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

Head injury predictors in sports trauma--a state-of-the-art review

Head injuries occur in a great variety of sports. Many of these have been associated with neurological injuries, affecting the central nervous system. Some examples are motorsports, cycling, skiing, horse riding, mountaineering and most contact sports such as football, ice and field hockey, soccer, lacrosse, etc. The outcome of head impacts in these sports can be very severe. The worst-case scenarios of permanent disability or even death are possibilities. Over recent decades, many In recent decades, a great number of head injury criteria and respective thresholds have been proposed. However, the available information is much dispersed and a consensus has still not been achieved regarding the best injury criteria or even their thresholds. This review paper gives a thorough overview of the work carried out by the scientific community in the field of impact biomechanics about head injuries sustained during sports activity. The main goal is to review the head injury criteria, as well as their thresholds. Several are reviewed, from the predictors based on kinematics to the ones based on human tissue thresholds. In this work, we start to briefly introduce the head injuries and their mechanisms commonly seen as a result of head trauma in sports. Then, we present and summarize the head injury criteria and their respective thresholds.

Concussive Injuries in Rugby 7s: An American Experience and Current Review

PURPOSE

There is a comparative lack of concussion incidence data on the new Olympic sport Rugby 7s. This study aimed to determine the incidence (number of concussions per 1000 playing hours [ph]), mean and median severity (days absence), and cause of concussive injuries.

METHODS

This is a prospective epidemiology study, amateur to elite/national candidate, male (9768) and female (3876) players in USA Rugby sanctioned tournaments, compliant with the international consensus statement for studies in rugby union.

RESULTS

Concussions in US Rugby 7s were 7.7/1000 ph (n = 67). Women encountered concussions at 8.1/1000 ph, and men at 7.6/1000 ph (risk ratio [RR] = 1.10, P = 0.593). Elite/national-level players encountered concussions at higher rates (18.3/1000 ph) than lower levels (6.4/1000 ph; RR = 5.48, P < 0.001). Nonelite backs had higher concussive injury rates compared with forwards (7.7/1000 ph; 3.6/1000 ph; RR = 1.28, P = 0.024). Women missed 36.7 d absence from play, meanwhile men missed 27.9 d (P = 0.245). Retrospective history recall reflected previous concussive injuries occurred in 43% of the current study's cohort; of these, 57% encountered multiple concussions within 1 yr. The incidence of repetitive concussions was not statistically different between genders (RR = 1.09, P = 0.754). Most concussions occurred from tackles (63%) and collisions (24%) (P = 0.056).

CONCLUSIONS

Sports-related concussions occurred with frequency among US amateur Rugby 7s players. US Elite tournament players sustained concussions at much higher rates than international male Rugby 7s counterparts. A substantial portion of US players who sustained a concussion had previous concussion injuries. Given the high rate of concussion, including repetitive concussive injuries, US Rugby 7s may benefit from concussion prevention measures similar to other contact sports such as instruction on proper tackling techniques, in-game and postgame medical assessment, and a standardized return-to-play protocol.

A systematic review and meta-analysis of concussion in rugby union

BACKGROUND

Rugby Union, a popular full-contact sport played throughout the world, has one of the highest rates of concussion of all full-contact sports.

OBJECTIVE

The aim of the current review was to systematically evaluate the available evidence on concussion in Rugby Union and to conduct a meta-analysis of findings regarding the incidence of concussion.

METHODS

Articles were retrieved via a number of online databases. The current review examined all articles published in English up to May 2014 pertaining to concussion in Rugby Union players. The key search terms included 'Rugby Union', 'rugby', 'union', and 'football', in combination with the injury terms 'athletic injuries', 'concussion', 'sports concussion', 'sports-related concussion', 'brain concussion', 'brain injury', 'brain injuries', 'mild traumatic brain injury', 'mTBI', 'traumatic brain injury', 'TBI', 'craniocerebral trauma', 'head injury', and 'brain damage'.

