Unilateral limbic epileptic status activity: stereo EEG, behavioral, and cognitive data

We report data from four patients with unilateral epileptiform status activity within different structures of the temporal lobe, recorded during stereoelectroencephalographic presurgical evaluation. The ictal clinical symptoms accompanying neocortical and mesiobasal limbic discharges (two patients with complex partial status epilepticus) consisted of various psychosensory and vegetative signs, which can be understood on the basis of the spatiotemporal analysis of the discharges. The other two patients with circumscribed long-lasting mesiobasal limbic epileptiform activity represent unilateral pure limbic status epilepticus and were characterized by a marked behavioral syndrome (with stickiness, aggressivity, etc.) and a monomorphic gustatory aura continua, respectively. The latter patient, with left hippocampal discharges of nearly continuous epileptiform character, was also assessed with tachistoscopic tasks. Performance revealed cognitive impairment only in the epileptically discharging hemisphere and in dependence on the quality of the EEG pattern. After unilateral selective amygdalohippocampectomy, the two patients with limbic status epilepticus were seizure free and had markedly improved behavior and cognitive functions. Thus, patients with nonconvulsive status epilepticus represent an ideal model, although rare, to correlate behavior alterations and brain dysfunction.