Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

M.A. in Psychology



First Advisor

Todd A. Smitherman

Second Advisor

John N. Young

Third Advisor

Kristin Austin

Relational Format



Worldwide, traumatic brain injuries (TBIs) are the leading cause of injury related death and disability for children and young adults, with an estimated 50 million TBIs occurring annually. Post-traumatic cognitive fatigue, or the perceived lack of mental energy needed to accomplish a goal, is a debilitating symptom of TBI, preventing many survivors from returning to work or enjoying their pre-injury quality of life. The mechanisms underlying TBI often cause executive function deficits, such as compromised ability to make adaptive decisions. Although decision-making and fatigue share portions of the same neural network, no literature to date has examined the potential mediating effect of cognitive fatigue on decision-making ability associated with TBI. The present study explored decision-making among a sample of TBI survivors compared to non-TBI controls and whether fatigue mediates this relationship. Additionally, this study examined the moderating effect of working memory on the relationship between fatigue and decision-making. People with TBI evidenced significantly compromised decision-making compared to controls. This effect was mediated by cognitive fatigue, such that an increase in cognitive fatigue resulted in better decision-making. While unexpected this may be explained through the coping hypothesis of fatigue, indicative of an effort-reward imbalance during later stages of the task. Better working memory capacity weakened the direct effect of the TBI on decision-making ability by reducing the influence of fatigue. Future studies shouldevaluate the effect of reward-based interventions on decision-making and whether cognitive rehabilitation efforts targeting working memory may lessen the influence of TBI on decision- making by alleviating fatigue.


Clinical Psychology

Available for download on Thursday, August 15, 2024