Objectives: To identify children with afebrile seizures in a national cohort, classify the seizures, and document progress in the first 10 years of life.
Design: Population based birth cohort study.
Setting: The child health and education study, which includes 16,004 neonatal survivors (98.5% of infants born in the United Kingdom during one week of April 1970).
Subjects: 14,676 children for whom relevant information was available.
Main outcome measures: Responses to parental and general practitioner questionnaires and hospital records at 5 and 10 years after birth.
Results: 84 children (42 boys, 42 girls) had had one or more afebrile seizure (incidence 5.7/1000). 63 children (31 boys, 32 girls) had epilepsy (incidence 4.3/1000). 49 of 55 children had a second seizure within a year of the first. The commonest seizure types were tonic-clonic (42) and complex partial (25). A greater proportion of children with complex partial seizures had recurrences. Children who had infantile spasms or a mixed seizure disorder had a poor outcome. All six children who died had symptomatic seizures in the first year, but seizures were not the direct cause of death.
Conclusions: The results of this study are probably representative of seizure patterns in the general population. Outcome after seizures is determined more by the underlying disease than by the seizures themselves.