Our experience in stereoelectroencephalography and electrical stimulation in a public hospital

Abstract

Purpose : Stereo- electroencephalography (SEEG) is a procedure performed for patients with intractable epilepsy in order to anatomically define the epileptogenic zone (EZ) and the possible related functional cortical areas. Electrical stimulation (ES) was developed to identify with precision cortical structures essential to language and motor function, and to trigger seizures. The aim of this study is to analyze electrical stimulation (ES) findings in our patient population. Method : We analyzed 30 patients with drug resistant epilepsy from our Video- EEG Unit, who underwent a SEEG as part of a surgical plan. Cognitive tasks performed during ES were: hand tapping, naming, automatic speech (counting), reading and verbal fluency. Results : From the 30 patients, we trigger theirs usual seizures in 25 (83.33%), 159 seizures: 25 (15.5%) were trigger with hippocampus stimulation, 15 (9.4%) amygdala, 30 (18.8%) other temporal areas, 50 (31.4%) frontal areas, 15 (9.4%) parieto- occipital areas, and 24 seizures (15%) were obtained with the stimulation of two continues areas. In 14 (46.6%) patients we stimulate eloquent brain regions: 8 (57%) language, 7 (50%) patients were evaluated the motor area, 2 (14.2%)sensitive areas, 4 (28.4%) visual and 5 (28.4%)auditory sensations. We define EZ in all of the patients, 8 (26.6%) mesial temporal lobe epilepsy, 2 (6.6%) other temporal areas, 13 (43.3%) frontal lobe epilepsy, 5 (21.7%) parieto- occipital epilepsy, 2 (6.6%) insular epilepsy. Conclusion : ES is a procedure that allowed us the accurate location of the EZ, the temporal space dynamics of the epiletogenic network and the functional mapping, to plan cortical resection without overlap and to improve postsurgical prognosis.