Intracranial EEG power and metabolism in human epilepsy

Abstract

EEG power and high frequency activity in the seizure onset zone has been increasingly considered for its relationship with seizures in animal and human studies of epilepsy. We examine the relationship between quantitative EEG measures and metabolic imaging in epilepsy patients undergoing intracranial EEG (icEEG) analysis for seizure localization. Patients with mesial temporal lobe epilepsy (MTLE) and neocortical epilepsy (NE) were studied. Metabolic imaging was performed with MR spectroscopic imaging using N-acetyl aspartate (NAA) and creatine (Cr). All data were acquired from the mesial temporal lobe such that a direct comparison of the same anatomical regions between the two groups could be performed. While no difference was seen in the total power recorded from the mesial temporal lobe, the MTLE group had significantly greater power in the high frequency bands. There was a significant positive exponential relationship between total icEEG power with NAA/Cr in MTLE, R= +0.84 p<0.001, which was not seen in NE. There was also a significant negative relationship between fractional gamma power with NAA/Cr in MTLE R= −0.66 p<0.02, also not seen in NE. These data argue that within the seizure onset zone, the tight correlation between total power and NAA/Cr suggests that total electrical output is powered by available mitochondrial function. These data are also consistent with the hypothesis that high frequency activity is an abnormal manifestation of tissue injury.

Pharmaco‐resistant Neonatal Seizures: Critical Mechanistic Insights from a Chemoconvulsant Model

“…This phenomenon has been previously reported in a similar animal model of continuous seizures over a 2h recording period (Zayachkivsky et al, ). Human EEGs also show a reduction in overall seizure power with treatment (Pan et al, ). BTN related seizure aggravation was associated with an increase in EEG spectral power, which is apparent in the 3rd h EEG trace (Fig.…”

Altered Electroencephalography Spectral Profiles in Rats with Different Patterns of Experimental Brain Dysplasia

“…These differences are likely not related to gross anatomical changes, such as volume reduction or heterotopia, but are rather mediated by more specific alterations in functional properties or spatial arrangement of cell populations, with (predominantly parvalbumin‐expressing) interneurons and astrocytes as potential targets with counteractive effects. A more complete understanding of these mechanisms could be useful not only due to the fact that different patterns of dysplasia correspond to differentially altered susceptibility to seizures (Setkowicz et al, ), but also because regulation of gamma activity itself has been implicated both in humans and in animal models of epilepsy (Pan et al, ; Tchekalarova et al, ).…”

Genetic programming and frequent itemset mining to identify feature selection patterns of iEEG and fMRI epilepsy data

“…From the above data for each patient we randomly picked multielectrode iEEG clips with interictal pathological gamma (i.e., 30–100 Hz adults, 30–70 Hz child) oscillations (PGOs) and without any epileptic biomarker activity in clinically marked SOZ electrodes as manually annotated a priori by epileptologists. We used interictal PGO data since various types of gamma brain activity offered utility as a potential SOZ biomarker (Bragin et al, 1999; Medvedev et al, 2011; Pan et al, 2009; Smart et al, 2012; Worrell et al, 2004). Our main focus was not to discern SOZ electrodes from non-SOZ electrodes (or seizures from non-seizures) but instead indirectly was to discern PGOs from non-PGOs and directly was to find consistently selected measures to discern PGOs and non-PGOs.…”