Electrical status epilepticus during slow-wave sleep (ESESS)

Epilepsy Action is indebted to Dr Richard Appleton, a Consultant Paediatric Neurologist who specialises in children’s epilepsy, and to Dr Rachel Kneen, Consultant Paediatric Neurologist and Dr Stewart Macleod, Specialist Registrar in paediatric neurology, at Alder Hey at Alder Hey Children’s Hospital, Liverpool, who have kindly prepared the information on this page.

This is a rare epilepsy syndrome. When it does happen, it usually appears 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.

Symptoms

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 partial motor seizure (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.

Diagnosis

The electroencephalogram (EEG), which measures the electrical activity going on inside the brain, shows continuous spike and wave epileptic activity during sleep – and especially during part of the sleep called ‘slow wave’ sleep. The EEG is often abnormal when the child is awake but may also 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.

Treatment

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

Sometimes a medication called prednisolone (a very mild steroid) may be effective in treating ESESS. There is another drug called sulthiame (Ospolot) which may also be helpful. A specialist in paediatric epilepsy can only prescribe this medication.

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

Prognosis

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.

Support organisation

Contact a Family, 209-211 City Road, London, EC1V 1JN, telephone 0808 808 3555, www.cafamily.org.uk