Detecting malingering in traumatic brain injury: Combining response time with performance validity test accuracy

The present study examined the incremental utility of item-level response time (RT) variables on a traditional performance validity test in distinguishing adults with verified TBI from adults coached to feign neurocognitive impairment.

Participants were 45 adults with moderate to severe TBI, 45 healthy adults coached to feign neurocognitive impairment (SIM), and 61 healthy adult comparisons providing full effort (HC). All participants completed a computerized version of the Test of Memory Malingering (TOMM-C) in the context of a larger test battery. RT variables examined along with TOMM-C accuracy scores included mean RTs (Trial 1, Trial 2, correct and incorrect trials) and RT variability indices.

Several RT indices differed significantly across the groups. In general, SIM produced longer, more variable RTs than HC and TBI. Of the RT indices, average RT for Trial 1 and 2 were the best predictors of group membership; however, classification accuracies were greatly influenced by the groups being compared. Average RT for Trial 1 and 2 showed excellent discrimination of SIM and HC. All RT indices were less successful in discriminating SIM and TBI. Average RT for Trial 1 and 2 added incremental predictive value to TOMM-C accuracy in distinguishing SIM from TBI.

Findings contribute to a limited body of research examining the incremental utility of combining RT with traditional PVTs in distinguishing feigned and bona fide TBI. Findings support the hypothesis that combining RT with TOMM-C accuracy can improve its diagnostic accuracy. Future research with other groups of clinical interest is recommended.