Prevalence and descriptive epidemiology of Lennox-Gastaut syndrome among Atlanta children

Purpose: To determine the prevalence and descriptive epidemiology of Lennox-Gastaut Syndrome (LGS) among metropolitan Atlanta children. Methods: We conducted a population-based study of LGS as part of the Metropolitan Atlanta Developmental Disabilities Study (MADDS) using a multiple-source surveillance system for epilepsy and developmental disabilities. Children were defined as having LGS if they had onset of multiple seizure types before age 11 years, with at least one seizure type resulting in falls, and an EEG demonstrating slow spike-wave complexes (<2.5 Hz). Mental retardation (MR) was not used as a diagnostic criterion. Results: The lifetime prevalence of LGS at age 10 years was 0.26/1,000. Ninety-one percent of those with LGS had MR (IQ less than or equal to 70), and 39% had a history of infantile spasms (IS). A comparison of children with LGS and those with multiple seizure types without slow spike-wave complexes demonstrated that those with LGS were more likely to have MR, history of IS, and multiple disabilities (MR, cerebral palsy, blindness, hearing impairment). Seventeen percent of all children in Atlanta with profound MR (IQ < 20) had LGS. Conclusions: LGS accounts for only 4% of all childhood epilepsy, yet is a significant contributor to childhood morbidity.