Lennox-Gastaut syndrome is the most distressing of childhood epilepsies. The children suffer frequent fits of many different types, and experience gradual mental deterioration. Infantile spasms often evolve into Lennox-Gastaut syndrome, and the age of onset is from 1 to 8 years, peaking at 3 to 5 years. The prognosis for children with Lennox-Gastaut syndrome is bleak.