Detecting autism in toddlers under two

In a boost for early detection programs, a US study shows autism can be diagnosed with a high level of accuracy in toddlers as young as 14 months

A US study showing that autism can be diagnosed with a high level of accuracy in toddlers as young as 14 months lends even more credibility to Australia’s early detection programs.   

Californian researchers found that a diagnosis of autism made at 14 months of age was sustained at three years of age in 79% of cases, climbing to an 83% accuracy rate in toddlers diagnosed at 16 months.

Currently, Australian GPs are advised to watch for “red flags” for autism in toddlers using questionnaires, such as the Modified Checklist for Autism in Toddlers-Revised (M-CHAT).

But there has been some hesitancy around using these diagnostic assessments before children reach the age of two, Andrew Whitehouse, a professor of autism at the Telethon Kids Institute, said.

“This study certainly could change practice,” he said. “We have just been thinking that two years of age is the youngest that we can go.”

The most exciting aspect of the study was that it employed existing diagnostic tools that were used in clinics “every day, all day, all over Australia”, Professor Whitehouse said.

These included the ADOS-2, the Mullen Scales of Early Learning and Vineland Adaptive Behavior Scales.

“There’s no doubt that we can diagnose young children with autism with a high degree of certainty,”  Emeritus Professor Bruce Tonge, a child psychiatrist affiliated with Monash University in Melbourne, said. “But we still have to be careful, because 83% is not every child.”

Toddler’s brains developed extraordinarily rapidly, so every month that passed without intervention for autism was a missed opportunity to radically transform the trajectory of that child’s life, Professor Tonge added.

“We have increasing evidence that early intervention can make a difference,” he said. “It doesn’t cure autism, but it makes the impact of the symptoms of autism less problematic.

“For example, if you can teach a young child with autism who can’t talk to use visual ways of communicating, that will avoid the necessity of the child having to have a meltdown or a tantrum because they can’t get their message through.”

The US study of around 1,200 toddlers found that autism couldn’t be reliably detected before a child’s first birthday.

That made sense because it was very difficult to measure autism-related behaviour in infants, Professor Whitehouse said. “There’s not a lot for us to observe,” he said.

What should raise those red flags for autism were notable absences of social behaviours at six, 12 and 18 months – “no signs of play, no reciprocal gestures like beginning to wave or point socially, or a lack the early development of language or verbal communication, such as babbling” – Professor Tonge said.

JAMA Pediatrics, online 29 April