1073 — Separate Main Effects of Mild TBI and PTSD in OEF/OIF Veterans: Support for the “Additive” Hypothesis
Shandera-Ochsner AL, Lexington VAMC, University of Kentucky; Berry DT, University of Kentucky; Harp JP, and Edmundson MS, Lexington VAMC, University of Kentucky; Graue LO, Lexington VAMC; Roach A, Frazier Rehabilitation Institute; Pape TL, Hines VAMC; Babcock-Parziale JL, Tuscon VAMC; High WM, Lexington VAMC, University of Kentucky;
While there is literature on the neuropsychological consequences of PTSD only (PTSD-o) and mild TBI alone (mTBI-o), less has been done to explore their combined effect. The goal of this study is to determine whether OEF/OIF Veterans with PTSD+mTBI have poorer cognitive and psychological outcomes than Veterans with PTSD-o, mTBI-o, or combat exposure alone. The specific aims of this study were to 1) Determine whether Veterans with PTSD+mTBI have deficits in information processing speed and response inhibition (relative to Veterans in the other groups), and 2) Explore characteristics of Veterans with PTSD+mTBI by examining differences on measures of psychiatric distress.
The final sample included 20 OEF/OIF Veterans with histories of deployment mTBI (mTBI-o), 19 with current PTSD (PTSD-o), 21 with PTSD+mTBI, and 21 combat controls (CC) (no PTSD and no mTBI). Groups were formed using structured interviews for mTBI and PTSD. All participants underwent comprehensive neuropsychological testing, including neurocognitive and psychiatric effort tests. Veterans who scored outside established cut points on any effort test were excluded from analyses.
Results of 2-way ANOVAs of cognitive tests revealed a significant PTSD x mTBI interaction on D-KEFS phonemic fluency. Significant main effects of PTSD were found on 3 D-KEFS switching tasks, D-KEFS trails (speeded sequencing) and verbal fluency, verbal memory (immediate, short, and long-delay), processing speed, and reaction time/variability. Significant main effects for mTBI were found on 2 D-KEFS switching tasks, short-delay verbal memory, processing speed, and reaction variability. 2-way ANOVAs of psychiatric tests revealed main effects of PTSD for a large number of MMPI-2-RF and other scores. mTBI showed main effects on several psychiatric variables.
Preliminary results suggest that the separate effects of current PTSD and history of deployment mTBI in OEF/OIF Veterans may produce significantly poorer neuropsychological profiles in those who have both.
The results inform the VA evaluation process for mTBI and PTSD and subsequent treatment of OEF/OIF Veterans. This study lays the groundwork for treatment outcome studies of evidence-based treatments for PTSD and/or mTBI by delineating the separate and overlapping effects associated with each condition.