Degree of hippocampal atrophy is not related to a history of febrile seizures in patients with proved hippocampal sclerosis

Objectives-To examine the degree of hippocampal atrophy in patients with te mporal lobe epilepsy and proved hippocampal sclerosis to determine whether or not patients with febrile seizures have more severe hippocampal atrophy. To determine whether or not there is a relation between age of seizure ons et, duration of temporal lobe epilepsy, or seizure frequency, and severity of hippocampal atrophy. Methods-Hippocampal volumes were measured from volumetrically acquired MR i mages in 77 consecutive surgical patients with temporal lobe epilepsy (37 f ebrile seizures (FS)+, 40 FS-) with proved hippocampal sclerosis, and compa red with 98 controls. Results-Ipsilateral and contralateral hippocampal volumes were not signific antly different between the FS+ and FS-groups. There was no difference in t he age of onset of habitual seizures, duration of epilepsy, or age at the t ime of surgery between these groups. No clinically significant correlations were found between hippocampal volumes and age of onset of first non-febri le seizure, duration of temporal lobe epilepsy, or complex partial and seco ndarily generalised seizure frequency, in patients with and without febrile seizures. Conclusions-Although febrile seizures was associated with hippocampal scler osis in 48% of patients in this surgical series, the degree of MRI determin ed hippocampal atrophy was not related to a history of such seizures. The r esults do not support the view that febrile seizures cause more severe hipp ocampal sclerosis and are consistent with the hypothesis that hippocampal s clerosis is a pre-existing abnormality.