Study: Autism May Be More Common Than Thought
Researchers Suggest Many Undiagnosed Kids Have Mild Autism
School Kids With Undetected Autism
Who are these uncounted children? When they looked at kids already identified as special-needs children, Kim and colleagues found pretty much the same autism prevalence and the same levels of disability as seen in U.S. and European studies.
The surprise came from the undiagnosed children in the general school population. Some two-thirds of the kids diagnosed with autistic disorder, and 90% of those with other ASDs (such as pervasive developmental disorders) had average or superior intelligence.
"Historically, we thought children with autism were pretty disabled. But intellectual disability isn't the core feature of autism," Gary W. Goldstein, MD, president and CEO of the Kennedy Krieger Institute and professor of neurology and pediatrics at Johns Hopkins University, School of Medicine. Goldstein was not involved in the Kim study but does serve on the board of Autism Speaks.
"The children newly identified in this study are those whose impairment is pretty much limited to the core features of autism: aberrant socialization, lack of communicating with other people in an accepted way, and restricted or repetitive behaviors," Goldstein says.
This suggests that autism and Asperger's syndrome may not be separate disorders, Leventhal says.
"This suggests there is a continuum running from children who are quite impaired to those with relatively mild cognitive and language problems to those who have no cognitive or language problems," he said. "The common variable happens to be difficulties with social process and social function. So drawing a line between Asperger's and ASD might not be as easy as it seemed with earlier criteria."
Regardless of how intelligent they are, how could children with ASD go undetected?
In South Korea, the typical school day lasts 12 hours, five to six days per week. It is a highly structured environment with an emphasis on academics rather than on socialization. The core features of ASD may more easily go unrecognized in such an environment.
U.S. schools are not organized this way. So how could a kid with ASD remain undiagnosed?
"It may be a lack of professionals in a community, or some families not seeking help due to cost, or it may be that some of these kids with ASD function quite well in the classroom setting," Dawson says. "But the same child at noon hour with peers may be socially isolated and awkward in relationships with peers. Having good social skills is absolutely essential for being successful in the real world."
The Kim study appears in the advance online issue of the American Journal of Psychiatry.