Epidemiology of absence epilepsy. II. Typical absences in children with encephalopathies.
A population-based study of absence epilepsy in Swedish children, aged 0-15 years, comprised cases selected on the basis of EEG criteria. Absence epilepsy was found in 119 of the 134 children with 3 Hz spike-and-wave discharges, and 12 of these 119 (10.1%) had typical absences in addition to other generalized seizures and slow irregular spike-and-wave activity on the EEG. The mean annual incidence of this type of absence epilepsy was 0.7/100,000. The median age at onset of absences was 6 years. Eight of the 12 patients had neurological abnormalities and/or severe mental retardation. The patients constitute a heterogeneous group of encephalopathies. They may have a genetic predisposition for absence epilepsy, causing it to appear during the course of a more severe, encephalopathy related, type of epilepsy.
Olsson
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Department of Paediatrics II, Gothenburg University, Sweden.
Hedström
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D000293:Adolescent; D000328:Adult; D001927:Brain Diseases / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004832:Epilepsy, Absence / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000150:complications; D008297:Male; D013548:Sweden / Q000453:epidemiology