Psychopathologie in der Epileptologie

Abstract

The observation of positive and negative seizure symptoms in the context of focal epileptic seizures represents a window to the brain, in particular if the localisation of the epileptic discharge can be accurately and reliably determined. The epileptic local dysfunction which gives rise to the aura of an epileptic patient represents a bridge between neurology and psychiatry because it can be viewed as short-lived (or in the case of aura continua or dyscognitive limbic status epilepticus as an extended) ictal psychosis. Of particular interest are complex epileptic hallucinations due to discharges in the limbic system because they are frequently associated with changes in the emotional and affective sphere as well as with mood changes. Epileptic de novo hallucinations often cannot be adequately described by patients because there exist no such phenomena in the real outer world. In the context of presurgical evaluation of possible candidates of epilepsy surgery direct recording and electrical stimulation of the brain have provided fascinating insights. Nowadays the invasive EEG methods are complemented by new and non-invasive functional imaging techniques, such as functional magnetic resonance imaging (fMRI), positron emission tomography (PET) and refined EEG mapping (such as LORETA or related techniques). EEG has the unsurpassable advantage of its excellent time resolution. In addition, focal or regional transitory inactivation of brain structures is possible and indicated in certain patients, as is the case in the so-called temporal lobe amobarbital memory test to predict postoperative memory outcome in patients in whom a selective therapeutic removal of amygdala and hippocampus is planned. Finally, important insights and impulses for modern brain research have emerged from the analysis of the sequels of therapeutic epilepsy surgeries, such as the so-called split-brain symptomatology observed as a consequence of total corpus callosum section. In this article we comment on some aspects of consciousness and awareness. We concentrate on the epileptic aura and epileptic hallucinations and illustrate some electroclinical findings. Aura continua and dyscognitive limbic status epilepticus as ictal phenomena and the interictal behavioural syndrome of temporal lobe epilepsy are referred to. Because auras most often represent memory flashbacks, some memory subsystems and their main brain substrates and the selective inactivation of medial temporal lobe structures by injection of amobarbital into the territory of the anterior choroidal artery are introduced and briefly discussed.