Sports-related concussion and its subsequent management have become a top priority within the sports medicine research spectrum. In order to properly understand the complex nature of concussion management, multiple aspects of the injury were explored including the psychobiological nature of the injury, risk for further injury, diagnostic concerns, and return to play decision making. While much research has been dedicated to these areas, one in particular, return to play, is the focus of this current research study. To date, there has not been a method for accurately predicting return to play time after an athlete has sustained sports-related concussion. In order to advance the understanding of return to play and the clinical management of concussion, the current study applied a unique statistical methodology to empirically develop an equation to predict average return to play time using a set of post-injury variables. This equation predicted average return to play time with significant accuracy and resulted in a strong correlation between predicted return to play time and observed return to play time. Importantly, the predication equation was moderately stable across multiple samples. The results suggest that return to play time can be successfully predicted via a set of post-injury variables. Thus, the understanding of concussion severity as well as the clinical management of the injury can be improved by providing clinicians with a better estimate of the length of time an athlete will be unable to participate in a given activity before full recovery.

This study analyzed the impact of a biofeedback intervention with athletes in sport, specifically those returning to play from a concussion. Although return to play protocols address the physical symptoms related to concussion (i.e., a mild traumatic brain injury), psychological issues related to the injury are often not addressed. Biofeedback is the use of technical equipment to assist an individual to understand physiology through immediate feedback of an action or stimulus and has been found to assist athletes with focus and concentration. In this study, a total of six athletes were recruited to complete a 12-week biofeedback (i.e., breathing) intervention. In addition to physiological markers, focus groups were also used before and after the intervention. The results point to the positive impact of the intervention, particularly the qualitative component. Participants expressed improvements related to anxiety, fear, anger, and relationships with family and friends. Limitations and future directions are discussed. / October 2016

According to the Guidelines for Diagnosing and Managing Pediatric Concussion, concussion is defined as “an injury to the brain caused by a blow to the head or to another part of the body that causes the head to spin or jolt” (Zemek, Duval, Dematteo, 2014, p. 40), and is a common injury among the youth population (National Institute of Health, 1999). When moving or remaining stationary the head can be stabilized in two ways: head stabilized in space and head stabilized on trunk (Bazarian, Veazie, Mookerjee, & Lerner, 2006). When under anxiety inducing conditions during development and when learning novel tasks individuals tend to shift from a head stabilized in space strategy to a head stabilized on trunk strategy in an effort to decrease the degrees of freedom required to move the head (Assaiante, McKinley, & Amblard, 1997). However, it is unclear whether certain pathologies result in movement strategies and whether these are influenced by the difficulty of the task performed. Objective The present study examined the effects of concussion on head stabilization strategies in adolescents while performing three dual-tasks. Participants Fifty-four participants, 24 concussed with post- concussion syndrome (age, 13.5 ± 1.9 years; 15 females, 9 males) and 30 healthy typically developing adolescents (age, 14.3 ± 1.7 years; 12 females, 18 males), performed one session of three dual-task conditions. Centre of pressure along with head, trunk and pelvis kinematics were captured during task performance using a Nintendo® Wii Balance Board and Ascension 3D Guidance TrakSTAR respectively. A head anchoring index (AI) was used to identify either head stabilized in space or head stabilized on trunk movement strategies, while center of pressure was collected to further support the use of movement strategies. Results There were no significant differences in AI between the two groups in any of the three dual-task conditions. Conclusion These results could be attributed to balance recovery or lack of balance problems in the concussed population.

A quiet stance framework and a control system perspective were used to explore healthy balance and balance after mild traumatic brain injury. Linear and non-linear centre of pressure analyses were applied. The foundation was laid by reviewing literature to understand how balance is achieved, how it is represented as a control system, what factors are known to affect balance, and the cornerstone—how to choose appropriate measures to quantify balance. To understand how mild traumatic brain injury affects the brain, a scoping review of the evolution of symptoms and effects was used to form a conceptual description. Findings described phases of functional effects that resulted from neurometabolic cascade; consequently, balance and dual-task functional effects were determined to stem from widespread not focal changes in the brain. Subsequent studies were tailored to address gaps in knowledge. Linear and non-linear centre of pressure measures were first investigated in healthy young adults to determine what supplemental information could be provided by non-linear measures describing local stability and scaling. It was found that linear and non-linear measures were complementary in assessing balance system input-output, control, and integration. Furthermore, normative non-linear data were established for single leg and tandem stance. Subsequently, these measures were investigated in young adults and adolescents with recent mild traumatic brain injury based on the hypothesis that altered mechanisms affecting balance would be reflected by changes in these measures. In young adults, increased complexity of short-term scaling indicated subtle changes to balance control after injury. In adolescents, linear and non-linear measures also demonstrated changes to output, control, and temporal relations of balance. Altered balance was also demonstrated while concurrently performing a Stroop task. On the whole, changes to multiple aspects of balance supported the concept of widespread effects resulting from mild traumatic brain injury. Balance control in quiet stance was further explored using three-dimensional state space reconstruction of centre of pressure. Visual representations demonstrated that dynamic structure within centre of pressure reflected control characteristics. These control characteristics were still present after mild traumatic brain injury.

