Making Decisions in Context in Post-9/11 Veterans with Comorbid Chronic Blast Mild Traumatic Brain Injury and...

Cognitive decrements in executive function and processing speed have been found in post-9/11 Veterans who have mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD). Decision making (DM) involves the coordination of cognitive sub-processes involving different brain regions known to be impacted by mTBI and/or PTSD, and so may be expected to be compromised. The ability to incorporate context is important because it plays a role in almost every cognitive and social process. However, DM abilities, including DM that requires taking context into account, are not typically assessed or investigated in Veterans.

We prospectively recruited Veterans deployed to Iraq or Afghanistan who had the following characteristics: (1) no TBI before deployment, (2) mTBI because of blast only, (3) current PTSD (diagnosed within 6 months), and (4) ≤49 years of age. Deployed Veterans with no mTBI or PTSD served as the comparison group. Veterans with mTBI and comorbid PTSD (mTBI + PTSD; n = 9) and Veterans without mTBI or PTSD (n = 8) performed the Cognitive Bias Task, a DM task in which participants are asked to make a decision based on preference, and the extent to which choices are influenced by contextual information is measured. To further understand any association between DM and mTBI + PTSD, participants also filled out questionnaires to measure neurobehavioral and PTSD symptoms. Because normality was violated in both groups, Fisher's Exact and Mann-Whitney tests and Spearman's rank order correlations were used.

Although Veterans without mTBI + PTSD made context-dependent choices, Veterans with mTBI + PTSD made context-independent choices (p = .034), similar to prior research examining individuals with severe TBI and left lateralized frontal lobe brain lesions. As expected, Veterans with mTBI + PTSD also demonstrated elevated scores on the symptom measures. Symptom measure scores were correlated with Cognitive Bias Task (CBT) scores and revealed a negative correlation between somatic, and marginally cognitive and arousal symptoms, and the extent to which context was incorporated into decisions.

Veterans an average of 4.0 years after blast injury who had active PTSD (mTBI + PTSD) did not incorporate contextual information when making their decisions. Because understanding context is required in many everyday activities, if findings replicate in studies with larger samples, clinical testing for DM difficulties and training for context incorporation may improve everyday function in Veterans with mTBI + PTSD.