EEG Source Imaging in Pediatric Epilepsy Surgery: A New Perspective in Presurgical Workup

Abstract

Summary:Purpose: Epilepsy is a relatively frequent disease in children, with considerable impact on cognitive and social life. Successful epilepsy surgery depends on unambiguous focus identification and requires a comprehensive presurgical workup, including several neuroimaging techniques [magnetic resonance imaging, positron emission tomography (PET), and single-photon emission computed tomography (SPECT)]. These may be difficult to apply in younger or developmentally delayed children or both, requiring sedation, and hence, a significant workforce. Modern electric source imaging (ESI) provides accurate epileptic source-localization information in most patients, with minimal patient discomfort or need for cooperation. The purpose of the present study was to determine the usefulness of ESI in pediatric EEG recordings performed with routine electrode arrays.Methods: Preoperative EEGs recorded from 19 to 29 scalp electrodes were reviewed, and interictal epileptiform activity was analyzed by using a linear source-imaging procedure (depthweighted minimum norm) in combination with statistical parametric mapping.Results: In 27 (90%) of 30 patients, the ESI correctly localized the epileptogenic region. These numbers compare favorably with the results from other imaging techniques in the same patients (PET, 82%; ictal SPECT, 70%). In extratemporal epilepsy, ESI was correct in all cases, and in temporal lobe epilepsy, in 10 of 13 cases. In two temporal lobe patients showing less-accurate ESI results, 128-electrode data could be analyzed, and in both cases, the 128-electrode ESI was correct.Conclusions: ESI with standard clinical EEG recordings provides excellent localizing information in pediatric patients, in particular in extratemporal lobe epilepsy. The lower yield in temporal lobe epilepsy seems to be due to undersampling of basal temporal areas with routine scalp recordings. Key Words: Epilepsy-Pediatric-EEG-Source imaging.The indication for early surgical intervention in children with refractory epilepsy should be actively investigated for two reasons: (a) to avoid the deleterious effect of epileptic seizures and antiepileptic medication on cognitive, intellectual, and social development (1,2); and (b) to increase the chances of postoperative functional reorganization due to the expected higher degree of brain plasticity in children (3-5). The surgical outcome is similar to that in adults (6-8) (i.e., between 60 and 80% of patients with temporal lobe epilepsy are postoperatively seizure free) (8-10). However, in extratemporal epilepsy, which is more frequent in pediatric patients, the outcome is still somewhat less favorable compared with surgical treatment of temporal lobe seizures. Overall, 50-75% benefit from surgical treatment, and evidence converges that the outcome deAccepted January 15, 2006. Address correspondence and reprint requests to Dr. G. Lantz at Functional Brain Mapping Laboratory, Department of Neurology, University Hospital, 24 Rue Micheli-du-Crest, CH-1211 Genève 14, Switzerland. E-mail Goran.Lant...

Intrinsic Coupling Modes in Source-Reconstructed Electroencephalography

“…On the other hand, theoretical studies have analytically shown that LORETA solution gives satisfactory results compared with other nonparametric inverse solution methods (Greenblatt et al, 2005;Grech et al, 2008). Direct comparisons of LORETA source estimation with intracranial recordings and electrocortical stimulation (Fuchs et al, 1999;Lantz et al, 1996;Michel et al, 1999;Zumsteg et al, 2006), fMRI (Groening et al, 2009;Schulz et al, 2008;Vulliemoz et al, 2009), and with postsurgical outcome (Michel et al, 2004;Sperli et al, 2006;Michel et al, 2012) show that LORETA can reliably identify intracranial sources. Therefore, functional connectivity patterns can be estimated by different source reconstruction approaches by which similar results will be approached.…”

Right parietal brain activity precedes perceptual alternation during binocular rivalry

“…The simplified realistic head model offers an easy and fast extraction of the head model and a fast and accurate analytical solution to the forward problem at the expense of being maybe somewhat less precise than finite element models based on the individual anatomy. Nevertheless, accurate source localization using this head model has been demonstrated in different clinical and experimental studies in the past [Groening et al, 2009;Michel et al, 2004;Phillips et al, 2005;Sperli et al, 2006;Vulliemoz et al, 2009].…”

Investigating Social Cognition in Infants and Adults Using Dense Array Electroencephalography (_dEEG)

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“…Here we present an overview of an established methodology that represents a significant improvement on conventional methodologies for studying EEG in infants and adults. Although several analytical software techniques can be used to establish indirect indices of source localization to improve the spatial resolution of d EEG, the HydroCel Geodesic Sensor Net (HCGSN) by Electrical Geodesics, Inc. (EGI), a dense sensory array that maintains equal distances among adjacent recording electrodes on all surfaces of the scalp, further enhances spatial resolution 4,5,6 compared to standard d EEG systems. The sponge-based HCGSN can be applied rapidly and without scalp abrasion, making it ideal for use with adults 7,8 , children 9,10,11 , and infants…”

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