Correlation of EEG, neuroimaging and histopathology in an epilepsy patient with diffuse cortical dysplasia

Abstract

The correlation between scalp EEG, intraoperative electrocorticogram, neuroimaging and histopathology was examined in a epilepsy child with diffuse cortical dysplasia. A 6-year-old girl with moderate mental retardation had suffered from intractable complex partial and generalized epilepsy since 2-year-old. MR images demonstrated unilateral large macrogyria/polymicrogyria and schizencephaly in the right occipital lobe. The epileptic focus was detected on the macrogyria by EEG and single-photon emission tomography. However, intraoperative electrocorticogram showed frequent spikes from the polymicrogyria and no paroxysmal activity in the macrogyria. The polymicrogyria was resected including the macrogyria using an image-guided system. The histological findings revealed that the macrogyria was covered and separated with glial bundles. It has been reported that epileptogenisity was produced from abnormal neurons and their arrangement in cortical dysplasia, however in this case, the major dysplastic lesion had no epileptogenisity, rather the focus might be in polymicrogyria around the lesion.(144 words)

Functional MRI in Malformations of Cortical Development: Activation of Dysplastic Tissue and Functional Reorganization

“…6,7 Invasive electroencephalogram (EEG) recordings have shown that heterotopia, polymicrogyria, and focal cortical dysplasia are all characterized by an intrinsic epileptogenicity, with the generation of isolated or rhythmic epileptiform discharges. [8][9][10] Connectivity with normal brain regions has been confirmed by pathological examination in nodular heterotopia, and visualized by means of diffusion tractography in band heterotopia. 11,12 Moreover, there is evidence that, in some patients with nodular heterotopia, ictal activity may start simultaneously in nodules and cortex.…”

“…Invasive electroencephalogram (EEG) recordings have shown that heterotopia, polymicrogyria, and focal cortical dysplasia are all characterized by an intrinsic epileptogenicity, with the generation of isolated or rhythmic epileptiform discharges 8–10 …”

Interictal regional polyspikes in noninvasive EEG suggest cortical dysplasia as etiology of focal epilepsies

“…Malformations of cortical development are disorders of cortical formation (proliferation, migration, and differentiation) and are frequently associated with medically refractory epilepsy (Brodtkorb et al, 1998; Hashizume et al, 2000). In selected patients, particularly with focal cortical dysplasia (FCD), resective epilepsy surgery is an option.…”

Emerging Surgical Strategies of Intractable Frontal Lobe Epilepsy with Cortical Dysplasia in Terms of Extent of Resection

“…However, surgery for frontal lobe epilepsy (FLE) has also been reported to be associated with a high failure rate because of difficulties in localizing the epileptic zone and the presence of eloquent areas. In addition, many articles that relate malformations of cortical development (MCD) were already published usually regarding clinical and pathological characteristics, as well as surgical outcomes, but few regarding the practical aspect of the extent of resection3,8,13,19,33).…”