Lennox-Gastaut Syndrome was defined by Dr. Henri Gastaut in France in 1966 as a very severe form of childhood epilepsy, with certain  common features. Dr. William G. Lennox in Boston described features of the EEG in this condition. The syndrome is named after the work of these two famous neurologists. 

Characteristics of Lennox-Gastaut Syndrome:

  • Multiple seizure types, including tonic (usually a requisite), atonic or drop attacks, atypical absence, myoclonic and generalized tonic-clonic seizures starting in childhood.
  • A characteristic EEG pattern (slow spike-waves) seen between seizures.
  • Cognitive impairment or developmental delay that is frequently progressive.

Before the seizures begin, 20 to 30% of children with LGS appear to have no neurologic deficit or developmental issues. These problems almost always appear during the course of LGS.

Tell me more about intellectual disabilities and LGS

Factors known to be associated with intellectual or developmental problems include: 

  • LGS with a defined cause.
  • A prior history of infantile spasms.
  • Onset of symptoms before age 1 to 2 years.
  • High seizure frequency.

Intellectual decline is typically seen over time. By adulthood, 95% to 100% of persons show cognitive problems. Some individuals do not show obvious intellectual impairment, especially if the seizures come on later in childhood and are not too frequent or severe.

In addition to the slowing or arrest of development, some children develop changes in behavior, mood or personality. Older children or adolescents often develop irritability, aggressiveness or social isolation. It is important to be aware of these other possible symptoms in order to help the child and family properly. The EEG abnormalities associated with LGS may account for some of the changes seen over time in intellectual function and behavior.

Reviewed by: Joseph I. Sirven MD / Patricia O. Shafer RN MN on 6/2014