Brian W. Benson

Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012

This paper is a revision and update of the recommendations developed following the 1st (Vienna 2001), 2nd (Prague 2004) and 3rd (Zurich 2008) International Consensus Conferences on Concussion in Sport and is based on the deliberations at the 4th International Conference on Concussion in Sport held in Zurich, November 2012.1–3 The new 2012 Zurich Consensus statement is designed to build on the principles outlined in the previous documents and to develop further conceptual understanding of this problem using a formal consensus-based approach. A detailed description of the consensus process is outlined at the end of this document under the Background section. This document is developed primarily for use by physicians and healthcare professionals who are involved in the care of injured athletes, whether at the recreational, elite or professional level. While agreement exists pertaining to principal messages conveyed within this document, the authors acknowledge that the science of concussion is evolving, and therefore management and return to play (RTP) decisions remain in the realm of clinical judgement on an individualised basis. Readers are encouraged to copy and distribute freely the Zurich Consensus document, the Concussion Recognition Tool (CRT), the Sports Concussion Assessment Tool V.3 (SCAT3) and/or the Child SCAT3 card and none are subject to any restrictions, provided they are not altered in any way or converted to a digital format. The authors request that the document and/or the accompanying tools be distributed in their full and complete format. This consensus paper is broken into a number of sections 1. A summary of concussion and its management, with updates from the previous meetings; 2. Background information about the consensus meeting process; 3. A summary of the specific consensus questions discussed at this meeting; 4. The Consensus paper should be read in conjunction with the SCAT3 assessment tool, the Child SCAT3 and the CRT …

Consensus statement on concussion in sport: the 4th international conference on concussion in sport, Zurich, november 2012

Paul McCrory, MBBS, PhD*; Willem H. Meeuwisse, MD, PhD†; Mark Aubry, MD‡; Robert C. Cantu, MD§; Jiři Dvořak, MD||; Ruben J. Echemendia, PhD¶; Lars Engebretsen, MD, PhD#; Karen Johnston, MD, PhD**; Jeffrey S. Kutcher, MD††; Martin Raftery, MBBS‡‡; Allen Sills, MD§§; Brian W. Benson, MD, PhD||||; Gavin A. Davis, MBBS¶¶; Richard Ellenbogen, MD##; Kevin M. Guskiewicz, PhD***; Stanley A. Herring, MD†††; Grant L. Iverson, PhD‡‡‡; Barry D. Jordan, MD§§§; James Kissick, MD||||||; Michael McCrea, PhD¶¶¶; Andrew S. McIntosh, PhD###; David Maddocks, LLB, PhD****; Michael Makdissi, MBBS, PhD††††; Laura Purcell, MD‡‡‡‡; Margot Putukian, MD§§§§; Kathryn Schneider, PhD||||||||; Charles H. Tator, MD, PhD¶¶¶¶; Michael Turner, MD####

