The effect of striking compliance in ice hockey impacts, and its influence on dynamic response and brain tissue strain was investigated in this study. In hockey, players can experience a broad range of striking/surface compliance during a head impact, from the stiff ice surface to highly compliant player collisions. An increase in striking compliance has been shown to extend the duration of an impact that is associated with an increase in risk of sustaining brain injuries. Three striking caps of low, medium, and high compliance were used to impact a helmeted 50th percentile Hybrid III male headform attached to an unbiased neckform. Each level of compliance was used to impact five high risk locations at three different velocities, representative of head impact scenarios in ice hockey. The dependent variables, peak resultant linear accelerations and peak resultant rotational acceleration as well as MPS, were analyzed using a multivariate analysis of variance (MANOVA) to determine if there were significant differences between the three controlled variables. The results demonstrate a significant effect of compliance, over the influence of velocity and acceleration. Conditions of low impact compliance resulted in higher response values compared to impacts of increased compliance. That being said, high compliance conditions remained in the range of concussion risk, even at the lowest velocity. The use of brain tissue modeling, compared to dynamic response alone, demonstrated an elevated risk of brain injury as a result of extended impact durations. Impact compliance in hockey is a factor that has not been considered when designing and testing helmet technology. The results of this study demonstrate that compliance is a determining factor in producing brain injury, and should be incorporated into helmet standard testing to mitigate risk. The results of this study have implications on brain injury risk that extend beyond the impacting scenarios of ice hockey. The results can be extrapolated to any contact sport that includes impacting scenarios against varied impacting compliances such as football and rugby.

The North American ice hockey world has come to realise that concussions are a major problem and a threat to the sport and to the National Hockey League (NHL). The media coverage of the concussions suffered by several NHL stars and of the scientific advancements in the detection and long-term effects of concussions has intensified over the last 20 years. A discourse analysis of Canadian newspaper coverage of concussions in the NHL in 1997-1999 and 2010-2012 focusing on the production of discursive objects and subjects reveals two important discourses. On the one hand, emerging objects of the discourses of blame and responsibility for the concussions in the NHL gained prominence in the later timeframe, especially blame on the NHL, the rulebook and hockey’s violent and risk-taking culture. On the other hand, a shift in reporting saw the emergence of a new subject position for the concussed hockey player, that of a frail and vulnerable subject. More NHL players are covered as ‘suffering’ subjects concerned with both physical pain and the mental health problems associated to concussions, rather than merely as athletes. Indeed, the impact of concussions on the personal lives of players is now an object of discourses that also produce the NHL player as a family member. Finally, former hockey players’ stories who have suffered serious concussions are recounted as a cautionary tale, opposing early retirement as a result of health issues to persistence in playing despite such health concerns.

Individuals with a history of multiple concussions may be at risk for relative weaknesses in executive functioning and processing speed. These weaknesses could adversely influence academic skills and academic success. This study determined if the relative weaknesses in executive functions and processing speed mediate associations between multiple concussions and academic outcomes in university students. To achieve this aim, university students with a history of three or more concussions (n = 58) were compared to two control groups (ns = 57) on measures of executive functions, processing speed, academic skills, and academic success. Results indicated no significant differences between the groups on measures of executive functioning or processing speed. The multiple concussion group endorsed significantly more psychological symptoms, had a slower reading rate, and had a lower grade point average (GPA) than controls with no history of concussion. Executive functioning and processing speed did not mediate the associations between concussion status and academic skills or academic success. Future research should investigate other potential mediators, such as psychological symptoms, that may account for differences in academic skills and performance amongst students with multiple concussions.

