Developmental and Epileptic Encephalopathy (DEE) refers to a group of severe epilepsies that are characterized both by seizures, which are often drug-resistant, as well as encephalopathy, which is a term used to describe significant developmental delay or even loss of developmental skills. In Developmental and Epileptic Encephalopathy, cognitive functions are influenced severely by seizures and interictal epileptiform activity, also by the neurobiological process behind Epilepsy. DEEs are also related to gene variants and the onset is usually during early childhood. The effect of seizures on cognitive function is partially dependent on the period of brain maturation i...