RESULTS

The final search outcome following the eligibility screening process resulted in the inclusion of 96 articles for this review. The meta-analysis included a total of 37 studies. The results of the meta-analysis revealed an overall incidence of match-play concussion in men's rugby-15s of 4.73 per 1,000 player match hours. The incidence of concussion during training was 0.07 per 1,000 practice hours. The incidence of concussion in women's rugby-15s was 0.55 per 1,000 player match hours. In men's rugby-7s match-play, concussion incidence was 3.01 per 1,000 player match hours. The incidence of concussion varied considerably between levels of play, with elite level play recording a rate of 0.40 concussions per 1,000 player match hours, schoolboy level 0.62 concussions per 1,000 player match hours, and the community or sub-elite level recording a rate of 2.08 concussions per 1,000 player match hours. The incidence of concussion in men's rugby-15s as a function of playing position (forwards vs. backs) was 4.02 and 4.85 concussions per 1,000 player match hours, respectively.

CONCLUSIONS

Concussion is a common injury sustained and reported in match play and to a lesser extent during practice by Rugby Union players. Based on the available published data, there appears to be a variation in risk of concussion across level of play, with the sub-elite level having the greatest incidence of injury. Future research focused on studying the acute consequences and best management strategies in current players, and the potential longer term outcomes of concussion in retired players, is needed. A focus on the areas of prevention, injury identification, and medical management, and risk for long-term outcomes will be of benefit to current athletes.

Helmets, head injury and concussion in sport

Research on the mechanism of concussion in recent years has been focused on the mechanism of injury as well as strategies to minimize or reverse injury. Sports-related head injury research has led to the development of head protective gear that has evolved over the years. Headgears have been designed to protect athletes from skull fractures, subdural hemorrhages and concussions. Over the years, through experience of athletes and continued scientific research, improvements in helmet design have been made. Although these advances have decreased the number of catastrophic injuries throughout sports, the effects on concussions are promising, but largely unproven. In this review, we will discuss development of helmets and studies analyzing their level of protection for both concussion and head injury. This will help us understand what future developments are still needed to minimize the risk of concussion among athletes in various forms of sports.

Networks of neuroinjury semantic predications to identify biomarkers for mild traumatic brain injury

Objective

Mild traumatic brain injury (mTBI) has high prevalence in the military, among athletes, and in the general population worldwide (largely due to falls). Consequences can include a range of neuropsychological disorders. Unfortunately, such neural injury often goes undiagnosed due to the difficulty in identifying symptoms, so the discovery of an effective biomarker would greatly assist diagnosis; however, no single biomarker has been identified. We identify several body substances as potential components of a panel of biomarkers to support the diagnosis of mild traumatic brain injury.

Methods

Our approach to diagnostic biomarker discovery combines ideas and techniques from systems medicine, natural language processing, and graph theory. We create a molecular interaction network that represents neural injury and is composed of relationships automatically extracted from the literature. We retrieve citations related to neurological injury and extract relationships (semantic predications) that contain potential biomarkers. After linking all relationships together to create a network representing neural injury, we filter the network by relationship frequency and concept connectivity to reduce the set to a manageable size of higher interest substances.

Results

99,437 relevant citations yielded 26,441 unique relations. 18,085 of these contained a potential biomarker as subject or object with a total of 6246 unique concepts. After filtering by graph metrics, the set was reduced to 1021 relationships with 49 unique concepts, including 17 potential biomarkers.

Conclusion

We created a network of relationships containing substances derived from 99,437 citations and filtered using graph metrics to provide a set of 17 potential biomarkers. We discuss the interaction of several of these (glutamate, glucose, and lactate) as the basis for more effective diagnosis than is currently possible. This method provides an opportunity to focus the effort of wet bench research on those substances with the highest potential as biomarkers for mTBI.

FMRI hypoactivation during verbal learning and memory in former high school football players with multiple concussions

Multiple concussions before the age of 18 may be associated with late-life memory deficits. This study examined neural activation associated with verbal encoding and memory retrieval in former athletes ages 40-65 who received at least two concussions (median = 3; range = 2-15) playing high school football and a group of former high school football players with no reported history of concussions matched on age, education, and pre-morbid IQ. Functional magnetic resonance imaging data collected during a modified verbal paired associates paradigm indicated that those with concussive histories had hypoactivation in left hemispheric language regions, including the inferior/middle frontal gyri and angular gyrus compared with controls. However, concussive history was not associated with worse memory functioning on neuropsychological tests or worse behavioral performance during the paradigm, suggesting that multiple early-life concussions may be associated with subtle changes in the verbal encoding system that limits one from accessing higher-order semantic networks, but this difference does not translate into measurable cognitive performance deficits.

