Incidence, risk, and protective factors of mild traumatic brain injury in a cohort of Australian nonprofessional male rugby players

Characteristics of potential concussive events in elite hurling: a video-analysis study

BACKGROUND

High-impact sports such as hurling place participants at risk of sport-related concussion (SRC).

AIMS

This study will evaluate the characteristics of potential concussive events (PCEs) that occur in elite male hurling to acquire an understanding of how they occur.

METHODS

The authors recorded PCEs and their characteristics throughout two seasons of inter-county GAA competition using broadcast footage based on a previously validated protocol.

RESULTS

A total of 183 PCEs were identified over 82 inter-county matches (2.23 per match; 59.5 per 1000 h of exposure). PCEs that occurred in the 4th quarter were significantly more likely to result in signs of SRC. Players most often intended to receive/control the sliotar (36.4%, n = 64) prior to PCEs. The most frequently observed mechanism was shoulder-to-head (20.2%, n = 37). Impacts to the lateral aspect of the head were 2.7 times more likely to result in visible signs than impacts to anteroposterior regions.

CONCLUSIONS

Players appear to be at a higher risk of SRC later in the match or when receiving the sliotar. Strikes to the lateral aspect of the head and those involving the shoulder appear to produce severe events. These findings provide initial guidance for the development of targeted player protection strategies.

Epidemiology of International Match Injuries in Scottish Rugby: A Prospective Cohort Study

Fifteen-a-side rugby union ("rugby") is a full-contact sport played separately by men and women, with large injury incidences reported previously. Context specific injury surveillance fulfils governing bodies' duty of care to understand risks to player welfare, yet no contemporary match injury epidemiology studies exist for international players in Scotland. The current study therefore aimed to describe the incidence, severity, burden and nature of match injuries sustained by Scotland's men's and women's national teams. A prospective cohort study of injuries recorded in matches across the 2017/18 and 2018/19 seasons was undertaken, with injury and exposure definitions in line with the international consensus for injury surveillance in rugby. Injury incidence was 120.0 (men) and 166.7/1,000 player match hours (women), injury severity was 12.0 (median) and 31.2 days (mean) for men, and 11.0 (median) and 30.2 days (mean) for women. Injury burden was 3,745 (men) and 5,040 days absence/1,000 player match hours (women). Concussion was the most common specific injury for men (22.5/1,000 hours) and women (26.7/1,000 hours). No statistical differences were found for incidence or severity measures between sexes. Injury incidence was greater than recent Rugby World Cup studies. High incidences of concussion reinforces the need for prevention strategies targeting this injury.

Prevention strategies and modifiable risk factors for sport-related concussions and head impacts: a systematic review and meta-analysis

OBJECTIVES

To evaluate prevention strategies, their unintended consequences and modifiable risk factors for sport-related concussion (SRC) and/or head impact risk.

DESIGN

This systematic review and meta-analysis was registered on PROSPERO (CRD42019152982) and conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA SOURCES

Eight databases (MEDLINE, CINAHL, APA PsycINFO, Cochrane (Systematic Review and Controlled Trails Registry), SPORTDiscus, EMBASE, ERIC0 were searched in October 2019 and updated in March 2022, and references searched from any identified systematic review.

ELIGIBILITY CRITERIA

Study inclusion criteria were as follows: (1) original data human research studies, (2) investigated SRC or head impacts, (3) evaluated an SRC prevention intervention, unintended consequence or modifiable risk factor, (4) participants competing in any sport, (5) analytic study design, (6) systematic reviews and meta-analyses were included to identify original data manuscripts in reference search and (7) peer-reviewed. Exclusion criteria were as follows: (1) review articles, pre-experimental, ecological, case series or case studies and (2) not written in English.

RESULTS

In total, 220 studies were eligible for inclusion and 192 studies were included in the results based on methodological criteria as assessed through the Scottish Intercollegiate Guidelines Network high ('++') or acceptable ('+') quality. Evidence was available examining protective gear (eg, helmets, headgear, mouthguards) (n=39), policy and rule changes (n=38), training strategies (n=34), SRC management strategies (n=12), unintended consequences (n=5) and modifiable risk factors (n=64). Meta-analyses demonstrated a protective effect of mouthguards in collision sports (incidence rate ratio, IRR 0.74; 95% CI 0.64 to 0.89). Policy disallowing bodychecking in child and adolescent ice hockey was associated with a 58% lower concussion rate compared with bodychecking leagues (IRR 0.42; 95% CI 0.33 to 0.53), and evidence supports no unintended injury consequences of policy disallowing bodychecking. In American football, strategies limiting contact in practices were associated with a 64% lower practice-related concussion rate (IRR 0.36; 95% CI 0.16 to 0.80). Some evidence also supports up to 60% lower concussion rates with implementation of a neuromuscular training warm-up programme in rugby. More research examining potentially modifiable risk factors (eg, neck strength, optimal tackle technique) are needed to inform concussion prevention strategies.

CONCLUSIONS

Policy and rule modifications, personal protective equipment, and neuromuscular training strategies may help to prevent SRC.

PROSPERO REGISTRATION NUMBER

CRD42019152982.

Soft-shell headgear in rugby union: a systematic review of published studies

Objectives

To review the rate of soft-shell headgear use in rugby union, consumer knowledge of the protection potential of soft-shell headgear, incidence of concussion reported in rugby headgear studies, and the capacity of soft-shell headgear to reduce acceleration impact forces.

Design

A systematic search was conducted in July and August 2021 using the databases SPORT Discus, PubMed, MEDLINE, CINAHL (EBSCO), Scopus, and Science Direct. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The protocol for this systematic review was registered on PROSPERO (registration number: CRD42021239595).

Outcome measures

Rates of headgear use, reports of estimated protection of headgear against head injury, incidence of concussion and magnitude of impact collisions with vs. without headgear, impact attenuation of headgear in lab studies.

Results

Eighteen studies were identified as eligible: qualitative (N = 4), field (N = 7), and lab (N = 7). Qualitative studies showed low rates of headgear use and varying understanding of the protection afforded by headgear. Field studies showed negligible association of headgear use with reduced impact magnitude in headgear vs. non-headgear cohorts. Lab studies showed increased energy attenuation for thicker headgear material, poorer performance of headgear after repetitive impacts and increased drop heights, and promising recent results with headgear composed of viscoelastic polymers.

Conclusions

Rates of adoption of soft-shell headgear remain low in rugby and any association between its use and reduction in acceleration impact forces remains unclear. Lab results indicating improved impact attenuation need to be validated in the field. Further headgear-related research is needed with youth and female rugby players.

Time Delta Head Impact Frequency: An Analysis on Head Impact Exposure in the Lead Up to a Concussion: Findings from the NCAA-DOD Care Consortium

Sport-related concussions can result from a single high magnitude impact that generates concussive symptoms, repeated subconcussive head impacts aggregating to generate concussive symptoms, or a combined effect from the two mechanisms. The array of symptoms produced by these mechanisms may be clinically interpreted as a sport-related concussion. It was hypothesized that head impact exposure resulting in concussion is influenced by severity, total number, and frequency of subconcussive head impacts. The influence of total number and magnitude of impacts was previously explored, but frequency was investigated to a lesser degree. In this analysis, head impact frequency was investigated over a new metric called ‘time delta’, the time difference from the first recorded head impact of the day until the concussive impact. Four exposure metrics were analyzed over the time delta to determine whether frequency of head impact exposure was greater for athletes on their concussion date relative to other dates of contact participation. Those metrics included head impact frequency, head impact accrual rate, risk weighted exposure (RWE), and RWE accrual rate. Athletes experienced an elevated median number of impacts, RWE, and RWE accrual rate over the time delta on their concussion date compared to non-injury sessions. This finding suggests elevated frequency of head impact exposure on the concussion date compared to other dates that may precipitate the onset of concussion.

