Symptom and performance validity in neuropsychological assessments of outpatients 15-30 years of age

ObjectiveIt has been suggested that performance validity tests (PVTs) assess the credibility of a patient's objective test performance, symptom validity tests (SVTs) assess the credibility of a patient's subjective complaints, and that PVTs and SVTs are independent measures. The aim of this study was to test this hypothesis and investigate the associations of PVTs and SVTs with cognitive tests and self-reported measures.MethodPatients 15-30 years of age were consecutively recruited from a neurorehabilitation outpatient clinic. The participants completed a battery of cognitive tests and self-reporting questionnaires as well as the Test of Memory Malingering (TOMM) and the Structured Inventory of Malingered Symptomatology (SIMS).ResultsForty-eight neurological patients of various etiologies were included. The TOMM (PVT) was related to cognitive tests across cognitive domains and unrelated to self-reporting measures. The SIMS (SVT) was related to other self-reported measures of perceived stress, anxiety, and depression, though also related to cognitive test of attention and processing speed. The PVT and the SVT were unrelated and hence seemed to measure two different constructs of validity.ConclusionsThis study supports the definition of PVTs and SVTs as two independent measures, consequently that both should be applied routinely in neuropsychological assessments.