Foramen ovale electrodes: a new technique enabling presurgical evaluation of patients with mesiobasal temporal lobe seizures.

A recently developed technique to record from the mesiobasal aspect of the temporal lobes by subdural electrodes inserted through the foramen ovale is described. Experience with this technique in 13 candidates for surgical epilepsy therapy is presented. Our results indicate that interictal epileptiform potentials as well as ictal discharges are reliably picked up by the foramen ovale electrode whenever nucleus amygdallae, hippocampus and parahippocampal gyrus show synchronous epileptic activity. The advantages of this technique are discussed.