Traumatic Brain Injury (TBI) is a growing global health problem. Mild forms of TBI (mTBI) such as concussions, represent the most common manifestation of this type of injury with children and youth (< 20 years old) among the most likely to sustain mTBI. There is growing evidence for the cumulative effects of repeated mTBI (rmTBI) suggesting that while a single concussion may not cause evident or long-lasting brain alterations, the summation of multiple mTBI may lead to more severe consequences. In contrast to severe TBI, lesions in mTBI patients are challenging to detect. Despite this, mTBI patients may still present with cognitive and emotional deficits. Cerebral microbleeds (CMBS), a subtle form of vascular damage, have been identified as an early hallmark in brain trauma and several neurodegenerative diseases. The cumulative effects of subtle but sustained microvascular damage could explain the persistent long-term functional deficits observed in mTBI. In this study, the awake closed-head injury (ACHI) model was used to investigate the association between rmTBI and microvascular damage in different brain regions in both male and female juvenile rats at one and seven days after the last injury. The results indicate that the injury paradigm used in this study (i.e. 8 impacts over 4 days) using the ACHI model is associated with an acute increase in sings of microvascular damage in both sexes that is no longer evident at a longer time point. These study is the first to describe the negative impact of rmTBI on CMBs in the juvenile using an awake animal model, and provides evidence for the potential involvement of this subtle form of vascular damage in the development of neurological deficits after rmTBI. / Graduate

Concussions have reached epidemic levels. There is no cure for concussions. Measures taken to reduce concussions have not been effective. The majority of research is focused on concussion causation and concussion management after the fact. The research continues but the number of concussions in athletics increases each year. No methodical approach to producing a specific protocol to strengthen the head and neck muscles exists and no systematic study of increase in neck musculature attributed to such a protocol is documented. Thus, this study will produce a standardized methodology for the reduction of concussive and subconcussive forces, laying the foundation for further research in this area. The research participants were healthy male and female college students, age range 18-24. There were 30 participants. Of the 30 subjects used for this study, 18 participants were randomly assigned to the experimental group and 12 participants in the control group. The participants followed a protocol consisting of 13 movements designed to sequentially train the musculature of the head, neck and upper back. The duration of the study was 8 weeks. The strength increases were significant in the active participant group. The hypertrophy of the head and neck muscles was equally as significant and even more impressive in the male group. The females exhibited minimal muscle hypertrophy. Every active participant experienced strength increases during the eight week study; likewise each active male participant exhibited neck circumference increases. The control group experienced negligible strength or hypertrophy increases. / Ph. D.

Introduction: Balance impairment is a commonly reported symptom of concussion. Very little research has been undertaken regarding the complexities of balance impairment after concussive injury in the pediatric population. Purpose: The objectives of this study were: 1) to identify the factors that are associated with balance impairments in children with concussion; 2) to review and evaluate four commonly used balance measures; and 3) to provide recommendations for the best methods of clinical evaluation of balance in children and youth after concussive injury. Methods: A cross-sectional balance evaluation was completed on 104 children, ages 5-18 who had a confirmed diagnosis of concussion. Four balance measures were examined to determine which was the most appropriate for evaluating balance post-concussion. Results: 37% of children were found to have balance impairment according to the BOT-2. The full logistic regression model was found to be not statistically significant however, mechanism of injury with an odds ratio of 2.1 and 95% CI [0.810, 5.027] indicates that children with sport-related injuries are twice as likely to have balance impairment than those with a non-sports-related injury. Chi-Square analyses showed a statistically significant association for mechanism of injury (χ2=11.05, p = 0.03) and age (χ2 = 0.04, p =-0.02) for children who presented with balance impairments and those who did not. Children with balance impairment may present with different symptom profiles than children without. Conclusion: Using a single method of assessment may not provide an accurate representation of balance impairment in children and youth after concussion. Based on the comparison of measurement properties and application of each measure to 104 children with concussion, the BOT-2 and the CB&M when used together provide the most comprehensive assessment of balance and postural instability in children with concussive injury. Age, mechanism of injury and site of impact may be leading factors in the development of balance impairment. / Thesis / Master of Science Rehabilitation Science (MSc)

