Autism May Be Detected Early through a Visual Test

autismAccording to a recent study, a signal of autism in young children can be detected through a simple visual test. This breakthrough provides parents with earlier opportunities for their children to benefit from the treatment and therapy that could aid in their development.

Through this test, scientists from Harvard University linked a specific chemical messenger in the brain, GABA, with autistic behaviors. Those on the autism spectrum were noted to typically have low levels of GABA, a messenger that calms the brain (as it resists the chemical messengers that stimulate it). Therefore, those with low levels of this messenger tend to be hyperactive or overstimulated. This may correlate to the fact that many individuals with autism also suffer from epilepsy.

The scientists from this study focused on visual tests that revealed an imbalance in chemical messengers that can either calm or over-stimulate the brain – a way to screen young children for autism spectrum disorders (ASD). According to Dr. Caroline Robertson from Harvard, “This is the first time, in humans, that a neurotransmitter in the brain has been linked to autistic behavior – full stop”.

GABA, which is an inhibitory neurotransmitter, is known to soothe anxiety, induce sleep, and calm trembling. Prior to now, GABA’s role in autism has been rather abstract. To link low levels with autism disorders, Dr. Robertson and her team conducted a binocular rivalry test, which consistently produces different results for those with autism compared to individuals who are not on the spectrum.

Typically, the brain is presented with two slightly different images (one from each eye), which combine to create a singular image. However, the binocular rivalry test forces each eye to take in separate images. Dr. Robertson states, “The end result is that one image is just suppressed entirely from visual awareness for a short period. [Therefore], if I show you a picture of a horse and an apple, the horse will entirely go away and you will just see the apple.” She states that as the brain cells force the suppression of the second image, they get tired, switching to the other image. The process repeats, and the images “rock back and forth”.

Through their studies, Dr. Robertson and her team noted that the process of oscillating between images takes significantly longer in those with autism. She states, “[Those with autism] spend the same amount of time in the steady state – where they see only one image – as the average person, it just takes them longer to switch between them, and the second image is not as deeply suppressed.” The team used magnetic resonance spectroscopy to conduct the brain imaging.

Through the test, the team found that levels of GABA were far lower than anticipated for those with autism. The issue may lie in the pathway where GABA produces signaling within the brain. Dr. Robertson sums up, “It’s not that there’s no GABA…it’s that there’s some step along the pathway that’s broken.”

Written By Erica Polis

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