Risk of Injury Associated With Body Checking Among Youth Ice Hockey Players

CONTEXT Ice hockey has one of the highest sport participation and injury rates in youth in Canada. Body checking is the predominant mechanism of injury in leagues in which it is permitted. OBJECTIVE To determine if risk of injury and concussion differ for Pee Wee (ages 11-12 years) ice hockey players in a league in which body checking is permitted (Alberta, Canada) vs a league in which body checking is not permitted (Quebec, Canada). DESIGN, SETTING, AND PARTICIPANTS Prospective cohort study conducted in Alberta and Quebec during the 2007-2008 Pee Wee ice hockey season. Participants (N = 2154) were players from teams in the top 60% of divisions of play. MAIN OUTCOME MEASURES Incidence rate ratios adjusted for cluster based on Poisson regression for game- and practice-related injury and concussion. RESULTS Seventy-four Pee Wee teams from Alberta (n = 1108 players) and 76 Pee Wee teams from Quebec (n = 1046 players) completed the study. In total, there were 241 injuries (78 concussions) reported in Alberta (85 077 exposure-hours) and 91 injuries (23 concussions) reported in Quebec (82 099 exposure-hours). For game-related injuries, the Alberta vs Quebec incidence rate ratio was 3.26 (95% confidence interval [CI], 2.31-4.60 [n = 209 and n = 70 for Alberta and Quebec, respectively]) for all injuries, 3.88 (95% CI, 1.91-7.89 [n = 73 and n = 20]) for concussion, 3.30 (95% CI, 1.77-6.17 [n = 51 and n = 16]) for severe injury (time loss, >7 days), and 3.61 (95% CI, 1.16-11.23 [n=14 and n=4]) for severe concussion (time loss, >10 days). The estimated absolute risk reduction (injuries per 1000 player-hours) that would be achieved if body checking were not permitted in Alberta was 2.84 (95% CI, 2.18-3.49) for all game-related injuries, 0.72 (95% CI, 0.40-1.04) for severe injuries, 1.08 (95% CI, 0.70-1.46) for concussion, and 0.20 (95% CI, 0.04-0.37) for severe concussion. There was no difference between provinces for practice-related injuries. CONCLUSION Among 11- to 12-year-old ice hockey players, playing in a league in which body checking is permitted compared with playing in a league in which body checking is not permitted was associated with a 3-fold increased risk of all game-related injuries and the categories of concussion, severe injury, and severe concussion.

Is protective equipment useful in preventing concussion? A systematic review of the literature

Objective: To determine if there is evidence that equipment use reduces sport concussion risk and/or severity. Data sources: 12 electronic databases were searched using a combination of Medical Subject Headings and text words to identify relevant articles. Review methods: Specific inclusion and exclusion criteria were used to select studies for review. Data extracted included design, study population, exposure/outcome measures and results. The quality of evidence was assessed based on epidemiologic criteria regarding internal and external validity (ie, strength of design, sample size/power calculation, selection bias, misclassification bias, control of potential confounding and effect modification). Results: In total, 51 studies were selected for review. A comparison between studies was difficult due to the variability in research designs, definition of concussion, mouthguard/helmet/headgear/face shield types, measurements used to assess exposure and outcomes, and variety of sports assessed. The majority of studies were observational, with 23 analytical epidemiologic designs related to the subject area. Selection bias was a concern in the reviewed studies, as was the lack of measurement and control for potentially confounding variables. Conclusions: There is evidence that helmet use reduces head injury risk in skiing, snowboarding and bicycling, but the effect on concussion risk is inconclusive. No strong evidence exists for the use of mouthguards or face shields to reduce concussion risk. Evidence is provided to suggest that full facial protection in ice hockey may reduce concussion severity, as measured by time loss from competition.

A prospective study of concussions among National Hockey League players during regular season games: the NHL-NHLPA Concussion Program

Background In 1997, the National Hockey League (NHL) and NHL Players’ Association (NHLPA) launched a concussion program to improve the understanding of this injury. We explored initial postconcussion signs, symptoms, physical examination findings and time loss (i.e., time between the injury and medical clearance by the physician to return to competitive play), experienced by male professional ice-hockey players, and assessed the utility of initial postconcussion clinical manifestations in predicting time loss among hockey players. Methods We conducted a prospective case series of concussions over seven NHL regular seasons (1997–2004) using an inclusive cohort of players. The primary outcome was concussion and the secondary outcome was time loss. NHL team physicians documented post-concussion clinical manifestations and recorded the date when a player was medically cleared to return to play. Results Team physicians reported 559 concussions during regular season games. The estimated incidence was 1.8 concussions per 1000 player-hours. The most common postconcussion symptom was headache (71%). On average, time loss (in days) increased 2.25 times (95% confidence interval [CI] 1.41–3.62) for every subsequent (i.e., recurrent) concussion sustained during the study period. Controlling for age and position, significant predictors of time loss were postconcussion headache (p < 0.001), low energy or fatigue (p = 0.01), amnesia (p = 0.02) and abnormal neurologic examination (p = 0.01). Using a previously suggested time loss cut-point of 10 days, headache (odds ratio [OR] 2.17, 95% CI 1.33–3.54) and low energy or fatigue (OR 1.72, 95% CI 1.04–2.85) were significant predictors of time loss of more than 10 days. Interpretation Postconcussion headache, low energy or fatigue, amnesia and abnormal neurologic examination were significant predictors of time loss among professional hockey players.

