Stereoelectroencephalography at Sainte-Anne Hospital, Paris, France

Stereoelectroencephalography (SEEG), which combines the exploration of identified intracerebral structures using depth electrodes and provides direct recording of local field potentials from multiple brain sites, was designed and developed in the 1950s by Jean Talairach and Jean Bancaud, in Sainte-Anne Hospital, Paris. For patients with focal drug-resistant epilepsy, when the non-invasive phase is insufficiently concordant or when relationships between the epileptogenic network and eloquent areas remain to be defined, the main purpose of SEEG is the optimal electrode implantation based on a main hypothesis and questions formulated during the non-invasive phase. Following an initial historical overview, the different steps of this non-invasive phase are described. Some of these steps, like semiology analysis, have remained relatively preserved, while others have considerably evolved, such as positron emission tomography combined with 3 Tesla magnetic resonance imaging (MRI), functional MRI (fMRI) and high-resolution EEG. We then outline the different steps of the SEEG procedure as performed in our institution. Here also, some steps remain quite unchanged such as intracerebral stimulation, amitriptyline and benzodiazepine tests while some others have strikingly evolved such as frameless robot-assisted, MRI-based implantation, depth-signal analyses and quantifications, and radio-frequency thermocoagulation.