Age-dependent spike localization in various epileptic syndromes.

The electroencephalograms from 276 patients with localization-related epilepsy were analyzed to compare the distribution of spike foci in different age groups. Patients were divided into five groups according to spike location in the frontal, central, temporal, occipital, or multiple cortical regions. The age of peak incidence was earliest in patients with occipital foci, followed by those with central foci and then those with frontal foci. A bimodal age distribution of patients with temporal foci was observed. Symptomatic patients frequently exhibited multiple and frontal foci, and a large number of idiopathic patients had central, temporal, and occipital foci. Multiple foci were detected in 27.5% of idiopathic patients. Age-related spike localization was uniformly observed, regardless of the epileptic syndrome. The analysis of these data indicates that there are two types of multiple foci, one correlated with organic lesions and the other with an idiopathic, functional nature.