What are they like?

Here's a typical story: Frank, a 7-year-old boy, often "blanks out" anywhere from a few seconds to 20 seconds at a time. During a seizure, Frank doesn't seem to hear his teacher call his name, he usually blinks repetitively, and his eyes may roll up a bit. During shorter seizures, he just stares. Then he continues on as if nothing happened. Some days Frank has more than 50 of these spells.

How long do they last?

Usually less than 10 seconds, but it can be as long as 20. They begin and end suddenly.

Tell me more

Absence seizures are brief episodes of staring. (Although the name looks like a regular English word, your neurologist may pronounce it ab-SAWNTZ.) Another name for them is petit mal (PET-ee mahl). During the seizure, awareness and responsiveness are impaired. People who have them usually don't realize when they've had one. There is no warning before a seizure, and the person is completely alert immediately afterward.

Simple absence seizures are just stares. Many absence seizures are considered complex absence seizures, which means that they include a change in muscle activity. The most common movements are eye blinks. Other movements include slight tasting movements of the mouth, hand movements such as rubbing the fingers together, and contraction or relaxation of the muscles. Complex absence seizures are often more than 10 seconds long.

Who gets them?

Absence seizures usually begin between ages 4 and 14. The children who get them usually have normal development and intelligence.

What's the outlook?

In nearly 70% of cases, absence seizures stop by age 18. Children who develop absence seizures before age 9 are much more likely to outgrow them than children whose absence seizures start after age 10.

Children with absence seizures do have higher rates of behavioral, educational, and social problems.

What else could it be?

Absence seizures can resemble some complex partial seizures or episodes of daydreaming:

How is the diagnosis made?

The EEG (electroencephalogram), which records brain waves, is helpful in diagnosing absence seizures. Having the child breathe very rapidly often will produce a seizure. Images of the brain such as CT and MRI scans are usually normal, so they are seldom needed if the EEG and other features are typical.

Topic Editor: Orrin Devinsky, M.D.
Last Reviewed:2/1/04