Children with autism spectrum disorder can be reliably diagnosed as young as 14 months, according to a US study. If results are confirmed by independent research, this would be the earliest age this has proven feasible.
Earlier detection means earlier treatment, which should improve outcomes, said University of California, San Diego Autism Centre for Excellence co-director Karen Pierce.
Autism screening should be first done at 18 months, according to the American Academy of Pediatrics. However, according to the Centres for Disease Control and Prevention, the average age of diagnosis in the US is four years.
That gap represents a missed opportunity to guide these very young children into normal social development, Pierce said.
"The brain is very plastic. It's developing at a really super-fast pace from birth to age 3," she said. "There's a lot of connections that are formed between brain cells. So hopefully we can shape those connections."
The study was published Monday in JAMA Pediatrics.
Results are based on development of 1,269 toddlers in San Diego County, selected from a universal screening program to detect possible autism. Children suspected of having ASD via screening were referred for an in depth developmental evaluation by a licensed clinician to determine whether they actually had autism or some other disorder.
The toddlers were originally assessed between 12 and 36 months, and had at least one follow-up evaluation.
For those originally diagnosed at 14 months, 79 percent were again found to be on the spectrum at follow-up. By 16 months, the diagnosis was 83 percent reliable. However, for those diagnosed at 12 to 13 months, the rate was just 50 percent.
Of the total number of toddlers assessed, seven originally placed on the spectrum went on to normal development, the study found. Contrarily, 105 toddlers originally diagnosed as not having autism were identified as being on the spectrum at a later visit.
"From a policy perspective, that tells parents and pediatricians to repeat screening," Pierce said.
The study is "well done and an important first step" to identifying autism as early as possible, said associate director of the Center for Autism Research at Children's Hospital of Philadelphia David Mandell.
Mandell said he and other autism experts have advocated earlier screening than what has been recommended by the US Preventive Services Task Force. The task force expressed concern that false diagnoses can cause harm by needlessly stressing patients.
On its website, the task force says "the current evidence is insufficient to assess the balance of benefits and harms of screening for autism spectrum disorder (ASD) in young children for whom no concerns of ASD have been raised by their parents or a clinician."
"It really flies in the face of the recommendations of the American Academy of Pediatrics, and other physician groups," Mandell said. "And so different research groups have been scrambling to try and put together pieces of the evidence."
Mandell said diagnoses of autism are known to be more stable than diagnoses of other developmental delays, for which the task force does recommend early screening.
A more skeptical view came from Mayada Elsabbagh, co-director of Transforming Autism Care Consortium, and a research scientist at Montreal Children's Hospital.
Elsabbagh said the social and communications skills measured for autism diagnosis aren't fully developed until toddlerhood. So a specific diagnosis in infancy isn't feasible.
However, she said it is possible to detect more general signs of developmental delay in infants.
"Therefore, while we can't tell if the condition we are dealing with is autism or another form of developmental delay or problem, it's critical that these kids and their families receive support and help during this uncertain period," Elsabbagh said.
Pierce said the study needs to be duplicated in toddlers living elsewhere than San Diego. This is now being performed in Phoenix. The evaluation criteria she developed are being used by other researchers.
Moreover, the San Diego research continues. The study enrolled 2,241 children. The 1,269 children in this study are those who have been in the program long enough to get a second evaluation, Pierce said. The others will be included once they have been re-evaluated.
In the longer run, the study will look for signs that intervention is effective in guiding children on the spectrum to normal development.
"We got all the kids in our study into early treatment and our next frontier is to check on them when they're at school age, to see how they're all doing," Pierce said. "Did all this early identification and getting into treatment and diagnosis pay off? Was that helpful to them in the long run?"
The research was funded in part, by the National Institute of Mental Health, part of the National Institutes of Health.
The San Diego Union-Tribune