TOMM Trial 1 as a performance validity indicator in a criminal forensic sample

Abstract

Objective: To determine the effectiveness of the Test of Memory Malingering Trial 1 (TOMM1) as a freestanding Performance Validity Test (PVT) as compared to the full TOMM in a criminal forensic sample.Method: Participants included 119 evaluees in a Midwestern forensic hospital. Criterion groups were formed based on passing/failing scores on other freestanding PVTs. This resulted in three groups: +MND (Malingered Neurocognitive Dysfunction), who failed two or more freestanding PVTs; possible MND (pMND), who failed one freestanding PVT; and –MND, who failed no other freestanding PVTs. All three groups were compared initially, but only +MND and –MND groups were retained for final analyses. TOMM1 performance was compared to standard TOMM performance using Receiver Operating Characteristic (ROC) analyses.Results: TOMM1 was highly predictive of the standard TOMM decision rules (AUC = .92). Overall accuracy rate for TOMM1 predicting failure on 2 PVTs was quite robust as well (AUC = .80), and TOMM1 ≤ 39 provided acceptable diagnostic statistics (Sensitivity = .68, Specificity = .89). These results were essentially no different from the standard TOMM accuracy statistics. In addition, by adjusting for those strongly suspected of being inaccurately placed into the −MND group (e.g. false negatives), TOMM1 diagnostics slightly improved (AUC = .84) at a TOMM1 ≤ 40 (sensitivity = .71, specificity = .94).Conclusions: Results support use of TOMM1 in a criminal forensic setting where accuracy, shorter evaluation times, and more efficient use of resources are often critical in informing legal decision-making.

Keywords:

• Forensic neuropsychology
• malingering
• performance validity
• response bias
• Test of Memory Malingering