Performance validity testing in a clinical sample of adults with sickle cell disease

Abstract

Objective: Neuropsychologists utilize performance validity tests (PVTs) as objective means for drawing inferences about performance validity. The Test of Memory Malingering (TOMM) is a well-validated, stand-alone PVT and the Reliable Digit Span (RDS) and Reliable Digit Span-Revised (RDS-R) from the Digit Span subtest of the WAIS-IV are commonly employed, embedded PVTs. While research has demonstrated the utility of these PVTs with various clinical samples, no research has investigated their use in adults with sickle cell disease (SCD), a condition associated with multiple neurological, physical, and psychiatric symptoms. Thus, the purpose of this study was to explore PVT performance in adults with SCD. Method: Fifty-four adults with SCD (Mage = 40.61, SD = 12.35) were consecutively referred by their hematologist for a routine clinical outpatient neuropsychological evaluation. During the evaluation, participants were administered the TOMM (Trials 1 and 2), neuropsychological measures including the WAIS-IV Digit Span subtest, and mood and behavioral questionnaires. Results: The average score on the TOMM was 47.70 (SD = 3.47, range = 34–50) for Trial 1 and 49.69 (SD = 1.66, range = 38–50) for Trial 2. Only one participant failed Trial 2 of the TOMM, yielding a 98.1% pass rate for the sample. Pass rates at various RDS and RDS-R values were calculated with TOMM Trial 2 performance as an external criterion. Conclusions: Results support the use of the TOMM as a measure of performance validity for individuals with SCD, while RDS and RDS-R should be interpreted with caution in this population.