CSWS EEG pattern

The EEG in children with this epilepsy syndrome is not normal, especially as they enter sleep. Almost continuous slow-spike-wave is seen during the slow sleep cycle. The EEG changes go away during the REM sleep cycle.

What is Epileptic Encephalopathy with Continuous Spike and Wave During Sleep?

The syndrome of Epileptic Encephalopathy with Continuous Spike and Wave During Sleep (CSWS) is a very rare form of epilepsy.

  • CSWS may start in children between 2 and 12 years of age, most often between 4 and 5 years of age.
  • Boys seem to be affected more often than girls.
  • The cause of CSWS is often found to be brain malformations (when an area of brain forms differently at birth), genetic, or metabolic conditions.
  • Multiple seizures types and changes in cognitive function are usually seen in children.

What do seizures in this syndrome look like?

Is Epileptic Encephalopathy with Continuous Spike and Wave During Sleep inherited?

  • The cause of CSWS is unknown. New (de novo) genetic mutations (changes in how genes work) have been found in some children. A gene called GRIN2A is known to be involved.
  • A family history of seizures or epilepsy is usually not seen.

How is this syndrome diagnosed?

  • A complete history and examination of a child with suspected CSWS is the first step.
  • An EEG (electroencephalogram) tests and possibly a prolonged EEG or video EEG is required to diagnose this syndrome. The EEG in children with this epilepsy syndrome is not normal, especially as they enter sleep.
  • Almost continuous slow-spike-wave is seen during the slow sleep cycle. These EEG changes may happen in more than 85% of the child’s sleep time. The EEG changes go away during the REM sleep cycle.
  • Genetic and metabolic tests may be ordered.
  • MRI (magnetic resonance imaging) scans can be normal, but they are needed to see if a structural problem in the brain is present.

How is Epileptic Encephalopathy with Continuous Spike and Wave During Sleep treated?

Seizures in children with CSWS are treated with anti-seizure medications. In rare instances, surgery may be recommended.

  • Medications often used are steroids, valproic acid (Depakote/Depakene), or high dose diazepam. Other medications that have been used to treat this epilepsy syndrome include clobazam (Onfi), ethosuximide (Zarontin), topiramate (Topamax), and levetiracetam (Keppra). Medications can be used together or by themselves, depending on what works for each child.
  • If seizures persist despite medication, a surgery called multiple subpial transections may be done. This type of surgery makes multiple small cuts in the brain cortex where the seizures begin.
  • Resective brain surgery is not usually an option, unless there is a brain malformation as the cause of the seizures.
  • Children with CSWS may have cluster seizures. These may respond to a rescue therapy that can be given at home, such as diazepam rectal gel (Diastat) or another form of benzodiazepine given into the nose (intranasally) or under the tongue. Sometimes children with clusters or long seizures need emergency medical treatment in a hospital.
    • Parents of children with CSWS should talk to the treating neurologist or health care provider to learn about seizure emergencies.
    • Talk to the health care team about what kind of rescue therapy could be used and when to use it.
    • When seizures last longer than usual or if a generalized seizure lasts too long (generally considered 5 minutes or longer), a child may need emergency medical care.​

What is the outlook for persons with this syndrome?

  • Children may be developing normally when the seizures first start. Yet usually 1 to 2 years later, a progressive decline in cognitive functioning happens.
  • Children with CSWS may improve during the teenage years. Seizures may improve or stop and speech may get better.
  • For some children, the abnormalities on EEG may continue into the adult years.
Authored By: 
Angel W. Hernandez MD | Pediatrics Editor
Authored Date: 
Monday, July 3, 2017