Comparison of postictal semiology and behavior in psychogenic nonepileptic and epileptic seizures

The available information on postictal semiology and behavior in patients with psychogenic nonepileptic seizure (PNES) is limited. In this study, we explore the differences in postictal semiology and behavior between patients with epileptic seizure (ES) and PNES and focus on clinical features that may be helpful in differentiating these two conditions.

In this retrospective study, video-electroencephalograph (video-EEG) of 144 seizures from 64 patients with PNES and 66 seizures from 42 patients with ES were reviewed. Three novel postictal behaviors were compared between the two groups: a) abrupt, brief, and rapid blinking or shaking of the head as if regaining sensorium or "coming out" of the ictal event; b) looking around the room with a scanning and uncertain look; c) posing a question of "what happened?" or a similar question to the others present in the room. In addition, differences in several other postictal characteristics were studied.

At least one of the three specific postictal behaviors was seen in 20.1% of patients with PNES but none of the patients with ES resulting in 100% specificity and 36% sensitivity. While mean ictal duration was significantly longer in patients with PNES (175.3 ± 168 s) compared to ES (105.4 ± 102.9 s), the interval between the end of ictal episode and first correct verbal response (74.5 ± 126.2 s versus 139.4 ± 185.4 s), or first followed command (84.1 ± 133.8 s versus 141.1 ± 192.1 s) were shorter. In the group with PNES, 59.7% of patients demonstrated a whispering or altered voice during the first correct verbal response versus 21.2% of patients in the group with ES. The first followed command was slow or erroneous in 49.3% of the patients with PNES and in 19.7% of the patients with ES.

In this study, we found significant differences between postictal semiology and behavior of patients with PNES and ES that can be helpful tools in distinguishing between these two conditions. Specifically, three novel postictal behaviors were studied and were found to have a high specificity, but low sensitivity, in distinguishing PNES from ES.