Despite being a common problem, there are many gaps in the understanding of mild traumatic brain injury (mTBI). Its pathophysiology is unclear, diagnostic criteria are variable, and the associated symptomatology is non-specific. As a result, there are challenges associated with precise mTBI diagnosis and treatment. The dissertation seeks to identify distinctive features, both clinical and pathophysiological, exclusively associated with mTBI. In addition, the neuroinflammatory component of mTBI is explored in detail in the context of inflammatory cytokines’ potential use as prognostic biomarkers and development of a targeted treatment. Three studies were conducted to explore mTBI. We conducted a retrospective chart review to identify the clinical presentation exclusively associated with mTBI that sets it apart from other similar conditions. This was accomplished through symptomatology comparison between the patients with head injuries that meet the ACRM (1993) criteria for mTBI diagnosis vs. those who do not. The results of this study showed that 20.5% of patients with chronic post-concussive symptoms do not meet the ACRM (1993) criteria of mTBI despite sustaining a head injury. In addition, no symptom specific differences were found between the two populations. A detailed systematic review and meta-analysis were also conducted to identify the common inflammatory cytokines associated with mTBI and to explore their potential use as prognostic biomarkers. The results show significantly elevated blood IL-6, IL-1RA, IFN-γ (at <24 hrs.) and MCP-1/CCL2 (within a week) levels in patients with mTBI compared to healthy controls in majority of the included studies. A meta-analysis was further conducted that supported these findings by showing significantly elevated IL-6, MCP-1/CCL2, and IL-1β levels in patients with mTBI in the acute stages (<7 days). In addition, elevated IL-6, TNF-α, IL-1RA, IL-10, and MCP-1/CCL2 levels were associated with poor prognosis in patients with mTBI. In addition, a systematic review was conducted to identify the inflammatory cytokines associated with adverse psychological outcome in population with mTBI. The results show that IL-6, TNF-α, IL-10, and CRP are associated with PTSD and/or depression in the population with mTBI, particularly in the chronic stages. Collectively, these studies show that all symptomatic patients with head trauma, whether or not they meet the subjective criteria of mTBI, should be managed and offered early rehabilitation to avoid long tern adverse consequences. In addition, this thesis supports the neuro-inflammatory hypothesis of mTBI and identifies inflammatory cytokines that could be potentially utilized as prognostic biomarkers and for the development of mTBI treatment. / Thesis / Doctor of Philosophy (PhD)

Mild traumatic brain injury (mTBI), or concussion, results from sudden acceleration or deceleration of the brain and subsequent complex tissue propagation of shock waves that disrupt structure and function. Concussions can cause many symptoms including headache, dizziness, and difficulty concentrating. These can be detrimental to children, a ecting their participation in school, sport, and social activities. Therefore, return to school (RTS) and return to activity (RTA) protocols have been developed to help safely return children to these activities without risking further injury. The goal of this study was to develop machine learning (ML) algorithms to predict RTA and RTS stages, that can easily be incorporated into a smartphone application (APP). Ideally this would assist children in tracking and determining their RTA and RTS progression leading them to a safe and timely return. Support vector machine classi er (SVC) and random forest (RF) algorithms were developed to predict RTA/RTS stages. Both were modeled on previously acquired data, and on newly acquired data, and results were compared. Models were trained and tested using accelerometry and symptom data from pediatric concussion patients. A sliding window technique and feature extraction were performed on raw acceleration data to extract suitable features, which were combined with yes/no symptom recordings as ML inputs. The dataset consisted of 67 participants aged 10 to 18, 42 female and 25 male, with a total of 844408 samples. The best results for RTS prediction showed average accuracy of 83% for RF and 66% for SVC. For RTA predictions, the best results had average accuracy of 60% for RF and 58% for SVC. For new data, RTS predictions showed an accuracy of 45% for RF and 41% for SVC. RTA predictions had an accuracy of 35% for RF and 30% for SVC. RF models had superior performance on all data. These results show that predicting RTA/RTS is possible with ML. However, improvements to these models can be made by training on more data prior to APP implementation. More data is needed, as recruitment during this study was limited due to Covid-19 restrictions. / Thesis / Master of Applied Science (MASc) / Concussions are recorded in approximately 300,000 athletes annually and are estimated to a ect up to 3.8 million individuals per year in the United States alone. Understanding when its safe to return to normal routine after an injury is important but challenging. Therefore, a series of stages have been developed to lead children through a safe and timely return to sport and activity after concussion. The goal of this study was to develop machine learning (ML) algorithms which predict these return stages using symptom recordings and gross body movement data. Algorithms could be incorporated into a smartphone application (APP) to provide accessible return guidelines for children with concussions. Algorithms were created and model performance was tested using symptom and body movement data collected from children after a concussive injury. The results of this study show that it is possible to predict return to school and return to activity stages with ML, and with improvements, can be used to facilitate return from injury

