LONGITUDINAL EEG AND CLINICAL STUDY OF CHILDREN WITH FEBRILE CONVULSIONS

1. 1. Two hundred unselected consecutive children with their first convulsion with fever of extracerebral origin were hospitalized for clinical and EEG study and were followed at 3 months, 6 months, 1 year and at yearly intervals thereafter; nineteen children from the poorly represented age groups less than 1 and more than 2 years old were studied and followed in the same way. Only one child was dropped from the study because she was found to have a brain abscess. 2. 2. EEG slowing in the 6 days after the febrile convulsion was found after about a third of the episodes. It was found after about half the episodes when the convulsion was long (> 30 min) or focal; when the temperature was high (> 39°C rectal) and when the preceding illness was long (> 36 h) or associated with vomiting or diarrhoea. 3. 3. EEG slowing acutely was most marked in the occipital leads, was often asymmetrical, and about doubled the chances that a child < 2.5 years old would later develop a spike focus. A spike focus developed in nineteen children, on the average 1.5 years after the febrile convulsion. 4. 4. Forty-two children later developed spike and wave abnormalities. When the age at the time of the febrile convulsion was < 2.5 years, the family incidence of convulsions was twice as high as in children of the same age who never developed paroxysmal abnormalities. Children > 2.5 years old at the time of their first febrile convulsion were quite apt to develop spike and wave discharges, but neither the family history nor later recurrences or epilepsy distinguished them from children of the same age who did not develop paroxysmal abnormalities. 5. 5. In this group of children the only prognostic feature was the age at the time of the first convulsion (Fig. 6). Chances were 2 to 1 that a child would develop recurrences if the age at onset was 13 months or less; 1 to 2 if the age at onset was 14-32 months; 1 to 5 if the child was more than 32 months old at the time of the first convulsion. A third of all recurrences had taken place within 6 months of the first episode; half within 13 months; and nearly all (88%) within 30 months. © 1968.