The impact of face shield use on concussions in ice hockey: a multivariate analysis

Objective: To identify specific risk factors for concussion severity among ice hockey players wearing full face shields compared with half face shields (visors). Methods: A prospective cohort study was conducted during one varsity hockey season (1997–1998) with 642 male ice hockey players (median age 22 years) from 22 teams participating in the Canadian Inter-University Athletics Union. Half of the teams wore full face shields, and half wore half shields (visors) for every practice and game throughout the season. Team therapists and doctors recorded on structured forms daily injury, participation, and information on face shield use for each athlete. The main outcome measure was any traumatic brain injury requiring assessment or treatment by a team therapist or doctor, categorised by time lost from subsequent participation and compared by type of face shield worn. Results: Players who wore half face shields missed significantly more practices and games per concussion (2.4 times) than players who wore full face shields (4.07 sessions (95% confidence interval (CI) 3.48 to 4.74) v 1.71 sessions (95% CI 1.32 to 2.18) respectively). Significantly more playing time was lost by players wearing half shields during practices and games, and did not depend on whether the athletes were forwards or defence, rookies or veterans, or whether the concussions were new or recurrent. In addition, players who wore half face shields and no mouthguards at the time of concussion missed significantly more playing time (5.57 sessions per concussion; 95% CI 4.40 to 6.95) than players who wore half shields and mouthguards (2.76 sessions per concussion; 95% CI 2.14 to 3.55). Players who wore full face shields and mouthguards at the time of concussion lost no playing time compared with 1.80 sessions lost per concussion (95% CI 1.38 to 2.34) for players wearing full face shields and no mouthguards. Conclusions: The use of a full face shield compared with half face shield by intercollegiate ice hockey players significantly reduced the playing time lost because of concussion, suggesting that concussion severity may be reduced by the use of a full face shield.

What are the most effective risk-reduction strategies in sport concussion?

Aim To critically review the evidence to determine the efficacy and effectiveness of protective equipment, rule changes, neck strength and legislation in reducing sport concussion risk. Methods Electronic databases, grey literature and bibliographies were used to search the evidence using Medical Subject Headings and text words. Inclusion/exclusion criteria were used to select articles for the clinical equipment studies. The quality of evidence was assessed using epidemiological criteria regarding internal/external validity (eg, strength of design, sample size/power, bias and confounding). Results No new valid, conclusive evidence was provided to suggest the use of headgear in rugby, or mouth guards in American football, significantly reduced players’ risk of concussion. No evidence was provided to suggest an association between neck strength increases and concussion risk reduction. There was evidence in ice hockey to suggest fair-play rules and eliminating body checking among 11-years-olds to 12-years-olds were effective injury prevention strategies. Evidence is lacking on the effects of legislation on concussion prevention. Equipment self-selection bias was a common limitation, as was the lack of measurement and control for potential confounding variables. Lastly, helmets need to be able to protect from impacts resulting in a head change in velocities of up to 10 and 7 m/s in professional American and Australian football, respectively, as well as reduce head resultant linear and angular acceleration to below 50 g and 1500 rad/s2, respectively, to optimise their effectiveness. Conclusions A multifactorial approach is needed for concussion prevention. Future well-designed and sport-specific prospective analytical studies of sufficient power are warranted.

