Introduction: The epilepsies of childhood are much more variable in expression and outcome than those of adults: the clinical and EEG features of epilepsy can change considerably with age.
Development: The neonatal epileptic encephalopathy, West and Lennox syndromes are present at different age, and each one shows a stereotyped association of seizures and EEG findings that are essentially pathognomonic for each syndrome. It is possible that these syndromes represent successive stages in maturation of an epileptic process, although there are differences between the disorders that may not be explained by the concept of age-dependent encephalopathy. Clinically it is very important to differentiate signs, symptoms and EEG findings in the West syndrome from the Lennox syndrome transition.
Conclusion: The study of the age-dependent epileptic encephalopathies will contribute to the understanding of the pathophysiology of epilepsy.