The incidence of concussive injury has continued to arise annually with up to 3.8 million concussions reported per year (Thurman 1999) and 15% of these injuries occurring with persistent symptoms (Kraus and Chu, 2005). Few studies have examined the differences between youth and adult concussion (Yeates et al, 2012; Gosselin et al, 2010) therefore it is unknown whether youth and adults pose a similar risk of sustaining a concussion following impact. For this reason, the purpose of this study is to determine if differences exist in the dynamic response of the head and brain tissue deformation characteristics between children and adolescents for falls in comparison to adult data which have resulted in concussive injuries. Patient data was collected from emergency room hospitals across Canada. After exclusion criterion was applied, 11 child and 10 adolescent falls were reconstructed using mathematical (MADYMO) model, physical model (Hybrid III Headforms) and finite element modelling. Both groups were compared to each other as well as an adult group collected by Post et al (2014b) using a one-way ANOVA and Welsh test. The results of this study show that the children produced the lowest values for all variables when compared to the adolescents and adults whereas the adolescents produced the largest (with the exception of MPS where the adolescent and adult MPS was the same). Although all results were above the suggested thresholds for risk of concussive injury, the youth produced the lowest brain tissue strain yet still suffered a concussion. This is important to note as it may suggest that children are at an increased risk of injury at a lower brain tissue strain level. Understanding the differences in parameters influencing concussive injury may aid researchers in comprehending the unique risk for youth at difference ages. This information would be useful in terms of protective equipment design, promoting safe play in games and management of patients following injury.

BACKGROUND: Concussions are frequent injuries sustained by collegiate athletes. They are often underdiagnosed and may lack adequate treatment due to a lack of standardization in diagnosis and return to play guidelines. Current research suggests that there is an increased risk of subsequent injury after returning to play among previously concussed athletes. Recurrent injuries have a detrimental impact on athletic careers and often result in early retirement from competitive sports. The relationship between sports-related concussions (SRCs) and subsequent musculoskeletal injuries in the NCAA reveals a lack of consensus on return to play (RTP) guidelines and management. Clinical guidelines are evolving with the progressive understanding of SRC pathophysiology. LITERATURE REVIEW FINDINGS: Previous research has found an association between concussion and subsequent acute musculoskeletal injuries, specifically lower extremity injuries. In addition, sports-specific athlete cohorts, such as soccer and football players, have been shown to have a high incidence of SRC. The exact mechanism of action linking SRC and subsequent acute injury is currently unknown. There are numerous etiologic possibilities offered in the literature, including gait alterations, neuromuscular control deficits, and impaired reaction time. However, further research is required to elucidate this relationship—in our review of the current literature we were able to find no studies evaluating the risk of both upper and lower extremity injury following SRC after returning to play in the NCAA population. PROPOSED PROJECT: The goal of the proposed retrospective cohort study of BU athletes is to evaluate the impact of concussion history on recurrent injury after returning to sports. Study inclusion criteria will consist of BU athletes diagnosed with concussions at a single NCAA Division I institution. This cohort will be collected from NCAA injury database and electronic medical records will be matched with controls who have not sustained concussions over the same period. CONCLUSIONS: History of concussion is associated with increased risk of recurrent injury in athletes, specifically at the collegiate level. Further work must be done at all levels of athletics to standardize return to play guidelines to prevent this increased risk of subsequent injury. SIGNIFICANCE: This study will help determine whether a relationship exists between concussion and subsequent sports-related injuries. This information may allow for closer monitoring of return to play and treatment of concussions. Additionally, it may encourage further developments to diagnostic criteria, education, and injury prevention.

