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Searching for the Onset of Autism


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Diffusion Tensor Image of Brain at Risk for Autism

Diffusion tensor image shows white matter pathways in infant at risk for autism. Warmer colors represent higher fractional anisotropy, a measure of white-matter organization. (Credit: Image created by Jason Wolff, University of North Carolina.)

Early behavioral intervention has shown some promise as a way to help children with autism. But it’s difficult to see the hallmarks of autism before two years of age with today’s diagnostic criteria. Could we find other methods?

Seeking to answer that question is Jed Elison at the California Institute of Technology, who is working with Ralph Adolphs at Caltech and Joe Piven at the University of North Carolina among other colleagues around the U.S. and Canada. Elison provided some preliminary findings at the Neuromagic 2012 conference held from May 7 to 10, 2012 on San Simón, the Island of Thought, near Vigo, Spain.

Today’s criteria, from the psychiatric bible called the DSM-IV, include attributes of social impairments, communication deficits, and repetitive patterns of behavior and restricted interests (either in intensity or content). “There’s a biological reality,” said Elison, “that you can’t capture perfectly with a classification system like this.” Nevertheless, there’s “no question that the classification system serves a very important role in identifying kids who require specialized clinical services” Recognizing the condition early can help. “There’s some evidence that early intervention alleviates” some of the behavioral challenges for these children, he added.

Elison and collaborative partners of the Infant Brain Imaging Study Network are recruiting families who have a child with autism and an infant sibling under six months of age. Because autism has a genetic component, they employ what they call the “high-risk-sibling” strategy to prospectively characterize the earliest markers of autism. They conduct longitudinal studies with the younger siblings—making an assessment of these infants at six months, 12 months and 24 months. Ideally, they will define the onset of symptoms and its developmental course.

In addition to assessing behavior, the researchers are also examining brain development, specifically the development of white matter microstructure, using diffusion tensor imaging. White matter includes part of the neuron called the axon that is responsible for transmitting electrical signals throughout the brain. “Cognitive and social-cognitive development requires efficient information processing, which consequently requires efficient signal transmission” said Elison. White matter is not developing the same in infants who go on develop autism, and a recent study suggests that these differences may appear as early as six months.

What about behavioral differences? The researchers are also very interested in subtle attentional and visual-orienting patterns that may be different very early in life. These behaviors are very important for subsequent social-cognitive development and might be amenable to targeted intervention.

Elison highlighted that many of the scientific themes relevant to magic or sleights of hand, including attentional orienting and joint attention, making eye contact, perceiving biological motion, and theory of mind (that is, making inferences about the mental or emotional state of another individual) are especially important themes for autism researchers. “Deficits in any of these areas could make individuals with autism less susceptible to magic,” said Elison.

Drawing a connection to the theme of the conference in his conclusion, Elison questioned whether susceptibility to magic or sleights of hand might also vary with development. Several of the attending magicians pointed out that performers must tailor their approach for different audiences and that very young children present unique challenges, because they may still engage in “magical thinking”—believing in unseen causes—and because their cultural knowledge and social-cognitive skills aren’t yet fully formed.

Mariette DiChristina About the Author: Editor in Chief, Mariette DiChristina, oversees Scientific American, ScientificAmerican.com, Scientific American MIND and all newsstand special editions. Follow on Twitter @mdichristina.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. eurotimbr 4:59 pm 05/16/2012

    What is diffusion tensor imaging? Don’t think I’ve seen that one before.

    Link to this

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