The relation of childhood seizures to hippocampal neuron loss, mossy fiber synaptic reorganization, and eventual hippocampal sclerosis was investigated at the Brain Research Institute, University of California, Los Angeles, and the Cleveland Clinic Foundation, OH. Surgical epilepsy cases had generalized seizures and extra-hippocampal prenatal cortical dysplasia or postnatal ischemic and encephalitic lesions, or complex partial hippocampal epilepsy. Extra-hippocampal childhood seizures of prenatal or postnatal etiology were associated with moderate fascia dentata and minimal Ammon’s horn neuron losses and signs of aberrant mossy fiber sprouting. Children with mesial temporal epilepsy showed patterns of neuron loss and mossy fiber sprouting, typical of adult form hippocampal sclerosis, whereas repeated extra-hippocampal generalized seizures were not associated with progressive hippocampal damage and sclerosis. [1]
COMMENT. The authors conclude that childhood seizures can damage postnatal development of hippocampal granule cells, contributing to chronic hippocampal complex partial epilepsy. Generalized seizures are not a cause of hippocampal sclerosis.