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An examination of neck strength, and other possible predictors of concussion risk in university athletes and how these variables relate to concussion recovery in this cohort. / Concussion incidence in university athletes has been increased drastically over the last two decades. Prevention of concussion injuries is still elusive and scarcely reported in the literature. Certain athletes are at greater risk for concussion than others. Identifying these risk factors is an important first step in identifying those who are at highest risk for concussion. Concussions are biomechanical injuries therefore addressing the strength of the neck musculature might be a significant modifiable risk factor in concussion prevention. Greater neck strength may help to attenuate the forces that cause concussion and either prevent injury or decrease the severity. There are some known risk factors for concussion, including age and female sex, however this does not account for all of the variability in concussion incidence in university athletes. Further exploration into the importance of neck strength and concussion in university athletes is required to identify alternative prevention strategies available to athletes. The purpose of this research was to examine if neck strength and anthropometric variables are significant predictors of concussion risk and concussion recovery time in Canadian university athletes. Chapter One provides a review of the current literature on concussion. It presents the background information for concussion risk, etiology, assessment, and management in university athletes. This chapter also reviews the literature to date on neck strength in concussion and assessments of neck strength in athletes. Chapter Two presents a study evaluating the risk of concussion in a group of Canadian university varsity athletes (n = 246). Neck strength and anthropometric variables are assessed for their significance in predicting concussion risk in this cohort along with published covariates. Neck pain and past concussion history were found to be the most significant predictors of concussion in this population. Chapter Three provides an exploration into the importance of neck strength and anthropometric variables in length of recovery in concussed athletes (n = 35). The Sport Concussion Assessment Tool, 3rd edition was used to evaluate symptom intensity in these athletes. A multiple linear regression model was used to predict recovery time. Symptom score and neck pain were the only significant predictors of concussion recovery time in varsity athletes. Chapter Four presents the implications of the two aforementioned studies for clinical practice, future research, and policy recommendations. More in-depth assessments prior to the beginning of competition should be considered in identifying athletes who are at greatest risk for concussion. Athletes with significant past concussion history should be evaluated more closely and informed of their heightened risk for subsequent injury. / Thesis / Master of Health Sciences (MSc)

The research presented herein is a combination of work done in two distinct subcategories of sport related head injury research. The body of work is aimed at increasing the understanding of head impact biomechanics across a broad spectrum of impact scenarios as well as the ability of helmets to affect head impact biomechanics over time. The first study utilizes in situ testing of controlled impacts of an instrumented head form to more fully characterize head accelerations resulting from impacts to the ice, board, and glass surfaces present in an ice hockey rink. The full characterization of head impacts across a spectrum of loading conditions and impact surfaces gives researchers insight into head impact tolerance and head protection capabilities and limitations in ice hockey. The second study details the development of a method to impact helmet pads for repeated loading studies based on published head impact exposure data. The third study uses this newly developed methodology to test the effects of a season of impacts on the energy absorbing properties of three different helmet padding technologies. The body of work is aimed at increasing understanding of head impact and concussion and the ability of existing helmet technologies to prevent these injuries with a goal of reducing the occurrence of injury. / Master of Science

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Background and Significance: The purpose of this study was to evaluate the effectiveness of the Barrow Brainbook (BBB) concussion education program as a tool to increase concussion knowledge among Arizona high school athletes and to modify attitudes and behaviors regarding concussion. Methods: This was a cross sectional study of Arizona high school athletes utilizing a 31 question multiple‐choice de‐identified survey. Attitude, knowledge, and behavior questions, as well as sport and level of participation were analyzed using the Wilcoxon Rank Sum test. Means between groups were analyzed using a two‐way ANOVA. Linear regression was used to determine if there was a relationship between number of years since completing BBB and concussion knowledge. Results: Surveys were distributed to 382 student athletes with 363 of those being completed. 224 students participated in BBB (62%). Knowledge and behaviors regarding concussion were not statistically significant when comparing students who had and had not participated in BBB. Those who participated in BBB scored more poorly on questions regarding attitudes about concussion than those who had not (p=0.033). Subsequent two‐way ANOVA testing showed that students who sustained a concussion scored worse (p<0.01) while completing BBB did not significantly affect attitude (p=0.399) when history of a concussion was brought in to the analysis. 90 students (25%) reported sustaining a concussion. Football and varsity level participation were significant for a higher mean number of concussions (p<0.05, p<0.05). There was no relationship between time since taking BBB and concussion knowledge (R2 was 0.007). Conclusions: In this study, there was no evidence to show that participating in the BBB program improved concussion knowledge, attitudes, or behaviors. Number of years since taking BBB was not a good predictor of concussion knowledge. Students who played football and participated at a varsity level were significantly more likely to sustain a concussion. Sustaining a concussion was associated with a higher attitude risk sum score. This is an evaluation of an educational tool specifically designed for adolescents that demonstrated no statistically significant change in increasing knowledge or modifying attitudes and behaviors in a population of high school athletes in Arizona.