The association of padded headgear with concussion and injury risk in junior Australian football: A prospective cohort study

OBJECTIVES

To assess whether padded headgear was associated with incidence of suspected sports-related concussion, non-sports-related concussion head injury, and injuries to other body regions in junior Australian football.

DESIGN

Prospective cohort injury surveillance.

METHODS

There were 400 junior players (42.5% female) enrolled across two seasons. Suspected sports-related concussion was defined by detection of observable signs on the field and medical assessment or missed match(es) due to suspected sports-related concussion. Non-sports-related concussion head injury and injuries to other body regions were defined as those that received medical assessment or resulted in a missed match.

RESULTS

There were 20 teams monitored over 258 matches. 204 players (2484 player hours) wore mandated headgear throughout the season and 196 (2246 player hours) did not. The incidence rate of suspected sports-related concussion was 3.17 (95% confidence interval: 3.04-3.30) per 1000 player-hours and no differences were observed between males and females (risk ratio 1.11; 95% confidence interval: 0.40-3.06). Headgear use was not associated with suspected sports-related concussion (risk ratio 1.09; 95% confidence interval: 0.41-2.97), non-sports-related concussion head injury (risk ratio 0.27; 95% confidence interval: 0.06-1.31), or injuries to other body regions (risk ratio 1.41; 95% confidence interval: 0.79-2.53).

CONCLUSIONS

Headgear use was not associated with reduced risk of suspected sports-related concussion, non-sports-related concussion head injury or injuries to other body regions. There was no difference in the rate of suspected sports-related concussion in female compared to male players, however, rates of non-sports-related concussion head injury and injuries to other body regions were higher in male players.

The Neurological Consequences of Engaging in Australian Collision Sports

Collision sports are an integral part of Australian culture. The most common collision sports in Australia are Australian rules football, rugby union, and rugby league. Each of these sports often results in participants sustaining mild brain traumas, such as concussive and subconcussive injuries. However, the majority of previous studies and reviews pertaining to the neurological implications of sustaining mild brain traumas, while engaging in collision sports, have focused on those popular in North America and Europe. As part of this 2020 International Neurotrauma Symposium special issue, which highlights Australian neurotrauma research, this article will therefore review the burden of mild brain traumas in Australian collision sports athletes. Specifically, this review will first provide an overview of the consequences of mild brain trauma in Australian collision sports, followed by a summary of the previous studies that have investigated neurocognition, ocular motor function, neuroimaging, and fluid biomarkers, as well as neuropathological outcomes in Australian collision sports athletes. A review of the literature indicates that although Australians have contributed to the field, several knowledge gaps and limitations currently exist. These include important questions related to sex differences, the identification and implementation of blood and imaging biomarkers, the need for consistent study designs and common data elements, as well as more multi-modal studies. We conclude that although Australia has had an active history of investigating the neurological impact of collision sports participation, further research is clearly needed to better understand these consequences in Australian athletes and how they can be mitigated.

Association between Polymorphism rs1799732 of DRD2 Dopamine Receptor Gene and Personality Traits among MMA Athletes

Four factors—namely, harm avoidance, novelty seeking, reward addiction and persistence—represent the nature of temperament that is not genetically determined in itself. It was shown in earlier studies that a strong propensity to look for novelty or a tendency to engage in risky behavior is correlated with genetic variants in the area of the genes encoding dopamine receptors. Therefore, the aim of this study is to determine whether there is a relationship between personality traits and genetic variants in the area of the DRD2 dopamine receptor gene in MMA athletes. The participants consisted of 85 mixed martial arts (MMA) athletes and 284 healthy, non-MMA male participants. Their personality traits were measured using the Revised Temperament and Character Inventory. Blood was collected for genetic assays and all samples were genotyped using the real-time PCR method. We observed a statistically significant effect of a complex factor of the DRD2 rs1799732 genotype on MMA participants’ control and reward dependence. Engaging in high-risk sport may be associated with several personality characteristics. The DRD2 rs1799732 polymorphism may be associated with reduced harm avoidance in martial arts athletes, thereby modulating athletes’ predisposition to participate in high-risk sport.

Soft-shell headgear, concussion and injury prevention in youth team collision sports: a systematic review

OBJECTIVES

To assess the association between soft-shell headgear (HG) use and sports-related concussion (SRC). Secondary objectives were to assess the association between HG and superficial head injury and investigate potential increase in injury risk among HG users.

DESIGN

A systematic search in Ovid MEDLINE, Cochrane Library, Scopus, PsycINFO and SPORTDiscus was conducted in April 2020. Inclusion criteria were youth <18, English language, in vivo studies published after 1980 that evaluated SRC and other injury incidence in HG users compared with non-users.

OUTCOME MEASURES

Incidence rates of SRC, superficial head injury or other injuries.

RESULTS

Eight studies were eligible. The majority (n=5) reported no difference in the rate of SRC among HG users versus non-users. One rugby study identified significantly lower risk of SRC for non-HG users (risk ratio (RR) 0.63; 95% CI 0.41 to 0.98) compared with HG users, whereas a cross-sectional survey of soccer players indicated higher risk of SRC for non-HG users (RR 2.65; 95% CI 1.23 to 3.12) compared with HG users. Three of the four studies investigating superficial head injury found no significant differences with HG use, though the soccer survey reported reduced risk among HG users (RR 1.86; 95% CI 0.09 to 0.11). Increased incidence of injuries to all body regions for rugby HG users was reported in two studies with adjusted RRs of 1.16 (95% CI 1.04 to 1.29) and 1.23 (95% CI 1.00 to 1.50).

CONCLUSIONS

HG use was not associated with reduced rates of SRC or superficial head injury in youth soccer and rugby. The possibility of increased injury risk to all body regions for rugby HG users was raised. The need for research specific to youth and female athletes was highlighted.

PROSPERO REGISTRATION NUMBER

CRD42018115310.

Sensation-Seeking and Impulsivity in Athletes with Sport-Related Concussion

PURPOSE OF REVIEW

Sport-related concussion (SRC) is a significant public health problem. Understanding the behavioral and personal factors that influence risk and incidence of SRC is critically important for appropriate care and management. Sensation-seeking and impulsivity have been posited to be two such factors that may be significantly associated with SRC. We performed a focused review of recent evidence of the relationships between sensation-seeking and impulsivity in athletes with SRC.

RECENT FINDINGS

While the research is relatively limited, extant findings demonstrate a significant relationship between sensation-seeking and contact sport participation and risk of prior and future SRC. Impulsivity appears to be common among athletes competing in high contact sports and may contribute to neural and functional brain changes following SRC; however, causal relationships between impulsivity, contact sport participation, and SRC have not been demonstrated. Both sensation-seeking and impulsivity are significantly associated with SRC in collegiate athletes. Interventions designed to ameliorate high levels of these constructs may prove to be beneficial avenues to reducing SRC risk and improving patient care and outcomes.

