Neuroimaging as a biomarker in symptom validity and performance validity testing.

How neuropsychological assessment findings are deemed valid has been a topic of numerous articles but few have addressed any role that neuroimaging studies could provide. Within military and various clinical samples of individuals undergoing neuropsychological evaluations, high levels of failure on measures of symptom validity testing (SVT) and/or performance validity testing (PVT) have been reported. Where 'failure' is defined as a below cut-score performance on some pre-determined set-point on a SVT/PVT measure, are such failures always indicative of invalid test findings or are there other explanations, especially based on informative neuroimaging findings? This review starts with the premise that even though the SVT/PVT task is designed to be simple and easy to perform, it nonetheless requires intact frontoparietal attention, working memory and task engagement (motivation) networks. If there is damage or pathology within any aspect of these networks as demonstrated by neuroimaging findings, the patient may perform below the cut-point as a result of the underlying damage or pathophysiology. The argument is made that neuroimaging findings should be considered as to where SVT/PVT cut-points are established and there should be much greater flexibility in SVT/PVT measures based on other personal, demographic and neuroimaging information. Several case studies are used to demonstrate these points.