Clinico-electrical evolution in pre-hypsarrhythmic stage: towards prediction and prevention of West syndrome

We investigated serial electroencephalographic (EEG) changes before the onset of spasms in patients with West syndrome (WS) due to perinatal injury in order to determine whether one can predict WS or not. In preterm infants with periventricular leukomalacia (PVL), depression of EEG activities is commonly followed by disorganized pattern during the early neonatal period. Disorganized patterns persist until the late neonatal period, but epileptiform discharges do not appear. Epileptiform discharges usually appear during early infancy in infants who later develop WS. As the onset of WS was relatively later in preterm infants with PVL, it may be possible to select the patients at risk for secondary prevention of WS with sufficient treatment period. In term infants with hypoxic-ischemic encephalopathy, all EEGs during the neonatal period did not reveal epileptiform discharges in the majority of patients. Multifocal spikes were very likely to be observed during early infancy, but hypsarrhythmia was observed immediately after their appearance. It is not always easy to select patients for prevention of WS with sufficient treatment period.