Microdysgenesis in surgical specimens from patients with epilepsy: occurrence and clinical correlations

Malformations of cortical development are commonly associated with epilepsy . In the first 139 consecutive patients in the Goteborg epilepsy surgery se ries, parenchymal malformations were found in 56.1% of the children and in 23.1% of the adults. Microdysgenesis (MDG), which was the most common paren chymal malformation, was found in 35.1% of the children and in 16.7% of the adults. The aim of this study was to identify clinical characteristics of patients with MDG. Mental retardation was found to be significantly more co mmon in patients with major parenchymal malformations and in patients with MDG compared with patients without parenchymal malformations. Patients with major parenchymal malformations as well as patients with MDG also had a si gnificantly earlier onset of seizures than patients without parenchymal mal formations, also when adjusting for mental retardation. Patients with MDG w ere in these clinical aspects shown to closely resemble patients with major malformations. These findings suggest that MDG is a pathoanatomical entity of clinical relevance, with implications both in mental retardation and in epileptogenesis.