Researchers may have found an effective way to screen very preterm infants—who have been shown to have a high risk for autism spectrum disorder (ASD)—to identify those who may be more vulnerable to ASD. By measuring and mapping early mental performance and classifying infants according to three trajectories (low declining, high declining, and high stable), they were better able to identify those who were most susceptible to a diagnosis of ASD at age 5 years. Their results are published in Pediatrics.
“The evolution of mental ability is better defined by longitudinal assessments than a cross-sectional evaluation. In our study, we classified the mental performance trajectory of children born preterm from age 6 to 24 months using GBTM and then associated the trajectory pattern to the ASD odds at 5 years of age. Because the heterogeneity of mental development existed in both the children with ASD and the children without ASD, our results provided a different perspective on ASD susceptibility based on the dynamic patterns of neurodevelopment in preterm infants,” wrote researchers led by Li-Wen Chen, MD, MSc, of the National Cheng Kung University, Tainan, Taiwan.
To determine whether early mental performance trajectory relates to ASD outcomes in children born extremely prematurely, Chen and colleagues conducted a population-based study. They included 319 very preterm infants in whom they assessed group-based trajectories of mental performance with the Bayley Scales of Infant Development at 6, 12, and 24 months. When the children were 5 years old, a diagnosis of ASD was establishing using the Autism Diagnostic Observation Schedule and the Autism Diagnostic Interview-Revised.
In all, 29 children were diagnosed with ASD, and Chen and fellow researchers found that mental performance between ages 6 months to 24 months fell into three trajectory patterns: low declining, high declining, and high stable. Correspondence of these trajectories to the prevalence of ASD at age 5 was highest (35%) in those with a low declining path, followed by the high declining (9%), and the high stable trajectories (3%).
In children with low-declining trajectories of mental performance, the odds of ASD was 15 times greater compared with the high-stable group (OR: 15; 95% CI: 3.8-59; P ˂ 0.001).
Upon multivariate regression modeling, researchers observed the greatest risk of falling into the low-declining trajectory in male infants who had longer exposures to oxygen therapy and whose mothers had a lower education level. Strong associations between inferior mental performance and lower gestational age, smaller birth weight, and small for gestational age were also seen.
In the 70 children with mental scores of less than 85 at 6 months, 18 showed improved mental scores by 24 months and 52 did not. In those with improved scores, none developed ASD at 5 years of age, compared with 23% of those with no improvement who developed ASD.
“The evolution of mental ability is better defined by longitudinal assessments than a cross-sectional evaluation. In our study, we classified the mental performance trajectory of children born preterm from age 6 to 24 months using [group-based trajectory modeling] GBTM and then associated the trajectory pattern to the ASD odds at 5 years of age. Because the heterogeneity of mental development existed in both the children with ASD and the children without ASD, our results provided a different perspective on ASD susceptibility based on the dynamic patterns of neurodevelopment in preterm infants,” concluded Chen and fellow researchers.
Study limitations include missing data, and a lack of detailed family histories, parent-child interaction patterns, and neuroimaging data.
In an accompanying editorial, Janet S. Soul, MDCM, and Sarah J. Spence, MD, PhD, both of Harvard University and Boston Children’s Hospital, Boston, MA, highlighted the increased risk of autism in preterm infants.
“Children born preterm are known to be at higher risk for developing ASD compared with their term-born counterparts, with an estimated 7% prevalence of ASD based on a recent large prospective study and a meta-analysis. This high prevalence is in contrast to the currently estimated prevalence of ASD in the United States of 1.8% in the general population,” they wrote.
In light of the increased risk for and prevalence of autism in these children, the results from Chen and colleagues are particularly important.
“The article by Chen et al in this issue of Pediatrics provides the first prospectively obtained data regarding whether there is an early developmental trajectory of prematurely born children that predicts who will develop ASD,” noted Soul and Spence.
“Perhaps most importantly, these findings provide an opportunity for initiating interventions in early life to mitigate ASD before the diagnosis of ASD can be definitively established. Identification of a constellation of prenatal and neonatal risk factors could help clinicians target infants at highest risk, while providing reassurance to parents whose infants are at low risk. Identification of high-risk infants with low cognitive scores at 6 months of age or those with declining scores over time could provide another opportunity to intensify early intervention services,” they concluded.
- In very preterm infants, classification according to early neurodevelopmental trajectories may help identify those at higher risk for developing autism spectrum disorders by the age of 5 years.
- Clinicians can use these early mental trajectory patterns for earlier diagnosis and targeted intervention in at-risk infants.
E.C. Meszaros, Contributing Writer, BreakingMED™
This study was supported by grants from the Taiwan Ministry of Science and Technology, the National Cheng Kung University, E-Da Hospital, and the National Cheng Kung University Hospital.
Chen, Soul, and Spence reported no conflicts of interest.
Cat ID: 135
Topic ID: 85,135,730,128,41,135,192,925