Abstracts

Rationale: Objective personality assessment is commonly utilized in inpatient epilepsy monitoring units to aid diagnosis. This study compared the Personality Assessment Inventory (PAI) and Minnesota Multiphasic Personality Inventory-2nd edition (MMPI-2) in differentiating patients who were ultimately diagnosed with either psychogenic non-epileptic seizures (NES) or epilepsy (ES) in the context of an inpatient hospital admission. Methods: The two groups (NES: n = 20; ES: n = 24) received their respective diagnoses following a multidisciplinary inpatient video-EEG monitoring evaluation and for the NES group, exclusion of a physiological etiology. No mixed NES and ES cases were included. Each subject completed both personality measures during the same admission and in a counterbalanced manner. Data from six subjects (3 NES, 3 ES) were excluded from further analysis secondary to invalid PAI or MMPI-2 profiles. The two groups were comparable with respect to age, gender, education, and cognitive ability (WAIS-III/WMS-III). The personality profiles were considered diagnostic of NES via T-score > 70 on the PAI SOM scale and modified Wilkus rules for the MMPI-2. Results: Using chi-square analyses, the overall accuracy rates for the PAI and MMPI-2 were 79% (p < .001) and 68% (p < .05), respectively. The positive predictive value (PPV) and negative predictive values (NPV) for the PAI were 1.0 and .70, respectively. For the MMPI-2, the PPV and NPV were .72 and .68, respectively. Conclusions: Overall, our findings indicate that the PAI better discriminates NES from ES patients as compared to the MMPI-2. These results coupled with a number of psychometric, practical, and economic advantages suggests that the PAI is a more useful personality measure for the inpatient epilepsy monitoring unit.