Long-term epidural intracranial pressure (ICP) recordings were performed in 10 hydrocephalic children, not affected by cerebral tumor. The work concerns the identification of A and B Lundberg's waves during normal sleep in the ICP pattern. Plateau-waves of high amplitude and long duration were measured in one patient. A base-line pressure higher than normal was found in the other cases in which waves during sleep were seldom revealed. Five children were monitored by studying the pressure pattern after shunt surgery. The Authors discuss the implication of the rarity of plateau-waves in infancy and the cause of this phenomenon.