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Electrical status epilepticus during slow-wave sleep (ESESS)


What is a syndrome?

A syndrome is a group of signs and symptoms that, added together, suggest a particular medical condition. In epilepsy, examples of these signs and symptoms would be things like the age at which seizures begin, the type of seizures, whether the child is male or female and whether they have physical or learning disabilities, or both. The results of an electroencephalogram (EEG) are also used to help identify epilepsy syndromes.

Epilepsy Action has more information about seizure types, learning disabilities, and the EEG.

If you would like to know more about an epilepsy syndrome, please speak to your doctor. If you would like to know more about epilepsy in general, please contact Epilepsy Action.

Electrical status epilepticus during slow-wave sleep (ESESS)

This is a rare epilepsy syndrome. The most common age for it to develop is in mid-childhood. It is also called ‘continuous spike-wave of slow sleep’. The cause of this syndrome is not known. It usually happens in children who already have epilepsy.


The first sign of any problem is usually that the rate of a child’s learning appears to slow significantly. Many of the children begin to have problems with either the understanding of speech and language (this is called receptive dysphasia) or expressing their own thoughts (expressive dysphasia) in the form of spoken language.

Epilepsy develops and different kinds of seizures can happen either during the day or during sleep. Many children will have absence (blank) seizures, some myoclonic (jerk) seizures and others will have focal (partial) motor seizures (seizures involving jerks of one side of the body only) particularly during the night. Some children will not have any seizures during the night.

However, despite the fact that sleep patterns are often severely disturbed due to the seizures, children with ESESS usually wake the next morning feeling quite refreshed.


The EEG shows continuous spike and wave epileptic activity during sleep, especially during part of sleep called ‘slow wave’ sleep. The EEG is often abnormal when the child is awake but in some cases, it may be normal. It is the EEG finding that gives the syndrome its name.

Metabolic (blood) tests, which look at the way the body works, and brain scans usually give normal results.


If seizures are a problem to the child, then epilepsy medicines may be suggested to control the seizures. These include sodium valproate (Epilim), ethosuximide (Zarontin) and clobazam (Frisium).

Sometimes prednisolone (a steroid medicine) may be effective in treating ESESS but this medicine needs careful monitoring. There is another medicine called sulthiame (Ospolot) which may also be helpful. Only a specialist in paediatric epilepsy can prescribe these medicines.

For some children their ESESS does not respond to any medicines.

If your child has this syndrome they may have prolonged or repeated seizures. Your child’s doctor will discuss a ‘rescue’ or emergency care plan with you to treat any prolonged or repeated seizures.

There may be research studies open that are relevant to this epilepsy syndrome. Your child’s doctor will be able to discuss this with you.

Information about treatments for children can be found on the Medicines for Children website.


For most young people an improvement is seen in the condition in the early teenage years. The EEG may return to normal and seizures become less frequent or stop altogether. At about this time an improvement in speech and language skills and learning is also seen. For some children, their ESESS may persist throughout childhood and into adult life.


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Epilepsy Action would like to thank Drs Richard Appleton and Rachel Kneen (at Alder Hey Children’s Hospital, Liverpool) and Stewart Macleod (at Yorkhill Children’s Hospital, Glasgow), consultants who specialise in children’s epilepsy, who have updated this fact sheet.


This information is exempt under the terms of The Information Standard.

  • Updated June 2016
    To be reviewed June 2019

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