Incidence of epileptic discharge in various epileptic syndromes

Three hundred eight patients with childhood and adolescent epilepsy were ex amined to clarify the incidence of epileptic discharges on initial and foll ow-up electroencephalograms. Epileptic discharges were found in 75.6% patie nts on the initial electroencephalogram, which is higher than figures previ ously reported for adults. The cumulative incidence of epileptic discharges was 92.3% by the third electroencaphalogram recording. However, in 17.1% p atients with nonspecific idiopathic generalized epilepsy, no epileptic disc harges were found even after three electroencaphalogram recordings. The inc idence of epileptic discharges in patients with generalized epilepsy (84.3% ) was significantly higher than in patients with localization-related epile psy (71.6%). The incidence of epileptic discharges in patients with partial seizures was lower than those in patients with generalized seizures. The i ncidence of epileptic discharges was low in the 0- to 3-year-old and 15- to 20-year-old groups, and high in the 3- to 12-year-old groups. In the posit ive epileptic discharge patients, 38.8% of electroencephalograms were abnor mal only during the waking or sleeping portion of the recordings. Knowing t he incidence of epileptic discharges for each type of epilepsy will be usef ul in planning further electroencephalogram research and performing electro encephalograms in the clinical setting. (C) 2001 by Elsevier Science Inc. A ll rights reserved.