The current study was designed to investigate the effect of concussion on verbal learning and memory performance in youth hockey players. Concussed participants completed the Rey Auditory Verbal Learning Test (RAVLT) prior to the start of the hockey season. Following recovery from concussion, six males (10-12 years), with one sustaining two concussions, completed a follow-up assessment. A difference score was calculated for five RAVLT index scores. Each instance of concussion was matched to two controls on age, gender, and testing protocol in order to control for the confounding influences of repeated testing sessions. Independent-samples t-tests revealed a trend towards a significant decrease in change scores for the concussed participants on the Delayed Recall Trial of the RAVLT. These results suggest that long-term verbal memory may be negatively affected by concussion; however, future studies are needed with larger sample sizes and additional follow-up points in order to better understand the impact.

The current study was designed to investigate the effect of concussion on verbal learning and memory performance in youth hockey players. Concussed participants completed the Rey Auditory Verbal Learning Test (RAVLT) prior to the start of the hockey season. Following recovery from concussion, six males (10-12 years), with one sustaining two concussions, completed a follow-up assessment. A difference score was calculated for five RAVLT index scores. Each instance of concussion was matched to two controls on age, gender, and testing protocol in order to control for the confounding influences of repeated testing sessions. Independent-samples t-tests revealed a trend towards a significant decrease in change scores for the concussed participants on the Delayed Recall Trial of the RAVLT. These results suggest that long-term verbal memory may be negatively affected by concussion; however, future studies are needed with larger sample sizes and additional follow-up points in order to better understand the impact.

There is an increasing concern surrounding brain trauma risks for young athletes participating in contact sports, as brain injuries in youth have detrimental consequences on their cognition, behaviour, and learning abilities (Ayr et al., 2009; Yeates and Taylor, 2005). Given the potential for future neurological and mental health issues, there is further need to quantify brain trauma within youth sport populations (Daneshvar et al., 2011). Ice hockey is a sport with high rates of brain injury in youth, and the shift from Pee Wee (ages 11-12) to Bantam (ages 13-14) hockey is an important transition period in which athletes are introduced to body checking (Black et al., 2017; Marar et al., 2012). The purpose of this study was to compare the brain trauma profiles between Pee Wee and Bantam hockey in terms of the head dynamic response, brain tissue deformation, and frequency of head impact events. Head impact events from 16 Pee Wee and 16 Bantam hockey games were analyzed, and 71 exemplar impact reconstructions were conducted. No differences were found between Pee Wee and Bantam for magnitudes of peak linear acceleration, peak rotational acceleration, or maximum principal strain (MPS). Overall frequency of head impact events was also similar between the two groups. However, chi-squared tests found that the type of head impact event was significantly associated with the age group (X2 (6) = 17.699, p = 0.006, φc = .347). Ice and boards head impact events were more frequent in Pee Wee, while shoulder and glass head impact events were more frequent in Bantam. There were slightly higher frequencies of events ≥26% MPS reported in Pee Wee. However, events were more frequently within the 17-25.9% MPS range for Bantam and were typically the result of shoulder to head impacts. While head impact events at younger ages are more accidental in nature, deliberate player contact from body checking is associated with greater risks for sustaining brain trauma. Policymakers should consider whether Bantam is the most appropriate age to continue allowing for body checking. Developing age-specific helmet technology may be an effective method for protecting against the unique brain trauma risks which are associated with different levels of youth hockey competition. Understanding the characteristics of how brain trauma occurs within youth hockey can help inform and guide future protective and preventative strategies to keep participation in this sport safe for all athletes.

No description available.