Abstract
Objective
While the use of validity testing in neuropsychological assessments to assist in differentiation between epileptic seizures (ES) and psychogenic non-epileptic events (PNEE) is becoming common, validity considerations regarding symptom self-reporting is seldom examined. This study seeks to add clarity by examining performance validity tests (PVT), and self-report measures of emotional symptoms and daily functioning, in a sample of those with either ES or PNEE.
Methods
Patients: Consecutive Veteran patients referred to an epilepsy monitoring unit for evaluation of intractable seizures, and subsequently diagnosed with ES (32) or PNEE (75). A fixed battery of psychological (Beck Depression Inventory-II, Patient Competency Rating Scale, Quality of Life in Epilepsy) and PVT (Test of Memory Malinger, Word Memory Test) measures were administered as part of a broader neuropsychological assessment. Patients were classified by both their diagnostic, and PVT pass/fail, statuses (PNEEpass, PNEEfail, & ESpass – ESfail was too small to analyze).
Results
PNEE reported more severe symptoms/impairments than ES (each p < .01) when ignoring PVT results. Importantly, when PVTs were considered, PNEEfail reported worse symptoms/impairments than PNEEpass (each p < .01), and PNEEpass and ESpass did not differ on emotional distress (p = .07).
Conclusions
Those with PNEE who fail PVTs report worse psychological distress and functional abilities than both those who pass and those with ES. This is likely due to symptom exaggeration. Validity testing should thus be considered a crucial component of assessment of these individuals: if invalid self-reporting is not accounted for, clinicians put themselves at risk for coming to faulty conclusions while more parsimonious explanations are available.