Abstracts

Rationale: 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 accuracy eloquent areas, such as language and motor function, and to trigger seizures. The aim of this study is to analyze SEEG and electrical stimulation (ES) findings in our patient population Methods: 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. We analyzed 30 patients with drug resistant epilepsy from our Video-EEG Unit, who underwent a SEEG as part of a surgical plan. During SEEG, bipolar stimulation using low frequency (typically 1 Hz) or high frequency stimulations (typically 50 Hz during 5 s) were used to map functional cortex or to trigger seizures. Stimulations were usually performed having already recorded spontaneous seizures. Electrical stimulation was stopped when induced-seizures appeared or after discharges on EEG recordings. Cognitive tasks performed during ES were: hand tapping, naming, automatic speech (counting, familiar lines, reciting), reading and verbal fluency. Results: From the 30 patients, we define de EZ as follows: 13 p (43%) Frontal lobe, 8 p(27%) mesial temporal lobe, 5 p (17%) parieto occipital areas, 2 p (6.5%) other temporal areas, 2 p (6.5%) insula. 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. Twenty patients underwent epilepsy surgery. Postsurgical outcome: Engel I/II: 12 p; Engel III: 8 patients Conclusions: SEEG is a procedure performed for a group of patients with intractable epilepsy. This procedure allowed us the accurate location of the EZ, the identification of the temporal space dynamics of the epileptogenic network and the functional mapping, to plan cortical resection and to improve post-surgical prognosis. In the group of patients whereas the EZ involved eloquent areas, postsurgical outcome is not so favorable, but could also improve quality of life, preserving this functional areas Funding: No funding