Chapter 5 - Medial Temporal Lobe Epilepsy (MTLE): The Epilepsy of the Hippocampal Declarative Memory System

Abstract

Medial temporal lobe epilepsy (MTLE) is the epilepsy of the hippocampo–frontal memory system. Slow-wave sleep has an important role in its organization with sleep slow oscillation. The most important consequence of the hippocampal participation in MTLE is interictal spiking penetrating into the physiological hippocampo–frontal memory consolidation system, interfering with memory consolidation during slow-wave sleep. It is likely that there are more MTLE symptoms linked to memory disturbances than we had expected. Contemporary research has evidenced that MTLE is a bilateral disease. In addition to the possibility of a genuine bilateral temporal involvement, several arguments support the possibility of a progressive scenario in which unilateral temporal lobe epilepsy may involve the contralateral lobe, resulting in a dynamic bilateral interrelationship. In MTLE, there is a continuum between uni- and bilateral participation of the temporal lobes. Interictal and subclinical activity and the dynamic relationship of both temporal lobes need to be taken into account when planning surgery. We need therapeutic strategies for targeting the interictal events (not just the seizures) and for improving the disorder of sleep plastic functions in MTLE.