- Autism is a neurodevelopmental disorder characterized by impaired social interaction and verbal communication.
- Studying the brains of infants who have older autistic siblings, using Magnetic resonance imaging (MRI) can help to diagnose autism early.
- The brain biomarker in infancy can help to identify autism in high-risk infants.
By studying the brains of infants who have an older autistic sibling, it is easy to identify the babies who will be diagnosed with autism during two years of age.
A research team from the University of Washington, a part of North American effort from the University of North Carolina used MRI to study the brains of low-risk infants and who had no family history of autism, and "high-risk" infants who had atleast one older sibling with autism.
The research study was published in the journal Nature.
The research study is the first one to possibly use the biomarker which can help identify infants in the high-risk pool. This study identifies that older sibling with autism will be diagnosed with autism spectrum disorder (ASD) at 24 months of age.
Annette Estes, director of the UW Autism Center and a research affiliate at UW Center on Human Development and Disability, or CHDD, said, "Typically, the earliest we can reliably diagnose autism in a child is age 2, when there are consistent behavioral symptoms, and due to health access disparities the average age of diagnosis in the U.S. is actually age 4."
"But in our study, brain imaging biomarkers at 6 and 12 months were able to identify babies who would be later diagnosed with ASD."
The research findings were capable of identifying a developmental tool for diagnosing autism biomarker in infancy, especially before behavioral symptoms can emerge.
Estes, said, "We don't have such a tool yet, But if we did, parents of high-risk infants wouldn't need to wait for a diagnosis of ASD at 2, 3 or even 4 years and researchers could start developing interventions to prevent these children from falling behind in social and communication skills."
Autism Spectrum Disorders
Around 3 million people in the United States have autism spectrum disorders. These people have social communication problems, and demonstrate a number of ritualistic, repetitive and stereotyped individuals.
One out of 68 babies in the United States were found to develop autism. And the risk for infants with an autistic older sibling may be high as one out of five births.
The research study included hundreds of children across the country and was led by four clinical sites in the United States, University of North Carolina-Chapel Hill, Washington, University in St.Louis and The Children's Hospital of Philadelphia. The Montreal Neurological Institute, the University of Alberta and New York University were also other key collaborators who were involved in the research study.
Stephen Dager, a UW professor of radiology and associate director of the CHDD, said, "We have wonderful, dedicated families involved in this study."
"They have been willing to travel long distances to our research site and then stay up until late at night so we can collect brain imaging data on their sleeping children. The families also return for follow-up visits so we can measure how their child's brain grows over time. We could not have made these discoveries without their wholehearted participation."
The research team obtained MRI scans of children while sleeping at 6, 12 and 24 months of age. The research study also assessed behavior and ability at the visit using criteria which are developed by Estes and her team.
They also found that babies who experienced autism had a hyper-expansion of the brain surface area between 6 to 12 months when compared to infants who had an older autistic sibling, and did not show any evidence of autism at 24 months of age.
There was an increased surface area growth rate in the first year of life which was further associated with an increased growth rate of brain volume in the second year of life.
The obtained data were designed to a computer program which consists of MRI calculations of brain volume, surface area and cortical thickness at 6 and 12 months of age, as well as the sex of the infants. This was capable of classifying the babies who are most likely to meet ASD criteria at 24 months of age.
The algorithm that was developed was used for a separate set of study participants.
Findings of the Study
The research team found that among 80% of infants who had an older autistic sibling, with brain differences at 6 and 12 months were clinically diagnosed with autism at 2 years of life.
This finding would help healthcare professionals to have an early intervention of autism.
Estes, said, "By the time ASD is diagnosed at 2 to 4 years, often children have already fallen behind their peers in terms of social skills, communication and language."
"Once you've missed those developmental milestones, catching up is a struggle for many and nearly impossible for some."
This research could actually examine interventions on children for a period before the syndrome can be present and may have a greater chance of improving outcomes after diagnosis.
Dager, said, "Our hope is that early intervention -- before age 2 -- can change the clinical course of those children whose brain development has gone awry and help them acquire skills that they would otherwise struggle to achieve."
Additional behavioral and brain imaging data on infants and children can help to understand the brain connectivity and neural activity between high-risk children who do and don't develop autism.
The research team also identified specific brain regions which are essential for acquiring early social behavior called joint attention. This was published as a separate study in the journal Cerebral Cortex.
Dager, said, "These longitudinal imaging studies, which follow the same infants as they grow older, are really starting to hone in on critical brain developmental processes that can distinguish children who go on to develop ASD and those who do not."
"We hope these ongoing efforts will lead to additional biomarkers, which could provide the basis for early, pre-symptomatic diagnosis and also serve to guide individualized interventions to help these kids from falling behind their peers."