Eighteen new-borns were studied, four of them were pre-term with a pregnancy of 35 weeks. They had an acute neurological symptomatology and also showed a E.E.G. with flat or hypoactive aspect in the neonatal period. The evolution of these patients is analyzed clinically and electroencephalographically of flat E.E.G. and an uncertain future in those cases with hypoactive E.E.G. A review of the literature on the problem was performed in order to compare the results of other series with those obtained in the present study, attending specially etiological, clinical, electroencephalographic and evolutive aspects.