The age-dependent epileptic encephalopathies.

The most severe epilepsies that affect neonates, infants, and children include Ohtahara, West, and Lennox-Gastaut syndromes. These three syndromes display considerable similarities and transitional features in their clinical symptoms, seizure phenomena, and electroencephalographic abnormalities. This review examines the similarities and differences between these three syndromes and the other severe epilepsies of infancy and childhood, and discusses the hypothesis that the three disorders form a continuum of epileptic encephalopathies that have a predictable age-related evolution.