Estimation of Epileptic Foci Using the Dipole Tracing Method in Epileptic Seizures with Structural Lesions of the Brain

Abstract

We estimated the position of the epileptic focus using the dipole tracing method (DTM) in three patients with epileptic seizures and structural lesions, and made comparisons between the foci and their lesions. Patient 1 had a large arachnoid cyst in the right temporal lobe, patient 2 had a tumor in the right hippocampus, and patient 3 had a tumor in the right amygdala. In patient 1, the epileptic focus was estimated to lie in the lateral portion of the right temporal lobe just outside the cyst; in patient 2, in the right hippocampus just under the tumor; and in patient 3, one in the right hippocampus just behind the tumor, another in the right superior temporal gyrus (rSTG). Except for the focus of patient 3 on rSTG, the epileptic foci in all three patients were estimated to lie near the lesions. These estimations correlated with past reports that most foci of seizures caused by brain lesions were located near the lesions. The results of ECoGs in patient 3 were in close correlation with those of DTM. Therefore, we conclude that DTM is a highly accurate method in the estimation of the foci in patients with brain lesions associated with epileptic seizures.