Developmental pediatrician James Coplan, M.D., reports on a study of 91 children he saw between 1997 and 2002 at the Regional Autism Center of The Children's Hospital of Philadelphia. Most patients were pre-schoolers or of elementary school age, and predominantly boys. The study appears in the July 2005 issue of Pediatrics.
The children in the study had autistic spectrum disorders (ASD), a group of neurodevelopmental disorders of impaired social communication. Those disorders include classic autism, pervasive developmental disorder and Asperger's syndrome. Dr. Coplan studied the relationship among three variables: the severity of the disorder (called atypicality), general intelligence (measured as IQ or developmental quotient) and time.
"These disorders are dynamic and change over time," says Dr. Coplan. "Although they are traditionally classified into mutually exclusive diagnostic boxes, they tend to blend into each other, and this model provides a way to look continuously at ASD, as the symptoms occur and develop along the autistic spectrum, and as the symptoms change over time."
Some children have severe autistic symptoms but high intelligence; others have mild symptoms and mental retardation, or combinations in between, he added. In explaining the model to parents, he sometimes draws an analogy to weight and height. Just as each individual can have a different combination of weight and stature, someone can have an individual combination of intelligence and degree of autism.