Life Sciences Commons^™

The Clinical Value Of Oculomotor Assessments Across The Continuum Of Concussion, Dillon Richards

Electronic Thesis and Dissertation Repository

Concussions are complex conditions that are difficult to manage medically. Variations in symptom presentation, intricate neurophysiological processes, and the availability of a variety of possible assessment tools may contribute to this complexity. Clinicians must use a broad approach, employing both subjective symptom assessment and objective assessments to confirm a diagnosis and/or monitor progression and recovery. Oculomotor function after concussion may be an important indicator of injury, given the interconnectedness of oculomotor function, vestibulo-ocular and visual systems, and even cognition. Oculomotor function may be assessed objectively or indirectly using patient-reported symptom checklists as part of subjective assessments. One way of objectively …

Potential Sex-Related Differences In Neurophysiology Post-Concussion, Alexandra N. Pauhl

Electronic Thesis and Dissertation Repository

The purpose of this study was to examine potential sex-related differences in neurophysiology in concussed and healthy individuals. There was a total of 21(9 F) participants in each group. The concussion (CONC) group reported to the lab within 72 hours, 1- and 2-weeks post-injury. The control (CONT) group followed a similar measurement schedule once recruited. Motor evoked potential (MEP) amplitude and cortical silent period (CSP) duration was measured in the first dorsal interosseous muscle using transcranial magnetic stimulation. There were no significant differences in MEP amplitude or CSP duration between the CONC and CONT group. As well, there was no …

The Impact Of Impacts: Repetitive Head Impact Exposure In Canadian University Football Players, Jeffrey S. Brooks

Electronic Thesis and Dissertation Repository

Due to the physical nature of the game and repeated head impacts between players each play, the sport of football has one of the highest incidence rates of concussion. With nearly two million participants, this incidence rate translates to a reserved estimate of 100,000 concussions per year due to the contact nature of the sport. Injury thresholds have proven difficult to establish, so American football concussion research has shifted focus to measuring the accumulation of repetitive head impacts. As there are numerous rule differences between Canadian and American football, head impact exposure may present differently for Canadian players. Accordingly, the …

Brain-Specific And Systemic Inflammatory Response Following Repetitive Concussive Impact In A Mouse Model, So Young Eo

Electronic Thesis and Dissertation Repository

Concussion is the most common form of mild traumatic brain injury (mTBI). TBI resolution is modulated by neuroinflammation, which is augmented by the infiltration of innate immune cells from the circulation. Peripheral, myeloid immune cells not only invade neural tissues but other organs as well causing local inflammation and tissue damage, known as systemic inflammatory response syndrome. Here, I assessed the temporal and anatomical nature of the neural and systemic cellular inflammatory response to repetitive, mTBI in a 3-hit mouse model of concussion. The results showed significant microglial activity, accumulation of peripheral myeloid cells and prominent axonal damage post-injury. The …

Oculomotor Executive Dysfunction During The Early And Later Stages Of Sport-Related Concussion Recovery, Brandon Webb

Electronic Thesis and Dissertation Repository

Executive dysfunction represents a persistent concussion deficit; however, it is largely unclear whether the deficit persists in an athlete after they have been deemed safe to return to play. In the present work, athletes with a sport-related concussion, and their age- and sex-matched controls, completed prosaccades and executive-related antisaccades: (1) 2-6 days post-concussion (i.e., initial assessment), and (2) 14-20 days after initial assessment and only when an athlete was medically cleared for safe return to play (i.e., follow-up assessment). Initial assessment antisaccades for the concussed group produced longer reaction times (RT) and more directional errors than the control group. The …

Multiparametric Mri Changes Persist Beyond Recovery In Concussed Adolescent Hockey Players, Kathryn Y. Manning Msc, Amy Achranz Bmsc, Robert Bartha Phd, Gregory A. Dekaban Phd, Christy Barreira Bsc, Arthur Brown Phd, Lisa Fischer Md, Kevin Asem Md, Timothy J. Doherty, Douglas D. Fraser Md Phd, Jeff Holmes Phd, Ravi S. Menon

Anatomy and Cell Biology Publications

Objective: To determine whether multiparametric MRI data can provide insight into the acute and long-lasting neuronal sequelae after a concussion in adolescent athletes.

Methods: Players were recruited from Bantam hockey leagues in which body checking is first introduced (male, age 11–14 years). Clinical measures, diffusion metrics, resting-state network and region-to-region functional connectivity patterns, and magnetic resonance spectroscopy absolute metabolite concentrations were analyzed from an independent, age-matched control group of hockey players (n 5 26) and longitudinally in concussed athletes within 24 to 72 hours (n 5 17) and 3 months (n 5 14) after a diagnosed concussion.

Results: …

Impaired Dynamic Cerebrovascular Autoregulation In Adolescent Concussion, Marcy Erin Moir

Electronic Thesis and Dissertation Repository

Although cerebrovascular impairments are believed to contribute to concussion symptoms, little information exists regarding brain vasomotor control in adolescent concussion, particularly during changes in arterial blood pressure (ABP). This research tested the hypothesis that adolescent concussion is marked by impaired dynamic cerebral autoregulation (dCA). Thirty concussed adolescents and thirty healthy controls completed two sit-to-stand trials. Cerebral blood flow velocity and ABP were measured continuously. Cerebrovascular resistance (CVR) was calculated and the rate of drop in CVR relative to the change in ABP provided the rate of regulation (RoR). The concussed adolescents were followed through rehabilitation for up to 12-weeks. At …

Evaluating Evolving Leukocyte Populations In Peripheral Blood Circulation Post-Concussion In A Human Longitudinal Analysis Of Female Athletes, Kevin A. Blackney

Electronic Thesis and Dissertation Repository

Concussions are generating increasing concern due to potential long-term neurological consequences. Currently there is no universally recognized diagnostic approach for concussion. I hypothesize that a signature temporal response of biomarkers of inflammation in systemic circulation will provide an objective diagnosis of concussion and could also be used to track patient recovery. The Western University women’s rugby team underwent blood draws at pre-season and post-season as a baseline evaluation, and players determined to have sustained a concussion underwent repeat blood analysis post-concussion. Blood samples were analyzed by flow cytometry to profile immune cell populations alongside accepted concussion assessments, and complete blood …

The Use Of P3b As An Indicator Of Neurophysiologic Change From Subconcussive Impacts In Football Players, Jeffrey S. Brooks

Electronic Thesis and Dissertation Repository

There is a growing appreciation in research that subconcussive impacts may affect cognitive functioning. Canadian University football players (n=45) were separated into three groups based on their position/skill (small skilled, big skilled and big unskilled). An impact measuring device (GForceTracker) was used to record the number of impacts that each player experienced in a season. Player groups were separated into two levels of impact exposure: low and high. Players completed baseline, midseason, postseason, and follow-up neurophysiological tests (four months later) to measure P3b amplitude in response to a visual oddball paradigm, and high versus low impact subgroups for each player …