3 Hz generalized spike wave

Example of the 3 Hz generalized spike wave

What is it like?

Childhood absence epilepsy (CAE) is an epilepsy syndrome with absence seizures that begin in young children. Absence seizures look like staring spells during which the child is not aware or responsive. The child's eyes may roll up briefly or the eyes may blink. Some children have repetitive movements like mouth chewing. Each seizure lasts about 10 seconds and ends abruptly. The child resumes normal activity right after the seizure. They often are not even aware that a seizure happened.

  • A child may have one or many (up to 100) absence seizures a day.
  • They often happen during exercise.
  • Children usually develop normally, though children with very frequent absence seizures can have learning difficulties.
  • One out of 3 of children may also have attention, concentration, and memory problems that started before the absence seizures were diagnosed. The problems often improve after seizure medications are started.
  • The old name for an absence seizure is a petit mal seizure. CAE used to be called petit mal epilepsy.

Who gets it?

CAE accounts for 1 to 4 out of 50 (2 to 8%) of people with epilepsy. Absence seizures usually begin between the ages of 3 and 11 years, most often between 5 and 8 years of age.

The cause is usually genetic. About 1 out of 3 families of children with CAE report a family history of similar seizures. The brothers and sisters of children with CAE have about a 1 in 10 chance of developing epilepsy.

How is CAE diagnosed?

  • A good history of what has happened and any other health and learning problems is the first step in diagnosing CAE. A physical exam looks for other problems that could cause or be associated with the seizures.
  • An EEG (electroencephalogram) is done to look for possible seizure activity. Often the child will be asked to hyperventilate for 3 to 5 minutes. This very quick breathing can trigger an absence seizure in over 80% of children with CAE. The EEG shows spike and wave discharges at 3 Hz (cycles per second) that are generalized (the same on both sides of the brain).
  • Hyperventilation can be done during an office visit without an EEG to see what the event looks like.
  • CT (computed tomography) and MRI (magnetic resonance imaging) scans of the brain are normal.
  • Screening for attention problems is recommended.

How is CAE treated?

  • In a recent study, ethosuximide (Zarontin) was shown to be the first drug of choice to treat absence seizures. Valproate (Depakote) was equally as effective as ethosuximide, but ethosuximide caused fewer problems with attention than valproate.
  • Lamotrigine (Lamictal) was less effective, but certain side effects were less frequent compared to ethosuximide and valproate. The side effects generally went away quickly and did not require stopping the drug during the study.
  • If absence seizures continue despite trying one of these seizure medications, combining these medications may help.
  • Other medications have been used to treat absence seizures, like methsuximide (Celontin). Some have been used, but have not been adequately studied in well-controlled trials, like topiramate (Topamax), zonisamide (Zonegran), levetiracetam (Keppra), benzodiazepines (clobazam, stiripentol), and in a few reports amantadine (Symmetrel).
  • Some children may also benefit from the ketogenic diet if their absences are not controlled by any combination of medicines.

What's the outlook for children with CAE?

  • At least 2 out of 3 children with CAE respond to treatment and the seizures disappear by mid-adolescence.
  • Problems with attention may continue despite controlling the seizures and is an important part of this epilepsy syndrome.
  • Approximately 10-15% of children will develop other seizure types in adolescence, usually generalized tonic-clonic and/or myoclonic seizures.

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Authored By: 
Gregory L. Holmes MD
Robert S. Fisher MD, PhD
Authored Date: 
Tuesday, September 3, 2013
Reviewed By: 
Angel Hernandez, MD
Reviewed Date: 
Wednesday, August 3, 2016