Incidence and Nature of Medical Attendance Injuries in English Community Rugby Union

BACKGROUND

Previous research has identified injury patterns during community-level rugby union match play, but none have investigated the frequency and reasons for on-field injury management.

PURPOSE

To establish the frequency, reasons, and patterns of on-field injury management in English community rugby, including differences between different levels of play.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Over 3 seasons, injury information was collected from 46 (2009-2010), 67 (2010-2011), and 76 (2011-2012) English community clubs (Rugby Football Union [RFU] levels 3-9). Club injury management staff reported information for all medical attendances during match play, including details on the injury site and type, playing position (seasons 2010-2011 and 2011-2012 only), and whether the player was removed from play. Clubs were subdivided into groups A (RFU levels 3 and 4 [mainly semiprofessional]; n = 39), B (RFU levels 5 and 6 [mainly amateur]; n = 71), and C (RFU levels 7-9 [social and recreational]; n = 79) to differentiate playing levels.

RESULTS

The overall medical attendance incidence was 229 per 1000 player-match hours (95% CI, 226-232), with 45 players removed per 1000 player-match hours (95% CI, 44-46). Attendance incidence for group A (294 per 1000 player-match hours; 95% CI, 287-301) was higher compared with group B (213; 95% CI, 208-218; P < .001) and C (204; 95% CI, 200-209; P < .001). There was a higher incidence of attendances to forwards (254; 95% CI, 249-259) compared with backs (191; 95% CI, 187-196; P < .001). The head was the most common specific site of injury (55 per 1000 player-match hours; 95% CI, 53-57) but the lower limb region overall accounted for most attendances (87; 95% CI, 85-89) and the greatest chance of removal from the pitch (22; 95% CI, 21-23).

CONCLUSION

With the likelihood of 1 injury for each team per match severe enough for the player to leave the pitch and with at least 1 attendance for a head injury per match, there is clear evidence that pitch side staff should be trained to recognize potentially serious injuries.

Return to rugby after brain concussion: a prospective study in 35 high level rugby players

Background:

Although guidelines based on expert opinions have been developed for the immediate management and return to play of athletes after a concussion, data are lacking on this issue.

Objectives:

Evaluate a standardized management of brain concussion among rugby players to prevent the recurrence.

Patients and Methods:

A prospective study was performed from September 2009 to June 2012. All rugby players who had a concussion when playing rugby were included. Patients were managed by a specialized hospital team with a specific protocol developed in collaboration with the medical staff of the rugby clubs included in the study. The series included 35 rugby players, with 23 professionals and 12 high-level players, 30 men and 5 women, mean age 23.1 ± 5.5 years old. The median number of previous concussions was 2 (0-30) episodes. According to the Cantu concussion severity classification, 3 athletes were grade 1, 12 were grade 2 and 20 were grade 3. None of the injured athletes was lost to follow-up. The primary endpoint was the occurrence of a new concussion within 3 months after the first in patients who returned to rugby.

Results:

Thirty-three patients returned to rugby after a mean 22.1 ± 10 days. The recurrence rate within 3 months was 2/33 (6.1%). The median delay before returning to rugby was 21 (7-45) days. Factors associated with a delayed return to play were young age, initial loss of consciousness, severity Cantu grade 3 and post-concussive syndrome of more than 5 days. Analysis of two failures showed that the initial injury was grade 3 and that both were professional athletes and had a history of concussion.

Conclusions:

This prospective study validated the study protocol for the management of concussion in rugby players.

Current topics in sports-related head injuries: a review

We review the current topic in sports-related head injuries including acute subdural hematoma (ASDH), concussion, and chronic traumatic encephalopathy (CTE). Sports-related ASDH is a leading cause of death and severe morbidity in popular contact sports like American football in the USA and judo in Japan. It is thought that rotational acceleration is most likely to produce not only cerebral concussion but also ASDH due to the rupture of a parasagittal bridging vein, depending on the severity of the rotational acceleration injury. Repeated sports head injuries increase the risk for future concussion, cerebral swelling, ASDH or CTE. To avoid fatal consequences or CTE resulting from repeated concussions, an understanding of the criteria for a safe post-concussion return to play (RTP) is essential. Once diagnosed with a concussion, the athlete must not be allowed to RTP the same day and should not resume play before the concussion symptoms have completely resolved. If brain damage has been confirmed or a subdural hematoma is present, the athlete should not be allowed to participate in any contact sports. As much remains unknown regarding the pathogenesis and pathophysiology of sports-related concussion, ASDH, and CTE, basic and clinical studies are necessary to elucidate the crucial issues in sports-related head injuries.

