Interpretation of SEEG recordings

The interpretation of SEEG recordings is a crucial step. It must be carried out by an epileptologist/neurophysiologist with sufficient training and qualification in this field. The objectives of the interpretation are to define the brain topography of interictal activities (irritative zone) and the epileptogenic zone, defined as the site of primary organization of ictal discharges. Several patterns of seizure onset are possible, the most typical including fast discharges. The interpretation of the SEEG is based on the recording of spontaneous activity but also on the results of intracerebral electrical stimulation. It must be done with accurate anatomical information on the location of the electrodes in terms of the patient's anatomy. Quantification of interictal activities (spikes, high frequency oscillations) and ictal activity (epileptogenicity index) is recommended. The interpretation of the SEEG must also take into account functional data and will be the basis for the final decision on the operability and type of intervention chosen.