Children who test positive in an autism screening at 18 months of age — but who were also born very prematurely — may not actually have the disorder.
Instead they may do poorly on the autism test due to unrelated delays in cognition or language, new research has found.
Researchers, led by pediatrician Bonnie E. Stephens, MD, FAAP, and assistant professor of pediatrics at Brown University’s Alpert School of Medicine, hypothesized that many formerly preterm infants who screen positive for ASD at 18 months do not have ASD but are having failing scores due to a cognitive or language delay, a common occurrence in 18-month-olds who had been born very prematurely.
For the study, researchers sought to determine the rate of false-positive screens for ASD taken at 18 and 30 months of age and to determine the connection between a positive screen and cognitive and language delay.
A total of 152 babies were screened for ASD at 18 months (age corrected for prematurity), and 116 babies were screened at 30 months corrected age. Children who had been born before 28 weeks’ gestation were measured in three ways, one of which was designed specifically for use in high-risk populations, including preterm infants.
Eighteen percent screened positive for ASD at 18 months, and 10 percent screened positive at 30 months. A very small percentage — 3 percent — screened positive on all three tests at either point in time, and all of the babies who screened positive for ASD on all three screening tests at 30 months were later diagnosed with ASD.
In addition, a positive screen at 18 or 30 months was associated with cognitive and language delay.
“While these findings have important implications, further work is needed,” Dr. Stephens said. “To determine which of these infants actually have ASD, a study that includes a formal diagnostic assessment on all children with a failed screen is needed.”
Stephens and her colleagues are hoping to get funding to support a multicenter study that would include more than 500 preterm children. “This will allow us to determine the true rate of ASD in this population, the rate of false-positive screens at 18 and 30 months, the optimal time to screen, and the optimal ASD screening tool for the extremely preterm population.
Approximately one in 110 U.S. children has Autism Spectrum Disorder (ASD), a group of complex developmental brain disorders that affect behavior, social skills and communication. The American Academy of Pediatrics (AAP) recommends that pediatricians screen all children for ASD at 18-24 months of age, and those who fail the screening test should be referred for a formal assessment.
The study was presented on May 1 at the Pediatric Academic Societies (PAS) annual meeting in Denver.
Source: American Academy of Pediatrics