Concussion/mild traumatic brain injury (mTBI) is a significant public health concern, particularly for young individuals and athletes. While the vast majority recover quickly and without lasting consequences, some will suffer from potentially long-term neuropsychiatric sequelae. These sequelae have been investigated in mTBI samples consisting largely of motor vehicle-related injuries, but very few have examined these following sport-related concussion (SRC). Further, new evidence indicates that participation in contact sports alone can result in similar problems with cognition and mood/anxiety. This thesis investigates neuropsychiatric sequelae in youth and young adults with concussion and who participate in contact sports. The hippocampus is known to be vulnerable to head injury, and animal models indicate that mTBI impairs hippocampal neurogenesis — the process of the growth, maturation, and integration of adult-born neurons. Hippocampal neurogenesis is well-recognized for its importance to cognition, and has more recently been linked to mood and anxiety. Accumulating evidence indicates that a test involving a component of high memory interference, the mnemonic similarity test (MST), is sensitive to neurogenesis-dependent conditions in humans. To the best of our knowledge, this thesis is the first to investigate whether the MST is sensitive to concussion, contact sport participation, and athletic anxiety. This thesis describes: (1) a critical review of the literature regarding the psychiatric sequelae of concussion, followed by (2) clinical profiles derived from retrospective data which document the new onset of immediate psychiatric problems in youth, and delayed psychiatric problems in youth with persistent concussion symptomology; that (3) anxiety is the most common and persistent psychiatric symptom in youth with concussion; that (4) concussion and contact sport participation negatively affect performance on the MST; that (5) a reprieve from contact sport participation is associated with an improvement in MST performance; that (6) these negative effects on the MST are not seen with other injuries; that (7) athletic anxiety impairs performance on the MST. Taken together, this thesis provides evidence that psychiatric problems can present immediately after concussion in persons without identifiable risk factors, and that concussion, contact sport participation, and athletic anxiety affect performance on a putatively neurogenesis-linked test. These results may implicate impaired hippocampal neurogenesis in postconcussion sequelae. / Thesis / Doctor of Philosophy (PhD)

published_or_final_version / Clinical Psychology / Doctoral / Doctor of Psychology

Background: Sports-related concussions (SRC) are very common in youth in the US and represent a major clinical challenge. Clinical Practice Guidelines (CPG) have been developed to help guide the health care provider (HCP) in the diagnosis and management of SRC. Seventy-three percent of HCPs report that they deviate from current concussion CPGs in their clinical practices. The Protection of Athletes with Head Injuries Law in Utah requires HCPs caring for youth with concussions receive continuing education (CE) regarding SRC every three years. Currently, there are no CE modules on SRC developed for nurse practitioners (NPs) in the state of Utah. Project Purpose: The purpose of this DNP project was to develop and pilot an evidence-based educational module for primary care NPs in Utah on the evaluation and management of SRC in children and adolescents under the age of 18 years old. Methods: The education module integrates the concussion education curriculum developed by Pamela Mapstone DNP, PCNP. The module incorporates current CPGs and an extensive literature search. Following development of the module three clinical experts in SRC independently reviewed the module. Modifications were made accordingly and a pilot study evaluating the quality and usability of the education module was conducted. Sixteen NPs working in Utah were invited to complete the module followed by a short survey related to user satisfaction. The final version of the education module was modified based on the results of the pilot study. Results: An education module on SRC in youth for NPs working in primary care in Utah was successfully developed and piloted for quality and usability. The results of the pilot study support the content addressing the learning objectives; and that the module was easy to use. Conclusion: The education module tailored to the needs of NPs working in primary care in Utah has the potential to improve NPs’ knowledge of SRC in youth. Further study is recommended to evaluate the effects of the education module on clinical practice outcomes.

