Dealing With The Seeg Sparse Setup: A Local Dipole Fitting Strategy

Stereo-electroencephalography (SEEG) is used in clinical routine as a golden standard for precisely delineating the epileptic before surgical resection. In recent years it has been demonstrated that the SEEG setup is also eligible for Electrical Source Imaging (ESI), usually achieved from non-invasive measurements such as EEG/MEG. We found out that the principal burden for reliable localization from SEEG comes from the particular implantations of the electrode shafts in cluster, yielding a partial vision of the cerebral activity around the implanted zones. There is evidence that a compromise between the number of electrodes, their spatial repartition, and their distance to the source has to be reached toward successful ESI from SEEG. We then introduce a spatial conditioning criteria aiming at adequately describing these requirements on the sensor configuration. Under supervised simulation with known source position, we identify eligible value of this criteria yielding globally the highest source localization performance. Subsequently, the strategy is assessed under a realistic simulation framework, demonstrating the relevance of our local approach.