PORTLAND, OR — For years, the VA has tried to come up with ways to differentiate veterans who have epileptic seizures (ES) as opposed to psychogenic nonepileptic seizures (PNES), which are especially common in those who fought in recent wars.

“Identification of clinically meaningful subgroups among patients with psychogenic nonepileptic seizures (PNES) or epileptic seizures (ES) is of potential value for assessing prognosis and predicting therapeutic response,” explained a recent article in the journal Epilepsy & Behavior.1

The report from the VA Portland Health Care System and Oregon Health & Sciences University noted that invalid performance on validity tests has been associated with noncredible complaints and worse cognitive test scores and may be one such classification criteria.

Researchers focused on invalid performance in Veterans with PNES or ES, and the association of invalid performance with cognitive test scores and subjective complaints.

Included in the study were patients were consecutive admissions to three VA epilepsy monitoring units. Researchers performed evaluations, including two validity tests: the Test of Memory Malingering (TOMM); and the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) over-reporting validity scales.

The study team then compared the frequency of invalid performance on the TOMM or MMPI-2-RF in patients diagnosed with PNES vs. ES. They evaluated the association of invalid performance with scores on the Repeatable Battery for Assessment of Neuropsychological Status (RBANS) and four subjective symptom measures including the Beck Depression Inventory-II and Quality of Life in Epilepsy-31.

Researchers identified Invalid TOMM performance in 25.3% of veterans diagnosed with PNES and 10.8% of those with ES (p = 0.03). In addition, invalid reporting on the MMPI-2-RF was found in 35.9% of the PNES group vs. 15.3% of the ES group (p = 0.01).

The study determined that the valid vs. invalid reporting on external measures were similar for ES and PNES groups and that patients with invalid vs. valid TOMM performance had lower scores on the RBANS (p < 0.001). Veterans with invalid performance had greater complaints on all subjective measures, with largest effect sizes for the MMPI-2-RF validity scales (p < 0.001).

Overall, the study determined that, among VA patients admitted for evaluation of poorly controlled seizures, invalid performance on validity tests was not uncommon.

“Cognitive test results and subjective reports from patients with invalid performance may not be credible,” the researchers pointed out. “These observations have implications for the analysis of clinical trials, where primary and secondary outcomes often rely on self-report measures.”


  1. Salinsky M, Binder L, Storzbach D, et al. Validity testing in veterans with epileptic seizures and psychogenic nonepileptic seizures [published online ahead of print, 2020 Jul 7]. Epilepsy Behav. 2020;111:107246. doi:10.1016/j.yebeh.2020.107246