Eslicarbazepine Acetate Modulates EEG Activity and Connectivity in Focal Epilepsy

Abstract

Introduction: Eslicarbazepine acetate (ESL) is an antiepileptic drug approved as monotherapy or add-on for the treatment of epilepsy with seizures of focal onset. ESL owns a good profile in terms of efficacy and tolerability, but its effects on EEG activity and connectivity are unknown. The purpose of this study was to investigate EEG activity and connectivity changes after ESL treatment in persons with focal epilepsy (PFE).Material and Methods: We performed a multicentre, longitudinal, retrospective, quantitative EEG study on a population of 22 PFE, and a group of 40 controls. We investigated the ESL-related changes of EEG power spectral activity and global connectivity [phase locking value (PLV), amplitude envelope correlation (AEC) and amplitude envelope correlation of orthogonalized signals (Ortho-AEC)] for standard frequency bands (delta to gamma). Seizure frequency was evaluated to assess ESL efficacy in our cohort.Results: ESL significantly enhanced both global power spectral density and connectivity for all frequency bands, similarly for all connectivity measures. When compared to the control group, Post-ESL power was significantly higher in theta and gamma band. Pre-ESL connectivity values were significantly lower than control for all frequency bands. Post-ESL connectivity increased and the gap between the two groups was no longer significant. ESL induced a 52.7 ± 41.1% reduction of seizure frequency, with 55% of clinical responders (reduction of seizures ≥50%).Discussion: ESL therapy induces significant enhancement of brain activity and connectivity. Post-ESL connectivity profile of epilepsy patients was similar to the one of healthy controls.

Transcranial direct current stimulation over the sensory‐motor regions inhibits gamma synchrony

“…This technique allows measuring cortical activity noninvasively, with high temporal resolution, with better spatial resolution than EEG (Chowdhury et al, ; Hedrich, Pellegrino, Kobayashi, Lina, & Grova, ; Larsen et al, ; Pellegrino et al, ; Pellegrino, Tomasevic, Herz, Larsen, & Siebner, ; von Ellenrieder et al, ). This technique is also especially suitable in the context of off‐line tDCS as it does not require the application of electrodes on the scalp and has no impact on tDCS montage (Pellegrino et al, ). Forty hertz sounds synchronized gamma activity over a very large area spanning from frontal to central, parietal and temporal regions reaching cortical surface far away from the primary auditory cortex, up to the sensory‐motor regions (Figure ).…”

“…For instance, gamma synchrony is increased in schizoaffective bipolar disorder (Brealy et al, ), Alzheimer's disease (Başar, Femir, Emek‐Savaş, Güntekin, & Yener, ), in first episode psychosis (Flynn et al, ) and after stroke (Pellegrino et al, ). Conversely, patients with schizophrenia exhibit reduced gamma synchronization (Krishnan et al, ; Thuné, Recasens, & Uhlhaas, ) and so do patients affected by focal epilepsy (Pellegrino et al, ; for review Herrmann & Demiralp, ; Krishnan et al, ; Thuné et al, ; Uhlhaas & Singer, ). tDCS has not been implemented in clinical practice yet, but tDCS has been applied in more or less all neuropsychiatric conditions (for review and guidelines on this topic please see Lefaucheur et al, ).…”

The P300 Event-Related Potential Component and Cognitive Impairment in Epilepsy: A Systematic Review and Meta-analysis

“…In the present meta-analysis, the prolongation of the P300 latency was most obvious in the generalized epilepsy group, indicating that the cognitive impairment was most severe in generalized epilepsy. Additionally, recent progress revealed the effects of AEDs on cortical activity and connectivity which could be measured by EEG (53). This finding may partly explain the prolongation of p300 latency and reduction of p300 amplitude in epileptic patients due to AEDs treatment.…”

Transcutaneous Vagus Nerve Stimulation Modulates EEG Microstates and Delta Activity in Healthy Subjects

“…The electroencephalogram (EEG) is a sensitive and reliable tool for substantiating cortical functions and activities. In particular, each EEG frequency band power (i.e., delta, theta, alpha, beta, gamma) has a functional role [ 12 ]. Moreover, numerous previous works showed that the resting-state EEG can be represented as a sequence of “microstates”, which consist of discrete cortical topographies that remain constant for about 40–120 ms [ 13 ].…”