Common Substrates of Medication-Resistant Temporal Lobe Epilepsy: Hippocampal Sclerosis, Focal Cortical Dysplasia, and Combined Pathologies

Temporal lobe epilepsy (TLE) is an etiologically heterogeneous syndrome that constitutes the largest proportion of refractory partial epilepsies. The most common substrates of TLE include focal cortical dysplasia (FCD) in children and hippocampal sclerosis (HS) in adults, with significant overlap of lesion types across age groups. In contrast with the developmental nature of FCD pathology, HS is considered a post-natally acquired condition. This paper highlights the clinical and functional characteristics of each, with an introduction to their classification systems and relevant diagnostic information.