title: Neural correlates of malingering in mild traumatic brain injury: A positron emission tomography study.
abstract: The detection of malingering in cognitive performance is a challenge in clinical and legal environments. Neuroimaging may provide an objective method to determine the source of failure on tests of symptom validity. Participants comprised 45 combat veterans, 31 with mild traumatic brain injury (mTBI), not seeking medical or legal compensation, who completed the Tombaugh Test of Memory Malingering (TOMM) and a positron emission tomography (PET) scan. Based on TOMM performance (i.e., less than 45 of 50 total correct, suggesting suboptimal effort or malingering), subjects were separated into poor TOMM score (PT; n=10) and good TOMM score (GT; n=35) groups. Voxel-based multiple regression analysis with Group (GT/PT) predicting uptake of fluorodeoxyglucose revealed decreased brain metabolism in the ventromedial prefrontal cortex of poor performers. The current findings may suggest that poor TOMM performance in those with combat trauma and mTBI may be related to ventromedial prefrontal cortical dysfunction. These findings have important implications for the disentanglement of feigned versus actual memory impairment, where the latter may be secondary to neural mechanisms not consistent with forgetting or deception.
authors.affiliation: Center of Excellence in Stress and Mental Health, San Diego VA Health Care System, La Jolla, CA, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
authors.forename: Andrea D
authors.initials: AD
authors.lastname: Spadoni
authors.affiliation: Center of Excellence in Stress and Mental Health, San Diego VA Health Care System, La Jolla, CA, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
authors.forename: Elena
authors.initials: E
authors.lastname: Kosheleva
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
authors.forename: Monte S
authors.initials: MS
authors.lastname: Buchsbaum
authors.affiliation: Center of Excellence in Stress and Mental Health, San Diego VA Health Care System, La Jolla, CA, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA. Electronic address: ansimmons@ucsd.edu.
authors.forename: Alan N
authors.initials: AN
authors.lastname: Simmons
mesh_terms: D000328:Adult; D001924:Brain Concussion / Q000150:complications / Q000000981:diagnostic imaging / Q000523:psychology; D001930:Brain Injuries / Q000150:complications / Q000000981:diagnostic imaging* / Q000523:psychology; D006801:Humans; D054542:Iraq War, 2003-2011; D008297:Male; D008306:Malingering / Q000150:complications / Q000000981:diagnostic imaging* / Q000523:psychology; D009415:Nerve Net / Q000000981:diagnostic imaging*; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography / Q000379:methods*; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging*; D014728:Veterans / Q000523:psychology; D055815:Young Adult
keywords: Combat trauma; Effort; Mild traumatic brain injury; PET; Test of memory malingering; Ventromedial prefrontal cortex