Overview

Absence seizures involve brief, sudden lapses of consciousness. They're more common in children than in adults.

Someone having an absence seizure may look like he or she is staring blankly into space for a few seconds. Then, there is a quick return to a normal level of alertness. This type of seizure usually doesn't lead to physical injury.

Absence seizures usually can be controlled with anti-seizure medications. Some children who have them also develop other seizures. Many children outgrow absence seizures in their teens.

Symptoms

An indication of simple absence seizure is a vacant stare, which may be mistaken for a lapse in attention that lasts about 10 seconds, though it may last as long as 20 seconds, without any confusion, headache or drowsiness afterward. Signs and symptoms of absence seizures include:

  • Sudden stop in motion without falling
  • Lip smacking
  • Eyelid flutters
  • Chewing motions
  • Finger rubbing
  • Small movements of both hands

Afterward, there's no memory of the incident. Some people have many episodes daily, which interfere with school or daily activities.

A child may have absence seizures for some time before an adult notices the seizures, because they're so brief. A decline in a child's learning ability may be the first sign of this disorder. Teachers may comment about a child's inability to pay attention or that a child is often daydreaming.

When to see a doctor

Contact your doctor:

  • The first time you notice a seizure
  • If this is a new type of seizure
  • If the seizures continue to occur despite taking anti-seizure medication

Contact 911 or emergency services in your area:

  • If you observe prolonged automatic behaviors lasting minutes to hours — activities such as eating or moving without awareness — or prolonged confusion, possible symptoms of a condition called absence status epilepticus
  • After any seizure lasting more than five minutes

Causes

Many children appear to have a genetic predisposition to absence seizures.

In general, seizures are caused by abnormal electrical impulses from nerve cells (neurons) in the brain. The brain's nerve cells normally send electrical and chemical signals across the synapses that connect them.

In people who have seizures, the brain's usual electrical activity is altered. During an absence seizure, these electrical signals repeat themselves over and over in a three-second pattern.

People who have seizures may also have altered levels of the chemical messengers that help the nerve cells communicate with one another (neurotransmitters).

Risk factors

Certain factors are common to children who have absence seizures, including:

  • Age. Absence seizures are more common in children between the ages of 4 and 14.
  • Sex. Absence seizures are more common in girls.
  • Family members who have seizures. Nearly half of children with absence seizures have a close relative who has seizures.

Complications

While most children outgrow absence seizures, some:

  • Must take anti-seizure medications throughout life to prevent seizures
  • Eventually have full convulsions, such as generalized tonic-clonic seizures

Other complications can include:

  • Learning difficulties
  • Behavior problems
  • Social isolation