Effects of antiepileptic drugs on EEG background activity in children with epilepsy: initial phase of therapy.

The effects of antiepileptic drugs (AED) on EEG background activity were evaluated in 37 newly treated children with epilepsy, compared with 46 age-matched healthy controls. Before AED therapy, the children with epilepsy, both partial (treated with carbamazepine, CBZ group) and generalized seizures (treated with valproic acid, VPA group), already exhibited significant slowing of EEG with increased delta and decreased alpha power. Following 3 to 6 months of AED therapy, this EEG slowing was enhanced in the CBZ group and reduced in the VPA group. Following 1 year of AED therapy, an increase in frequency was recognized in the CBZ group. These results suggest that 1) most children with epilepsy already exhibit slowing of the EEG at the onset of seizures, which may reflect CNS developmental deficit, 2) the short-term effects on EEG are different between CBZ and VPA, and 3) EEG development with age continues under continuous AED administration. The EEG background activity in children with epilepsy is affected by many factors, which include the underlying CNS dysfunction of the epilepsy itself and also AED therapy (type of AEDs, duration of therapy, etc).