All ETDs from UAB

Advisory Committee Chair

Despina Stavrinos

Advisory Committee Members

Richard D Davis

Michael Crowe

Daniel Mirman

Thomas Novack

Document Type


Date of Award


Degree Name by School

Doctor of Philosophy (PhD) College of Arts and Sciences


Every year, millions of people in the United States sustain a traumatic brain injury (TBI). Subsequently, a subset of people with TBIs may incur roadway crashes due to poorer vehicle maneuvering and problems with higher-order driving skills such as speed control and lane maintenance. Research is needed to better understand what relates to driving aptitude following TBI. Previous research in individuals with TBI has focused on objective cognition, the set of mental abilities that help to process information for memory, planning, and action. TBIs can result in cognitive difficulties, which for some, may last months after mild cases and a lifetime after moderate-to-severe TBIs. To date, most studies have used performance on cognitive tasks (i.e., objective cognition) to predict driving ability after TBI, finding that lower cognitive ability related to poorer on-road and simulated driving ability. An emerging line of research shows that subjective cognition may additionally predict poor driving after TBI. One subjective cognitive complaint after TBI is the metacognitive awareness of mental fog, or problems with cognitive processes accompanied by mental clutter. The current study expanded this research by examining whether subjective cognitive difficulty and cluttered thought can predict simulated driving performance in a cross-sectional evaluation of individuals who have sustained mild and moderate-to-severe TBI. Findings illustrated higher mental fog in mild TBI compared to healthy controls although not significantly different from moderate-to-severe cases. Mental fog was unrelated to cognitive performance after mild TBI but linked to disrupted updating and slowed processing speed after moderate-to-severe TBI. Regarding primary outcomes, higher mental fog corresponded to more self-reported driving difficulties after mild TBI and faster average speeds after moderate-to-severe TBI. Subjective cognition, thus, appears relevant to safer driving after TBI alongside objective cognitive performance. After injury, assessing mental fog may be beneficial in identifying those less likely to return to drive and whom require training or rehabilitation.