Hippocampal sclerosis and temporal lobe epilepsy: cause or consequence?

Hippocampal sclerosis is a very common feature of temporal lobe epilepsy (complex partial seizures or limbic epilepsy). It is found in approximately 50–75% of temporal lobe resections made for medically intractable limbic epilepsy (Honavar and Meldrum, 1997); indeed the presence of sclerosis is a good indicator for a positive outcome to surgery. A very long-standing question is whether hippocampal sclerosis is the consequence of repeated seizures, or whether it plays a role in the development of the epileptic focus. Longitudinal MRI studies will, no doubt, soon provide an answer to the question of whether sclerosis represents part of a pathological progression of the hippocampal epileptic focus in humans (Meierkord et al. , 1997; Van Paesschen et al. , 1998). Several lines of work suggest that hippocampal sclerosis is not absolutely necessary for long-lasting epileptic foci. First, there are a …