Catalina Dunoyer

Different features of histopathological subtypes of pediatric focal cortical dysplasia

Focal cortical dysplasia (FCD) is the most frequent pathological finding in pediatric epilepsy surgery patients. Several histopathological types of FCD are distinguished. The aim of the study was to define distinctive features of FCD subtypes.

Surgery for Epilepsy Due to Cortical Malformations: Ten‐year Follow‐up

Summary:  Children with malformations of cortical development represent a significant proportion of pediatric epilepsy surgery candidates. From a cohort of 40 children operated on between 1980 and 1992 with malformation of cortical development, 38 were alive and had data 10 years after surgery. Age at surgery ranged from 6 months to 18 years (mean, 9.6 years). Thirty‐six had partial seizures, and two had infantile spasms; 20 were nonlesional. Pathologic diagnoses were cortical dysplasia (n = 31) and developmental tumor (n = 7). At 10‐year follow‐up, 15 (40%) were seizure free, 10 (26%) had >90% seizure reduction, and 13 (34%) were improved or unchanged. Children seizure free at two‐year follow‐up were likely to remain seizure free. Ten‐year seizure freedom was 72% in children with developmental tumors and 32% in the cortical dysplasia group. Complete resection was statistically significant for favorable outcome, and no patient with an incomplete resection was seizure free.

Low‐grade focal cortical dysplasia is associated with prenatal and perinatal brain injury

Purpose:  Prenatal and perinatal adverse events are reported to have a pathogenetic role in focal cortical dysplasia (FCD). However, no data are available regarding the prevalence and significance of this association. A cohort of children with significant prenatal and perinatal brain injury and histologically proven mild malformations of cortical development (mMCD) or FCD was analyzed.

Intravenous Valproate Dosing in Neonates

The loading dosage of intravenous valproate required to achieve a desired serum concentration in neonates is not known. Two neonates with seizures received loading doses of intravenous valproate over 30 minutes. Serum valproate concentrations were measured 45 minutes and 3 hours after initiation of the infusion. Both neonates had received phenobarbital and phenytoin before the loading infusions. In the first patient, a loading dose of intravenous valproate of 10 mg/kg increased the 45-minute postinfusion serum valproate concentration to 41 μg/mL with a 3-hour postinfusion serum valproate concentration of 33 μg/mL. In the second patient, a loading dose of 25 mg/kg increased the 45-minute postinfusion serum valproic acid concentration to 100 μg/mL with a 3-hour postinfusion serum valproic acid concentration of 78 μg/mL. We found that each 1 mg/kg of intravenous valproate increased the 45-minute and 3-hour postinfusion serum valproic acid concentrations by approximately 4 μg/mL and 3 μg/mL, respectively. We suggest that these figures be used to calculate the desirable loading dose of intravenous valproate in neonates until larger studies are conducted. The volume of distribution and the serum clearance of valproate were approximately 0.245 L/kg and 25 mL/h/kg, respectively. (J Child Neurol 2000;15:827-829).

Near-infrared spectroscopy to define cognitive frontal lobe functions.

Near-infrared spectroscopy (NIRS) monitors changes in the regional cerebral oxygenation (rSO2) and has been used to study cerebral physiologic functions in normal states and during epileptic seizures. Yet, the limitations and pitfalls of the technique are not fully understood. The authors evaluated NIRS changes over the frontal lobes during language tasks known to be associated with the integrity of the dominant frontal lobe in 17 normal adults (handedness: 14 right, 3 left). Recording protocol involved a baseline (3 minutes) with the subject relaxed and thinking of a blue sky and a second baseline during voluntary mouth movements mimicking speech. Two standardized neuropsychological word-generation tasks (controlled word-association tests: CFL and Animals) were then administered (4 minutes total) followed again by the two baseline procedures. Mouth movement without verbalization increased rSO2 values in excess of 2 SD of baseline fluctuations in 70% of the subjects. A t-test comparison of these baseline measurements was statistically significant (P < 0.0001). A general linear model repeated-measures procedure was then used to statistically examine NIRS increments during the cognitive tasks above and beyond the contribution produced by mouth movements during the second baseline. Compared to the second baseline, rSO2 further increased significantly during the word generation tasks (left frontal F value = 21.4, P < 0.0001; right frontal F value = 15.2, P < 0.001), confirming the utility of the technique. There was no apparent difference related to handedness. These findings corroborate the usefulness of NIRS to demonstrate focal cerebral activation during an “executive” language task. However, interpretation of changes can be confounded by extracerebral factors such as mouth movement, a finding of particular relevance in NIRS clinical applications.

The diagnostic utility of intracranial EEG monitoring for epilepsy surgery in children

There are limited data on the indications for the use of chronic invasive electroencephalography (EEG) monitoring (IEM) for pediatric epilepsy surgery.

The diagnostic utility of 3D electroencephalography source imaging in pediatric epilepsy surgery.

The aim of this study was to investigate the utility of three‐dimensional electroencephalography source imaging (3D‐ESI) with low‐resolution electroencephalographic data in the pediatric noninvasive presurgical evaluation, and to compare the findings with positron emission tomography (PET) and ictal single‐photon emission computed tomography (iSPECT).

The diagnostic utility of 3D-ESI rotating and moving dipole methodology in the pre-surgical evaluation of MRI-negative childhood epilepsy due to focal cortical dysplasia.

This study investigates whether a combined rotating dipole (RD) and moving dipole (MD) solution enhances three‐dimensional electroencephalography (EEG) source imaging (3D‐ESI) localization in magnetic resonance imaging (MRI)–negative pediatric patients with focal cortical dysplasia (FCD).

Response: Added value and limitations of electrical source localization.

Laurent Koessler Georgia Ramantani Louis G. Maillard l.maillard@chu-nancy.fr Neurology Department, University Hospital of Nancy, Nancy, France; Neurology Department, University Hospital of SartTilman, Li ege, Belgium; Faculty of Medecine, University of Li ege, Li ege, Belgium; CRAN, UMR 7039, Lorraine University, Vandœuvre-l es-Nancy Cedex, France; CNRS, CRAN, UMR 7039, Vandœuvre-l es-Nancy Cedex, France; Division of Child Neurology, University Children’s Hospital, Z€urich, Switzerland; and Swiss Epilepsy Center, Z€urich, Switzerland