Padded Headgear does not Reduce the Incidence of Match Concussions in Professional Men's Rugby Union: A Case-control Study of 417 Cases

Concussion is the most common match injury in rugby union. Some players wear padded headgear, but whether this protects against concussion is unclear. In professional male rugby union players, we examined: (i) the association between the use of headgear and match concussion injury incidence, and (ii) whether wearing headgear influenced time to return to play following concussion. Using a nested case-control within a cohort study, four seasons (2013-2017) of injury data from 1117 players at the highest level of rugby union in England were included. Cases were physician-diagnosed concussion injuries. Controls were other contact injuries (excluding all head injuries). We determined headgear use by viewing video footage. Sixteen percent of cases and controls wore headgear. Headgear use had no significant effect on concussion injury incidence (adjusted odds ratio=1.05, 95% CI: 0.71-1.56). Median number of days absent for concussion whilst wearing headgear was 8 days, compared with 7 days without headgear. Having sustained a concussion in the current or previous season increased the odds of concussion more than four-fold (odds ratio=4.55, 95% CI: 3.77-5.49). Wearing headgear was not associated with lower odds of concussions or a reduced number of days' absence following a concussion.

Predicting Risk of Sport-Related Concussion in Collegiate Athletes and Military Cadets: A Machine Learning Approach Using Baseline Data from the CARE Consortium Study

OBJECTIVE

To develop a predictive model for sport-related concussion in collegiate athletes and military service academy cadets using baseline data collecting during the pre-participation examination.

METHODS

Baseline assessments were performed in 15,682 participants from 21 US academic institutions and military service academies participating in the CARE Consortium Study during the 2015-2016 academic year. Participants were monitored for sport-related concussion during the subsequent season. 176 baseline covariates mapped to 957 binary features were used as input into a support vector machine model with the goal of learning to stratify participants according to their risk for sport-related concussion. Performance was evaluated in terms of area under the receiver operating characteristic curve (AUROC) on a held-out test set. Model inputs significantly associated with either increased or decreased risk were identified.

RESULTS

595 participants (3.79%) sustained a concussion during the study period. The predictive model achieved an AUROC of 0.73 (95% confidence interval 0.70-0.76), with variable performance across sports. Features with significant positive and negative associations with subsequent sport-related concussion were identified.

CONCLUSION(S)

This predictive model using only baseline data identified athletes and cadets who would go on to sustain sport-related concussion with comparable accuracy to many existing concussion assessment tools for identifying concussion. Furthermore, this study provides insight into potential concussion risk and protective factors.

The Relationship between Sport-Related Concussion and Sensation-Seeking

Sensation-seeking, or the need for novel and exciting experiences, is thought to play a role in sport-related concussion (SRC), yet much remains unknown regarding these relationships and, more importantly, how sensation-seeking influences SRC risk. The current study assessed sensation-seeking, sport contact level, and SRC history and incidence in a large sample of NCAA collegiate athletes. Data included a full study sample of 22,374 baseline evaluations and a sub-sample of 2037 incident SRC. Independent samples t-test, analysis of covariance, and hierarchical logistic regression were constructed to address study hypotheses. Results showed that (1) among participants without SRC, sensation-seeking scores were higher in athletes playing contact sports compared to those playing limited- or non-contact sports (p < 0.001, R² = 0.007, η²_p = 0.003); (2) in the full study sample, a one-point increase in sensation-seeking scores resulted in a 21% greater risk of prior SRC (OR = 1.212; 95% CI: 1.154-1.272), and in the incident SRC sub-sample, a 28% greater risk of prior SRC (OR = 1.278; 95% CI: 1.104-1.480); (3) a one-point increase in sensation-seeking scores resulted in a 12% greater risk of incident SRC among the full study sample; and (4) sensation-seeking did not vary as a function of incident SRC (p = 0.281, η²_p = 0.000). Our findings demonstrate the potential usefulness of considering sensation-seeking in SRC management.

Development of an Eco-Friendly Head Impact Protection Device

Nowadays, the number of people practising contact sports has increased. In many of them, using head protective equipment is not mandatory, even if the use of headbands could increase the level of safety regarding several types of traumatic brain injuries. Many commercial solutions are currently available, based on plastic-based foams providing a decent level of protection and comfort to the user. This work introduces the use of agglomerated cork as an eco-friendly alternative to synthetic foams but at least keeping safety levels. Cork is a natural cellular material that has been showing excellent crashworthiness properties. In this study, cork agglomerate density is carefully chosen to be incorporated into a protective headband. Results are compared against three other commercial headbands. For each one, the risk of brain injury was analysed for different injury thresholds and impact energies. The results clearly demonstrate that the cork-based apparel may provide comparable, and in some cases, better performances, outlasting the commercial ones.

Second Impact Syndrome. Myth or reality?

INTRODUCTION

Second impact syndrome (SIS) is a devastating condition occurring in sport-induced mild brain injury. SIS is drastically defined by anamnestic, clinical and radiological criteria, which is unusual in the field of cranial traumatology. The purpose of this study was to provide a literature review of this syndrome.

MATERIAL AND METHODS

We conducted a literature review of all published studies on PubMed. The keywords were "second impact syndrome and catastrophic head injury", "second impact syndrome and sport", "repeat concussion and catastrophic brain injury", "catastrophic head injury and concussion", "catastrophic head injury", "concussion and second impact syndrome", "concussion and repetitive head injury".

RESULTS

Eighty-two full-text articles were assessed for eligibility. Finally, 41 studies were included in qualitative synthesis and 21 were included in quantitative synthesis.

DISCUSSION

The number of cases reported in the literature was extremely small compared to the population at risk, i.e., the number of athletes exposed to repeated concussions. SIS was similar to talk and die syndrome, with which it shares certain characteristics. If we consider SIS according to "talk and deteriorate tables", it opens up interesting perspectives because they are specific in children and adolescents. Taking into account the scarcity of this syndrome, one may question whether athlete-intrinsic features may be involved in at least some cases of SIS. On a pathophysiological level, many explanations remained unsatisfactory because they were unable to explain all the clinical phenomena and observed lesions. Triggering the trigeminocardiac reflex is a crucial element in explaining the sequence of clinical events. Its association with a state of neurogenic inflammation provides an almost complete explanation for this particular condition. Finally, on a practical level, a concussion occurring during the playing of a sport must be considered as any other injury before allowing a return to play.

Factors Associated With Self-Reported Concussion History in Middle School Athletes

OBJECTIVE

Identifying personal characteristics associated with sustaining a concussion is of great interest, yet only a few have examined this in children. The purpose of this study was to examine the association between sex, neurodevelopmental disorders, health history, and lifetime history of self-reported concussion in 12- and 13-year-old athletes.

DESIGN

Cross-sectional study.

SETTING

Middle schools.

PARTICIPANTS

Participants were 1744 twelve- and thirteen-year-old student athletes who completed preseason Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) testing, including a self-report questionnaire about previous concussions, developmental diagnoses, and previous medical treatment.

INDEPENDENT VARIABLES

Age, sex, attention-deficit/hyperactivity disorder (ADHD), learning disabilities (LDs), and previous treatment for migraine.

MAIN OUTCOME MEASURES

Self-reported history of concussion.

