The identification and management of concussion is a growing public health issue. The science of concussion research and the clinical management of children and adolescents who have experienced concussion are rapidly evolving, presenting many challenges and opportunities for those serving this population. A concussion can impact cognitive, communicative, academic, and social success; students affected by concussion may be eligible for special education services. The current study is a national survey of speech language pathologists (SLPs) aimed at characterizing concussion knowledge and management in the schools. One thousand surveys were sent to school-based SLPs from 10 states. Twenty-eight percent of surveys were returned and the results offer a snapshot of current SLP practices and support improved identification and management of concussed children. Findings indicate school-based SLPs' uncertainty in some aspects of concussion knowledge and their role in concussion management. Increased training in pediatric TBI and concussion is needed, and research directed at identifying and developing sensitive assessments and effective treatments for pediatric concussion is required to ensure quality service delivery.

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Introduction: The cognitive benefits of physical activity and sport on executive function are of interest to researchers, especially considering the subsequent interventions that could be implemented. However, researchers frequently use different approaches to conceptualize and measure executive function, often using only a few computerized tasks. My Master’s thesis, therefore, aims to investigate the associations between executive function and physical activity and sport through two different studies to obtain a robust evaluation of executive function: 1) A quantitative study examining physical activity, sport and concussion history in university students and their effect on executive function, and 2) A qualitative study exploring the executive functions engaged during a game from elite university athletes’ experiences. Methods: Quantitative Study. Canadian university students (n=247) completed an online study with nine computerized executive function tasks and a behavioural self-report of executive function, as well as questions assessing weekly physical activity, athletic status, and concussion history. Structural equation modelling and linear regression were conducted to predict executive function based on age, sex, physical activity, athletic status and concussion history. Qualitative study. Canadian university athletes (n=19) participated in semi-structured interviews via Zoom to determine the executive functions engaged during a game. Thematic analysis was used to analyze the interview transcripts. Results: Quantitative Study. The three-factor model of executive function had an overall good fit: χ2 = 66.38, df = 51, p = 0.07, CFI = 0.95, TLI = 0.93, RMSEA = 0.04 [90% CI: 0.00–0.06], SRMR = 0.05. No direct relationship was found between the factors and age, physical activity, concussion history, or athletic status. Sex was significantly related to inhibition, b = 0.52, p = 0.02, such that males had greater inhibition. Physical activity (b = 0.09, p < .01), concussion history (b = 3.29, p < .05) and athletic status (b = -4.01, p < .05) were found to be significant predictors in the regression predicting self-reported executive functioning. Qualitative study. Three themes were generated: 1) Engaging in pre-play or pre-game planning, organization and decision making, 2) Engaging in mid-play problem solving and purposive action and 3) Engaging in post-play or post-game information processing, emotional control and effective performance. Conclusions: The quantitative study found that physical activity, athletic status and concussion history were predictive of subjective but not objective executive function. The qualitative study determined that athletes engage many executive functions that are dependent on the timing of both the play and the game (pre-, mid- or post-). Real-life behavioural manifestations of executive functioning are more challenging to assess and measure but may be better predicted by and relate to life factors such as physical activity and sport participation. The results of my thesis provide support for future research to utilize and develop more unique and ecologically valid methods of measuring EF in the field of physical activity and sport. / Graduate

Traumatic Brain Injury (TBI) is a global health problem and concussion, or mild TBI (mTBI), accounts for up to 75% of all brain injuries occurring annually in the US. There is also growing awareness that repeated mild traumatic brain injury (r-mTBI) can result in cumulative neuropathology and learning and memory deficits, however there is a paucity of preclinical data as to the extent these deficits manifest. R-mTBI in juvenile populations is of special interest as not only is this a high risk group, but this is also a time period when the human brain continues to mature. The hippocampus is a brain region important for learning and memory processes, and r-mTBI during the juvenile period may particularly disrupt the development of cognitive processes. To examine this issue we used a model of awake closed head injury (ACHI), and administered 8 impacts over a 4 day period to juvenile male and female rats (P25-28). At 1 or 7 days after the last injury, a cohort of rats was used for behavioural testing to study anxiety and risk-taking behaviours and cognitive abilities. From a different cohort, hippocampal slices were generated and used for in vitro electrophysiological recordings, and the capacity for long-term depression (LTD) and long-term potentiation (LTP) was examined in the medial perforant path (MPP)-dentate gyrus (DG) synapse. Our results showed that r-mTBI impaired hippocampal-dependent spatial learning and memory and that r-mTBI significantly impaired the capacity for LTD but not LTP in both sexes. These data are the first to describe the negative impact of r-mTBI on LTD in the juvenile DG in both males and females, and provide evidence for the delayed development of neurological deficits with r-mTBI. / Graduate

