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Spectrum: Autism Research News

New techniques promise early diagnosis for autism

by  /  17 April 2008

This article is more than five years old. Autism research — and science in general — is constantly evolving, so older articles may contain information or theories that have been reevaluated since their original publication date.

Play time: Observing how very young children play and interact with others can help diagnose them early.

By the time children reach their third birthdays, their behavior can reliably predict whether they have an autism spectrum disorder.

But newer techniques promise to diagnose autism in children who are younger than 2 years old, and perhaps before they turn 1, according to a report published in March1. Several researchers are also exploring genetic and neurobiological indicators of autism that could aid in earlier diagnosis.

Clinicians rely on three main techniques to diagnose autism in children older than 3: the Autism Diagnostic Observation Schedule (ADOS), the Autism Diagnostic Interview-Revised, and the Diagnostic and Statistical Manual of Mental Disorders (DSM).

These instruments assess how children communicate, interact socially and play. Clinicians can gauge developmental and behavioral characteristics, such as a lack of social or emotional reciprocity, delay in language development and repetitive movements, such as finger flapping. Another important component is input from parents about their children’s developmental history.

“The instruments we have are pretty reliable for diagnosing children down to about 18 months of age,” says Stephen Sheinkopf, a psychologist at the Center for Autism and Developmental Disabilities at Bradley Hospital in Rhode Island. “Our challenges are really in understanding how to best make firm diagnoses in younger children.”

Some efforts to diagnose younger children rely on written questionnaires parents fill out, such as the Checklist for Autism in Toddlers, which promises to detect signs of autism in children as young as 16 months2. Others build on existing techniques, such as a toddler-specific version of ADOS that is being developed.

These efforts look at more subtle symptoms in younger children, such as irregularities when playing with toys ― tapping a fork on a table instead of pretending to eat with it, for example ― or struggling to open a jar without looking to an adult for help3.

“There are going to be good advances in the coming years as we figure out what the right mix of symptoms are to look for in younger children,” says Sheinkopf.

For example, Sheinkopf has found that preverbal children with autism struggle with phonation, or the production of vocal sounds4.

This feature was included in previous editions of the DSM, but dropped in the latest version because it’s too subtle, says Sheinkopf. A better understanding of vocalizations could make them useful for early diagnosis, he says.

Assessing attention:

Clinicians have also become more adept at assessing joint attention ― which involves sharing the experience of observing an object or event, and is marked by eye contact and gestures.

For example, when a wind-up toy moves, a typically developing child will look back and forth between the caregiver and the toy, as if to say, “Do you see what I see? That’s neat.” When the toy stops moving, the child may point to it and make eye contact to request that the adult wind it up again, or pick it up and hand it to the adult.

In contrast, a child likely to develop autism may be unable to engage with others in this way.

Better assessing joint attention and other advances could together enable earlier diagnosis, and also help cut down on the number of false positives. With current techniques, about one in four children tagged as being likely to develop autism turns out not to have the disorder5.

There are also new techniques in development that could help diagnose younger children. Several studies have shown reduced activity in the parts of the brain that process emotions in children with autism, suggesting that brain scans could be a diagnostic tool ― although those studies are preliminary, according to Zachary Warren, clinical assistant professor of psychiatry at Vanderbilt University’s Treatment and Research Institute for Autism Spectrum Disorders.

Clinical psychologist Ami Klin and his colleagues at the Yale Child Study Center are tracking eye movements in siblings of children with autism, who are at high risk of developing the disorder.

The premise for their study is that children with autism spend more time looking at mouths than at eyes, whereas typically developing children focus on others’ eyes6. Klin says the technique could help diagnose autism within the first 4 to 6 months of life.

In the past year, there has also been tremendous progress in the genetics of autism, although it is too early to say whether the presence of any of the markers can predict autism.

One strong candidate is a duplication of the gene 15q11-q13. In at least one case in which a child had inherited the duplication from his mother, the marker proved to be predictive of autism7.

“Knowing the risk got him into intervention services earlier,” says Edwin Cook, psychiatrist at the University of Chicago Medical Center.

Still, Cook says, identifying genetic markers can only indicate increased risk. For a child old enough to be screened for symptoms, he says, “we do not have a biomarker that’s better than careful assessment.”