What Is Lennox-Gastaut Syndrome?

Lennox-Gastaut syndrome (LGS) is a seizure disorder. Children with LGS will have:

  1. several different kinds of seizures
  2. some degree of intellectual disability
  3. abnormal findings on an EEG (a test to see brain waves/electrical activity)

LGS begins in children when they're 3 to 5 years old. It's a lifelong condition that requires a high level of care.

What Kinds of Seizures Happen in Lennox-Gastaut Syndrome?

The different seizure types in LGS can cause a variety of symptoms.

Seizure Types

Tonic seizures:

  • muscles suddenly become stiff
  • last about 20 seconds
  • usually involve both sides of the body
  • often happen during sleep

Atonic seizures:

  • muscles briefly and unexpectedly go weak or limp (called "drop attacks")
  • last less than 20 seconds
  • can involve the whole body or just certain parts
  • after the seizure, the child recovers quickly

Other types:

  • Atypical absence seizures: staring spells with blinking, smacking or chewing, rubbing hands together (called automatisms)
  • Myoclonic seizures: brief muscle twitches or jerks in the neck, shoulders, upper arms, and face
  • Tonic-clonic seizures: convulsions with rhythmic jerks, rigid muscles, loss of consciousness, and eyes rolling back

What Causes Lennox-Gastaut Syndrome?

Lennox-Gastaut syndrome can be caused by multiple conditions. For example, early brain injury from infection or trauma, genetic causes, or brain malformations can all lead to LGS.

Sometimes, LGS has no clear cause.

How Is Lennox-Gastaut Syndrome Diagnosed?

LGS is diagnosed by a pediatric neurologist (a doctor who specializes in brain, spine, and nervous system problems). Testing includes:

  • EEG. Children with LGS will have a pattern showing "generalized slow spike and wave."
  • VEEG, or video electroencephalography (EEG with video recording)
  • CAT scan and MRI to look inside the brain

How Is Lennox-Gastaut Syndrome Treated?

Seizures in LGS don't usually respond well to medicines. Other treatments include:

  • neurostimulation (a device that stimulates nerves to stop seizures)
  • the ketogenic diet (a strict high-fat, low-carbohydrate diet)
  • surgery, such as corpus callosotomy where the "bridge" that connects the two brain hemispheres is cut. This works best for tonic and atonic seizures, and might not help the other types of seizures.

How Can I Help My Child?

Caring for a child with LGS can be challenging. Work with your child's care team to set up needed appointments and therapies.

Make sure that you and other adults and caregivers (family members, babysitters, teachers, coaches, etc.) know what to do during a seizure. Your child may need to wear a helmet to prevent head injury during seizures.

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Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2020 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.

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