Numerous and varied paroxysmal spells in neonates and infants may be nonepileptic in nature. The knowledge of typical epileptic and nonepileptic events in neonates and infants will aid the clinician in the correct diagnosis. The most important tool in determining epileptic from nonepileptic events is a careful clinical history. However, if the history does not disclose the diagnosis, a videotape of the event or a concomitant video-EEG recording may be helpful (28-30).
Neonatal and infant electroencephalograms can be difficult to interpret. The EEG matures from the neonate to adolescence, with the most dramatic temporal changes occurring during the newborn period. EEG patterns that are normal for one age group may be abnormal for infants just a few weeks older. In addition, "epileptiform discharges" (spikes, sharp waves) may be a normal brainwave pattern at certain ages. For example, multifocal sharp transients are a normal brainwave pattern for premature infants, initially appearing at 29 weeks gestation, and may persist up to 40 weeks gestation, particularly in quiet sleep. However, multifocal sharp transients that are repetitive, persistently unilateral, polyphasic, occur in the term newborn during the awake state, or occur after 40 weeks gestation are considered abnormal discharges (Figure 6.2). Frontal sharp transients first appear at 35 weeks gestation and persist up to 46 weeks gestation in quiet sleep. Frontal sharp transients are usually surface negative, less than 200 msec, and have voltages between 50 and 150 v. Frontal sharp transients that are repetitive, unilateral, or occur after 46 weeks gestation are abnormal. In addition, abnormal epileptiform activity in the neonate is less an
indication of specific susceptibility to seizures ("epilep-togenicity") than a measure of the underlying encephalopathy. In general, one should be conservative in using interictal spikes or sharp waves to diagnose neonatal seizures (31).
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