It’s often said that “the eyes say it all,” but regardless of their outward expression, the eyes may also be able to signal neurodevelopmental disorders such as ASD and ADHD, according to new research from Flinders University and the University of South Australia.
In the first study of its kind, researchers found that retinal recordings can identify distinct signals for attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), providing a potential biomarker for each requirement.
Using an “electroretinogram” (ERG) — a diagnostic test that measures the electrical activity of the retina in response to a light stimulus — the researchers found that children with ADHD had higher overall energy, while children with autism had lower ERG energy.
The preliminary findings point to promising results for improving diagnosis and treatment in the future, says Flinders University optometrist Dr. Paul Constable.
“ASD and ADHD are the most common neurodevelopmental disorders of childhood. But because they often share similar features, diagnosing the two conditions can be long and complex,” says Dr. Constable.
Our research aims to improve this. By exploring how retinal signals respond to light stimuli, we hope to develop more accurate and early diagnoses for different neurodevelopmental conditions.
“Retinal signals have specific nerves that generate them, so if we can identify these differences and map them into specific pathways that use different chemical signals that are also used in the brain, we can show clear differences for children with ADHD, ASD, and potentially other neurodevelopmental conditions.”
“This study provides preliminary evidence for the neurophysiological changes that not only distinguish ADHD and ASD from typically developing children, but also evidence that they can be distinguished from one another based on characteristics of the ERG.”
According to the World Health Organization, one in 100 children has an autism spectrum disorder, with 5-8% of children having ADHD.
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by hyperactivity, difficulty paying attention, and difficulty controlling impulsive behaviors. Autism spectrum disorder (ASD) is also a neurodevelopmental condition in which children behave, communicate, interact and learn differently than most other people.
Associate researcher and expert in human and artificial cognition at the University of South Australia, Dr Fernando Marmoljo Ramos, says the research has the potential to expand to other neurological conditions.
“Ultimately, we are looking at how the eyes can help us understand the brain,” says Dr. Marmolego Ramos.
“While more research is needed to identify abnormalities in retinal signaling for these and other neurodevelopmental disorders, what we have observed so far shows that we are on the cusp of something amazing.
“It is really about looking at this space; in this case, the eyes can reveal everything.”
This research was conducted in partnership with McGill University, University College London and Great Ormond Street Hospital for Children.
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