A functional classification of seizures and its distribution in a mentally retarded population

A functional classification of seizure impairment was described and its distribution examined in a population classified as mentally retarded in childhood and followed to age 22. Twenty-five percent of the sample had some history of seizures up to age 22. Seizure histories were found for 19 percent of these retarded persons in the preschool years and 13 percent in each period of early, late, and postschool years. A drop in minor seizure impairment occurred after age 5. A slightly higher frequency of seizure histories among males was found, largely due to subjects whose IQs were 50 to 59, where 44 percent of the males and 5 percent of the females had seizure histories. No significant association was found between degree of seizure impairment and severity of mental retardation.