EEG microstates during resting-state and dissociative events in patients with psychogenic non-epileptic seizures.
Cecilia Catania, Marco Mancuso, Adolfo Mazzeo, Enrico Michele Salamone, Biagio Orlando, Alessandra Morano, Giorgio Leodori, Sara Casciato, Giancarlo Di Gennaro, Anna Teresa Giallonardo, Carlo Di Bonaventura, Emanuele Cerulli Irelli
Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology May 1, 2025 DOI: 10.1016/j.clinph.2025.03.002
Summary
During psychogenic non-epileptic seizures (PNES), microstate C, linked to the default mode network (DMN), exhibits a striking decrease in duration and coverage. In a study involving 22 PNES patients and 24 healthy controls, significant differences were observed: microstate C duration decreased by approximately 36% during seizures compared to resting state. Additionally, PNES patients showed a 29% longer microstate C duration in resting state than controls. These findings highlight crucial neurophysiological changes that may illuminate the pathophysiology of these dissociative events.
Abstract
Previous neuroimaging studies indicate complex network alterations in psychogenic non-epileptic seizures (PNES) patients, but brain activity modifications occurring during PNES remain unexplored. This study aimed to analyze EEG microstate metrics in PNES patients both during events and resting state to investigate the neurophysiological changes underlying these dissociative events. We recruited 22 PNES patients and 24 age- and sex-matched healthy controls. Inclusion criteria included a history of PNES and at least one recorded akinetic PNES during video-EEG. A two-way repeated-measures ANOVA revealed significant class*condition interactions for microstate duration (p = 0.017), coverage (p = 0.012), and global field power (GFP) (p = 0.008). Post-hoc FDR-adjusted paired t-tests showed a significant decrease in microstate C duration (p = 0.036), coverage (p = 0.04), and GFP (p = 0.036) during PNES events compared to resting state. Mann-Whitney U tests showed significantly higher microstate C duration in PNES patients during resting state compared to controls (p = 0.009). Microstate C, previously associated with the default mode network, showed increased duration during resting state and decreased representation during PNES, suggesting a prominent shift in neural activity dynamics within this network during dissociative events. These findings provide insights into neurophysiological changes occurring during PNES, suggestingan interplay between pathological and adaptive mechanisms in their pathophysiology.