A simple eye test that measures the response of the human retina can be used to spot disorders such as Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder (ADHD), according to scientists.
The research from Flinders University and the University of South Australia found that recordings from the retina could potentially offer biomarkers for the two conditions.
Using the ‘electroretinogram’ (ERG) – a diagnostic test that measures the electrical activity of the retina in response to light – researchers found that children with ADHD showed higher overall ERG energy, whereas children with ASD showed less ERG energy.
Dr Paul Constable, research optometrist at Flinders University, said the preliminary findings indicated promising results for improved diagnoses and treatments in the future.
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He said: "ASD and ADHD are the most common neuro-developmental disorders diagnosed in childhood. But as they often share similar traits, making diagnoses for both conditions can be lengthy and complicated.
"Our research aims to improve this. By exploring how signals in the retina react to light stimuli, we hope to develop more accurate and earlier diagnoses for different neuro-developmental conditions.
“Retinal signals have specific nerves that generate them, so if we can identify these differences and localise them to specific pathways that use different chemical signals that are also used in the brain, then we can show distinct differences for children with ADHD and ASD and potentially other neuro-developmental conditions."
According to the World Health Organization (WHO), one in 100 children has ASD, with 5 to 8% of children diagnosed with ADHD.
ADHD is a neuro-developmental condition characterised by being overly active, struggling to pay attention, and difficulty controlling impulsive behaviours.
ASD is also a neuro-developmental condition where children behave, communicate, interact, and learn in ways that are different from most other people.
Constable added: "This study delivers preliminary evidence for neurophysiological changes that not only differentiate both ADHD and ASD from typically developing children, but also evidence that they can be distinguished from each other based on ERG characteristics."
Dr Fernando Marmolejo-Ramos, co-researcher and expert in human and artificial cognition at the University of South Australia, said the research has potential to extend across other neurological conditions.
"Ultimately, we’re looking at how the eyes can help us understand the brain," he said.
"While further research is needed to establish abnormalities in retinal signals that are specific to these and other neuro-developmental disorders, what we’ve observed so far shows that we are on the precipice of something amazing.
"It is truly a case of watching this space; as it happens, the eyes could reveal all."
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