Risk of injury associated with bodychecking experience among youth hockey players

Background: In a previous prospective study, the risk of concussion and all injury was more than threefold higher among Pee Wee ice hockey players (ages 11–12 years) in a league that allows bodychecking than among those in a league that does not. We examined whether two years of bodychecking experience in Pee Wee influenced the risk of concussion and other injury among players in a Bantam league (ages 13–14) compared with Bantam players introduced to bodychecking for the first time at age 13. Methods: We conducted a prospective cohort study involving hockey players aged 13–14 years in the top 30% of divisions of play in their leagues. Sixty-eight teams from the province of Alberta (n = 995), whose players had two years of bodychecking experience in Pee Wee, and 62 teams from the province of Quebec (n = 976), whose players had no bodychecking experience in Pee Wee, participated. We estimated incidence rate ratios (IRRs) for injury and for concussion. Results: There were 272 injuries (51 concussions) among the Bantam hockey players who had bodychecking experience in Pee Wee and 244 injuries (49 concussions) among those without such experience. The adjusted IRRs for game-related injuries and concussion overall between players with bodychecking experience in Pee Wee and those without it were as follows: injury overall 0.85 (95% confidence interval [CI] 0.63 to 1.16); concussion overall 0.84 (95% CI 0.48 to 1.48); and injury resulting in more than seven days of time loss (i.e., time between injury and return to play) 0.67 (95% CI 0.46 to 0.99). The unadjusted IRR for concussion resulting in more than 10 days of time loss was 0.60 (95% CI 0.26 to 1.41). Interpretation: The risk of injury resulting in more than seven days of time loss from play was reduced by 33% among Bantam hockey players in a league where bodychecking was allowed two years earlier in Pee Wee compared with Bantam players introduced to bodychecking for the first time at age 13. In light of the increased risk of concussion and other injury among Pee Wee players in a league where bodychecking is permitted, policy regarding the age at which hockey players are introduced to bodychecking requires further consideration.

Consensus statement on Concussion in Sport - The 4th International Conference on Concussion in Sport held in Zurich, November 2012.

the 4th International Conference on Concussion in Sport held in Zurich, November 2012 Paul McCrory, Willem H Meeuwisse, Mark Aubry, Bob Cantu, Jiří Dvořák, Ruben J Echemendia, Lars Engebretsen, Karen Johnston, Jeffrey S Kutcher, Martin Raftery, Allen Sills, Brian W Benson, Gavin A Davis, Richard G Ellenbogen, Kevin Guskiewicz, Stanley A Herring, Grant L Iverson, Barry D Jordan, James Kissick, Michael McCrea, Andrew S McIntosh, David Maddocks, Michael Makdissi, Laura Purcell, Margot Putukian, Kathryn Schneider, Charles H Tator, Michael Turner

Sport concussion assessment tool: baseline values for varsity collision sport athletes

Objective: To determine baseline symptom and neurocognitive norms for non-concussed and previously concussed varsity athletes using the sport concussion assessment tool (SCAT). Study Design: Descriptive cohort study. Setting: University of Calgary. Subjects: 260 male and female university football, ice hockey and wrestling athletes over three seasons (2005–7). Methods: A baseline SCAT was completed during preseason medical evaluation. Subjects were grouped as follows: all participants, men, women, never concussed (NC) and previously concussed (PC). Main Results: The mean age of participants was 20.5 years (range 17–32). In total, 41.2% of all athletes had a total post-concussion symptom scale (PCSS) score of 0. The mean baseline PCSS scores were as follows: all participants 4.29; men 3.52; women 6.39; NC 3.75 and PC 5.25. The five most frequently reported symptoms for all athletes were fatigue/low energy (37% of subjects), drowsiness (23%), neck pain (20%), difficulty concentrating (18%) and difficulty remembering (18%). The median immediate recall score was 5/5 for all groups. Women scored a median of 5/5 on delayed recall, whereas all remaining groups scored a median of 4/5. Months in reverse order were successfully completed by 91.6% of subjects. All participants, women and PC scored a median of 6 on reverse digits, whereas men and NC scored a median of 5. Conclusions: The mean SCAT baseline PCSS score was approximately 5, although just under half of the athletes scored 0. Female athletes scored better on tests of neurocognitive function. PC athletes scored better than NC athletes on all neurocognitive tests except delayed five-word recall.