The purpose of this study is to examine the structure of neurobehavioral symptoms in service members with physical and/or psychological trauma to determine the diagnostic specificity of these symptoms. Previous literature has demonstrated that orthopedic injured, mild traumatic brain injury (MTBI), and healthy controls shared similar levels of postconcussive symptom complaints, which suggest that postconcussion-like symptoms are not unique to MTBI. To the best of my knowledge, this is the first study examining this phenomenon in a sample of recently redeployed service members. Dimensional analysis of the PCL-C and NSI using SEM did not produce a model that was consistent with previous literature and principle component analyses did not produce a simple solution for posttraumatic stress or neurobehavioral symptoms. Thus, the study does not provide evidence for construct validity for either instrument. Implications for these findings are that clinicians need to be aware that these instruments may not be measuring coherent constructs within this population as purported and should judiciously interpret and report the results of these instruments.

The sternocleidomastoid (SCM) and upper trapezius (UT) muscles are the primary dynamic stabilizers of the head and neck and likely attenuate head acceleration with direct and indirect impacts. Increasing the strength of the SCM and UT through cervical resistance training has been recommended to prevent concussions in football players. The purpose of this study was to examine the effects of an eight-week isoinertial cervical resistance training program on SCM and UT muscle activity (EMG) and kinematic responses of the head and neck during a standard football tackle in college-aged males. Sixteen college-aged males (21.6 ± 2.8 y, 94.6 ± 13.3 kg) with previous high school football or rugby playing experience completed an eight-week isoinertial cervical resistance training program consisting of three sets of 10 repetitions of neck extension, flexion, right and left lateral flexion at 60-80% of 10 repetition maximum two to three times a week. Isometric cervical strength, neck girth, EMG, and kinematic responses of the head and neck during a standard football tackle were measured before and after training. All kinematic data were gathered using a three-dimensional motion capturing system. Training resulted in 7 and 10% increases in isometric cervical extension and left lateral flexion strength, respectively, but no changes were seen in isometric flexion or right lateral flexion strength or neck girth. Additionally, training had no influence on the EMG responses of the SCM or UT, peak linear (7.23 vs. 7.59 g, p = 0.115; pre- vs. post-training) or angular (431.96 vs. 452.37 rad/s2, p = 0.864) head accelerations during the standard football tackle. The UT demonstrated approximately 40% higher absolute EMG activity than the SCM during tackling both before and after training. Under the current experimental conditions, despite modest increases in isometric cervical extension and left lateral flexion strength, the eight-week isoinertial cervical resistance training program failed to augment dynamic stabilization of the head and neck during a standard football tackle in college-aged males. Future research should examine the effects of both slow speed load-intensive and high speed low-to-moderate load intensity isoinertial training as well as plyometric training in decreasing head acceleration during football tackling for injury prevention purposes.

Short-term and long-term neurological damage as a result of sports-related brain trauma is a major concern for athletes today. In the last decade, studies of subconcussive repetitive head impacts (RHI) in contact sports have found associations with functional and structural brain changes, even in the absence of diagnosed concussion. Risk and thresholds for brain dysfunction in the setting of sports-related RHI remain poorly understood. This prospective study enrolled 119 athletes (72 contact, 47 noncontact) of both sexes (79 male, 40 female), to explore the effect of one season of subconcussive RHI on brain function in high school football, boys lacrosse, and boys and girls soccer versus a comparison group of noncontact athletes. This study is the first to assess the effects of one season of RHI exposure on traditional and novel cognitive measures as well as self-reported emotion, sleep and headache in high school athletes. Contact sport athletes wore a commercial accelerometer to investigate if there is a dose-response relationship between RHI exposure and brain function. Paired t-test comparisons of all measures revealed contact sport athletes were not different than noncontact athletes in experiencing negative changes over the course of one season on the assessment battery. Given the number of subjects evaluated and the resultant power to detect change, this study had an 82.5% power to detect a Cohenʼs d of 0.66. Regression analysis of multiple measures of RHI among contact sport athletes did not identify a significant relationship between exposure and changes in cognition, emotion, sleep or headache over one season. Secondary analyses found significant relationships between a greater number of total head impacts at postseason assessment and higher scores on NIH Emotion Battery elements Perceived Stress (p=0.0002) and Perceived Hostility (p=0.0004), but it was unrelated to total years of football exposure. Overall, this study showed that there does not appear to be an association between one season of RHI exposure and short-term changes in cognition or self-reported aspects of emotion, sleep, or headache. Results from this study may help in the design of future investigations that will increase our understanding of the short-term consequences of RHI. Future studies should concentrate on the question of a clinically significant threshold at which RHI above a certain magnitude is more likely to cause brain dysfunction.