RESULTS

A minority of athletes (13.7%) reported previous concussions (1 concussion, n = 181; 2 concussions, n = 41; and 3+ concussions, n = 17). A small proportion reported a history of ADHD (4.4%), LD (2.8%) or migraine treatment (4.0%). Higher rates of self-reported previous concussions were associated with male sex [16.9% vs 9.1%; χ(1) = 21.47, P < 0.001] and previous migraine treatment [31.9% vs 13.0%; χ(1) = 20.08, P < 0.001]. There were no differences in self-reported concussion history between 12- and 13-year olds (P = 0.18) and those with/without ADHD (P = 0.41) or LDs (P = 0.06). The overall logistic regression model was statistically significant [χ(5) = 42.01, P < 0.001] but explained only 4.3% of the variance. Previous treatment for migraine [P < 0.001, Exp(B) = 3.30] and male sex [P < 0.001, Exp(B) = 2.06] were independently associated with a self-reported concussion history, whereas age, LD, and ADHD were not (P's > 0.05).

CONCLUSIONS

Male sex and previous migraine treatment were associated with higher rates of self-reported previous concussions in both independent and multivariate models in middle school athletes, whereas age, ADHD, and LDs were not.

Mouthguard use in youth ice hockey and the risk of concussion: nested case–control study of 315 cases

Background

Concussion is the most common injury in youth ice hockey. Whether mouthguard use lowers the odds of concussion remains an unanswered question.

Objective

To determine the association between concussion and mouthguard use in youth ice hockey.

Methods

Nested case–control design. Cases and controls were identified from two prospective cohort studies using valid injury surveillance methods. Cases were players concussed during a game or practice; controls were players who sustained a non-concussion injury during a game or practice. The primary exposure was mouthguard use at time of injury; mouthguard type (dental custom fit or off the shelf) was a secondary exposure. Physician-diagnosed or therapist-suspected concussion was the primary outcome. Dental injury was a secondary outcome. Multilevel logistic regression with random effect at a team level was used to obtain ORs for the mouthguard effect, adjusted for level of play, age group, position, concussion history, mechanism of injury, cohort, session type and body checking policy.

Results

Among cases, 236/315 (75%) were wearing a mouthguard at time of injury, while 224/270 (83%) controls were wearing a mouthguard at time of injury. Any mouthguard use was associated with an adjusted OR for concussion of 0.36 (95% CI 0.17 to 0.73). Off-the-shelf mouthguards were associated with a 69% lower odds of concussion (adjusted OR: 0.31; 95% CI 0.14 to 0.65). Dental custom-fit mouthguards were associated with a non-significant 49% lower odds of concussion (adjusted OR: 0.51; 95% CI 0.22 to 1.10). No dental injuries were identified in either cohort.

Conclusion

Mouthguard use was associated with lower odds of concussion. Players should be required to wear mouthguards in youth ice hockey.

Sports-related concussion management as a control problem: using STAMP to examine concussion management in community rugby

The effective management of sports-related concussion is an on-going problem in amateur sport due to a number of systemic issues. These factors have often been studied in isolation with minimal consideration for the interactions between them, or the overall system in which they occur. The aim of this research was to model the actors, controls, and feedback mechanisms influencing the management of concussion in community rugby union using the Systems-Theoretic Accident Model and Processes (STAMP) method. Findings show that there are currently many inadequate controls, that are directly and indirectly impacting effective concussion management. The practical implications of these findings are discussed (e.g. improved guideline education, mandatory medical presence, rule amendments). Additionally, the model provides a sound framework similar team sports can use to inform research into injury management and prevention (e.g. rugby league, hockey, AFL). Practitioner Summary: Research shows that concussion management in regional sport is inconsistent due to contextual limitations. Systems-Theoretic Accident Model and Processes was applied to identify the systemic factors currently influencing concussion management practices in community sport. Findings show inadequate controls precipitate concussion management gaps. Practical implications of the findings are discussed.

The Epidemiology of Sport-Related Concussion: What the Rehabilitation Clinician Needs to Know

Sport-related concussion is common in full-contact and collision sports. Epidemiology studies use different types of surveillance systems and concussion definitions. Concussion incidence rates vary across age, sex, sport, and level of competition. Incidence rates are increasing, likely due to higher rates of reporting following improved knowledge and increased regulations. In this review, we summarize 7 key concepts related to concussion epidemiology: concussion definition, changes in concussion knowledge, reliability and accuracy of injury surveillance systems, conservative management and return to play, reliability of self-report, incidence of concussion across levels of play, and understanding the behaviors of players, coaches, and medical personnel from a multidisciplinary management perspective. J Orthop Sports Phys Ther 2019;49(11):768-778. doi:10.2519/jospt.2019.9105.

A systems approach to understanding the identification and treatment of sport-related concussion in community rugby union

AIM

The aim of the present study was to utilise a systems thinking approach to explore the perceived responsibilities for identifying and treating concussion held by different actors across the community rugby system (e.g., players, coaches, parents, medics, referees, and management), as well as their role-specific concussion management strategies.

METHODS

A systems approach was taken to assess what different stakeholders within rugby systems perceive their roles to be regarding concussion identification and treatment. Through an online survey, 118 members of the amateur (community) rugby union system were asked about their role-specific concussion management responsibilities and strategies. Respondents included players, parents, medics, coaches, club managers, administrators, and volunteers.

RESULTS

The majority of respondents indicated that they were able to identify the symptoms of rugby-related concussion, however, only medics stated their responsibility to use formal concussion assessments (e.g., SCAT2). A smaller number of the respondents indicated that they were involved in treating concussion within their current role/s (majority of which were medics).

CONCLUSIONS

This study illustrated that the current challenges in the identification and treatment of rugby-related concussion in community sport may be due to role/responsibility confusion and possible overreliance on field-side medics. These findings offer insight into the possible limitations of the current concussion management guidelines and may offer empirically based direction for future revisions.

History of concussion and risk of subsequent injury in athletes and service members: A systematic review and meta-analysis

Risk of secondary injury after a primary concussion in sports and military contexts is an emerging area of interest in research. The purpose of this review was to provide an evidence synthesis describing risk of injury in athletic and military populations with and without a history of concussion. Electronic database searches were completed through September 7, 2018 in PubMed, EMBASE, CINAHL and SCOPUS. Peer-reviewed observational studies of any design with participants who were athletes or service members; measured the outcome of any type of injury; and compared injury between those with and without a history of concussion were included. Risk of bias was assessed using the Q-Coh II. Twenty-seven articles were included. Seventeen meta-analyses were completed for risk of any injury, risk of concussion, and risk of extremity injury using odds, hazard, and rate ratios. The results indicate significantly increased odds of all injuries (OR = 2.55; 95%CI 1.85,3.52); concussion (OR = 3.73; 95%CI 2.41,5.78); and lower extremity injuries (OR = 1.60; 95%CI 1.32,1.94) in those with a history of concussion compared to those without. Additional analyses reveal this increased risk is apparent when looking at time to event data and rate of injury based on number of exposures. While the reasons for the increased incidence of secondary injury associated with a concussion are not yet understood, there are potentially behavioral attributes and motor control deficits that contribute. It is suggested that research is needed to determine if active therapeutic treatment for disturbances in sensorimotor and neuromotor control after concussion could attenuate the increased risk for injury.

Insomnia and daytime sleepiness: risk factors for sports-related concussion

OBJECTIVE/BACKGROUND

Poor quality and inadequate sleep are associated with impaired cognitive, motor, and behavioral components of sport performance and increased injury risk. While prior work identifies sports-related concussions as predisposing factors for poor sleep, the role of sleep as a sports-related concussion risk factor is unknown. The purpose of this study was to quantify the effect of poor sleep quality and insomnia symptoms on future sports-related concussion risk.

