Review article
Deciphering the concepts behind “Epileptic encephalopathy” and “Developmental and epileptic encephalopathy”

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Abstract

The recent introduction of the term ‘developmental and epileptic encephalopathy’ by the International League Against Epilepsy has added another conceptual layer to understanding the most severe group of epilepsies. An epileptic encephalopathy is defined by the presence of frequent epileptiform activity that impacts adversely on development, typically causing slowing or regression of developmental skills, and usually associated with frequent seizures. Many of the epileptic encephalopathies are now known to have an identifiable molecular genetic basis. The term ‘developmental’ was introduced as there are multiple facets leading to developmental impairment in affected individuals. The underlying genetic cause often results in developmental delay in its own right, with the epileptic encephalopathy further adversely affecting development. Treatment of the epileptic encephalopathy may improve developmental progress, so early recognition and active management are essential to improve developmental outcomes. Equally, understanding that the genetic aetiology independently leads to developmental impairment means that precision therapies need to be holistic in addressing the devastating consequences of this group of diseases.

Section snippets

Why does the concept of epileptic encephalopathy matter?

Recognition of an epileptic encephalopathy is critical as it suggests that there may be a remediable component with the potential to lead to reversal of developmental slowing, allowing the patient to make developmental gains and show improvement in cognition. The aim of treatment of an epileptic encephalopathy is too suppress epileptiform activity, in order to allow developmental progress. By optimising management for a specific epileptic encephalopathy, the clinician may be able to ameliorate

What are the developmental and epileptic encephalopathies?

The term ‘epileptic encephalopathy’ in the 2010 ILAE classification proposal [1] was modified to ‘developmental and epileptic encephalopathy’ (DEE) in the formal 2017 revision of the classification [13]. This change was made as many of the genes causing epileptic encephalopathies are recognised to independently adversely impact development. This is well illustrated by SCN2A which encodes the alpha 2 subunit of the sodium channel. SCN2A is a well established cause of autism spectrum disorder due

Differentiating a developmental encephalopathy from a developmental and epileptic encephalopathy

A developmental encephalopathy is not the same as a DEE or an epileptic encephalopathy. A developmental encephalopathy refers to developmental delay or intellectual disability, representing a static disability although the degree of disability may become more evident with age. Patients with a developmental encephalopathy have a higher risk of epilepsy than the general population but this does not mean that they have an epileptic encephalopathy. In this population, genetic causes are also

Acknowledgements

This work was supported by Australian National Health and Medical Research Council Program Grant 1091593 and Practitioner Fellowship 1104831.

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