Helmets in sport: fact and fallacy

Head injuries and the prevention of both the short-term and long-term consequences have received heightened awareness in recent years. Education and legislative efforts have promoted both appropriate treatment of concussion and pushed the use of helmets for protection from head injuries. Current scientific data would suggest that helmets are effective at decreasing the risk of serious head injuries. However there is no evidence to suggest that helmets are protective against concussive injuries or the long-term impact of repetitive head trauma.

Sport-related concussions

Traumatic brain injury (TBI) is a major cause of lifelong disability and death worldwide. Sport-related traumatic brain injury is an important public health concern. The purpose of this review was to highlight the importance of sport-related concussions. Concussion refers to a transient alteration in consciousness induced by external biomechanical forces transmitted directly or indirectly to the brain. It is a common, although most likely underreported, condition. Contact sports such as American football, rugby, soccer, boxing, basketball and hockey are associated with a relatively high prevalence of concussion. Various factors may be associated with a greater risk of sport-related concussion, such as age, sex, sport played, level of sport played and equipment used. Physical complaints (headache, fatigue, dizziness), behavioral changes (depression, anxiety, irritability) and cognitive impairment are very common after a concussion. The risk of premature return to activities includes the prolongation of post-concussive symptoms and increased risk of concussion recurrence.

The incidence of injury among male and female intercollegiate rugby players

Background:

The National Collegiate Athletic Association classifies women’s rugby as an emerging sport. Few studies have examined the injury rates in women’s collegiate rugby or compared injury rates between sexes.

Hypothesis:

Injury rates will differ between female and male intercollegiate club rugby players.

Study Design:

Descriptive epidemiological study.

Methods:

Five years of injury data were collected from the men’s and women’s rugby teams at a US service academy using the institution’s injury surveillance system. The primary outcome of interest was the incidence rate of injury during the study period per 10,000 athlete exposures. Incidence rate ratios (IRRs) were calculated using a Poisson distribution to compare the rates by sex.

Results:

During the study period, the overall incidence rate for injury was 30% higher (IRR = 1.30, 95% CI: 1.09, 1.54) among men when compared with women; however, the distribution of injuries varied by sex. The incidence rate for ACL injury among women was 5.3 times (IRR = 5.32, 95% CI: 1.33, 30.53) higher compared with that among men. Men were 2.5 times (IRR = 2.54, 95% CI: 1.03, 7.52) more likely to sustain a fracture. The rate of acromioclavicular joint injury was 2.2 times (IRR = 2.19, 95% CI: 1.03, 5.19) higher among men when compared with women. Men were 6.6 times (IRR = 6.55, 95% CI: 2.65, 20.91) more likely to have an open wound than women.

Conclusion:

There are differences in injury rates and patterns between female and male American rugby players.

Clinical Relevance:

The differences in injury patterns may reflect distinct playing styles, which could be the result of the American football background common among many of the male players.

Toward objective markers of concussion in sport: a review of white matter and neurometabolic changes in the brain after sports-related concussion

Abstract Sports-related concussion is an issue that has piqued the public's attention of late as concerns surrounding potential long-term sequelae as well as new methods of characterizing the effects of this form of injury continue to develop. For the most part, diagnosis of concussion is based on subjective clinical measures and thus is prone to under-reporting. In the current environment, where conventional imaging modalities, such as computed tomography and magnetic resonance imaging, are unable to elucidate the degree of white matter damage and neurometabolic change, a discussion of two advanced imaging techniques-diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS)-is undertaken with a view to highlighting their potential utility. Our aim is to outline a variety of the approaches to concussion research that have been employed, with special attention given to the clinical considerations and acute complications attributed to concussive injury. DTI and MRS have been at the forefront of research as a result of their noninvasiveness and ease of acquisition, and hence it is thought that the use of these neuroimaging modalities has the potential to aid clinical decision making and management, including guiding return-to-play protocols.

