Effectiveness of the Comalli Stroop Test as a measure of negative response bias

Practice guidelines recommend the use of multiple performance validity tests (PVTs) to detect noncredible performance during neuropsychological evaluations, and PVTs embedded in standard cognitive tests achieve this goal most efficiently. The present study examined the utility of the Comalli version of the Stroop Test as a measure of response bias in a large sample of "real world" noncredible patients (n = 129) as compared with credible neuropsychology clinic patients (n=233). The credible group performed significantly better than the noncredible group on all trials, but particularly on word-reading (Stroop A) and color-naming (Stroop B); cut-scores for Stroop A and Stroop B trials were associated with moderate sensitivity (49-53%) as compared to the low sensitivity found for the color interference trial (29%). Some types of diagnoses (including learning disability, severe traumatic brain injury, psychosis, and depression), very advanced age (⩾80), and lowered IQ were associated with increased rates of false positive identifications, suggesting the need for some adjustments to cut-offs in these subgroups. Despite some previous reports of an inverted Stroop effect (i.e., color-naming worse than color interference) in noncredible subjects, individual Stroop word reading and color naming trials were much more effective in identifying response bias.