Hybrid Micro-macro Electrodes in Patients With Epilepsy

Inclusion Criteria: * Patient 18 years old or older suffering from drug-resistant focal epilepsy. * Candidate for epilepsy surgery. * Requires evaluation with intracranial stereo-EEG electrodes. * Able and willing to provide informed consent. Exclusion Criteria: * Any acute infection (e.g. fever, throat infection). * Skin or scalp infection over the implantation site. * Thin or fragile skull bones, which would prevent stereo-EEG electrodes from being anchored safely. * Increased risk of infections, either from a medical condition or from immunosuppressant medication. * Increased risk of bleeding, either from a medical condition or from antiplatelet or anticoagulant medication. * Severe concomitant medical disease (including, but not limited to, cardiovascular, respiratory, renal or hepatic disease). * Severe concomitant psychiatric disease or major psychological distress. * Women who are pregnant or breastfeeding during the study. * Patients who have an implanted stimulation device (e.g. pacemaker, defibrillator, neurostimulator).