Risk modifiers for concussion and prolonged recovery

Context:

Currently, no consensus exists for grading the severity of concussions. Identification of risk factors that may affect concussion risk and the likelihood of prolonged recovery can be of value to providers who manage concussion.

Evidence Acquisition:

Relevant studies were identified through MEDLINE (1996-2011) using the keywords concussion, postconcussive syndrome, and risk or risk factor. Targeted searches for specific risk factors were conducted with additional keywords, such as gender and migraine. Manual review of reference lists was also performed to identify pertinent literature.

Results:

For risk factors of concussion, history of prior concussion and female sex have the most supporting evidence. Sports with consistently high risk for sustaining a concussion include football, men’s ice hockey, and women’s soccer. Younger athletes appear to be more susceptible to concussion, but data are limited and inconsistent. Protective equipment does not definitively alter concussion risk, though it protects against other injuries. Symptoms such as long headaches, migraines, amnesia, and multiple symptoms appear to be associated with prolonged recovery. Younger age may also increase the risk of prolonged concussion.

Conclusion:

High-quality evidence for risk modifiers in concussion remains sparse. Prior concussion, collision sports, female sex, and women’s soccer are the strongest known risk factors. Evidence for most other factors is inconclusive.

Epidemiology of concussion in sport: a literature review

OBJECTIVE

The purpose of this study was to summarize sport concussion incidence data, identify sports that present higher injury frequency, reveal the degree of risk in some lesser-known sports, and outline specific details within the sports literature that raise additional concerns, such as helmet-to-helmet contact and player positions that experience frequent impact.

METHODS

A systematic literature review of Pub Med using keyword search on injury, concussion, and sports was performed through May 2012. Abstracts were identified, selections were made based upon inclusion criteria, and full-length articles were obtained. Additional articles were considered following review of reference sections. Articles were reviewed and tabulated according to sport.

RESULTS

Two hundred eighty-nine articles were screened, and 62 articles were reviewed. The overall incidence of concussion in sport ranged from 0.1 to 21.5 per 1000 athletic exposures. The lowest incidence was reported in swimming and diving. Concussion incidence was highest in Canadian junior ice hockey, but elevated incidence in American football remains a concern because of the large number of participants.

CONCLUSIONS

The literature reviewed included incidence of concussion on the field of play under real-world conditions and influenced by the current culture of sport. The studies examined in this article show that there is risk of concussion in nearly every sport. Some sports have higher concussion frequency than others, which may depend upon the forces and roles of the positions played in these sports. Younger athletes have a higher incidence of concussion, and female incidence is greater than male in many comparable sports. Headgear may reduce concussion in some sports but may also give athletes a false sense of protection.

Where do we go from here? An inside look into the development of Georgia's Youth Concussion Law

Currently, all 50 states and the District of Columbia have youth concussion laws based on the core principals of the 2009 Lystedt Law of Washington State. On April 23, 2013, the state of Georgia signed into law House Bill 284, "The Return to Play Act of 2013" and became one of the last states to pass youth concussion legislation. This Act became effective on January 1, 2014. The purpose of this report is to highlight the legislative process of enacting Georgia House Bill 284 and compare it to the legislation of other states.

The neuropathology of sport

The benefits of regular exercise, physical fitness and sports participation on cardiovascular and brain health are undeniable. Physical activity reduces the risk for cardiovascular disease, type 2 diabetes, hypertension, obesity, and stroke, and produces beneficial effects on cholesterol levels, antioxidant systems, inflammation, and vascular function. Exercise also enhances psychological health, reduces age-related loss of brain volume, improves cognition, reduces the risk of developing dementia, and impedes neurodegeneration. Nonetheless, the play of sports is associated with risks, including a risk for mild TBI (mTBI) and, rarely, catastrophic traumatic injury and death. There is also growing awareness that repetitive mTBIs, such as concussion and subconcussion, can occasionally produce persistent cognitive, behavioral, and psychiatric problems as well as lead to the development of a neurodegeneration, chronic traumatic encephalopathy (CTE). In this review, we summarize the beneficial aspects of sports participation on psychological, emotional, physical and cognitive health, and specifically analyze some of the less common adverse neuropathological outcomes, including concussion, second-impact syndrome, juvenile head trauma syndrome, catastrophic sudden death, and CTE. CTE is a latent neurodegeneration clinically associated with behavioral changes, executive dysfunction and cognitive impairments, and pathologically characterized by frontal and temporal lobe atrophy, neuronal and axonal loss, and abnormal deposits of paired helical filament (PHF)-tau and 43 kDa TAR deoxyribonucleic acid (DNA)-binding protein (TDP-43). CTE often occurs as a sole diagnosis, but may be associated with other neurodegenerative disorders, including motor neuron disease (CTE-MND). Although the incidence and prevalence of CTE are not known, CTE has been reported most frequently in American football players and boxers. Other sports associated with CTE include ice hockey, professional wrestling, soccer, rugby, and baseball.

