Validity of the clinical and content scales of the Multiphasic Personality Inventory Minnesota 2 for the diagnosis of psychogenic non-epileptic seizures

Abstract

Introduction: The use of the Multiphasic Personality Inventory Minnesota 2 (MMPI-2) for the diagnosis of psychogenic non-epileptic seizures (PNES) is controversial. This study examines the validity of the clinical scales and, unlike previous works, the content scales.

Methods: Cross-sectional study of 209 patients treated in the epilepsy unit. We performed a logistic regression analysis, taking video-electroencephalography as the reference test, and as predictor variables age, sex, IQ and clinical (model A) or content scales (model B) of the MMPI-2. The models were selected according to the Aikake index and compared using the DeLong test.

Results: We analyzed 37 patients with PNES alone, or combined with seizures, and 172 patients with seizures only. The model consisting of sex, Hs (hypochondriasis) and Pa (paranoia) showed a sensitivity of 77.1%, a specificity of 76.8%, a percentage of correct classification of 76.8%, and an area under the curve (AUC) of 0.836 for diagnosing CNEP. Model B, consisting of sex, HEA (health concerns) and FRS (fears), showed a sensitivity of 65.7%, a specificity of 78.0%, a percentage of correct classification of 75.9% and an AUC of 0.840. DeLong's test did not detect significant differences.

Conclusions: The MMPI-2 has a moderate validity for the diagnosis of PNES in patients referred to an epilepsy unit. Using content scales does not significantly improve results from the clinical scales.

Keywords: Basic scales; Content scales; Crisis epilépticas; Crisis no epilépticas psicógenas; Escalas básicas; Escalas de contenido; Inventario Multifásico de Personalidad de Minnesota 2; Multiphasic Personality Inventory Minnesota 2; Psychogenic non-epileptic seizures; Seizures.