Sign Up for a Free Account
  • Updated 04.03.2024
  • Released 10.18.1993
  • Expires For CME 04.03.2027

Epileptic encephalopathy with spike-wave activation during sleep



This article emphasizes the clinical and EEG features of epileptic encephalopathy with continuous spike-and-wave during sleep and the occurrence of secondary bilateral synchronies as a mechanism for the generalization of previously focal epileptic discharges. In addition, the article points out that this syndrome may appear in children, starting first with idiopathic focal epilepsies, and also in children with prenatal cerebral lesions. This article discusses language development and impairment in children and adolescents with the disorder.

Historical note and terminology

Electrical status epilepticus during sleep in children was first reported in 1971 by Patry, Lyagoubi, and Tassinari (100). They described six patients with a peculiar EEG pattern characterized by apparently subclinical spike-and-waves occurring almost continuously during NREM sleep with dramatic improvement during awaking and REM sleep. Five of them had epileptic seizures and were intellectually impaired. An interesting feature was that one child never had seizures and had normal motor development but no acquisition of speech. A few years later, in 1977, Tassinari and colleagues introduced the terms “encephalopathy related to electrical status epilepticus during sleep” and “electrical status epilepticus during slow sleep” for this syndrome (130; 124).

Questions regarding the term of status without detectable simultaneous clinical signs as well as the finding of electrical status epilepticus during slow sleep in nonepileptic children prompted the use of the term “epilepsy with continuous spike and waves during slow sleep,” which was adopted by the Commission on Classification and Terminology of the International League Against Epilepsy in 1989 (86; 121; 20).

In 2001, the International League Against Epilepsy (ILAE) Task Force on Classification proposed a group of syndromes named epileptic encephalopathies, which included epilepsy with continuous spike-wave during slow sleep and Landau-Kleffner syndrome, among others (30). Many common features and possible similar physiopathological mechanisms of production between these two syndromes have been proposed, leading to questions of whether they are two distinct entities or subclasses of a single syndrome (28; 54; 23; 116; 107; 34; 127; 128; 117).

Interestingly, a group of patients with particular evolutive features was recognized: children with benign childhood epilepsy with centrotemporal spikes, now termed “self-limited epilepsy with centrotemporal spikes” (SeLECTS) (119), with initially typical clinical and EEG features who follow an atypical course or later on develop a Landau-Kleffner syndrome electrical status epilepticus during slow sleep (02; 35; 34). Of note, the new terminology, which replaces “benign childhood epilepsy with centrotemporal spikes” with the term “self-limited epilepsy with centrotemporal spikes,” was proposed to remove the term “benign” from the syndrome, as these patients may present with comorbidities, including attention-deficit/hyperactivity disorder or cognitive deficits related to language and executive function (119), further highlighting the clinical spectrum associated with epileptic encephalopathy with continuous spike-and-wave in sleep.

In 2022, the ILAE proposed new terminology to describe this syndrome. The newest classification describes developmental or epileptic encephalopathy (DEE) and epileptic encephalopathy (EE) with spike-and-wave activation in sleep (SWAS) as a spectrum of conditions that are characterized by combinations of cognitive, language, behavioral, and motor regression associated with marked spike-and-wave activation in sleep. This syndrome is intended to replace syndromes previously named “epileptic encephalopathy with continuous spike-and-wave in sleep” and “atypical benign partial epilepsy” (pseudo-Lennox syndrome). The term “Landau–Kleffner syndrome” is defined as a subtype of EE-SWAS in which there is a specific regression primarily affecting language with an acquired auditory agnosia (119).

This is an article preview.
Start a Free Account
to access the full version.

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Questions or Comment?

MedLink®, LLC

3525 Del Mar Heights Rd, Ste 304
San Diego, CA 92130-2122

Toll Free (U.S. + Canada): 800-452-2400

US Number: +1-619-640-4660



ISSN: 2831-9125