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Purpose: Determine if blood messenger RNA (mRNA) expression patterns in children with newly diagnosed untreated idiopathic epilepsy are different from those in healthy controls. Determine the differential expression patterns between epilepsy patients with generalized onset or partial onset seizures compared to healthy controls. Methods: Whole blood was obtained from otherwise healthy pediatric patients with newly diagnosed untreated idiopathic epilepsy along with healthy pediatric controls. mRNA was isolated and hybridized to Affymetrix HGU 133 2.0+ microarrays. Analysis was performed using Genespring. Differentially expressed gene lists resulted from comparison of (1) epilepsy and control groups and (2) seizure type subgroups with controls. Tissue expression and gene ontology analysis was performed using DAVID. Key Findings: Thirty-seven epilepsy patients and 28 controls were included. Overall, 575 genes were differentially expressed in subjects with epilepsy compared to controls. The generalized seizure subgroup versus control (GvC) gene list and the partial seizure subgroup versus control (PvC) gene list were different (p < 0.05). Tissue expression analysis identified almost half of the genes in GvC and PvC as brain based. Functional group analysis identified several biologically relevant pathways. In GvC, these included mitochondria and lymphocyte activation. In PvC, we identified apoptosis, inflammatory defense, and cell motion pathways. Significance: A unique, biologically meaningful mRNA expression pattern is detectable in whole blood of pediatric subjects with new-onset and untreated epilepsy. This analysis finds many similar pathways to those identified in brain studies examining lesional intractable epilepsy. Blood mRNA expression patterns show promise as a target for biomarker development in pediatric epilepsy. [ABSTRACT FROM AUTHOR]

Objective The predictive value of intraoperative electrocorticography ( ECoG) in pediatric epilepsy surgery is unknown. In a population of children undergoing ECoG followed typically by invasive extraoperative monitoring ( IEM) and resection, we aimed to determine the relationship between frequent ECoG abnormalities and the seizure onset zone and outcome after resection. Methods We retrospectively identified 103 children with preresection ECoG of sufficient technical quality. ECoG records were scored based on electrode location and frequency, blinded to the seizure-onset zone and outcome. Electrographic seizure and spike locations were identified. Locations of seizures and spike populations were then compared to the location of seizure-onset zone defined by IEM using subdural electrodes and resection margin. Results Electrographic seizures were identified in 11 (11%) of 103 patients. A spike population of one or more was noted in 79 (77%) of 103 patients. In 50 (63%) of 79 patients, spike populations correlated with seizure-onset zone location. The overall surgical outcome was good ( ILAE 1 to 3) in 53 (52%) of 101 patients. Outcome was good in seven (78%) of nine patients when electrographic seizure location was resected. The best outcomes were obtained with resection of both the seizure-onset zone and ECoG abnormalities to include seizures and spike locations (22/33 good outcome, 67%, p = 0.008). There was a significantly better outcome in children with complete resection of ECoG-identified spike populations (14/26, 62% good outcome) compared to when none were resected (4/14, 29%, p = 0.043). Significance Electrographic seizures and frequent spikes are frequently seen on pre-resection ECoG in children. The brain locations corresponding to these discharges are highly concordant with the seizure-onset zone; resection of these regions is correlated with good seizure outcome. Further research is needed to design interventions that increase the reliability of ECoG prediction of the epileptogenic zone and obviate the need for IEM. [ABSTRACT FROM AUTHOR]