It usually develops between one and eight years of age and is characterised by several seizure types and developmental delay.
Seizures are generally difficult to control due to their resistance anti-epileptic drugs.
In many instances, LGS is a sequel to infantile spasms which are sudden spasms or bending of the body, either at the trunk or neck. These usually commence at between three and eight months and may develop into the mixed seizure pattern, which characterises LGS, at two to three years. It is estimated that LGS occurs in between three to 11 per cent of childhood epilepsies with slightly more males than females affected. The average age of onset is three years. Seizures Seizures are always of several types and a child may experience some or all of these types.