Popular screen may mistake intellectual disability for autism
A common autism screening tool misses more than 70 percent of autistic toddlers but flags more than 80 percent of non-autistic toddlers who have intellectual disability, a new study of children in Norway reports1.
The study adds to a mounting body of evidence that the tool, the Modified Checklist for Autism in Toddlers (M-CHAT), is not sufficient on its own to identify signs of autism.
Along with previous research in Norway, the results also help clarify which children the M-CHAT flags and which ones it misses, says lead author Roald Øien, professor of special education at UiT – the Arctic University of Norway in Tromsø.
“Basically, we find that screening at 18 months identifies kids with pretty severe delays,” he says, such as a low intelligence quotient (IQ), poor communication skills and prominent autism traits. Conversely, autistic children who fall closer to the typical range of abilities are significantly less likely to be identified by the M-CHAT at 18 months of age.