Autistic Children See Movement TWICE as Quickly
By RACHEL REILLY
Children with autism see simple movement twice as quickly as other children their age, according to a new study.
Scientists think this this hypersensitivity to motion may provide clues to what causes the disorder.
The findings may explain why some people suffering with autism are sensitive to bright lights and loud noises.
‘We think of autism as a social disorder because children with this condition often struggle with social interactions, but what we sometimes neglect is that almost everything we know about the world comes from our senses.
‘Abnormalities in how a person sees or hears can have a profound effect on social communication,’ says Duje Tadin, one of the lead authors on the study and an assistant professor of brain and cognitive sciences at the University of Rochester.
Although previous studies have found that people with autism possess enhanced visual abilities with still images, this is the first research to discover a heightened awareness of motion. The findings were reported in the Journal of Neuroscience by Tadin, co-lead author Jennifer Foss-Feig, a postdoctoral fellow at the Child Study Center at Yale University, and colleagues at Vanderbilt University.
In the study, 20 children with autism and 26 typically-developing children, all aged 8 to 17, viewed brief video clips of moving black and white bars.
They were asked to indicate which direction the bars were heading, right or left. Each time a participant chose the correct direction, the next video clip became slightly shorter and so a little more difficult.
When a child made a mistake, the next video became a bit longer and thus easier to see. In this way, the researchers were able to measure how quickly children with autism can perceive motion. The researchers found that when the bars in the image were just barely visible, both groups of children performed identically. When the contrast or darkness of the bars was increased all participants in the study got better at perceiving the direction of movement.
‘But kids with autism, got much, much better—performing twice as well as their peers,’ says Foss-Feig.
In fact, the worst performing participant with autism was roughly equal to the average of the participants without autism.
‘This dramatically enhanced ability to [see] motion is a hint that the brains of individuals with autism keep responding more and more as intensity increases. The scientist said that while this could be seen as an advantage, in most circumstances the heightened sense could cause sensory overload.
Such hypersensitive perception is the neural signature for a brain that is unable to dampen its response to sensory information, note the authors.
This same increase in brain ‘excitability’ is also found in epilepsy, which is strongly linked to autism.
In fact, as many as one third of individuals with autism also have epilepsy. Normally, the brain puts the brakes on its responses to sound, taste, touch, and other stimuli when they become too intense.
The research builds on earlier findings that people with autism process visual stimuli differently.
For example, previous studies have shown that people with autism are better able to perceive basic patterns, are able to see simple line images more quickly, and are more focused on details than those without the condition. In contrast, in more complex tasks, like facial recognition, these enhancements become impairments.