Long-term prognosis of Lennox-Gastaut syndrome.

We investigated the long-term prognosis of Lennox-Gastaut syndrome (LGS) in 72 patients followed up for > 10 years. Long-term seizure and intellectual outcomes were poor, as previously reported. The diagnosis of LGS was first made in the age range from 2 to 15 years with peak occurrence at 5 years. Progressive IQ score deterioration with age was apparent. At the last examination, 33% of patients with cryptogenic and 55% with symptomatic LGS had lost the characteristics of LGS, and their seizure disorders were classifiable as symptomatic generalized epilepsies, severe epilepsy with multiple independent spike foci, or localization-related epilepsies. Disabling drop attacks appeared in 46% of patients and tended to occur at older than 10 years. Gait deterioration was recognized in 12 patients and seemed to be due largely to progression of the epileptic encephalopathy. The gait disturbances, as well as increased frequency of violent drop attacks, were disabling in daily life and resulted in some patients being wheelchair bound.