Imaging the cortical effect of lamotrigine in patients with idiopathic generalized epilepsy: A low-resolution electromagnetic tomography (LORETA) study

Clemens, Béla; Piros, Pálma; Bessenyei, Mónika; Tóth, Márton; Hollódy, Katalin; Kondákor, István

doi:10.1016/j.eplepsyres.2008.06.002

Cited by 16 publications

(21 citation statements)

References 40 publications

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“…This finding harmonizes with VPA-related decrease of local CSD in frontal but not posterior areas in IGE (Clemens et al, 2007). Baseline theta EEGfC abnormality was greater between anterior than between posterior ROIs.…”

Section: Limitations Of the Broad-band Approachsupporting

confidence: 81%

“…Because its localization accuracy is limited, activity of small ROIs may be falsely localized. However, a prior study demonstrated that VPA alters LORETA activity in widespread cortical regions (Clemens et al, 2007), so very precise localization was presumably not essential in this study. We discuss EEGfC results at sub-lobar, lobar and network levels, which is a usual approach in the neuroimaging literature (Anderson and Hamandi, 2011).…”

Section: Interpretation Of the Results In The Topographic Domainmentioning

confidence: 93%

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Valproate treatment normalizes EEG functional connectivity in successfully treated idiopathic generalized epilepsy patients

et al. 2014

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Aim. To investigate the effect of chronic VPA treatment of EEG functional connectivity in successfully treated idiopathic generalized epilepsy (IGE) patients. Patients and Methods. 19-channel waking, resting-state EEG records of 26 IGE patients were analyzed before treatment (IGE) and after the 90th day of treatment (VPA), in seizurefree condition. Three minutes of artifact-free EEG background activity (without epileptiform potentials) was analyzed for each patient in both conditions. A group of 26 age-matched healthy normative control persons (NC) was analyzed in the same way. All the EEG samples were processed to LORETA (Low Resolution Electromagnetic Tomography) to localize multiple distributed sources of EEG activity. Current source density time series were generated for 33 regions of interest (ROI) in each hemisphere for four frequency bands. Pearson correlation coefficients (R) were computed between all ROIs in each hemisphere, for four bands across the investigated samples. R values corresponded to intrahemispheric, cortico-cortical functional EEG connectivity (EEGfC). Group and condition differences were analyzed by statistical parametric network method. Main results. (p<0.05, corrected for multiple comparisons). 1. The untreated IGE group showed increased EEGfC in the delta and theta bands, and decreased EEGfC in the alpha band (as compared to the NC group). 2. VPA treatment normalized EEGfC in the delta, theta and alpha bands. 3. Degree of normalization depended on frequency band and cortical region. Conclusions. VPA treatment normalizes EEGfC in IGE patients.

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Section: Limitations Of the Broad-band Approachsupporting

confidence: 81%

Section: Interpretation Of the Results In The Topographic Domainmentioning

confidence: 93%

Valproate treatment normalizes EEG functional connectivity in successfully treated idiopathic generalized epilepsy patients

et al. 2014

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“…Midparietal rhythmic theta activity is a genetic marker of increased seizure liability in myoclonicastatic epilepsy of childhood (Doose and Baier, 1988). Valproate and lamotrigine decreased theta oscillations in successfully treated generalized epilepsy patients as compared to the untreated state (Clemens et al, 2007a(Clemens et al, , 2008. On the other hand, experimental data argue for the seizure-gating effect of increased theta activity in animal epilepsy (Miller et al, 1994;Colom et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Theta EEG source localization using LORETA in partial epilepsy patients with and without medication

Clemens

Bessenyei

Fekete

et al. 2010

Clinical Neurophysiology

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Objective. To investigate and localize the sources of spontaneous, scalp-recorded theta activity in patients with partial epilepsy (PE).Methods. 9 patients with beginning, untreated PE (Group1), 31 patients with already treated PE (Group2), and 14 healthy persons were investigated by means of spectral analysis and LORETA, low resolution electromagnetic tomography (1 Hz very narrow band analysis, age-adjusted, Z-scored values). The frequency of main interest was 4 to 8 Hz Results. Group analysis. Group1 displayed bilateral theta maxima in the temporal theta area (TTA), parietal theta area (PTA), and frontal theta area (FTA). In Group2, theta activity increased all over the scalp as compared to the normative mean (Z=0) and also to Group1. Maximum activity was found in the TTA, PTA, and FTA. However, in the PTA and FTA the centers of the abnormality shifted towards the medial cortex. Individual analysis: all the patients showed preferential activation (maximum Zvalues) within one of the three theta areas. 2Conclusion. EEG activity in the theta band is increased in anatomically meaningful patterns in PE patients, which differs from the anatomical distribution of theta in healthy persons.Significance. The findings contribute to our understanding of the sources of theta rhythms and the pathophysiology of PE.

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“…Although some of these drugs (e.g. VPA) have only limited or no effect on spectral band power of patients with CE (Hongou et al 1993) and in patients with primary generalized epilepsy (Benninger et al 1985), the attenuation of frontal (theta and delta) activity is well documented (Clemens et al 2007b). However, as the semi-quantitative single-subject analysis demonstrated there was no systematic contribution of any medication on the alpha band, i.e.…”

Section: Why Did We Observe Spectral Power Increases Predominantly Inmentioning

confidence: 98%

Does Greater Low Frequency EEG Activity in Normal Immaturity and in Children with Epilepsy Arise in the Same Neuronal Network?

et al. 2010

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Greater low frequency power (<8 Hz) in the electroencephalogram (EEG) at rest is normal in the immature developing brain of children when compared to adults. Children with epilepsy also have greater low frequency interictal resting EEG activity. Whether these power elevations reflect brain immaturity due to a developmental lag or the underlying epileptic pathophysiology is unclear. The present study addresses this question by analyzing spectral EEG topographies and sources for normally developing children and children with epilepsy. We first compared the resting EEG of healthy children to that of healthy adults to isolate effects related to normal brain immaturity. Next, we compared the EEG from 10 children with generalized cryptogenic epilepsy to the EEG of 24 healthy children to isolate effects related to epilepsy. Spectral analysis revealed that global low (delta: 1-3 Hz, theta: 4-7 Hz), medium (alpha: 8-12 Hz) and high (beta: 13-25 Hz) frequency EEG activity was greater in children without epilepsy compared to adults, and even further elevated for children with epilepsy. Topographical and tomographic EEG analyses showed that normal immaturity corresponded to greater delta and theta activity at fronto-central scalp and brain regions, respectively. In contrast, the epilepsy-related activity elevations were predominantly in the alpha band at parieto-occipital electrodes and brain regions, respectively. We conclude that lower frequency activity can be a sign of normal brain immaturity or brain pathology depending on the specific topography and frequency of the oscillating neuronal network.

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Imaging the cortical effect of lamotrigine in patients with idiopathic generalized epilepsy: A low-resolution electromagnetic tomography (LORETA) study

Cited by 16 publications

References 40 publications

Valproate treatment normalizes EEG functional connectivity in successfully treated idiopathic generalized epilepsy patients

Valproate treatment normalizes EEG functional connectivity in successfully treated idiopathic generalized epilepsy patients

Theta EEG source localization using LORETA in partial epilepsy patients with and without medication

Does Greater Low Frequency EEG Activity in Normal Immaturity and in Children with Epilepsy Arise in the Same Neuronal Network?

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