Performance on the Test of Memory Malingering is predicted by the number of errors on its first 10 items on an inpatient epilepsy monitoring unit

Abstract

Objective: Performance validity testing is an increasingly vital component of neuropsychological evaluation, though administration of stand-alone performance validity tests (PVTs) can be time-consuming. As the Test of Memory Malingering (TOMM) is among the most commonly used and researched PVTs, much work has focused on creating abbreviated versions while preserving diagnostic accuracy. A recent addition to this effort, errors on the first 10 items of Trial 1 (TOMMe10), was analyzed for its utility in predicting TOMM performance. Method: Subjects were 180 veterans seen on a long-term epilepsy monitoring unit. TOMM learning trials, Word Memory Test (WMT), and WAIS-IV Digit Span (for Reliable Digit Span; RDS) were administered as part of a larger battery. Performance invalidity was classified using established cut scores. Diagnostic classification statistics were calculated predicting TOMM, WMT, and RDS performance, including sensitivity, specificity, receiver operating characteristics (ROC), and positive and negative predictive values for multiple TOMMe10 cut scores. Results: A cut score of ≥2 errors on TOMMe10 yielded the highest sensitivity (.88) while maintaining ≥.90 specificity when predicting TOMM (also supported by ROC analysis). This cut score was also optimal when validated against combinations of PVTs (e.g. two of TOMM, WMT, and RDS; WMT and/or RDS). Conclusions: TOMMe10 shows great promise in predicting future TOMM performance. In settings where time with patients is at a premium, ≥2 errors on TOMMe10 may be used as an early TOMM discontinue criteria, allowing examiners to use their limited time more effectively. The use of TOMMe10 in settings with varying TOMM failure base rates was discussed.