PATIENTS/METHODS

In this study, 190 NCAA Division-1 athletes completed a survey battery, including the Insomnia Severity Index (ISI) and National Health and Nutrition Examination Survey (NHANES) Sleep module. Univariate risk ratios for future sports-related concussions were computed with ISI and NHANES sleepiness scores as independent predictors. An additional multiple logistic regression model including sport, sports-related concussion history, and significant univariate predictors jointly assessed the odds of sustaining a concussion.

RESULTS

Clinically moderate-to-severe insomnia severity (RR = 3.13, 95% CI: 1.320-7.424, p = 0.015) and excessive daytime sleepiness two or more times per month (RR = 2.856, 95% CI: 0.681-11.977, p = 0.037) increased concussion risk. These variables remained significant and comparable in magnitude in a multivariate model adjusted for sport participation.

CONCLUSION

Insomnia and daytime sleepiness are independently associated with increased sports-related concussion risk. More completely identifying bidirectional relationships between concussions and sleep requires further research. Clinicians and athletes should be cognizant of this relationship and take proactive measures - including assessing and treating sleep-disordered breathing, limiting insomnia risk factors, improving sleep hygiene, and developing daytime sleepiness management strategies - to reduce sports-related concussion risk and support overall athletic performance.

Unravelling the interaction between the DRD2 and DRD4 genes, personality traits and concussion risk

Background

Concussion occurs when biomechanical forces transmitted to the head result in neurological deficits. Personality may affect the balance between safe and dangerous play potentially influencing concussion risk. Dopamine receptor D2 (DRD2) and dopamine receptor D4 (DRD4) genetic polymorphisms were previously associated with personality traits.

Objectives

This case-control genetic association study investigated the associations of (1) DRD2 and DRD4 genotypes with concussion susceptibility and personality, (2) personality with concussion susceptibility and (3) the statistical model of genotype, personality and concussion susceptibility.

Methods

In total, 138 non-concussed controls and 163 previously concussed cases were recruited from high school (n=135, junior), club and professional rugby teams (n=166, senior). Participants were genotyped for DRD2 rs12364283 (A>G), DRD2 rs1076560 (C>A) and DRD4 rs1800955 (T>C) genetic variants. Statistical analyses including structural equation modelling were performed using the R environment and STATA.

Results

The rs1800955 CC genotype (p=0.014) and inferred DRD2 (rs12364283-rs1076560)-DRD4 (rs1800955) A-C-C allele combination (p=0.019) were associated with decreased concussion susceptibility in juniors. The rs1800955 TT and CT genotypes were associated with low reward dependence in juniors (p<0.001) and seniors (p=0.010), respectively. High harm avoidance was associated with decreased concussion susceptibility in juniors (p=0.009) and increased susceptibility in seniors (p=0.001). The model showed that a genetic variant was associated with personality while personality was associated with concussion susceptibility.

Conclusion

These findings highlight the linear relationship between genetics, personality and concussion susceptibility. Identifying a genetic profile of 'high risk' behaviour, together with the development of personalised behavioural training, can potentially reduce concussion risk.

Association of Dynamic Balance With Sports-Related Concussion: A Prospective Cohort Study

BACKGROUND

Concussion is one of the most common sports-related injuries, with little understood about the modifiable and nonmodifiable risk factors. Researchers have yet to evaluate the association between modifiable sensorimotor function variables and concussive injury.

PURPOSE

To investigate the association between dynamic balance performance, a discrete measure of sensorimotor function, and concussive injuries.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

A total of 109 elite male rugby union players were baseline tested in dynamic balance performance while wearing an inertial sensor and prospectively followed during the 2016-2017 rugby union season. The sample entropy of the inertial sensor gyroscope magnitude signal was derived to provide a discrete measure of dynamic balance performance. Logistic regression modeling was then used to investigate the association among the novel digital biomarker of balance performance, known risk factors of concussion (concussion history, age, and playing position), and subsequent concussive injury.

RESULTS

Participant demographic data (mean ± SD) were as follows: age, 22.6 ± 3.6 years; height, 185 ± 6.5 cm; weight, 98.9 ± 12.5 kg; body mass index, 28.9 ± 2.9 kg/m²; and leg length, 98.8 ± 5.5 cm. Of the 109 players, 44 (40.3%) had a history of concussion, while 21 (19.3%) sustained a concussion during the follow-up period. The receiver operating characteristic analysis for the anterior sample entropy demonstrated a statistically significant area under the curve (0.64; 95% CI, 0.52-0.76; P < .05), with the cutoff score of anterior sample entropy ≥1.2, which maximized the sensitivity (76.2%) and specificity (53.4%) for identifying individuals who subsequently sustained a concussion. Players with suboptimal balance performance at baseline were at a 2.81-greater odds (95% CI, 1.02-7.74) of sustaining a concussion during the rugby union season than were those with optimal balance performance, even when controlling for concussion history.

CONCLUSION

Rugby union players who possess poorer dynamic balance performance, as measured by a wearable inertial sensor during the Y balance test, have a 3-times-higher relative risk of sustaining a sports-related concussion, even when controlling for history of concussion. These findings have important implications for research and clinical practice, as it identifies a potential modifiable risk factor. Further research is required to investigate this association in a large cohort consisting of males and females across a range of sports.

Use of Blood Biomarkers in the Assessment of Sports-Related Concussion-A Systematic Review in the Context of Their Biological Significance

OBJECTIVES

To critically review current knowledge on the positive and negative predictive value of blood biomarkers for concussion; to illustrate the clinical and biological contexts that help evaluate the use of these markers in sport-related traumatic brain injuries (TBIs).

METHODS

This systematic review was performed in accordance with PRISMA guidelines. We reviewed the measurement, clinical utility, endpoint, and biological significance of blood biomarkers in concussion.

RESULTS

A total of 4352 publications were identified. Twenty-six articles relating to blood biomarkers were included in the review. Four common blood biomarkers, namely S100B, tau, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP), were examined. Overall, the studies showed S100B measurement and use, either acutely or at several time points, can distinguish injured from noninjured patients with an uncertain degree of utility in predicting mortality. At present, S100B has largely become an acceptable biomarker of TBI; however, studies have begun to highlight the need to incorporate clinical symptoms instead of S100B concentration in isolation on the basis of inconsistent results and lack of specificity across published studies. Further research is needed to evaluate and validate the use of tau, NSE, and GFAP as a diagnostic aid in the management of concussion and TBI.

CONCLUSIONS

At present, blood biomarkers have only a limited role in the evaluation and management of concussion. Although several biomarkers of brain injury have been identified, continued research is required. S100B holds promise as the most clinically useful diagnostic biomarker. Blood biomarkers, in combination with other clinical data, such as head computed tomography, would maximize the diagnostic accuracy. The methodological limitations evident in blood biomarker research results in the need for the clinical utility of blood biomarker use in concussion to be further explored.

Comparison of branded rugby headguards on their effectiveness in reducing impact on the head

Aim

To compare the available brands of rugby headguards and evaluate their impact attenuation properties at various locations on the cranium, with regard to concussion prevention.

Methods

Seven different branded headguards were fitted onto a rigid headform and drop-tested in three different positions. An accelerometer measured the linear acceleration the headform experienced on impact with the ground. Each test involved dropping the headform from a height that generated 103.8 g on average when bare, which is the closest acceleration to the upper limit of the concussion threshold of 100 g. A mean peak acceleration for each drop position was calculated and compared with the bare baseline measurement.

