factors including personal identity through sport, financial motivations, and navigating uncertainty in the context of long-term risks.

Summary

The authors propose a novel treatment algorithm based on real patient cases to guide medical retirement decisions after concussion in sport.

Game Schedules and Rate of Concussions in the National Football League

Background

Concussion prevention in the National Football League (NFL) is an important priority for player safety. The NFL now has modified game schedules, and one concern is that unconventional game schedules, such as a shortened rest period due to playing on a Thursday rather than during the weekend, may lead to an increased risk of injuries.

Hypothesis

Unconventional game schedules in the NFL are associated with an increased rate of concussion.

Study Design

Descriptive epidemiological study.

Methods

This study analyzed concussions and game schedules over the NFL regular seasons from 2012 to 2015 (4 years). Documented numbers of concussions, identified by use of the online database PBS Frontline Concussion Watch, were summarized by regular-season weeks. Association of days of rest and game location (home, away, or overseas) with the rate of concussion was examined by use of the χ² test. Logistic regression analysis was performed to examine the relationships of days of rest and home/away games to the risk of repeated concussions, with adjustment for player position.

Results

A total of 582 concussions were analyzed in this study. A significantly greater number of concussions occurred in the second half of the season (P < .01). No significant association was found between the rate of concussion and the days of rest, game location, or timing of the bye week by the team or the opponent (P > .05). Game schedules were not significantly associated with the occurrence of repeat concussions (P > .05).

Conclusion

Unconventional game schedules in the NFL, including playing on Thursday and playing overseas, do not seem to put players at increased risk of concussions.

Heart rate variability and implication for sport concussion

Finding sensitive and specific markers for sports-related concussion is both challenging and clinically important. Such biomarkers might be helpful in the management of patients with concussion (i.e. diagnosis, monitoring and risk prediction). Among many parameters, blood flow-pressure metrics and heart rate variability (HRV) have been used to gauge concussion outcomes. Reports on the relation between HRV and both acute and prolonged concussion recovery are conflicting. While some authors report on differences in the low-frequency (LF) component of HRV during postural manipulations and postexercise conditions, others observe no significant differences in various HRV measures. Despite the early success of using the HRV LF for concussion recovery, the interpretation of the LF is debated. Recent research suggests the LF power is a net effect of several intrinsic modulatory factors from both sympathetic and parasympathetic branches of the autonomic nervous system, vagally mediated baroreflex and even some respiratory influences at lower respiratory rate. There are only a few well-controlled concussion studies that specifically examine the contribution of the autonomic nervous system branches with HRV for concussion management. This study reviews the most recent HRV- concussion literature and the underlying HRV physiology. It also highlights cerebral blood flow studies related to concussion and the importance of multimodal assessment of various biological signals. It is hoped that a better understanding of the physiology behind HRV might generate cost-effective, repeatable and reliable protocols, all of which will improve the interpretation of HRV throughout concussion recovery.

Facts and values: on the acceptability of risks in children's sport using the example of rugby - a narrative review

A clash of values has been identified between those who assert that:1. all childhood injuries, regardless of origin, are inherently undesirable and should be prevented and;2. those who believe that some measure of injury to children is an acceptable compromise for the physical benefits associated with physical activity and the development of abilities to appraise and deal with risks.A debate regarding whether the tackles and collisions permitted in schools' rugby represent acceptable risks, and what steps should be taken if they do not, exemplifies the issue.Questions regarding the magnitude of injury risks in sport are issues of fact and can be quantified via the results of injury surveillance studies. Risks are neither high nor low in isolation; they are relatively high or low with reference to other activities or across groups participating in an activity. Issues of the acceptability of a given degree of risk are value dependent. Research regarding perceptions of risk reveals wide variations in the degree of risk people view as acceptable. Factors impacting on risk perception include whether the risks are well known and understood, whether they are 'dread' risks and the degree to which people undertake the risks voluntarily and feel they have control over them.Based on the evidence currently available, the risks to children playing rugby do not appear to be inordinately high compared with those in a range of other childhood sports and activities, but better comparative information is urgently needed. Further evidence, however, should not necessarily be expected to result in the resolution of acceptable risk debates-pre-existing values shape our perspectives on whether new evidence is relevant, valid and reliable.