Their seizures are very difficult to control with AEDs. There is therefore some point in making the distinction between these groups for patient counseling purposes. Cortical dysplasia is not necessarily associated with severe epilepsy or even epilepsy. A person may have histologically equivalent dysplasia in two cortical sites separated by much space. One region gives rise to seizures but the other does not.
Cortical dysplasia tends to spare the hippocampal formation and principally affects the neocortex.
Cortical gliosis can occur following any brain injury - trauma, infection. Traumatic insults which produce epilepsy are more frequent with lesions that penetrate the skull and particularly those which penetrate the dura . These areas are recognized by cystic changes within the brain parenchyma with loss of volume of adjacent brain. Partial epilepsy tends to be associated with cavernous hemangiomas and arteriovenous malformations. Seizures may in fact be the only clinical manifestation with these lesions.