Results

Each headguard demonstrated a significant decrease in the mean peak acceleration from the baseline value (all p≤0.01). Overall the Canterbury Ventilator was the most effective headguard, decreasing the impact force on average by 47%. The least effective was the XBlades Elite headguard, averaging a force reduction of 27%. In five of the seven headguards, the right side of the headwear was the most effective at reducing impact force.

Conclusion

Overall, the results indicate that it would be beneficial to wear a headguard during rugby in order to reduce the impact forces involved in head collisions. There was also a clear difference in performance between the tested brands, establishing the Canterbury headguard as the most effective. However, only one model of headguard from each brand was tested, so further research evaluating all other models should be considered.

Perceptual-cognitive three-dimensional multiple-object tracking task can help the monitoring of sport-related concussion

Objectives

While the rate of sport-related concussion is increasing, more effective tools are needed to help monitor the diagnosis and return to play of athletes. The three-dimensional multiple-object tracking (3D-MOT) exercise is a perceptual-cognitive task that has shown predictive power towards the dynamic requirements of real-world activities such as sport. This study introduced the use of the 3D-MOT task, along with the Standardized Assessment of Concussion (SAC) and Modified Balance Error Scoring System (M-BESS) tests, for diagnosis and return to play in professional sports.

Methods

Fifty-nine professional athletes were tested with the 3D-MOT, SAC and M-BESS tests at 48 hours following the injury. The same measures were employed to evaluate the return to play following the standard concussion management protocol. The SAC and M-BESS tests were also performed in pre-season (baseline) in 32 out of the 59 athletes.

Results

The injured athletes exhibited poor performance on 3D-MOT at 48 hours post injury compared with return to play (p<0.001) as well as compared with healthy professionals' performance scores (p<0.001). Importantly, learning rate, which participants are thought to have an expert advantage on this perceptual-cognitive task, was totally disrupted at 48 hours post injury compared with healthy professionals (p<0.001). The 3D-MOT performance was also correlated to the total number of symptoms (p=0.020), SAC (p=0.031) and M-BESS (p=0.004) scores at 48 hours. Not surprisingly, SAC and M-BESS tests' usefulness for monitoring concussion was found to be weak, particularly when test performance following the injury was compared to baseline (p=0.056 and 0.349 for SAC and M-BESS, respectively).

Conclusion

3D-MOT could help monitor sport-related concussion in professional athletes. The discussion also covers the critical importance of perceptual-cognitive assessment following concussion in the athletic population.

Primary prevention of contact sports-related concussions in amateur athletes: a systematic review from the Eastern Association for the Surgery of Trauma

BACKGROUND

Awareness of the magnitude of contact sports-related concussions has risen exponentially in recent years. Our objective is to conduct a prospectively registered systematic review of the scientific evidence regarding interventions to prevent contact sports-related concussions.

METHODS

Using the Grading of Recommendations Assessment, Development, and Evaluation methodology, we performed a systematic review of the literature to answer seven population, intervention, comparator, and outcomes (PICO) questions regarding concussion education, head protective equipment, rules prohibiting high-risk activity and neck strengthening exercise for prevention of contact sports-related concussion in pediatric and adult amateur athletes. A query of MEDLINE, PubMed, Scopus, Cumulative Index of Nursing and Allied Health Literature, and Embase was performed. Letters to the editor, case reports, book chapters, and review articles were excluded, and all articles reviewed were written in English.

RESULTS

Thirty-one studies met the inclusion criteria and were applicable to our PICO questions. Conditional recommendations are made supporting preventive interventions concussion education and rules prohibiting high-risk activity for both pediatric and adult amateur athletes and neck strengthening exercise in adult amateur athletes. Strong recommendations are supported for head protective equipment in both pediatric and adult amateur athletes. Strong recommendations regarding newer football helmet technology in adult amateur athletes and rules governing the implementation of body-checking in youth ice hockey are supported.

CONCLUSION

Despite increasing scientific attention to sports-related concussion, studies evaluating preventive interventions remain relatively sparse. This systematic review serves as a call to focus research on primary prevention strategies for sports-related concussion.

LEVEL OF EVIDENCE

IV.

PROSPERO REGISTRATION NUMBER

#42016043019.

A Comparison of Cognitive Function in Former Rugby Union Players Compared with Former Non-Contact-Sport Players and the Impact of Concussion History

AIM

This study investigated differences in cognitive function between former rugby and non-contact-sport players, and assessed the association between concussion history and cognitive function.

METHODS

Overall, 366 former players (mean ± standard deviation [SD] age 43.3 ± 8.2 years) were recruited from October 2012 to April 2014. Engagement in sport, general health, sports injuries and concussion history, and demographic information were obtained from an online self-report questionnaire. Cognitive functioning was assessed using the online CNS Vital Signs neuropsychological test battery. Cohen's d effect size statistics were calculated for comparisons across player groups, concussion groups (one or more self-reported concussions versus no concussions) and between those groups with CNS Vital Signs age-matched norms (US norms). Individual differences within groups were represented as SDs.

RESULTS

The elite-rugby group (n = 103) performed worse on tests of complex attention, processing speed, executive functioning, and cognitive flexibility than the non-contact-sport group (n = 65), and worse than the community-rugby group (n = 193) on complex attention. The community-rugby group performed worse than the non-contact group on executive functioning and cognitive flexibility. Compared with US norms, all three former player groups performed worse on verbal memory and reaction time; rugby groups performed worse on processing speed, cognitive flexibility and executive functioning; and the community-rugby group performed worse on composite memory. The community-rugby group and non-contact-sport group performed slightly better than US norms on complex attention, as did the elite-rugby group for motor speed. All three player groups had greater individual differences than US norms on composite memory, verbal memory and reaction time. The elite-rugby group had greater individual differences on processing speed and complex attention, and the community-rugby group had greater individual differences on psychomotor speed and motor speed. The average number of concussions recalled per player was greater for elite rugby and community rugby than non-contact sport. Former players who recalled one or more concussions (elite rugby, 85 %; community rugby, 77 %; non-contact sport, 23 %) had worse scores on cognitive flexibility, executive functioning, and complex attention than players who did not recall experiencing a concussion.

CONCLUSIONS

Past participation in rugby or a history of concussion were associated with small to moderate neurocognitive deficits (as indicated by worse CNS Vital Signs scores) in athletes post retirement from competitive sport.

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.

Attitudes towards protective headgear in UK rugby union players

Background/aim

Concussions in rugby union pose a major threat to player welfare. Research has found protective headgear offers no significant protection against concussions but suggests a large proportion of players perceive headgear to be effective in preventing concussions. This study aimed to explore UK rugby union players’ attitudes towards wearing protective headgear.

Methods

545 rugby union players (85% male) from a range of playing standards completed an online survey. Quantitative and qualitative data were collected on player attitudes towards protective headgear use. Descriptive statistics, multiple regressions and content analysis were used to analyse the responses.

Results

37% of players believed that headgear was effective in preventing head injuries. Playing group was found to be inversely associated with headgear effectiveness (∆R²=0.01, B=−0.13, p=0.02), with youth players holding stronger beliefs that headgear is effective at preventing head injuries compared with all senior groups. The main reasons cited for wearing headgear related to protection from minor injuries (55%) with only 10% of responses related to concussion prevention.

Conclusions

There appears to be a good awareness in UK players that protective headgear is not effective at preventing concussions. Continued education is vital to ensure players are fully aware of the limitations of headgear, and players who wear it do not engage in overly reckless behaviours as a result.

