Psychogenic nonepileptic seizures: Are they a freeze reaction?

Psychogenic nonepileptic seizures (PNES) clinically resemble epileptic seizures (ES) but lack epileptic activity at the time of the seizure and are also not due to any other pathophysiological disorder. The integrative cognitive model (ICM) suggests that PNES is an automatic reaction generated from distorted memory and is perceived as uncontrollable and unwanted. Furthermore, the ICM model implies that a PNES event occurs due to an external or internal cue. Intrigued by this assumption, we wanted to examine why a PNES event occurs at a particular moment by investigating the pre-ictal behavior. This study is a retrospective study. We included all patients diagnosed with PNES or ES admitted to our long-term video-EEG monitoring unit (LTVEM) between 01/01/2018 and 30/08/2020. Using thorough video analysis, we checked the patient's state at the onset of the event and looked back to see what the patient was doing before the event onset. We defined 4 types of pre-ictal behavior A. Inactivity. B. Environment arrangement c. Other. D. No apparent pre-ictal behavior. Thirty patients with PNES and 30 patients with ES were included in the study. In total, 46 PNES events and 56 ES events were recorded and analyzed. In 33 /46 PNES seizures (72%), a type A, A + B or C pre-ictal behavior was observed compared to 1/56 ES (1.78%) with type A pre-ictal behavior. All other pre-ictal behavior in the ES group were of type D. Patients with PNES have a unique pre-ictal behavior before most PNES events with motor manifestations. Since the pre-ictal behavior consists mainly of inactivity, we believe it may imply that PNES represents a freeze reaction or a reconstruction of a freeze reaction.

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Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.