Abstracts

Rationale: It is widely accepted that the behavioral manifestation of seizures is stereotypical, i.e., in a given patient, a specific cluster of behaviors occur during each seizure. Semiological studies in the past have focused on the lateralizing value of ictal behavior or defining specific cluster of behaviors that occurs in patients with seizures involving specific region of the brain. To our knowledge, a systematic study of ictal stereotypy within individual patients with epileptic events has so far been missing in the modern literature. For instance, it remains to be determined if a patient with epileptic seizures exhibits , during each ictal event, 1) exactly the same kind of behaviors with similar durations (issue of communality) and 2) whether these behaviors occur in the same order (issue of directionality). It also remains to be known to what degree these two issues can be applied to psychogenic seizures or to other forms of stereotyped involuntary behavior seen in patients with movement disorders. In this study we describe a method of studying the degree of communality and directionality of epileptic and non-epileptic events. Understanding the issues of communality and directionality of behaviors exhibited during ictal events can provide useful information about the neuroanatomical correlates of seizure propagation. Methods: We selected randomly 20 patients with epileptic seizures (verified by ictal EEGs) and 10 patients with psychogenic events (without any EEG correlates). In all patients, video recordings of the events were reviewed and the type, duration, and order of exhibited behaviors were documented. The issue of communality of ictal behavior was studied using conventional frequency and cluster analysis whereas the issue of directionality was studied using a matrix analysis. Results: Our results indicate that in each patient with epileptic events, there are “core behaviors” that occur every single time the patient has an event and these behaviors follow unanimously the same order. However, we also found that there are certain behaviors, which we call non-core events that occur randomly throughout the seizures. By comparison, in each patient with non-epileptic events, while the measure of communality of behavior was as strong as in patients with epileptic events, the measure of directionality of events was deficient. Conclusions: We describe here a novel way of dissecting and quantifying the behavioral profile of events in a given patient. We hypothesize that this method will prove reliable in distinguishing epileptic from non-epileptic events and may yield important information about the neuroanatomical correlates of ictal behavior in patients with epileptic events.