In autism screening, the watchword is caution

One-year-olds who, while distracted by a toy, do not respond to their own name the first or second time it is called may have a developmental abnormality such as autism spectrum disorder. This failure to respond could be one of the earliest indications of the condition, according to a study published in the April Archives of Pediatrics and Adolescent Medicine.

This finding is one of a handful published in this journal's special autism theme issue suggesting markers that could lower the average age of diagnosis of the disorder. Most children are now diagnosed at 3 or 4 years old, and earlier diagnosis may translate to earlier interventions.

"If we can pick these abnormalities up at 12 to 18 months, we think we can intervene even earlier when the brain is very plastic, and we might have a bigger impact," said Sally Ozonoff, PhD, senior author on the paper and professor of psychiatry at the M.I.N.D. Institute at the University of California, Davis. "We might be able to prevent these problems from ever occurring, but we have to detect them first."

Other papers found that older parents were at increased risk of having an autistic child, and younger siblings of those with autism may lag in the development of various problem-solving, language and relationship skills.

Lowering the age of diagnosis is viewed as crucial to improving the functionality of children with developmental disorders. The American Academy of Pediatrics issued the first guidelines on this issue in May 2001. A revision was published in July 2006 calling for the incorporation of developmental surveillance into every well-child visit and formal screening at 9, 18 and 30 months of age. The American Medical Association also supports educating and enabling physicians to identify children with developmental delay, autism and other developmental disabilities.

"We're talking about something that affects one in 166 kids. It's very, very prevalent," said Joseph F. Hagan, MD, co-editor of AAP's book, Bright Futures: Guidelines for Health Supervision of Infants, Children, and Adolescents.

Fears about false-positives, negatives

But while interest in autism screening is growing and investigators are looking at numerous possibilities to improve them, including biomarkers, the wider use of such tools is eliciting concerns about false-positives that could frighten parents and stigmatize the child.

"It's exciting that there's so much research going in this area, but I'm concerned about the stress that it might give the families. False-positives are really scary," said Lynne Smith, MD, associate professor of pediatrics at Harbor-UCLA Medical Center. "We can screen right now for a breast cancer gene in newborns, but what are you going to do with it?"

And authors and other experts expressed the need for caution before incorporating these studies into any screening algorithm. Notably, the infants in the name-calling study already had a higher chance of developing these disorders, and it's unknown how sensitive and specific this test would be in those who are of average risk. The increased risk conferred by being born of older parents was statistically significant but not great. Also unclear is what in these children's genetics or environment creates this phenomenon.

"It's significant but, by and large, most children of older parents are going to be just fine. We're talking about a modestly elevated risk," said Lisa Croen, PhD, lead author on that paper and an epidemiologist in the Kaiser Permanente Northern California's division of research.

In addition, siblings of autistic children were not performing as well, but most were not doing badly enough to be diagnosed with a specific developmental delay. It's not yet clear what, if anything, these differences mean.

"It could be a developmental blip that they grow out of and catch up by themselves. It could be with a little intervention they catch up. We just don't know," said Wendy L. Stone, PhD, lead author on the sibling study and professor of pediatrics at Vanderbilt Kennedy Center for Research on Human Development in Nashville, Tenn. "We really need to follow these children and understand the extent to which these differences do matter."

Significant concerns about false-negatives also are on the radar. For example, Dr. Smith's daughter, who has autism and was the focus of an accompanying commentary she wrote in the same Archives, would have passed the name-calling test at 1 year but would have failed it later. "She absolutely responded to her name. It could give parents a false sense of security."

Many experts are also worried about financing the services that will be needed by the growing number of children who will be identified with this disorder. Resources are limited for the children who already have been diagnosed.

"We are facing an access to treatment crisis. Getting children into appropriate services is a nightmare," said Patricia Manning-Courtney, MD, guest co-editor of the issue and director of the Kelly O'Leary Center for Pervasive Developmental Disorders at Cincinnati Children's Hospital Medical Center. "It's never been easy, but now it's even harder."

According to a pair of studies, also in this issue of the journal, average health care expenditures for an individual patient with an autism spectrum disorder, after adjusting for inflation, increased by 20.4% from 2000 to 2004. The lifetime social cost per patient, including expenses related to care and lost productivity, was estimated to be $3.2 million.