What are they like?

Here's a typical story: "It's hard to tell when Kathy's having one of her "staring spells". During the spells she doesn't respond as quickly as at other times. But even when she's not having a seizure she often just stares and responds slowly."

How long do they last?

Usually 5 to 30 seconds (commonly more than 10), with a gradual beginning and ending.

Tell me more

Atypical (a-TIP-i-kul) means unusual or not typical. The person will stare (as they would in any absence seizure) but often is somewhat responsive. Eye blinking or slight jerking movements of the lips may occur. This behavior can be hard to distinguish from the person's usual behavior, especially in those with cognitive impairment. Unlike other absence seizures, these seizures usually cannot be produced by rapid breathing.

Who gets them?

They generally begin before age 6. Most of the children affected have below-average intelligence and other types of seizures that are difficult to control. Many have Lennox-Gastaut syndrome.

What's the outlook?

Atypical absence seizures usually continue into adulthood.

What else could it be?

Sometimes ordinary behavior for these children will look like an atypical absence seizure. Daydreaming and inattentiveness can mimic these seizures.

How is the diagnosis made?

The diagnosis can be difficult if the behavior during seizures is similar to the child's usual behavior. The EEG (electroencephalogram), which records brain waves, will be used, but most children with these seizures have patterns on their EEG when they're not having a seizure that are similar to the seizure pattern.

Topic Editor: Steven C. Schachter, M.D.
Last Reviewed:12/15/06