Abstracts

RATIONALE: Diagnosis of pseudoseizures is difficult when symptoms mimic epileptic seizures. Accurate diagnosis avoids costly (and unnecessary) investigation and therapy, and leads to appropriate psychological treatment. The MMPI-2 has shown good initial results in identifying patients with pseudoseizures. Among 3 groups of carefully diagnosed patients with a robust sample size, we evaluated the MMPI-2 for its accuracy in diagnosing pseudoseizures on an inpatient epilepsy unit. This study is the first to report sensitivity and specificity for this test. METHODS: There were three patient groups: Pseudoseizures (n=49; with no electrographic evidence of epilepsy), Epilepsy (n=73; with no documented pseudoseizures), and Mixed (n=30). Rules were developed to declare MMPI-2 clinical scale configurations a "pseudoseizure" profile - where Hs and/or Hy are clinically significant, and are the highest scales. Content scale elevations were also inspected, with Hea expected to be the highest. Agreement with neurologists' telemetry-based diagnoses was calculated. RESULTS: Clinical profiles were not different between Pseudoseizure and Mixed groups. Hy and Hs were significantly elevated and were the highest scales for these patients. Hea was the highest (and clinically significant) Content scale. Profiles in both groups were significantly different from the Epilepsy group, where the mean profiles were in the normal range. Sensitivity of the MMPI-2 in the classification of pseudoseizures was 93.7%. The Specificity was 94.5%. CONCLUSIONS: (1) Patients with Mixed seizures (both epilepsy and pseudoseizures) may have personality characteristics similar to those who exclusively have pseudoseizures. (2) MMPI-2 profiles indicative of pseudoseizures show highest elevations on scales Hs and/or Hy with T scores > 65.; in most cases Hea is the highest Content scale. (3) On an inpatient epilepsy unit, the MMPI-2 provides a highly accurate, cost-effective contribution to the certainty of the diagnosis of pseudoseizures.