Page Summary

  • Lennox-Gastaut Syndrome (LGS) designates a type of epilepsy with multiple different types of seizures.
  • Intellectual development is usually, but not always, impaired.
  • In about a quarter of children, no cause can be identified. 
  • Acounts for only 2 to 5 percent of childhood epilepsies.
  • Usually LGS persists through childhood and adolescence to adult years.
  • While seizures usually don't respond to seizure medications, advances in treatment offer hope and help for people with LGS.

What is Lennox-Gastaut syndrome?

The Lennox-Gastaut syndrome (LGS) is a type of epilepsy with multiple types of seizures, particularly tonic (stiffening) and atonic (drop) seizures. Intellectual development is usually, but not always, impaired. The EEG shows characteristic patterns of background slowing and spike-wave bursts at frequencies less than 2.5 per second. There a many underlying causes of this condition, but in about a quarter of children, no cause can be identified.

Tell me more

  • Lennox-Gastaut Syndrome (LGS) accounts for only 2 to 5% of childhood epilepsies, but often need help from both pediatric and adult epilepsy specialists and other health care professionals.
  • Seizures in people with LGS tend to be hard to control and long-term treatment is usually needed. 
  • Intellectual and behavioral problems that often accompany LGS pose many challenges for individuals and families. 
  • This epilepsy syndrome usually persists through childhood and adolescence to adult years. It may look or affect people differently at various ages.  
  • In the last few years, several new treatments have emerged. While none are a cure for LGS, this is good news for a group of children that historically has had few good treatment options.

How do you treat LGS?

Treatment is difficult, because the seizures often don't respond to seizure medications or AEDs. The intellectual changes do not respond to any currently available medicine or treatment either.

  • Partial relief of seizures, and also falls and injuries from seizures, may be obtained by valproic acid, lamotrigine, topiramate, felbamate, clonazepam, rufinamide, clobazam and occasionally other medications.
  • Stimulation of the vagus nerve in the neck, with an implanted pacemaker (VNS Therapy) sometimes improves seizures in people with LGS.
  • Dietary therapies may be very helpful for some people when their diet can be monitored carefully. 
  • An operation to separate the two halves of the brain, called corpus callosum surgery, may reduce seizures and injuries, but obviously is a big undertaking.
  • LGS continues to present great challenges to children and adults with the syndrome, their families and their health care team. Much more research is needed to identify better therapies.
Authored by: James Wheless, MD | Robert Fisher, MD, PhD | Joseph Sirven, MD on 9/2013

The Epilepsy Foundation would like to thank Lundbeck for their generosity in providing an unrestricted educational grant in support of the Lennox-Gastaut Syndrome section on

Editor's note: This section was sponsored by the generosity of Lundbeck. However, in order to avoid any possible sponsorship bias, the sponsor was not known to either the author or the editor.