Neuropsychological effects of self-reported deployment-related mild TBI and current PTSD in OIF/OEF veterans

Current combat veterans are exposed to many incidents that may result in mild traumatic brain injury (mTBI) and/or posttraumatic stress disorder (PTSD). While there is literature on the neuropsychological consequences of PTSD only (PTSD-o) and mTBI alone (mTBI-o), less has been done to explore their combined (mTBI+PTSD) effect. The goal of this study was to determine whether Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) veterans with mTBI+PTSD have poorer cognitive and psychological outcomes than veterans with PTSD-o, mTBI-o, or combat exposure-only. The final sample included 20 OIF/OEF veterans with histories of self-reported deployment mTBI (mTBI-o), 19 with current PTSD (PTSD-o), 21 with PTSD and self-reported mTBI (mTBI+PTSD), and 21 combat controls (CC) (no PTSD and no reported mTBI). Groups were formed using structured interviews for mTBI and PTSD. All participants underwent comprehensive neuropsychological testing, including neurocognitive and psychiatric feigning tests. Results of cognitive tests revealed significant differences in performance in the mTBI+PTSD and PTSD-o groups relative to mTBI-o and CC. Consistent with previous PTSD literature, significant differences were found on executive (switching) tasks, verbal fluency, and verbal memory. Effect sizes tended to be large in both groups with PTSD. Thus, PTSD seems to be an important variable affecting neuropsychological profiles in the post-deployment time period. Consistent with literature on civilian mTBI, the current study did not find evidence that combat-related mTBI in and of itself contributes to objective cognitive impairment in the late stage of injury.