The authors report on their experience gained through a prospective study of 144 infants who developed seizures during the first 3 weeks of life. Only full-term neonates weighing 2,500 gm or more were included. Follow-up averaged 4 years. Seven subjects were lost on follow-up, leaving a total of 137. The clinical features of the convulsive episode are described, and a classification is presented of the most common seizure types, which differ significantly from those met in older babies. Observation of these different types of neonatal seizures may assist in discovering etiological factors and in formulating a prognosis. While no etiological clues were found in one fourth of the neonates, factors of probable etiological importance were established in three-fourths. High in the list of presumptive etiology were metabolic disturbances; intracerebral birth injuries and perinatal anoxia, once considered main causes for neonatal seizures, were considerably less frequent in this series. Central nervous system infection or malformation were met with about equal incidence. The only factor in common in eight babies was a marked postmaturity, and there was a history of pre-eclamptic toxemia in five. More than one factor of potential etiological significance was present in several babies. The study showed that mortality and morbidity run high for neonates with seizure states, the outcome being poor for about half of the cases. In contrast, the other half of the convulsing babies did quite well, often with spontaneous remission and normal psychic and motor development. We found that prognosis based on abnormal (or normal) neurological signs in a convulsing neonate show poor correlation with the state of the child when reevaluated years later. Certain etiological factors, as well as certain types of seizures, seem to carry better prognostic significance.
Electroencephalographic investigation carried out along careful criteria during the newborn period has been found helpful for this series of convulsing babies. Neonates with seizures and a normal EEG had an 86% chance of normal development at age 4 years, regardless of other clinical data. In contrast, neonates with either a "flat," "periodic," or "multifocal" EEG had only a 7% chance of normal development. "Unifocal" EEG abnormalities showed more equivocal correlations. At the end of the study, about 50% of the subjects were found to be normal, while about 30% had survived with some serious neurological defect and 20% had died. There were 23 complete neuropathological examinations. The most helpful clinical and laboratory procedures for the "work-up" of a convulsing neonate are outlined, including a method for the rapid detection of metabolic disorders through diagnostic intravenous infusions.