How variable are psychogenic nonepileptic seizures? A retrospective semiological study.

Purpose: To classify patients with psychogenic nonepileptic seizures (PNES) according to a recently proposed classification system and investigate the variability of PNES semiology.

Methods: We retrospectively investigated all patients with PNES admitted at the Jefferson Comprehensive Epilepsy Center from 2012 through 2016. We classified their seizures after retrospectively reviewing their recorded videos during their video-EEG monitoring admission and investigated the seizure variability. We extracted all the clinical data from their medical records. We also studied factors potentially associated with seizure variability.

Results: Forty nine patients were studied and 220 seizures were reviewed and classified. Mean number of seizures per patient was 4.5. Twenty seven (55%) patients had subjective seizures, 26 (53%) had generalized motor, 14 (29%) had akinetic and five (10%) had focal motor seizures. Twenty eight (57%) patients had only one seizure class, while 19 (39%) patients had two different seizure classes and two (4%) patients had three seizure classes. Among 28 patients with one seizure class, 14 (50%) patients had variable semiologies from one seizure to the other. Hence, 71.5% of the patients showed either inter- or intra-class variability, whereas seizures were stereotypical in 28.5%. No demographic or clinical factors were significantly associated with variability of PNES semiology.

Conclusion: Neither the stereotypy nor the variability of PNES can or should be used as a marker of the disease and to differentiate PNES from epilepsy. The variability of the episodes of PNES does not hinder an appropriate classification of these seizures.