A prospective study of physician-observed concussion during a varsity university hockey season: white matter integrity in ice hockey players. Part 3 of 4

OBJECT

The aim of this study was to investigate the effect of repetitive head impacts on white matter integrity that were sustained during 1 Canadian Interuniversity Sports (CIS) ice hockey season, using advanced diffusion tensor imaging (DTI).

METHODS

Twenty-five male ice hockey players between 20 and 26 years of age (mean age 22.24 ± 1.59 years) participated in this study. Participants underwent pre- and postseason 3-T MRI, including DTI. Group analyses were performed using paired-group tract-based spatial statistics to test for differences between preseason and postseason changes.

RESULTS

Tract-based spatial statistics revealed an increase in trace, radial diffusivity (RD), and axial diffusivity (AD) over the course of 1 season. Compared with preseason data, postseason images showed higher trace, AD, and RD values in the right precentral region, the right corona radiata, and the anterior and posterior limb of the internal capsule. These regions involve parts of the corticospinal tract, the corpus callosum, and the superior longitudinal fasciculus. No significant differences were observed between preseason and postseason for fractional anisotropy.

CONCLUSIONS

Diffusion tensor imaging revealed changes in white matter diffusivity in male ice hockey players over the course of 1 season. The origin of these findings needs to be elucidated.

Summary of evidence-based guideline update: evaluation and management of concussion in sports: report of the Guideline Development Subcommittee of the American Academy of Neurology

OBJECTIVE

To update the 1997 American Academy of Neurology (AAN) practice parameter regarding sports concussion, focusing on 4 questions: 1) What factors increase/decrease concussion risk? 2) What diagnostic tools identify those with concussion and those at increased risk for severe/prolonged early impairments, neurologic catastrophe, or chronic neurobehavioral impairment? 3) What clinical factors identify those at increased risk for severe/prolonged early postconcussion impairments, neurologic catastrophe, recurrent concussions, or chronic neurobehavioral impairment? 4) What interventions enhance recovery, reduce recurrent concussion risk, or diminish long-term sequelae? The complete guideline on which this summary is based is available as an online data supplement to this article.

METHODS

We systematically reviewed the literature from 1955 to June 2012 for pertinent evidence. We assessed evidence for quality and synthesized into conclusions using a modified Grading of Recommendations Assessment, Development and Evaluation process. We used a modified Delphi process to develop recommendations.

RESULTS

Specific risk factors can increase or decrease concussion risk. Diagnostic tools to help identify individuals with concussion include graded symptom checklists, the Standardized Assessment of Concussion, neuropsychological assessments, and the Balance Error Scoring System. Ongoing clinical symptoms, concussion history, and younger age identify those at risk for postconcussion impairments. Risk factors for recurrent concussion include history of multiple concussions, particularly within 10 days after initial concussion. Risk factors for chronic neurobehavioral impairment include concussion exposure and APOE ε4 genotype. Data are insufficient to show that any intervention enhances recovery or diminishes long-term sequelae postconcussion. Practice recommendations are presented for preparticipation counseling, management of suspected concussion, and management of diagnosed concussion.

Time-to-subsequent head injury from sports and recreation activities

OBJECTIVE

To provide population-based risk estimates for sustaining subsequent head injuries (HIs), which occur in sports and recreation (SR).

DESIGN

Population-based, retrospective, cross-sectional study.

SETTING

Retrospective review of data from 2 tertiary care and 3 community care emergency departments (EDs) in Edmonton, Alberta, Canada.

PATIENTS

Individuals younger than 36 years presenting to an ED with an SR-related injury between April 1, 1997, and March 31, 2008. There were 9246 subsequent ED records identified for 8958 patients in the main analysis.

