Epilepsy syndromes in patients with childhood-onset seizures in Finland.

Childhood-onset epilepsy is a common disorder. There is insufficient data on the distribution of epilepsy syndromes in the population and their effect on long-term prognosis. This report presents the data on epilepsy syndromes in a childhood-onset epilepsy cohort. A population-based active-prevalence cohort of all children under 16 years of age residing in the catchment area of Turku University Hospital with active epilepsy between 1961 and 1964 was monitored prospectively until 1992. Etiology, seizure type, and epilepsy syndromes were classified according to the recent guidelines of the International League Against Epilepsy. The etiology of seizures was idiopathic in 28%, cryptogenic in 22%, and remote symptomatic in 50%. Seizures were classifiable in 235 patients (96%) and included 157 (64%) with partial seizures and 88 (36%) with generalized seizures. Epilepsy syndromes could be classified in 223 patients (91%) and included 152 (62%) localization-related syndromes, 61 (25%) generalized epilepsy syndromes, and 10 (4%) with syndromes not determined as being focal or generalized. Prognosis for both survival and remission was dependent on etiology and on the specific epilepsy syndrome. The authors conclude that the International League Against Epilepsy guidelines can be successfully applied to a population-based cohort with childhood-onset epilepsy. Accurate classification of syndromes is important because in many cases long-term outcome may be largely determined by the underlying epilepsy syndrome.