Neuropsychological performance in treatment-seeking Operation Enduring Freedom/Operation Iraqi Freedom Veterans with a history of mild traumatic brain injury.

Introduction: Clinical neuropsychological presentation of treatment-seeking Veterans with a remote history of mild traumatic brain injury (mTBI) is widely variable. This manuscript seeks to better characterize cognitive concerns in the post-acute phase following mTBI and to identify the neuropsychological profiles of a large sample of clinically referred Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) Veterans with a history of mTBI and current cognitive complaints. We hypothesized that a minority of cases would exhibit valid and widespread neuropsychological deficits.

Method: Retrospective chart reviews of neuropsychological testing and mental health symptoms and diagnoses were conducted on 411 clinically referred OEF/OIF/OND Veterans with a history of mTBI. Groups were created based on scores on performance validity measures and based on overall neuropsychological performance.

Results: A total of 29.9% of the sample performed below normative expectations on at least one performance validity test (PVT). Of those Veterans performing adequately on PVTs, 60% performed within normal limits on virtually all neuropsychological measures administered, leaving only 40% performing below expectations on two or more measures. Mood and neurobehavioral symptoms were significantly elevated in Veterans performing below cutoff on PVTs compared to Veterans who performed within normative expectations or those with valid deficits. Neurobehavioral symptoms were significantly correlated with mental health symptom reports but not with injury variables.

Conclusions: In summary, in a large sample of clinically referred Veterans with persistent cognitive complaints after mild TBI, a third demonstrated invalid clinical neuropsychological testing, and, of those performing at or above cutoff on PVTs, over half performed within normative expectations across most neuropsychological tests administered. Results highlight the importance of objective assessment of cognitive functioning in this population as subjective reports do not correspond to objective assessment in the majority of cases.