Initial development of Minnesota Multiphasic Personality Inventory–2–Restructured Form (MMPI–2–RF) scales to identify patients with psychogenic nonepileptic seizures

Abstract

Long term video-EEG (electroencephalography) monitoring in an epilepsy monitoring unit (EMU) will remain the gold standard for differential diagnosis of epilepsy from psychogenic nonepileptic seizures. However, neuropsychologists are routinely part of the differential diagnosis team and utilize personality assessment measures to add supportive data for the diagnosis. The most accurate scale on the Minnesota Multiphasic Personality Inventory–2–Restructured Form (MMPI–2–RF) in terms of differential diagnosis appears to be RC1 (Somatic Complaints) with a classification rate of 68% (Locke et al., 2010). This is not as helpful as neuropsychologists would like. Our aim in the current study was to determine whether another set of MMPI–2–RF items could provide improved classification accuracy. Using a combination of modern psychometric techniques and clinical judgment, we developed two complementary scales based on a physical complaints factor (Psychogenic Nonepileptic Seizures Physical Complaints, PNES-pc) and an attitudes factor (Psychogenic Nonepileptic Seizures Attitudes, PNES-a). The combination of these scales classified 73% of the sample, an improvement over comparable single or combined MMPI–2–RF scales. Cross validation is needed to warrant use in clinical practice. Information on scoring, sensitivity, specificity, and likelihood ratios at various levels of endorsement is provided.

Keywords:

• Psychogenic seizures
• Nonepileptic seizures
• Epilepsy
• Epilepsy monitoring unit
• Minnesota Multiphasic Personality Inventory–2–Restructured Form

Acknowledgments

This work was supported by an MMPI–2/MMPI–2–RF rescoring grant from the University of Minnesota Press.