Influence of poor effort on neuropsychological test performance in U.S. military personnel following mild traumatic brain injury

Abstract

The purpose of this study was to examine the influence of poor effort on neuropsychological test performance in military personnel following mild traumatic brain injury (MTBI). Participants were 143 U.S. service members who sustained a TBI, divided into three groups based on injury severity and performance on the Word Memory Test and four embedded markers of poor effort: MTBI-pass (n = 87), MTBI-fail (n = 21), and STBI-pass (n = 35; where STBI denotes severe TBI). Patients were evaluated at the Walter Reed Army Medical Center on average 3.9 months (SD = 3.4) post injury. The majority of the sample was Caucasian (84.6%), was male (93.0%), and had 12+ years of education (96.5%). Measures included the Personality Assessment Inventory (PAI) and 13 common neurocognitive measures. Patients in the MTBI-fail group performed worse on the majority of neurocognitive measures, followed by the Severe TBI-Pass group and the MTBI-pass group. Using a criterion of three or more low scores <10th percentile, the MTBI-fail group had the greatest rate of impairment (76.2%), followed by the Severe TBI-Pass group (34.3%) and MTBI-pass group (16.1%). On the PAI, the MTBI-fail group had higher scores on the majority of clinical scales (p < .05). There were a greater number of elevated scales (e.g., 5 or more elevated mild or higher) in the MTBI-fail group (71.4%) than in the MTBI-pass group (32.2%) and Severe TBI-Pass group (17.1%). Effort testing is an important component of postacute neuropsychological evaluations following combat-related MTBI. Those who fail effort testing are likely to be misdiagnosed as having severe cognitive impairment, and their symptom reporting is likely to be inaccurate.

Framing the Results: Assessment of Response Bias Through Select Self-Report Measures in Psychological Injury Evaluations

“…Simulators produced the highest mean validity scores on NIM. Their findings are consistent with previous research in which high scores on NIM have been associated with poor effort on PVTs or compensation-seeking populations (see Lange, Pancholi, Bhagwat, Anderson-Barnes, & French, 2012). For instance, higher NIM scores were observed for compensation-seeking patients with mild TBIs than for patients who were not compensation seeking but also had mild TBIs (Whiteside, Galbreath, Brown, & Turnbull, 2012).…”

Factors associated with neurocognitive performance in OIF/OEF servicemembers with postconcussive complaints in postdeployment clinical settings

“…Study results also demonstrate that despite the use of an effort measure with limited sensitivity, the base rate of PVT failure in a military sample was still notable. Taken together, these results support previous findings [37][38]54] highlighting the importance of PVTs in an Active Duty military population referred for mTBI evaluation. ).…”

Auditory difficulties in blast-exposed Veterans with clinically normal hearing

“…Also, similar to the findings of Gallun et al, the performance of the participants in the current study was The finding that performance is poor on some but not all measures suggests that participants exhibit taskspecific deficits rather than a global functional deficit. It has, however, been noted in both civilian and Veteran populations that poor effort and symptom exaggeration are common following TBI [52][53] and that poor effort can account for more than 50 percent of the variance on cognitive performance [54]. Indeed, it has been suggested that Veterans who sustained TBI that report postconcussive symptoms differ from those who do not report postconcussive symptoms on, among other things, degree of possible symptom exaggeration, poor effort, depression, and traumatic stress, while postconcussive disorder rarely occurred in the absence of these symptoms [55].…”