Working Memory, Processing Speed, and Memory Functioning Are Minimally Predictive of Victoria Symptom Validity Test Performance

A sound performance validity test is accurate for detecting invalid neuropsychological test performance and relatively insensitive to actual cognitive ability or impairment. This study explored the relationship of several cognitive abilities to several performance indices on the Victoria Symptom Validity Test (VSVT), including accuracy and response latency. This cross-sectional study examined data from a mixed clinical sample of 88 adults identified as having valid neurocognitive test profiles via independent validity measures, and who completed the VSVT along with objective measures of working memory, processing speed, and verbal memory during their clinical neuropsychological evaluation. Results of linear regression analyses indicated that cognitive test performance accounted for 5% to 14% of total variance for VSVT performance across indices. Working memory was the only cognitive ability to predict significant, albeit minimal, variance on the VSVT response accuracy indices. Results show that VSVT performance is minimally predicted by working memory, processing speed, or delayed verbal memory recall.

Working Memory and Intelligence Are Associated with Victoria Symptom Validity Test Hard Item Performance in Patients With Intractable Epilepsy

Loring et al. (Journal of Clinical and Experimental Neuropsychology, 2005:27;610–617) observed relationships between VSVT hard item performance and IQ and memory indices in epilepsy surgical candidates, with a potential confound of low FSIQ on VSVT performance. The present study replicated the Loring et al. study in a larger sample and extended their findings by examining the relationships among VSVT performance, FSIQ, and working memory. A total of 404 patients with medically intractable epilepsy completed a comprehensive neuropsychological assessment. Differences in WAIS-III and WMS-III performance were examined as a function of VSVT hard score categories as determined by Grote et al. (2000)—that is, valid, >20/24; questionable, 18–20; or invalid, <18. Quantile regression models were constructed to compare the strength of the relationship between FSIQ and VSVT at various points of the FSIQ distribution. Linear regression analyses examined working memory as a potential mediator between FSIQ and VSVT performance. The invalid group performed more poorly than the valid and questionable groups on multiple measures of intelligence and memory. The strength of the relationship between FSIQ and VSVT hard item performance decreased as FSIQ increased, and working memory mediated this relationship. Results suggest VSVT hard item scores may be impacted by working memory difficulties and/or low intellectual functioning. (JINS, 2013, 19, 1–10)