We still often diagnose ADHD and autism in a subjective way: with questionnaires and conversations. How nice would it be if a more objective diagnosis could take place? That may not even be that far away due to the development of a retinal scan.

Certain retinal biomarkers are unique to autism and ADHD. Australian researchers from Flinders University and the University of South Australia have found a way to detect and scan these biomarkers in children’s eyes.

The scans are performed using a so-called electroretinogram (ERG). This is a diagnostic test that measures the amount of electrical activity of the retina after exposure to a light stimulus.

Difficult diagnosis
Children with ADHD produced a greater than average amount of ERG energy, while children with autism showed a lower than average dose of ERG energy. Research optometrist Dr Paul Constable is excited about the results and sees opportunities for better diagnosis and treatment in the future. Autism and ADHD are the most common neurodevelopmental disorders in children. But some characteristics are the same, making the diagnosis a long and complicated process.”

The new research aims to improve this. “We want to know exactly how the activity of the retina is related to the light stimuli. In this way, we hope to be able to provide a more accurate and earlier diagnosis for various neurodevelopmental disorders,” said Constable.

“Retinal signals are delivered by specific nerves. Our goal is to identify these differences and pinpoint the precise nerve pathways and chemical processes that are also used in the brain. If we can do that, we can map the differences between children with ADHD, autism and any other neurological disorders,” explains Constable.

Mirrors of the soul
Fellow researcher Fernando Marmolejo-Ramos says the study certainly has the potential to detect other neurological disorders as well. “Ultimately, we’re looking at how the eyes can help us understand the brain,” says Marmolejo-Ramos. “More research is needed to understand the abnormalities of retinal signals specific to ADHD, autism and other neurodevelopmental disorders. But what we have discovered so far is extraordinary,” he enthuses. “Every day we get a glimpse of the future of science. And at the end of the ride, the eyes really seem to betray everything.”

What exactly is ADHD?

ADHD is a neurodevelopmental disorder. Children with attention deficit hyperactivity disorder (ADHD) are easily distracted and have difficulty concentrating. They are very busy (hyperactive) and often do things without thinking (impulsive). This can lead to problems within the family, at school, at work and in social interaction.

According to the World Health Organization (WHO), 5 to 8 percent of children are diagnosed with ADHD. There is no cure or cure, but there are means and therapies to treat the symptoms. The best known drug is Ritalin, with the active ingredient methylphenidate. The sleep hormone melatonin is sometimes prescribed for sleeping problems.

It is still difficult to determine whether a child has ADHD or autism. Photo: Soupstock

What exactly is an Autism Spectrum Disorder (ASD)?

Autism is a neurodevelopmental disorder in which children behave, react and communicate in a different way than usual. They also learn things in a different way than their peers.

More than 1 percent of the Dutch population has a form of autism, or Autism Spectrum Disorder (ASD). Most people with autism have normal to high intelligence. An estimated 30 percent have an intellectual disability. ADHD is relatively common in people with autism.

According to psychiatrist and autism professor Wouter Staal, autism is the ‘collective name for behavioral characteristics that indicate a vulnerability in the following areas: social interaction, communication, flexibility in thinking and acting and filtering and integrating information.’ Handbook for psychological diagnoses DSM mentions as criteria, among other things, problems with social communication and social interaction, limited and repetitive behavior patterns, interests and activities and hyper- or under-sensitivity to sensory stimuli.