Friday Science Review: April 19, 2013
April 19, 2013
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Author’s note: I will be taking over writing duties from John Holyoake for the Friday Science Review. If you wish to know more about me, you can find my short bio on our contributors page – http://crossborderbiotech.ca/about/
Anxiety disorders are becoming increasingly prevalent in our society, and are highly detrimental to an individual’s well being, both physically and mentally. Children with autism spectrum disorder (ASD) are particularly susceptible to anxiety disorders, but their deficits in communication often make it difficult for them to express feelings of anxiousness. Being unable to express these feelings may lead to an exacerbated anxiety response in children with ASD, because they are often exceedingly aware of their surroundings and may become more socially withdrawn. A study published in PLoS One led by Dr. Azadeh Kushki at the Holland Bloorview Kids Rehabilitation Centre in Toronto sought to address this problem by determining a physiological marker that signals anxiety in children with ASD, which would allow for improvement in their care.
Children with ASD and typically developing children performed an anxiety-inducing task while activity of the autonomic nervous system, the part of our nervous system that unconsciously controls visceral functions, was evaluated using three different measures. The researchers found that two of these measures, heart rate and perspiration, were elevated even at rest in children with ASD, whereas the third measure, skin temperature, was comparable at rest between children with ASD and typically developing children. However, during the anxiety-inducing task the skin temperature of children with ASD increased, whereas the skin temperature of typically developing children decreased, the normal response during stress.
The results of this study offer three important findings. First, the observation that heart rate and perspiration are elevated at rest in children with ASD supports previous reports that these children have elevated generalized anxiety. Second, the difference in changes in skin temperature between children with ASD and typically developing children observed during the stressful task offer a potential non-invasive measure of anxiety in children with ASD. Finally, the generalized difference in visceral functions observed between children with ASD and typically developing children indicates that children with ASD experience inappropriate regulation of their autonomic nervous system, specifically over-activity in the division of the autonomic nervous system that controls stress responses. This final finding warrants further investigation in order to understand whether inappropriate regulation of the autonomic nervous system contributes to increased generalized anxiety in children with ASD, or if it simply accompanies general anxiety caused by other characteristics of the disorder.