J Clin Exp Neuropsychol. 2023 Aug 9:1-9. doi: 10.1080/13803395.2023.2244161. Online ahead of print.
BACKGROUND: Although studies have shown unique variance contributions from performance invalidity, it is difficult to interpret the meaning of cognitive data in the setting of performance validity test (PVT) failure. The current study aimed to examine cognitive outcomes in this context.
METHOD: Two hundred and twenty-two veterans with a history of mild traumatic brain injury referred for clinical evaluation completed cognitive and performance validity measures. Standardized scores were characterized as Within Normal Limits (≥16th normative percentile) and Below Normal Limits (<16th percentile). Cognitive outcomes are examined across four commonly used PVTs. Self-reported employment and student status were used as indicators of “productivity” to assess potential functional differences related to lower cognitive performance.
RESULTS: Among participants who performed in the invalid range on Test of Memory Malingering trial 1, Word Memory Test, Wechsler Adult Intelligence Scale-Fourth Edition Digit Span aged corrected scaled score, and the California Verbal Learning Test-Second Edition Forced Choice index, 16-88% earned broadly within normal limits scores across cognitive testing. Depending on which PVT measure was applied, the average number of cognitive performances below the 16th percentile ranged from 5 to 7 of 14 tasks. There were no differences in the total number of below normal limits performances on cognitive measures between “productive” and “non-productive” participants (T = 1.65, p = 1.00).
CONCLUSIONS: Results of the current study suggest that the range of within normal limits cognitive performance in the context of failed PVTs varies greatly. Importantly, our findings indicate that neurocognitive data may still provide important practical information regarding cognitive abilities, despite poor PVT outcomes. Further, given that rates of below normal limits cognitive performance did not differ among “productivity” groups, results have important implications for functional abilities and recommendations in a clinical setting.