Influence of the Hippocampal Atrophy Extent on Secondary Generalized Tonic-Clonic Seizures in Temporal Lobe Epilepsy

Abstract

Eventhough the hippocampal sclerosis (HS) is crucial in pathophysiology of temporal lobe epilepsy TLE, the seizure semiology in relation to the extent of hippocampal atrophy (HA) has not been well addressed. We attempted to investigate whether the extent of HA contributes to secondary generalized tonic-clonic seizure (2GTCS) occurrence in TLE. Clinical information in medical records, archived data of video-EEG monitoring (VEM) of 11 TLE patients were reviewed and findings of temporal lobe magnetic resonance imaging’s (TLMRIs) of those patients were analyzed. According to the extent /of HA and the presence of amygdala atrophy (AA) in TLMRI findings, patients were divided into partial hippocampal atrophy group (PHA) (3 patients: HA limited to a partial portion of hippocampus), diffuse hippocampal atrophy group (DHA) (3 patients: extensive HA from head to tail of hippocampus) and amygdala atrophy group (AA) with HA (5 patients). We analyzed 2GTCS occurrence rate (rate during previous one years and during VEM period) between PHA and DHA, between AA and only HA group, and between AA, DHA and PHA. There was no significant difference in age, sex, onset age, febrile seizure history and seizure duration. Both 2GTCS rate of the previous one month and that during VEM monitoring period were not significantly different between DHA and PHA, between AA and HA, and between AA, DHA and PHA, either. We preliminarily conclude that neither the hippocampal atrophy extent nor the presence of amygdala atrophy influenced the occurrence of 2GTCS in TLE.