Traumatic Brain Injury Alters Word Memory Test Performance by Slowing Response Time and Increasing Cortical Activation: An fMRI Study of a Symptom Validity Test Mark D. Allen & Trevor ChuangKuo Wu & Erin D. Bigler Received: 5 October 2010 / Accepted: 28 July 2011 / Published online: 19 August 2011 # Springer Science+Business Media, LLC. 2011 Abstract The Word Memory Test (WMT) is an established symptom validity test that relies on verbal memory performance to make inferences about “effort.” Previous studies, using a functional MRI (fMRI) adaptation of the WMT with healthy controls, have shown that successful completion of the WMT relies on a widespread network of neural systems associated with high cognitive effort. Additional studies using the same fMRI paradigm with patients with severe traumatic brain injury (TBI) suggest that increased activation of cortical regions associated with cognitive load are recruited to meet the cognitive challenges that the WMT places on a compromised neural system. This study builds on previous findings as a result of highly uncommon circumstances in which fMRI data on the WMT task were made available from the very same individual both 1 year before and 1 year after sustaining a TBI. Interestingly, the effect of TBI did not appear to impair performance on the WMT in terms of standard accuracy measurements, though response times were notably slower. The main fMRI finding was a significantly stronger and more widespread pattern of activation post-injury, particu- larly in the frontal and parietal brain regions, suggesting that stronger engagement of these networks was necessary to sustain accurate WMT performance compared to pre- injury testing. This unique source of data, together with previous findings, suggests a more complex relationship between effort and performance levels on the WMT than what is commonly assumed. Keywords fMRI . Word Memory Test . Neuropsychological assessment . Symptom validity testing . Effort testing Introduction Symptom validity tests (SVTs) are commonly administered when evaluating the cognitive effects of traumatic brain injury (TBI) and are intended to assess “effort” on the part of the patient (Millis 2009). One well-established and commonly used SVT is the Word Memory Test (WMT, Green 2003). As a typical SVT, the WMT employs a cognitive task, in this case a series of verbal memory tests, which most individuals can perform without error. The construct that a simple SVT assesses “effort” centers on the fact that passing the SVT shows that a minimal level of effort has been exerted to pass a task that is commonly M. D. Allen (*) : T. C. Wu : E. D. Bigler Department of Psychology, Brigham Young University, 1022 SWKT, Provo, UT 84602, USA e-mail: m_allen@byu.edu T. C. Wu e-mail: trevorwu2002@yahoo.com E. D. Bigler e-mail: erin_bigler@byu.edu M. D. Allen : T. C. Wu : E. D. Bigler Neuroscience Center, Brigham Young University, Provo, UT, USA E. D. Bigler The Brain Institute of Utah, University of Utah, Salt Lake City, UT, USA E. D. Bigler Department of Psychiatry, University of Utah, Salt Lake City, UT, USA M. D. Allen Functional Imaging Unit, Riverwoods Imaging Center, Provo, UT, USA Psychol. Inj. and Law (2011) 4:140–146 DOI 10.1007/s12207-011-9105-4