Abstracts

Rationale: The definitive distinction between convulsive epileptic and psychogenic non-epileptic seizures requires video-EEG recording of typical attacks. However, video-EEG monitoring is usually requested when seizures are refractory to therapy. It is important to identify non-epileptic seizures earlier if possible. The aim of this study is to evaluate the diagnostic value of a structured witness interview focused on ictal and postictal features that have demonstrated value in distinguishing between epileptic and nonepileptic convulsive seizures. Methods: We prospectively interviewed all adult patients with convulsive attacks of unknown nature admitted to the Vanderbilt University epilepsy monitoring unit during a one year period. We identified and interviewed the accompanying family member or friend who had witnessed the largest number of witnessed convulsive attacks. The structured interview was based on a questionnaire (table 1) with 12 questions regarding ictal and postictal features. All questions had one of three possible answers: yes, no or unknown. Results: A total of 46 patients (33 women and 13 men) were included in this study. The mean age was 42 ± 12 years. Following video-EEG monitoring, epileptic seizures were diagnosed in 19 patients and non-epileptic seizures were diagnosed in the remaining 27 patients. All ictal features and the postictal features related to breathing demonstrated significant predictive value with a combined diagnosis accuracy of 82.6%. Postictal confusion was the only feature that did not show any predictive value. Seizure duration and breathing loudness were the best predictors. Conclusions: Witness description of ictal and postictal fdeatures using a structured interview is helpful in distinguishing epileptic from non-epileptic convulsive seizures. This may help in rapid initiation of appropriate therapy for patients with recent onset epileptic seizures, and referral of patients with suspected nonepileptic seizures for video-EEG monitoring.