Different patterns of cerebral activation in genuine and malingered cognitive effort during performance on the Word Memory Test

Abstract

Primary objective: The Word Memory Test (WMT) is a popular symptom validity test in which individuals are required to remember and recall semantically-related word pairs. Research shows successful WMT completion employs a wide neural network which is involved in tasks requiring high cognitive effort. The primary purpose of this study was to replicate earlier fMRI findings using a larger sample and extend previous findings by including male and female subjects. The second purpose was to investigate the neural networks involved during intentional malingering on the WMT.Research design: For all trials, a time-series ANCOVA design was implemented using SPM5 software.Methods and procedures: Ten subjects (five male and five female) underwent fMRI imaging while completing the WMT in full-effort and simulated poor effort conditions.Main outcome and results: Full-effort trials found activation peaks in dorsolateral prefrontal cortex, superior parietal lobe, anterior cingulate, bilateral lingual cortices and anterior insula/frontal operculum, supporting earlier findings. Simulated poor effort trials had similar foci of activation, with additional peak strength in surrounding cortical regions identified previously as relevant to simulated malingering. No sex differences were observed in either condition.Conclusions: These findings demonstrate the neural underpinnings of WMT performance in normal and simulated performance.