Researchers at Dartmouth College have identified a non-verbal, neural marker of autism that could potentially be used to diagnose the condition in the future. The marker shows that individuals with autism are slower to dampen neural activity in response to visual signals in the brain. This finding is independent of intelligence and could offer an objective way to screen for autism. The study, published in Current Biology, aims to develop neural markers that can work with non-verbal individuals and improve the early diagnosis of autism.
Autism is currently difficult to screen for in children, with the average diagnosis occurring around four years old. The researchers found that individuals with autism have differences in inhibiting neural signals, which affects sensory processing and visual information. The human brain experiences rocking back and forth when presented with two different images simultaneously, toggling between the left and right eye. The autistic brain, however, shows slower switching between images, known as slower binocular rivalry, due to inhibitory neural transmission differences.
This slower switching is a result of difficulty in filtering and regulating sensory signals, specifically in suppressing one image due to GABA neurotransmitter issues. The study used brain imaging to measure the slow rate of binocular rivalry in individuals with autism. The research team accurately determined the presence and severity of autism using brain imaging along with traditional clinical assessments. Neural data from an EEG electrode on the visual region of the brain predicted autism presence with 87% accuracy.
The study found that higher levels of autism were associated with a slower rate of binocular rivalry, indicating slower switching between images. This visual test has the potential to be a non-verbal marker of autism in adults and could aid in diagnosis. The researchers are now investigating whether the test can also detect autism in pre-verbal children and non-verbal adults. If successful, this test could potentially be developed into a screening tool for autism.
This research provides new insights into the condition, as differences in visual processing may help understand the autism spectrum. However, it is important to note that while this non-verbal marker shows promise, it may not detect autism in all individuals. The Dartmouth Autism Research Initiative, led by Caroline E. Robertson, aims to further understand sensory perception in autism. The team works with individuals diagnosed with autism, PDD-NOS, and Asperger’s Syndrome. The study involved researchers from Johns Hopkins University, Dartmouth, and the Massachusetts Institute of Technology.
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