Sports related concussions result in 300,000 brain injuries in the United States each year. The purpose of this study was to utilize an in-helmet system that measures and records linear head accelerations to analyze head impacts from collegiate football. The Head Impact Telemetry (HIT) System is an in-helmet system with six spring mounted accelerometers and an antenna that transmits data via radio frequency to a sideline receiver and laptop computer system. The data reported by the HIT System includes the time of impact, location of impact, and linear acceleration resultant of the head center of gravity. The algorithm and in-helmet application for this system were validated in five series of tests. In particular, the validation emphasized that the HIT System measurements are of the player's head and not helmet accelerations as evidenced by the helmet acceleration being 16.6 (± 3.2) times greater than the peak head accelerations measured by the HIT System and dummy cg accelerometers. Using 130 head impacts in five different test configurations, the mean error in measuring peak linear acceleration was 0.01% (±18%). A total of 11,604 head impacts were recorded from the Virginia Tech football team throughout the 2003 and 2004 football seasons during 22 games and 62 practices from a total of 52 players. The acceleration data distribution was right skewed with a mean impact acceleration magnitude of 20.9 g and maximum value of 172.6 g. The HIC determined for each impact from a 15 millisecond time period was similarly distributed with the mean equal to 17.9, and the maximum equal to 969.6. A total of three impacts with three different players resulted in concussions. These impacts had peak linear accelerations of 55.7 g, 136.7 g, and 117.6 g with HIC values of 120.6, 518.4, and 355.6 respectively. Each of these hits was among the highest recorded for each respective player. Although the incidence of injury data is limited, this study presents an extremely large data set from human head impacts that provides valuable insight into the lower bounds of mild traumatic brain injuries. / Master of Science

Background: Despite the increased awareness and education to the public, concussions in children continue to ensue without proper concussion education and management in school systems. Whether the child suffers a concussion in school or at home, it is essential for school nurses to have proper concussion education and evidence based management strategies to further monitor post-concussive symptoms in the school setting. Concussion symptoms can affect the student up to 7-10 days following the injury. Concussions can range from mild to severe, with symptoms lasting hours, days, months or longer. Children who experience a concussion can experience academic challenges that will affect them in the classroom. Without proper concussion education for school nurses, concussed youth may experience post-concussive symptoms. School nurses have a significant role, collaborating with the parents, providers, and the student in providing accommodations and support while transitioning back into the classroom. Purpose: To assess the knowledge of Utah school nurses regarding concussion education and management of the concussed student. In addition evaluating the educational intervention, which changed the knowledge base of the participants. Methods: A one group pre-test and post-test design was used. Study materials were emailed via the Utah School Nurse Association listserv to all Utah school nurses. A concussion educational power point was provided to these nurses before having them complete the post-test. Results: The results of the paired sample t-test revealed that there was a significant difference (p= .000) in comparison of the pre-test and post-test results after viewing the concussion educational power point. Conclusion: The results of this study showed that there was a significant difference between pre-test and post-test results after viewing the concussion educational power point. Therefore it can be concluded that providing education and awareness regarding concussion and its management will increase the knowledge and ultimately may change practice which in turn may improve patient outcomes.