Abstracts

Summary: Epileptiform discharges not accompanied by obvious clinical events are regarded as subclinical or interictal. They are found in up to 80% of patients with epilepsy but are only weakly related to seizure frequency or seizure severity. Indeed their clinical relevance in highly controversial and a principle of treatment is to avoid over-interpretation of epileptiform activity. Experimental data shows that interictal spikes and ictal discharges are generated by different populations of neuron through different cellular and network mechanisms and may represent a condition that delays or prevents seizure onset. However, in the immature brain seizure discharges may cause neuronal cell loss. In older children and adults interictal discharges can be accompanied by brief interruption of cognitive function even in the absence of overt seizures (transitory cognitive impairment). In children with Landau-Kleffner syndrome and CSWS (continuous spike-waves during slow sleep) prolonged nocturnal discharges can have devastating effects on language and / or behavior. This multi-disciplinary workshop will discuss the pathophysiology of interictal discharges and the significance of epileptiform activity in neonates and in older children.