Cortical dysplasia: zones of epileptogenesis

Cortical dysplasia describes a wide range of cerebral cortex structural anomalies and is a condition attributed to multiple etiologies including disruption in the migration of the maturing neurons, disturbance of the process of programmed cell death in the fetal brain, and even noxious environmental influence. Cortical dysplasia can be focal or diffuse and the insult depends more on the timing of the defect in neural development and to a lesser extent the cause. Identification of cortical dysplasia can be done using high resolution magnetic resonance imaging (MRI), histological examination of affected tissue, and EEG. Dysplastic lesions have shown intrinsic epileptogencity. Scalp EEG and electrocorticography (ECoG) reveal several unique patterns including continuous spikes or sharp waves, abrupt runs of high frequency spikes, and periodic spike complexes that occur during sleep. EEG and ECoG can help to guide the surgical resection. Developments in the understanding and treatment of epilepsy caused by cortical dysplasia are occurring rapidly. This article will attempt to provide a brief overview of cortical dysplasia to hopefully prepare and encourage the reader to further investigate cortical dysplasia.