Testing the ‘seizure scaffold’: What can experimental simulation tell us about functional seizures (seizures that resemble epileptic seizures but are not)?

November 23, 2020

Abstract, originally published in Epilepsy & Behavior

Introduction: It has been suggested for over 100 years that patterns of neurological symptoms and signs in functional neurological disorders may be shaped at a neural level by underlying ideas or preconceptions how neurological symptoms present. This study used experimental simulation to probe ideas about seizures in healthy volunteers, with a view to compare with features commonly observed in functional and epileptic seizure disorders.

Methods: Sixty healthy volunteers were instructed to simulate an epileptic seizure. The episodes were video-recorded and assessed by three qualified markers for the presence of clinical features commonly observed in functional seizures (FS), epileptic seizures, and syncope.

Results: Simulated seizures were hyperkinetic (83%), hypokinetic (7%), or staring (10%). Fifty-two percent had their eyes open and 45% eyes closed. Tremor was observed in 70%, while clonic jerking was only present in 17%. The majority of volunteers maintained a normal or floppy body posture. Head shaking side-to-side was observed in 38%, while guttural cries, stertorous breathing, tearfulness, and hyperventilation were absent in all volunteers.

Discussion: Our results suggest that simulated seizures not only resemble functional seizures [seizures that resemble epileptic seizures but are episodes of impaired self-control and not associated with epileptic EEG discharges] more closely than epileptic seizures but also show some important differences. Subjective seizure experiences in people with functional seizures, not captured by this experimental simulation, remain a core determinant of semiology.