Developmental and Epileptic Encephalopathies

What is developmental and epileptic encephalopathy (DEE)?

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 the DEEs, there are two factors that contribute to the developmental delay.

  • Developmental encephalopathy implies that developmental delays are the direct result of the underlying cause of their epilepsy.
  • In addition, some children with DEEs also have an epileptic encephalopathy due to very frequent seizures and markedly abnormal EEGs, which may substantially worsen developmental problems.

Importantly, if seizure control can be improved, the Epileptic Encephalopathy component of the delay should improve, however the Developmental Encephalopathy component will not change.

Most DEEs begin early in life, often starting in infancy. Children often have very frequent and severe seizures which can be of multiple types. Often epileptic spasms, tonic or atonic seizures and myoclonic seizures can be seen. In most cases, seizures are life long, although less commonly can abate with time with certain syndromes or specific causes.

The electroencephalographs (EEGs) in children with DEEs are typically very abnormal, showing diffuse slowing of the background, and frequent seizure discharges. However, in some cases, the EEGs done early on (before or very shortly after the seizure onset) may not show abnormalities.