This report was based on 27 cases with petit mal absence, which were followed for more than three to thirteen years at the Department of Pediatrics of Keio University from January 1963to September 1973.
1, 934 electroencephalographic (EEG) records obtained from 837 children (495 boys, 342 girls), who visited our outpatient clinic at under 5 years of age because of convulsions, were analyzed in relation to age.