Horse riding is a popular global activity involving a wide range of sporting events including dressage, endurance riding, eventing, show jumping, horse racing and rodeo. Unfortunately, horse riding and equestrian sporting events, report a high prevalence of concussion. The most common mechanism for brain injury in equestrian events involve high levels of linear and rotational acceleration during head impacts when falling from a horse. These accelerations create injurious brain tissue strain. While both linear and rotational accelerations occur during head impacts, the rotational components of acceleration are closely linked to brain tissue strain. To reduce brain strain, helmet technologies have been developed with the aim to reduce head rotational accelerations during an impact. The most common rotational managing technology, multi-directional impact protection system (MIPS), employs a low friction layer to reduce the amount of rotational acceleration sustained by the brain during head impacts. MIPS tests equestrian helmets using a monorail drop rig with a 45-degree steel anvil covered in 80 grit sandpaper at 6.2 m/s. The surface experiencing impact in the MIPS test method is a very low compliant surface (steel). It is impacted at a velocity of 6 m/s, and an anvil angle of 45-degrees. In contrast, most impacts in equestrian involve high compliant material such as sand or turf with an average impact velocity is 9 m/s, and the average angle of impact of 27 degrees. The proposed rotational testing method employed by MIPS may not fully represent the most common accidents involving equestrian events. The objective of this research was to evaluate the effectiveness of a helmet with rotational technology to reduce linear and rotational acceleration, rotational velocity, and maximum principal strain (MPS) in equestrian helmets. An equestrian specific test protocol was developed using the common impact conditions for concussive events for equestrian riders. Nine m/s impact velocity, with an angle of 26.5 degrees to the horizontal axis, and an anvil compliance consisting of 66 mm of 602 vinyl nitrile foam with synthetic grass to represent turf impacts was reported as the most common impact characteristics. Using a Rail Guided Launcher, a helmeted Hybrid III headform was launched and impacted a low and high compliance anvil using the defined velocity and angle parameters. Two equestrian helmet types were impacted, a conventional helmet with no rotational technology and the same helmet model with rotational technology. The impact locations tested included front, side, and rear boss, as these were the most common impact locations reported for concussive events in equestrian. Linear and rotational acceleration and rotational velocity were measured using a DTS SLICE sensor installed inside the headform. The linear and rotational acceleration curves were then used as input to the University College Dublin Brain Trauma Model (V2.0) to calculate MPS. Statistical analysis included four t-tests, two 2x2x3 ANOVA's with 8 pairwise Tukey post-hoc test, significance set to α=0.05. The results were not uniform across impact locations and anvil compliances, the rear boss impact location in helmets with rotational technology revealed significantly lower rotational accelerations and rotational velocity. The results revealed helmets with rotational technology should be designed to perform under these high-energy conditions. If the rotational technology was designed with these considerations, it would be possible to investigate the potential of rotational technologies to decrease dynamic head response and the brain tissue strain.

Objective: To extend previous research designs and examine cognitive performance up to 30 days postconcussion. Method: A prospective cohort design was used to examine 2000 athletes from 8 mid-Michigan area high schools to compare baseline neurocognitive performance with postconcussion neurocognitive performance. All concussed athletes were readministered the Immediate Post Assessment and Cognitive Test (ImPACT) at 2, 7, 14, 21, and 30 days postconcussion. Results: A total of 72 high school athletes (aged 15.8 ± 1.34 years) sustained a concussion. A significant within-subjects effect for reaction time (F = 10.01; P= 0.000), verbal memory (F = 3.05; P = 0.012), motor processing speed (F= 18.51; P = 0.000), and total symptoms following an injury (F= 16.45; P= 0.000) was found. Concussed athletes demonstrated a significant decrease in reaction time up to 14 days postconcussion (P = 0.001) compared with baseline reaction time. Reaction time returned to baseline levels at 21 days postinjury (P = 0.25). At 7 days postinjury, impairments in verbal memory (P= 0.003) and motor processing speed (P= 0.000) were documented and returned to baseline levels by 14 days postinjury. Concussed athletes self-reported significantly more symptoms at 2 days postconcussion (P = 0.000) and exhibited a resolution of symptoms by 7 days postinjury (P = 0.06). Conclusion: High school athletes could take up to 21 days to return to baseline levels for reaction time. These data support current recommendations for the conservative management of concussion in the high school athlete.

