Abstracts

Rationale: This study reported 8 non lesional temporal lobe epilepsy cases who underwent pre-surgical evaluation by Sterotactic Electroencephalography (SEEG). The SEEG recording data showed ictal onset from both mesial temporal structure (Amygdala and Hippocampus) as well as lateral neocortical structure. However, the final histology showed only pathology at the lateral neocortical structure. Methods: We retrospective studied 8 patients in our institute who underwent SEEG electrodes implantation followed by temporal lobectomy for non lesional temporal epilepsy. Patient demographic, seizure history, non invasive evaluations and SEEG data were reported. Final histological finding in both mesial temporal and lateral neocortical structures were illustrated. Results: All 8 patients had no temporal lobe lesion from MRI study. One patient had remote history of ganglioglioma resection at the occipital lobe. One patient had failed subdural grids monitoring from another institute. Three patients had interictal bilateral hypometabolism from PET study. Five patients had interictal hypometabolism at both mesial and lataral temporal areas. SEEG data showed ictal onset at mesial structure before spreading to lateral neocortical stucture in 6 patients. SEEG data showed ictal onset at both mesial and lateral neocortical structure in 2 patients. The final histological demonstrated focal cortical dysplasia at the lateral neocortical stucture in all 8 patients. There were non specific changed in mesial structure of these 8 patients. All patients had favorable outcome (Engel I) after surgery. Conclusions: Ictal pattern and location from SEEG electrodes are crucial data to determine surgical resection plan. It is possible that the sensitivity to localize ictal activity and propagation is not precisely detected in these electrodes. Further study is needed to determine the the electrodes sensitivity, pattern of ictal propagation in the network of temporal epilepsy