RBANS Validity Measures and the TOMM in Veterans Undergoing Seizure Monitoring

Abstract

Objective: To assess the validity of embedded measures of performance validity, the effort index (EI) and effort scale (ES) of the repeatable battery for the assessment of neuropsychological status (RBANS), in Veterans with seizures; to compare the frequency of failure on the test of memory malingering (TOMM) in patients with epileptic versus psychogenic nonepileptic seizures (PNES).

Methods: Seizure diagnosis was established for 309 participants in epilepsy monitoring units using conventional diagnostic criteria who completed both the TOMM and RBANS. The criterion for performance invalidity was failure on any trial of the TOMM. We examined multiple EI and ES cutoffs to establish optimal sensitivity and specificity.

Results: An RBANS EI cutoff score of greater than three was optimal with specificity of .98, sensitivity of.19, and positive Likelihood Ratio of 10 but was not useful when below this cutoff. Confidence intervals indicate the need for confirmation of a failed EI with another performance validity test (PVT). No ES cutoff had sufficient specificity for clinical use. Invalid TOMM performance but not invalid RBANS performance was significantly more common in persons with PNES than in persons with epileptic seizures.

Conclusions: In Veterans undergoing seizure monitoring, the RBANS EI was useful as a screen when positive that requires confirmation with another PVT. The RBANS ES was not useful. Invalid performance on the TOMM was more common in persons with PNES than in persons with epileptic seizures.

Keywords: Performance validity; Psychogenic seizures; RBANS; Seizure disorders; TOMM.