PREICTAL PSEUDOSLEEP - A NEW FINDING IN PSYCHOGENIC SEIZURES

Background and objective: The diagnosis of psychogenic seizures (pseud oseizures) may be difficult and usually rests on video-EEG monitoring. We observed that pseudoseizures often arise out of a state that we te rmed preictal pseudosleep. The objective of this study was to investig ate this potential new sign in pseudoseizures. Methods: We prospective ly studied all patients who underwent noninvasive monitoring over a 10 -month period. Patients were monitored for a duration of 1 to 19 days (mean 4.9), and were divided into two groups: pseudoseizures and epile ptic seizures. Patients with both conditions were excluded. Preictal p seudosleep was defined as a state that resembled normal sleep by behav ioral criteria alone (i.e. patient motionless and eyes closed), while EEG showed evidence of wakefulness (alpha rhythm, active EMG, and rapi d eye movement). This state had to be sustained for at least 1 minute before clinical onset. Results: Patients had 1 to 25 (mean 7) clinical events recorded. Preictal pseudosleep was seen in 10 of 18 patients w ith pseudoseizures and in none of 39 patients with epileptic seizures, yielding a sensitivity of 56% and a specificity of 100% for pseudosei zures. Conclusion: Because of a high specificity, preictal pseudosleep may be a useful adjunctive finding to support the diagnosis of pseudo seizures.