Diagnostic utility of the Structured Inventory of Malingered Symptomatology for identifying psychogenic non-epileptic events

Abstract

The Structured Interview of Malingered Symptomatology (SIMS) is a self-report instrument that asks patients whether they experience atypical or implausible symptoms. The instrument has not been evaluated in an epilepsy population, and the potential for it to accurately distinguish between patients with psychogenic non-epileptic events (PNEE) and epileptic event groups has not been established. The SIMS was administered to patients in long-term video-EEG monitoring of these patients, 91 with PNEE and 29 with epilepsy were included in this study. Structured Interview of Malingered Symptomatology total scores as well as neurological and affective subscales were found to be predictors of group membership. Sensitivity and specificity across several different base rates of PNEE as well as maximum level likelihood ratios are presented. The findings not only demonstrate the utility of marked score elevations in differentiating PNEE from epilepsy but also point to considerable caution in interpreting mild elevations. Implications for the utility of this instrument in epilepsy evaluations are discussed.