Differences in sensory brainwaves of autistic teenagers could assist in earlier diagnosis and support

19 November 2019

Variances have been found in the brainwaves responsible for visual perception between autistic teenagers and those teens not on the autism spectrum. Researchers believe this could assist in earlier diagnosis and help inform how support is given to young people with autism.

Cognitive neuroscience post-doctoral researcher at Macquarie University, Dr Robert Seymour, worked alongside researchers at the Aston Neuroscience Institute (ANI), located at Aston University in Birmingham, United Kingdom.

The researchers focused on sensory areas of the brain because a substantial number of people with autism report issues with processing incoming sensory information, often suffering from hypersensitivity, meaning that bright lights, loud sounds or crowded situations can be overwhelming.

The findings, which have been published in the journal BRAIN, found that different patterns of brain-wave activity were triggered in teenagers diagnosed with Autism Spectrum Disorder (ASD) compared to neuro-typical teenagers, when performing the same simple visual task.

“The results suggest that even during very basic sensory processing, there are differences in the pattern of brain waves between autistic individuals and their peers who do not have ASD. This is important, given that sensory symptoms were recently added to the condition’s diagnostic criteria,” says Dr Seymour.

“Our results might also explain why over 90 per cent of autistic individuals report atypical sensory responses to visual stimuli,” he says. “These experiences are often described in terms of hyper-sensitivities, with more pronounced responses to certain stimuli which result in overwhelming and unpleasant sensations.”

At the Aston Brain Centre, the research team used Magnetoencephalography (MEG), an imaging technique that measures the small magnetic fields produced by neuronal activity in the brain, to look at brain activity within the visual system of 18 teenagers with a diagnosis of ASD and 18 teenagers without the diagnosis (aged between 14-20 years). They specifically measured brainwave activity in the visual cortex.

It was found that so-called ‘alpha’ brain waves were less connected from higher level to lower level brain regions in the autistic visual system. In addition, brainwaves across a broader range of frequencies (gamma range) were ‘dysregulated’ in the autistic group, meaning they were not organised as efficiently over time and in synchrony with alpha waves.

In Australia, the latest government figures suggest at least 164,000 people have autism, representing about 1 in 150 Australians. Of those who were estimated to have autism in 2015, 143,900 were identified as also having a disability (physical or intellectual), i.e. 88 per cent. In the UK, there are around 700,000 autistic people – that’s more than 1 in 100 people – with approximately 33 per cent estimated to have a learning disability, as well as there being three-million carers and families (National Autistic Society).

The findings of this study, titled Dysregulated Oscillatory Connectivity in the Visual System in Autism Spectrum Disorder, could in future allow for an alternative approach to early diagnosis of autism, offering a new perspective on the current understanding of how circuitry in the brain of an individual with ASD functions.

The project’s lead, Professor Klaus Kessler, Professor of Cognitive Neuroscience, at the ANI says the research is just the beginning.

“We found an interesting link between brain connectivity and autistic symptoms, as measured via a questionnaire. This finding suggests that in the future, MEG brain scanning could potentially aid clinicians as a tool for earlier ASD diagnosis. Our research could also lead to interventions aimed at managing sensory issues in ASD. These might include brain stimulation techniques; and neuro-feedback training.”

The next stage of the research will be to broaden out the MEG scan tests to younger children under the age of 12 years old.

“This is the first step in a long process of understanding autism, improving diagnosis and implementing interventions,” says Dr Seymour. “In future we might be able to look at using a combination of MEG scanning and formal clinical assessments.”

Brain-waves were localised to the occipital lobe of the brain, where visual information is processed

Brain-waves were localised to the occipital lobe of the brain, where visual information is processed

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Preparations being made for a Magnetoencephalography (MEG) scan, conducted at the Aston Neuroscience Institute

Preparations being made for a Magnetoencephalography (MEG) scan, conducted at the Aston Neuroscience Institute

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