EVIDENCE FOR CLINICAL UTILITY OF NEUROPSYCHOLOGICAL DATA DESPITE PERFORMANCE VALIDITY FAILURES
Rosenblatt, Andrew S.
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The purpose of this study was to examine neuropsychological performance by the number of PVT failures and the extent of failing performance on a PVT. Previous research has demonstrated that in relevant patient samples, performance validity tests (PVT’s) account for a significant amount of the variance in neuropsychological test performance, with relevant factors including the number of PVT failures and designated cut scores. The literature is unclear regarding recommendations for whether testing should continue despite evidence of test invalidity early in an assessment. However, patients with poor PVT performances often still perform within at least the average range on some measures (i.e., within normal limits, WNL), implicating the possibility of ruling out frank neuropsychological impairment despite PVT failures. 257 OEF/OIF/OND Veterans with a history of mild traumatic brain injury (mTBI) were seen for a comprehensive clinical neuropsychological evaluation. Standardized neuropsychological test scores were utilized to calculate global deficit scores (GDS), which were then used to classify individuals as neuropsychologically impaired or WNL. Placement in a PVT “pass” or “fail” group was determined by cutoffs of between 1 and 4+ out of 5 PVT fails. GDS was also compared when failure on the WMT or TOMM was determined by common cut scores or at-or-below chance level of performance. While chi-square analyses demonstrated significant relationships between GDS and PVT performance, moderately high rates of individuals with WNL GDS occurred among those failing multiple PVTs. The relationship between GDS and PVT failure severity was also found to be significant, and more modest yet notable rates of GDS falling WNL were observed even when PVT performance was at-or-below chance level. This study demonstrated that despite the relationship between PVT failures and poor neuropsychological performance, multiple PVT failures and at-or-below-chance level PVT performance may coincide with sufficient effort on other tests. These results demonstrate that neuropsychological test data may still be clinically useful even when multiple PVTs are failed even at-or-below chance level of performance.