The association between harm avoidance personality traits and self-reported concussion history in South African rugby union players

OBJECTIVES

Personality traits have been proposed to affect the risk of sports concussion, but evidence is limited. Cloninger's Tridimensional Personality Questionnaire (TPQ) measures novelty seeking, harm avoidance (HA), and reward dependence traits. The aim of this study was to investigate the relationship between TPQ scores and concussion history in rugby union players.

DESIGN

Cross-sectional study.

METHODS

Rugby players from high schools, senior amateur clubs, and professional teams provided a self-reported concussion history and completed the TPQ. Participants reporting no previous concussions formed the control group, while participants reporting concussion formed the case group. A one-way analysis of covariance, with age as a covariate, was used to examine the differences in TPQ scores between groups.

RESULTS

Of the 309 participants, 54% reported a minimum of one concussion (junior: 47%; amateur: 52%; professional: 72%). HA scores were significantly higher in junior players without a history of concussion compared to cases (p=0.006). Specifically, the junior control group had higher "anticipatory worry" (p=0.009) and "fear of uncertainty" (p=0.008). In contrast, the professional control group had lower HA scores than cases (p=0.009), while the amateur cohort displayed no differences between control and case groups.

CONCLUSIONS

This study identified a novel association between HA and concussion in rugby players, adding evidence to the role of personality in a multifactorial risk-model of concussion. The findings suggest that lower HA may lead to increased dangerous play in youth rugby, influencing concussion susceptibility. Contrasting associations in the professional cohort suggest further research is required to understand the role of personality in concussion.

Concussion

Concussion has been recognized as a clinical entity for more than 1000 years. Throughout the 20th century it was studied extensively in boxers, but it did not pique the interest of the general population because it is the accepted goal of the boxer to inflict such an injury on their opponent. In 2002, however, the possibility that repetitive concussions could result in chronic brain damage and a progressive neurologic disorder was raised by a postmortem evaluation of a retired player in the most popular sports institution in the United States, the National Football League. Since that time concussion has been a frequent topic of conversation in homes, schools, and on television and has become a major focus of sports programs in communities and schools at all levels. Now all 50 states, the District of Columbia, and the National Collegiate Athletic Association have enacted laws and rules to protect the athlete.

Concussion Incidence and Recurrence in Professional Australian Football Match-Play: A 14-Year Analysis

Background

Concussion incidence rates in professional Australian football may be underreported due to the injury classification definition. A myriad of factors contribute to concussion risk; however, there is limited long-term surveillance in Australian football. This study analysed concussion in one Australian football team over an extended period.

Method

Match-play concussion injuries in one team (n = 116 participants) were diagnosed and treated by the team physician over 14 years. Analysis of factors related to concussion including matches played, time of day and season, and return to play provided an insight into occurrence and recurrence rates.

Results

140 concussions were recorded (17.6 per 1000 player match hours). A strong relationship was evident between matches played and concussion incidence (r = 0.70) and match conditions did not negatively affect the concussion rate. Whether an athlete returned to play in the same match or suffered a loss-of-consciousness concussion (p = 0.84), their ensuing rate of concussion was not affected.

Conclusion

Concussion in professional Australian football was related to the number of matches played. Further, neither previous incidence nor loss of consciousness affected future concussion risk. This study provides ecologically valid evidence of the concussion incidence rate in professional Australian football and has implications for the management of athletes sustaining concussion injuries.

Long-term health outcomes after exposure to repeated concussion in elite level: rugby union players

BACKGROUND

There is continuing concern about effects of concussion in athletes, including risk of the neurodegenerative disease chronic traumatic encephalopathy. However, information on long-term health and wellbeing in former athletes is limited.

METHOD

Outcome after exposure to repeated brain injury was investigated in 52 retired male Scottish international rugby players (RIRP) and 29 male controls who were similar in age and social deprivation. Assessment included history of playing rugby and traumatic brain injury, general and mental health, life stress, concussion symptoms, cognitive function, disability and markers of chronic stress (allostatic load).

RESULTS

The estimated number of concussions in RIRP averaged 14 (median=7; IQR 5-40). Performance was poorer in RIRP than controls on a test of verbal learning (p=0.022) and of fine co-ordination of the dominant hand (p=0.038) and not significantly different on other cognitive tests (p>0.05). There were no significant associations between number of concussions and performance on cognitive tests. Other than a higher incidence of cardiovascular disease in controls, no group differences were detected in general or mental health or estimates of allostatic load. In RIRP, persisting symptoms attributed to concussion were more common if reporting more than nine concussions (p=0.028), although these symptoms were not perceived to affect social or work functioning.

CONCLUSIONS

Despite a high number of concussions in RIRP, differences in mental health, social or work functioning were not found late after injury. Subtle group differences were detected on two cognitive tests, the cause of which is uncertain. Prospective group comparison studies on representative cohorts are required.

What strategies can be used to effectively reduce the risk of concussion in sport? A systematic review

AIM OR OBJECTIVE

To examine the effectiveness of concussion prevention strategies in reducing concussion risk in sport.

DESIGN

Systematic review according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines.

DATA SOURCES

Eleven electronic databases searched and hand-search of references from selected studies.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

The following were the study inclusion criteria: (1) contained original human research data; (2) investigated an outcome of concussion or head impact; (3) evaluated a concussion prevention intervention; (4) included sport participants; (5) analytical study designand (6) peer-reviewed. The following were the exclusion criteria: (1) review articles, case series or case studies and (2) not in English.

RESULTS

The studies selected (n=48) provided evidence related to protective gear (helmets, headgear, mouthguards) (n=25), policy and rule changes (n=13) and other interventions (training, education, facilities) (n=10). Meta-analyses demonstrate a combined effect of a 70% reduction (incidence rate ratio (IRR)=0.3 (95% CI: 0.22 to 0.41)) in concussion risk in youth ice hockey leagues where policy disallows body checking, and the point estimate (IRR=0.8 (95% CI: 0.6 to 1.1)) suggests a protective effect of mouthguards in contact and collision sport (basketball, ice hockey, rugby).

SUMMARY/CONCLUSIONS

Highlights include a protective effect of helmets in skiing/snowboarding and the effectiveness of policy eliminating body checking in youth ice hockey. Future research should examine mouthguards in contact sport, football helmet padding, helmet fit in collision sport, policy limiting contact practice in youth football, rule enforcement to reduce head contact in ice hockey and soccer, ice surface size and board/glass flexibility in ice hockey and training strategies targeting intrinsic risk factors (eg, visual training).

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2016:CRD42016039162.

Concussions and Head Injuries in English Community Rugby Union Match Play

BACKGROUND

Previous research has described general injury patterns in community-level rugby union, but specific information on time-loss head injuries has not been reported.

PURPOSE

To establish the incidence and nature of significant time-loss head injuries in English community rugby match play, and to identify the injury risk for specific contact events.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Over 6 seasons, injury information was collected from 46 (2009-2010), 67 (2010-2011), 76 (2011-2012), 50 (2012-2013), 67 (2013-2014), and 58 (2014-2015) English community rugby clubs (Rugby Football Union levels 3-9) over a total of 175,940 hours of player match exposure. Club injury management staff reported information for all head injuries sustained during match play whereby the player was absent for 8 days or greater. Clubs were subdivided into semiprofessional (mean player age, 24.6 ± 4.7 years), amateur (24.9 ± 5.1 years), and recreational (25.6 ± 6.1 years) playing levels. Contact events from a sample of 30 matches filmed over seasons 2009-2010, 2010-2011, and 2011-2012 provided mean values for the frequency of contact events.

