Abstracts

RATIONALE: To analyze the extended hippocampal damage and clinical features in patients with epilepsy and destructive brain lesions of early development.
METHODS: Fifty one adult patients were divided into three main groups according to the topographic distribution of the lesion on the magnetic resonance imaging (MRI): hemispheric (H) (n=9); main arterial territory (AT) (n=25); arterial borderzone (Bdz) (n=17). The mean areas of each hippocampal slice of the different groups were compared to the mean area of a control group in order to evaluate the changes in volume distribution along the hippocampal axis.
RESULTS: Visual analysis showed hippocampal atrophy (HA) in 74,5% of the patients and volumetric study in 92%. The HA was bilateral in six patients and it was more severe ipsilateral to the main lesion. The HA was unilateral in 41 patients and at the same side of the main lesion, except in two. The frequency of unilateral or bilateral HA was not different among groups (p[gt]0.05). Volume loss was diffuse but more concentrated on the anterior section of the hippocampus in patients of all groups. There was a shortening of the long axis of the hippocampus in patients of group H which was not present in the other groups. Duration of epilepsy correlated weakly with the volume of the hippocampus ipsilateral to the main lesion (r=-0.29, p=0.046). Extra-temporal ictal semiology was the most common presentation (66%), although EEG epileptiform discharges were more common over the temporal lobes (64%). The patients without HA had seizures with extratemporal semiology and interictal epileptiform activity localized outside the temporal lobes.
CONCLUSIONS: The HA in these patients with large destructive lesions of early development seems to be related to the insult that caused the main lesion. The role of long term repetitive seizures appear to have minor additional effect in HA. Although the majority of patients in this series have extratemporal epilepsy, the high frequency of HA and epileptiform activity over the temporal lobe suggests that their epileptic syndrome is related to a more diffuse epileptogenic area, also involving the mesial temporal structures. These findings may have major importance in surgical planning of patients with destructive brain insults of early development who present intractable seizures.
[Supported by: Funda[ccedil][atilde]o de Amparo [agrave] Pesquisa do Estado de S[atilde]o Paulo - FAPESP; S[atilde]o Paulo, SP, Brazil]