April Flowers for redOrbit.com – Your Universe Online
A wide range of complex neurodevelopment disorders make up the autism spectrum disorder. In the US, the rate of children being born with some version of autism is on the rise. The Centers for Disease Control and Prevention (CDC) reports that in 2000, the rate of autism was an estimated 1 child in every 150. In 2010, that rate had increased to 1 child in every 68. Autism occurs in all racial, ethnic and socioeconomic groups, and is five times more common among males than females. Despite the rising prevalence, researchers still do not know exactly what causes autism.
People who suffer from autism have a variety of symptoms, including difficulty interacting with others, repetitive behaviors, and hypersensitivity to stimuli like sound and touch. A new study from MIT describes a hypothesis that could account for the wide variety of behavioral symptoms. It may also provide a neurological foundation for many of the disparate features of autism spectrum disorder. The results of their study have been published in Proceedings of the National Academy of Sciences.
According to the study, autism might be rooted in an impaired ability to predict events and other people’s actions. The world is a “magical” place to the autistic child, rather than an orderly one, because of seemingly random and unpredictable events. If this is true, then repetitive behaviors and an insistence on a highly structured environment become coping strategies rather than symptoms. If validated, the MIT team’s unifying theory could offer new strategies for the treatment of autism.
“At the moment, the treatments that have been developed are driven by the end symptoms. We’re suggesting that the deeper problem is a predictive impairment problem, so we should directly address that ability,” MIT professor of brain and cognitive sciences Pawan Sinha explained in a recent statement.
“I don’t know what techniques would be most effective for improving predictive skills, but it would at least argue for the target of a therapy being predictive skills rather than other manifestations of autism,” he added.
Parental reports of autistic children insisting on very controlled, predictable environments lead the team to consider the idea of prediction skills as a possible underlying cause for autism.
“The need for sameness is one of the most uniform characteristics of autism,” Sinha says. “It’s a short step away from that description to think that the need for sameness is another way of saying that the child with autism needs a very predictable setting.”
Most of us routinely use prediction skills to manage daily activities and events. For example, we predict other people’s behaviors, or the likely trajectory of a ball in flight, to know how to behave in that situation. The MIT team believes that autistic children may not have the same computational abilities for prediction.
Such a deficit could produce many of the most common autism symptoms such as repetitive behaviors and insistence on rigid structure — which have been shown to soothe anxiety. This is true even for people without autism.
“These may be proactive attempts on the part of the person to try to impose some structure on an environment that otherwise seems chaotic,” Sinha says.
Prediction, and the lack thereof, also plays a role in sensory stimuli. People with prediction skills are able to handle background noises because they can predict that the noise will continue and therefore block it out. This is true with other stimuli as well. A lack of prediction skills would explain why such sensory stimuli overwhelm autistic children.
Another symptom of autism is an inability to understand another person’s thoughts, feelings or emotions – called the “theory of mind.” The researchers suggest that this stems from an inability to predict behaviors based on past interactions.
The study indicates that the timing of the predictive impairment may play a major role in the different symptoms of autism displayed by different children.
“In the millisecond range, you would expect to have more of an impairment in language,” Sinha says. “In the tens of milliseconds range, it might be more of a motor impairment, and in the range of seconds, you would expect to see more of a social and planning impairment.”
The theory also suggests that some cognitive skills which are based more on rules than prediction would be unharmed, or even enhanced, by the lack of prediction skills in autistic individuals. These skills would include things such as math, drawing and music — traditionally noted as strengths for autistic children.
The researchers have already started testing elements of the prediction deficit hypothesis. “The hypothesis is guiding us toward very concrete studies,” Sinha says. “We hope to enlist the participation of families and children touched by autism to help put the theory through its paces.”
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May we suggest – Autism Spectrum Disorder (revised): The Complete Guide to Understanding Autism
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