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Subconcussions in sport is a growing field of interest and concern as deteriorative effects of these impacts have been shown in athletes without a diagnosed concussion. Detecting subconcussions is extremely difficult and there is no standardized method to recognize these injuries. A first step in identifying subconcussion is taking a closer look at concussions. The vestibular system has been shown to be negatively affected after concussive injuries which can be quantified via oculomotor function and pupillometry. Currently, King Devick (KD) style tests and Pupillary Light Reflex (PLR) are two popular tests that can be administered to athletes to gather clinical eye measures relating to oculomotor function and pupillometry. This study aimed to investigate how clinical eye measures change through serial in-season testing of Division 1 (D1) soccer athletes. Head impacts throughout a soccer season were recorded and we hypothesized that a greater number of head impacts would result in negative clinical changes even in the absence of a diagnosed concussion. No major trends were observed in soccer athletes that can be associated with trends seen in concussed populations. Soccer athletes were found to be slightly more likely to test abnormally than non-contact controls and soccer athletes with a greater number of head impacts were found to have slightly more abnormal tests than athletes with fewer head impacts. Overall, this study provides a dataset of pre and post-season measurements and uniquely includes multiple in-season measurements to provide a new perspective on oculomotor function and pupillary light reflex over the course of a sports season. / Master of Science / Subconcussions in sport is a growing field of interest and concern as deteriorative effects of these impacts have been shown in athletes without a diagnosed concussion. Detecting subconcussions is extremely difficult and there is no standardized method to recognize these injuries. The first step at identifying subconcussions is to more closely look at concussions. Eye movements and pupil response to stimuli can be affected after a concussive injury. Currently, King Devick (KD) style tests and Pupillary Light Reflex (PLR) are two popular tests that can be administered to athletes to gather clinical eye measures relating to eye motion and pupil response to stimuli. This study aimed to investigate how clinical eye measures change through repeated in-season testing of Division 1 (D1) soccer athletes. Head impacts throughout a soccer season were recorded and we hypothesized that a greater number of head impacts would result in negative clinical changes even in the absence of a diagnosed concussion. No major trends were observed in soccer athletes that can be associated with trends seen in concussed populations. Soccer athletes were found to be slightly more likely to test abnormally than non-contact controls and soccer athletes with a greater number of head impacts were found to have slightly more abnormal tests than athletes with fewer head impacts. Overall, this study provides a dataset of pre and post-season measurements and uniquely includes multiple in-season measurements to provide a new perspective on clinical eye measures over the course of a sports season.

Head and neck injuries are common in contact sports. Proper function of the cervical spine sensorimotor system is important in limiting these injuries. Repetitive stress incurred during contact sport participation may negatively affect this system and increase injury risk. Currently, there is a paucity of research examining contact sport exposure and cervical spine sensorimotor function. The purpose of this study was to examine the effect of contact sport participation on cervical sensorimotor function. The independent variables were group (rugby, non-contact), sex (male, female), and time (pre-season, post-season). The primary dependent variable was neck position sense error as measured by total neck reposition (TNRE) error and maximum neck reposition error (MaxNRE). Secondary dependent variables included neck disability index, signs and symptom (S/S) number, symptom severity, concussion history, cervical range of motion, and isometric neck strength. This prospective observational study included forty-nine participants (15 male rugby, 11 female rugby, 11 non-contact male control, 12 non-contact female control) from Temple University campus recreation club sport teams. Athletes participated in two testing sessions, one prior to the season (i.e., pre-season) and one following the season. Data were analyzed using descriptive and inferential statistics. Independent-sample t-tests with Bonferroni corrections were used to assess statistically significant differences in dependent variables at pre-season between groups (Aim 1) and sex (Aim 2). Independent-samples t-tests with Bonferroni correction were also used to explore statistically significant differences in dependent variables change scores from pre-season to post-season between groups (Aim 1). Pearson correlations (r &gt; .60) were used to assess potential covariates but none were identified. Pearson correlations were also used to evaluate the relationship between pre-season maximum and total neck reposition sense error and the following dependent variables: years of contact sport participation, concussion S/S number and severity score, global cervical range of motion and global cervical isometric strength (Aim 3). For Aim 1, between group differences were identified for global cervical isometric strength, t (1, 45) = 2.98, p = .005, and total joint reposition error t (1, 45) = 2.78, p = .008, only. There were no significant change score differences between groups across time. For Aim 2, sex differences were identified in years of contact sport exposure (p = .004), height (p &lt; .001) and global isometric strength (p &lt;.001), only. For Aim 3, preseason concussion S/S number and severity scores were significantly correlated (p &lt; .05) with total joint reposition error (r = .352) and maximum joint reposition error (r = .476). The present study findings indicate a difference in cervical spine sensorimotor function between collegiate club rugby athletes and controls. Specifically, rugby athletes exhibited significantly greater neck reposition sense error than controls. Additionally, concussion S/S scores were related to reposition sense error. Differences in position sense error were not identified between males and females, however females did exhibit less neck strength mirroring previous reports. These findings suggest that exposure to contact sport-related impacts may lead to changes in cervical spine sensorimotor function. These changes are important as they could represent an increased risk of injury and can be modified proactively. A comprehensive cervical spine pre-season examination including concussion S/S and position sense assessments could identify individuals needing preventative intervention. Future research should explore the risk associated with these proprioceptive deficits and the benefits of proactive therapeutic intervention designed to mitigate sensorimotor deficits in contact sport athletes. / Kinesiology