Abstracts

RATIONALE: Aetiological evaluation in epilepsy surgery demonstrates increasingly dual pathology of hippocampal sclerosis (HS) and malformations (MF). This is related to the technical improvement of imaging technics. We made an autopsy study to analyse the coincidence of HS and MF. METHODS: 650 brains of patients with epilepsy were formalin fixed, and paraffin embedded. The 10 m slices were studied by light microscope. We separated 4 groups of epilepsy manifestation: under 1 (I), between 2 and 5 (II), between 6 and 20 (III), and over 21 years of age (IV). The malformations were separated into migration disturbances, maturation disturbances and the combination of migration and maturation disturbances. RESULTS: The overall frequency of HS in 650 brains was 30.5 %. From this, 58 % had additional MF. The frequency in the different epilepsy manifestation groups was different: Group I, 66 %, group II, 70 %, group III 54 % group IV, 34 %. The differences to group III and IV are significant. The type of malformation was also different in relation to the manifestation groups. In group I and II there was almost 50 % of each migration and maturation disturbances. In group III and IV there were 2/3 migration disturbances and only 1/3 maturation disturbances. CONCLUSIONS: The frequency of dual pathology with the HS and MF is related to the manifestation time of epilepsy. Early manifestation is more frequently related to dual pathologoy than later manifestation. The type of malformation is also related to the manifestation time of epilepsy. As earlier the manifestation time of epilepsy, as higher is the frequency of maturation disturbances. This probably points to the fact that both HS and maturation disturbances might have the same aetiological background. The observation that the frequency of dual pathology is higher in early manifestation times, correlates well with the clinical observation of higher rates of drug resistancy in early manifested epilepsy.