Developmental Surveillance Best for Early Autism Detection

Pam Harrison

May 19, 2015

SALT LAKE CITY — Developmental surveillance using the Social Attention and Communication Study–Revised (SACS-R) checklist, not autism-specific screening tools targeting high-risk individuals, is the most useful way of identifying infants and toddlers with autism spectrum disorder (ASD), new research shows.

"We know that early intervention can greatly increase positive outcomes for children with ASD, so we want to develop tools that can be used in the general community," Josephine Barbaro, PhD, Olga Tennison Autism Research Centre, La Trobe University, Bundoora, Australia, told Medscape Medical News.

"SACS is a developmental surveillance program where children's development is monitored via professional observations at each routine consultation rather than screening a 'high-risk' child, which is a once-off screen at a particular point in time," she said.

"And we strongly believe that the SACS methodology should be used in place of screening tools, as it is far more accurate and sensitive than any screening tool developed to date."

The study was presented at the International Meeting for Autism Research (IMFAR) 2015.

No False Positives

In the initial SACS study, investigators trained maternal and child health (MCH) nurses to monitor children for ASD at routine 12-, 18-, and 24-month health checkups.

On the basis of this initial study, investigators found that SACS had an 81% positive predictive value (PPV), an estimated sensitivity of 83.8%, and an estimated specificity of 99.8% for the early identification of ASD.

In the current study, investigators used SACS-R. SACS-R contains brief checklists of key social-communication markers of ASD at age 12, 18, and 24 months.

MCH nurses used SACS-R to assess children's social and communication skills during routine health consultations at each of these time points.

"All children identified 'at risk' for ASD on the SACS-R were referred for developmental assessments every 6 months until 2 years of age and were followed-up at 3.5 years to confirm diagnoses," the investigators note.

Children were assessed with the ADOS-Toddler and Mullen Scales of Early Learning at each assessment as well, and the ADI-R was administered at 24 months.

All children who were monitored between 12 and 24 months were also followed with an SACS-preschool checklist at their 3.5-year MCH consultations, and "at risk" children were again referred for assessment.

To date, 13,779 children have been monitored; of those, 232 have been identified as being at risk for ASD (approximately 1.7% of the overall sample).

Another 169 children have been further assessed; 138 children in this group have met the criteria for ASD (PPV, 81.7%).

As Dr Barbaro emphasized, no true false positive results have been identified to date, inasmuch as no child identified as being at risk on the SACS-R assessment was a typically developing child.

These findings, though preliminary, suggest that current prevalence rates of ASD in this large-community SACS sample is 1 in 73.

This is very close to the 1 in 68 prevalence rate for ASD reported by the US Centers for Disease Control and Prevention.

"We wanted to test SACS-R in a low-risk sample, namely, a community-based sample, because we wanted to see if we can monitor children at routine health checkups, regardless if there are any concerns about their development already," said Dr Barbaro.

"And we are arguing that the way in which we monitor children for ASD should change, that is, surveillance across time using professional observations rather than screening at one time point using parental questionnaires."

Investigators are now in the process of developing a mobile app, called ASDetect, in partnership with on the basis of their SACS model. The app will be available later in the year.

Positive Approach

Commenting on the study for Medscape Medical News, Catherine Lord, PhD, director, Center for Autism and the Developing Brain, White Plains, New York, said that the real question is whether there is a way to have a sequence of events so that broader problems, such as communication delay or general development delay, are detected early and then to follow those children who have autism to make sure that they are not lost.

"There are other surveillance instruments, and while the one they used in Australia did very well, there are others we use here that are also very broad," she said.

"So I think this screening approach is certainly very positive, but it's a very different healthcare system in Australia compared to the US, where everything is done much more in private practice," Dr Lord said.

The implication is that differences in two healthcare systems may make it more difficult to test children in the United States as systematically as they were tested in Australia.

Neither Dr Barbaro nor Dr Lord have reported any relevant financial relatinships.

International Meeting for Autism Research (IMFAR) Annual Meeting 2015. Abstract 18974. Presented May 15, 2015.


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