Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Anatomy and Cell Biology

Supervisor

Owen, Adrian M.

2nd Supervisor

Wilson, Timothy D.

Co-Supervisor

Abstract

Healthy normal aging and cumulative head trauma (concussion and subconcussion), can influence cognition independently and concomitantly leading to substantial late-life cognitive impairments (e.g., as seen in increased rates of dementia). With this as motivation, this dissertation explores three aspects of aging, head injury and cognition using the Cambridge Brain Sciences (CBS) cognitive battery (www.cambridgebrainsciences.com).

Study 1 (Chapter 2): Concussion-specific testing combines assessments from multiple domains to evaluate a variety of functions. While clinically relevant, their succinct nature limits the amount of cognitive information available. Eighteen male football athletes were examined at baseline using the Sport Concussion Assessment Tool (SCAT) 3, and CBS battery. SCAT3 cognition test (Standardized Assessment of Concussion) scores significantly correlated with just the verbal cognitive domain assessed by CBS. This suggests a narrow scope which may miss other aspects of cognition that could be equally vulnerable in concussion.

Study 2 (Chapter 3): It is likely that both subconcussive and concussive impacts contribute to the cognitive changes seen in retired athletes. What remains unclear is when these changes first appear and how they can be detected. This study compared 81 male football athletes (high cumulative impact burden) and matched controls (low cumulative impact burden) on cognitive test performance and response time. Results demonstrated response time deficits (slowed and more variable) without score impairments in football athletes in comparison to controls, which may represent pre-clinical compensatory mechanisms mitigating an increased cognitive demand.

To address limitations in repeating Study 2 in contact sport retirees, Study 3 (Chapter 4) employed discriminant function analysis (DFA) to reduce the CBS battery for better application in aging populations. 118 younger and 118 older participants were included. Five of the 12 CBS tests were necessary to retain 98% of the variance accounted for between groups in the full model. Additionally, CBS tests were divided into 3 categories based on significant differences in the full and reduced models: no significant differences (n = 2), ii significant differences only on full model (n = 5), and significant differences on both models (n = 5). Results support the use of a modified CBS battery in age-related studies.

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