Age-related clinical and neurophysiologic characteristics of intractable epilepsy associated with cortical malformation.

PURPOSE: To elucidate the relationship between the characteristics of cortical malformation (CM) and those of associated epilepsy, and also to investigate the prognostic value of the clinical and magnetic resonance imaging (MRI) findings for the seizure and mental outcome.

METHODS

We studied 41 patients with CM and epilepsy, and the patients were divided according to the age at onset of epilepsy into two groups: one group of 15 patients with very early onset before age 3 months, and the other group of 26 patients with onset at 3 months or later. Statistical relationship was examined between the types of dysplastic lesions demonstrated by MRI and the age at onset of epilepsy. The effects of the onset age and the features of CM on the outcome of seizures and mental or developmental state also were analyzed.

RESULTS

The very early-onset epilepsy was related to the dysplastic patterns of reduced sulci and blurred cortical-subcortical junction, which suggested focal CM, whereas the later-onset epilepsy was related to polymicrogyria. The age at onset of epilepsy was related to the poor seizure outcome, and both the onset age and wide distribution of CM were related to severe retardation.

CONCLUSIONS

The type of CM influences the expression of associated epilepsy, especially its age-related features. The age at onset of epilepsy plays an important role in the seizure and mental outcome.