RESULTS

The overall incidence for time-loss head injuries was 2.43 injuries per 1000 player match hours, with a higher incidence for the amateur (2.78; 95% CI, 2.37-3.20) compared with recreational (2.20; 95% CI, 1.86-2.53) ( P = .032) playing level but not different to the semiprofessional (2.31; 95% CI, 1.83-2.79) playing level. Concussion was the most common time-loss head injury, with 1.46 per 1000 player match hours. The tackle event was associated with 64% of all head injuries and 74% of all concussions. There was also a higher risk of injuries per tackle (0.33 per 1000 events; 95% CI, 0.30-0.37) compared with all other contact events.

CONCLUSION

Concussion was the most common head injury diagnosis, although it is likely that this injury was underreported. Continuing education programs for medical staff and players are essential for the improved identification and management of these injuries. With the majority of head injuries occurring during a tackle, an improved technique in this contact event through coach and player education may be effective in reducing these injuries.

Epidemiology and location of rugby injuries treated in US emergency departments from 2004 to 2013

Rugby participation in the US is increasing, and with its inclusion in the 2016 Summer Olympics, the increased participation rates are expected to continue. Naturally, as participation increases, so too do rugby-related injuries. The difference in injury patterns with regard to age and gender illustrates differences in how the game is being played. Understanding what accounts for these emerging injury patterns will help guide future injury prevention efforts. This study provides an update on injury rates for the growing population of rugby players in the US, especially young players. Our results focus on the variation of injury types and the injury rates of various levels of rugby players, including youth, collegiate, and recreational. Using injury data from the National Electronic Injury Surveillance System, we analyzed data in rugby patients for age, gender, body region, type of injury, and severity. We employed statistical weights to calculate national injury estimates. During the 10 years studied, the trend in the number of rugby injuries among all age groups showed a statistically significant increase (R=0.804, P=0.005). The average age of injury was 21.5±6.3 years with facial and head injuries constituting >33% of all injuries, representing a proportional increase of >10%. Men were most frequently injured in the face (18.2%) and head (15.9%); women were most frequently injured in the head (23%) and shoulder (12.3%). There were 9,059 concussions, constituting 7% of all injuries.

Video analysis of concussion injury mechanism in under-18 rugby

BACKGROUND

Understanding the mechanism of injury is necessary for the development of effective injury prevention strategies. Video analysis of injuries provides valuable information on the playing situation and athlete-movement patterns, which can be used to formulate these strategies. Therefore, we conducted a video analysis of the mechanism of concussion injury in junior-level rugby union and compared it with a representative and matched non-injury sample.

METHODS

Injury reports for 18 concussion events were collected from the 2011 to 2013 under-18 Craven Week tournaments. Also, video footage was recorded for all 3 years. On the basis of the injury events, a representative 'control' sample of matched non-injury events in the same players was identified. The video footage, which had been recorded at each tournament, was then retrospectively analysed and coded. 10 injury events (5 tackle, 4 ruck, 1 aerial collision) and 83 non-injury events were analysed.

RESULTS

All concussions were a result of contact with an opponent and 60% of players were unaware of the impending contact. For the measurement of head position on contact, 43% had a 'down' position, 29% the 'up and forward' and 29% the 'away' position (n=7). The speed of the injured tackler was observed as 'slow' in 60% of injurious tackles (n=5). In 3 of the 4 rucks in which injury occurred (75%), the concussed player was acting defensively either in the capacity of 'support' (n=2) or as the 'jackal' (n=1).

CONCLUSIONS

Training interventions aimed at improving peripheral vision, strengthening of the cervical muscles, targeted conditioning programmes to reduce the effects of fatigue, and emphasising safe and effective playing techniques have the potential to reduce the risk of sustaining a concussion injury.

Football Players' Perceptions of Future Risk of Concussion and Concussion-Related Health Outcomes

Concussion is increasingly recognized as a risk of participation in contact and collision sports. There have been few examinations of athletes' perceptions of their susceptibility to concussion or concussion-related health consequences. We examine college football players' perceptions of their risk of sustaining a concussion and concussion-related health consequences in their future, whether these perceptions change over time, and how concussion history is related to perceived future risk of concussion and concussion-related health consequences. A survey was administered to National Collegiate Athletic Association Division I Football Championship Series athletes on 10 teams in 2013 and to nine of those teams in 2014. Athletes answered questions assessing their perceptions of concussion and potential concussion-related health consequences. Approximately 40% of athletes believed there was a strong possibility that they would sustain a concussion in the future, while approximately one-in-four thought a concussion would make them miss a few games. About one-in-10 athletes predicted dementia, Alzheimer's disease, or chronic traumatic encephalopathy would develop from concussions. These beliefs were stronger among athletes who had sustained previous concussions. Across the two years studied, athletes' perceptions of the risk of concussion and missing a few games because of concussion decreased significantly. Overall, a substantial proportion of college football players believe they will have long-term health consequences as a result of sustaining sport-related concussions. The true incidence and prevalence of many of these outcomes are unknown. Further research is needed to determine whether athletes have an accurate perception of the risks of these outcomes developing.

Biomechanical Perspectives on Concussion in Sport

Concussions can occur in any sport. Often, clinical and biomechanical research efforts are disconnected. This review paper analyzes current concussion issues in sports from a biomechanical perspective and is geared toward Sports Med professionals. Overarching themes of this review include the biomechanics of the brain during head impact, role of protective equipment, potential population-based differences in concussion tolerance, potential intervention strategies to reduce the incidence of injury, and common biomechanical misconceptions.

Incidence and Factors Associated With Concussion Injuries at the 2011 to 2014 South African Rugby Union Youth Week Tournaments

OBJECTIVE

To determine the concussion incidence and to identify factors associated with concussion in South African youth rugby union players.

DESIGN

Prospective cohort study.

SETTING

Injury surveillance was completed at the South African Rugby Union Youth Week tournaments (under-13, under-16, and under-18 age groups).

PARTICIPANTS

South African youth rugby union players. A total of 7216 players participated in 531 matches between 2011 and 2014.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Concussion incidence was calculated per 1000 player-match-hours with 95% CIs. Poisson regression was used to calculate the incidence rate ratio (IRR) between factors (age, time period, playing position, and activity at the time of concussion) potentially associated with concussions.

RESULTS

The concussion incidence was 6.8/1000 player-match-hours (95% CI, 5.5-8.1) across all age groups. Under-13s (IRR, 1.5; P = 0.09) and under-16s (IRR, 1.7; P = 0.03) had higher concussion incidence rates than the under-18 age group. The incidence was higher in the third (IRR, 2.1; P = 0.04) and fourth (IRR, 2.5; P = 0.01) quarters of matches compared with the first quarter. Sixty-two percent of concussions occurred in the tackle situation. The tackler had a 4-fold greater concussion rate (IRR, 4.3; P < 0.001) compared with the ball carrier. The hooker and loose forwards had higher incidence rates than several other player positions (P < 0.05).

CONCLUSIONS

The reported concussion incidence falls within the broad range previously reported in youth rugby. The evidence highlighted in this study may contribute to targeted concussion prevention strategies and provide a baseline against which the effectiveness of future interventions can be measured.