EEG frequency during spike‐wave discharges may predict treatment outcome in patients with idiopathic generalized epilepsies

Summary We report findings concerning the relationship between electroencephalography (EEG) frequency during spike‐and‐wave discharges (SWDs) and response to treatment in 21 patients with idiopathic generalized epilepsy (IGE). We studied patients whose EEG contained SWDs lasting at least 4 s. Among these patients, two groups could be distinguished on the basis of a subtle difference in EEG frequency during the first 2 s of the burst. The two groups differed markedly in their clinical response to medication, with the group becoming seizure‐free during the next 1–2 years showing a spike‐wave onset frequency of >3.2 Hz, and those not seizure‐free