Defining the Relationship between Anxiety and Driving Performance in Post-9/11 Veteran

Background: Post-9/11 combat Veterans with a history of Traumatic Brain Injury (TBI) and symptoms of Post-Traumatic Stress Disorder (PTSD) endorse more driving difficulty and higher levels of anxiety behind the wheel than healthy combat Veterans. This project extended prior findings by directly examining the relationship between TBI and PTSD symptom severity and simulated driving performance in combat Veterans of Iraq and Afghanistan. We specifically focused on the interactive effects of physiological arousal, subjective anxiety, attentional resources, and cognitive appraisal on driving performance.;Objectives: We measured simulated driving performance of combat Veterans across symptom severity and driving conditions with differing demands. We expected that all Veterans would commit more driving errors in a challenging drive condition as compared to a baseline drive and that Veterans with more severe symptomatology would demonstrate a relatively larger decrease in driving performance across conditions than Veteran controls. We further hypothesized that elevated physiological arousal and subjective anxiety would contribute to decreased driving performance across groups and conditions, and that higher symptomatology would predict higher levels of distress and poorer driving performance than Veteran controls.;Methods: Thirty post-9/11 combat Veterans completed measures of emotional, physical, and neuropsychological functioning. Driving performance was measured via established simulator variables. Participants drove training and baseline routes, completed cognitive testing and anxiety-provoking tasks, then drove a more challenging route that included complex situations and auditory stimuli. Cardiac interbeat intervals (IBI) and subjective units of distress (SUDS) served as distress variables. Driving performance and distress levels were compared across symptom severity and drive conditions.;Results: All Veterans committed more driving errors and reported more distress in the challenge drive as compared to their own performance in the baseline drive. Drivers with higher levels of PTSD performed worse and reported higher anxiety than those without PTSD at baseline, and these disparities increased as driving demand increased. Increased PTSD severity was associated with 1) more variability in speed management and consistency, 2) higher deviation from the mean in amount of time required to complete the challenge route, 3) increased heart rate variability, 4) and higher subjective anxiety. In addition, drivers with more severe PTSD symptomatology 1) were more likely to notice and interpret neutral auditory stimuli as threatening, 2) reported more combat exposure, and 3) reported more significant depression and TBI symptomatology than those with less severe PTSD.;Conclusions: These data provide evidence for a cycle of cognitive, emotional, and behavioral learned responses that Veterans adopted while deployed to combat and have difficulty disengaging from after returning home.