MAIN OUTCOME MEASURES

Clinically diagnosed HI occurring in SR activities after an index presentation, and the number of days between ED presentations for diagnosed SR-HIs.

RESULTS

Individuals with 1 and 2 previous SR-related HIs were 2.62 [95% confidence interval (CI), 2.23-3.07] and 5.94 times, respectively, more likely (95% CI, 3.43-10.29) to sustain a subsequent HI than those without a previous HI. The median time-to first HI was 758 days from an initial injury and decreased to 613 days and 303 days for those at risk of second and third SR-related HIs (P < 0.0001). Individuals aged 7 to 13 years were 4.29 times more likely (95% CI, 2.65-6.92) to sustain an HI when presenting with a subsequent SR injury, compared with those aged 30 to 35 years.

CONCLUSIONS

The odds of sustaining a subsequent HI substantially increase with each successive HI. Time between SR-related HIs shortens as the number of HIs increases. Initial HI may be a key marker to institute high-risk injury prevention measures directed at young persons who present to EDs.

Protective equipment and the prevention of concussion - what is the evidence?

The complex nature of the evaluation and management of concussion lends to controversy, and the immediate and long-term implications still are being investigated. Various types of protective equipment have been used as a means to prevent concussions, and protective equipment is being used more frequently in different sports. Recent investigations have suggested that a protective, but not preventive, effect may be afforded by mouthguard use in rugby players, headgear use in soccer players, and customized mandibular orthotic use in football players. The use of faceshields has not shown a proven benefit in preventing the incidence of sport-related concussion in ice hockey or field hockey participants. Further studies are needed to clarify the role of protective equipment in the prevention of sport-related concussion.

The current status of postconcussion syndrome

PURPOSE OF REVIEW

Concussion produces a brief disruption in mental status and is associated with a variety of physical and cognitive symptoms which typically diminish during the first several days to weeks posttrauma. This review highlights problems in defining and measuring concussion, the mildest form of traumatic brain injury (TBI). Furthermore, the 'natural' course of recovery correlates of postconcussion syndrome (PCS) and guidelines for clinical management are discussed.

RECENT FINDINGS

Traditional measures of TBI severity (e.g. length of loss of consciousness or period of posttraumatic amnesia) do not correlate with persistent concussion symptoms. Abnormal eye movements, cerebrovascular disturbances, extra-axial injuries, alcohol intoxication at time of injury, and presence of an axis I disorder are associated with persistent symptoms. Early management of physical, cognitive, and emotional symptoms following concussion may reduce long-term morbidity. Techniques used to help concussed athletes return to play appear useful when evaluating and treating concussion in nonathletes.

SUMMARY

The study of concussion and PCS has increased significantly over the past 10 years, with recent research supporting an underlying biological cause for initial symptomatology. Persistent symptoms may be associated with both neurological and non-neurological variables. Early and serial monitoring and treatment of symptoms appears to result in substantial improvement in the vast majority of concussed patients.

Reduced processing speed in rugby union players reporting three or more previous concussions

The issue pertaining to the effect of multiple self-reported sports-related concussions on cognitive function is controversial. Although this topic has received increased attention in the literature recently, the issue remains unresolved. Evidence supporting a detrimental cognitive effect has been reported at a sub-concussive level and following one, two, and three or more previous concussions. However, numerous studies have been unable to replicate these findings. Additionally, discrepancies between neuropsychological testing formats have been identified, where studies utilizing traditional tests tend to support the notion of detrimental cognitive effects whereas studies with computerized tests have tended to demonstrate no effect. The present study sought to examine possible detrimental cognitive effects in a sample of adult male rugby union players who reported a history of three or more concussions (n = 34) compared with those who reported no previous concussions (n = 39). A computerized neuropsychological battery and a traditional neuropsychological measure of processing speed were administered for this purpose. Findings revealed that there were differences between groups on two processing speed measures from both traditional and computerized tests. Athletes with a history of multiple concussions performed significantly lower on these measures than those with no history of concussion. These results provide further evidence to suggest that a history of three or more self-reported concussions in active athletes may have a detrimental effect on cognitive function. Future research may focus on identifying moderating factors in an attempt to resolve some of the conflicting findings and identify potential athletes at risk for sustaining cognitive deficits.