Saliva, pupil size differences in autism show system in overdrive

July 13, 2012 By Karen Henry
Saliva, pupil size differences in autism show system in overdrive
Christa Anderson, left, University of Kansas assistant research professor, and Kathryn Unruh, 2012 KU honors graduate in behavioral neuroscience, use technologies such as eye-tracking, pupil measurement, salivary responses and neuroimaging to look for biomarkers of autism and investigate the autonomic nervous system as a possible nexus of the disorder.

(Medical Xpress) -- University of Kansas researchers have found larger resting pupil size and lower levels of a salivary enzyme associated with the neurotransmitter norepinephrine in children with autism spectrum disorder.

However, even though the levels of the enzyme, salivary alpha-amylase (sAA), were lower than those of typically developing in samples taken in the afternoon in the lab, samples taken at home throughout the day showed that sAA levels were higher in general across the day and much less variable for children with ASD.

“What this says is that the autonomic system of children with ASD is always on the same level,” said Christa Anderson, assistant research professor. “They are in overdrive.”

The sAA levels of typically developing children gradually rise and fall over the day, said Anderson, who co-directed the study with John Colombo, professor of psychology.

Norepinephrine (NE) has been found in the blood plasma levels of individuals with ASD, but some researchers have questioned whether these levels were just related to the stress from blood draws.

The KU study addressed this by collecting salivary measures by simply placing a highly absorbent sponge swab under the child’s tongue and confirmed that this method of collection did not stress the children by assessing their stress levels through cortisol, another hormone.

Collecting sAA levels has the potential for physicians to screen children for ASD much earlier, noninvasively and relatively inexpensively, said Anderson.

But Anderson and Colombo also see pupil size and sAA levels as biomarkers that could be the physiological signatures of a possible dysfunction in the autonomic nervous system.

“Many theories of autism propose that the disorder is due to deficits in higher-order brain areas,” said Colombo. “Our findings, however, suggest that the core deficits may lie in areas of the brain typically associated with more fundamental, vital functions.”

The study, published online in the May 29, 2012 Developmental Psychobiology, compared children between the ages of 20 and 72 months of age diagnosed with ASD to a group of typically developing children and a third group of children with Down syndrome.

Both findings address the Centers for Disease Control’s urgent public health priority goals for ASD: to find biological indicators that can both help screen children earlier and lead to better understanding of how the nervous system develops and functions in the disorder.

Colombo is the director and Anderson is research faculty member of the University of Kansas Life Span Institute, which focuses on neurodevelopmental and translational research across the life span.

Explore further: Study shows delays in siblings of children with autism spectrum disorders

Related Stories

Study shows delays in siblings of children with autism spectrum disorders

May 16, 2012
A new University of Miami (UM) study shows that one in three children who have an older sibling with an Autism Related Disorder (ASD) fall into a group characterized by higher levels of autism-related behaviors or lower levels ...

Study explores autism co-occurring conditions and diagnosis change

January 24, 2012
(Medical Xpress) -- In a new Pediatrics article, researchers at the Johns Hopkins Bloomberg School of Public Health examined the relationship between the co-occurring conditions in children with Autism Spectrum Disorders ...

Eye-tracking reveals variability in successful social strategies for children with autism

February 27, 2012
In a study published in the March 2012 issue of the Journal of the American Academy of Child and Adolescent Psychiatry, Katherine Rice and colleagues, from the Marcus Autism Center, Children's Healthcare of Atlanta, and Emory ...

Scientists identify potential biomarker to help diagnose autism

April 27, 2012
(Medical Xpress) -- Autism is difficult to diagnose because of a lack of specific biological markers and a variability of symptoms, ranging from mild in some individuals to severely disabling in others.

New study looks at medication use of kids with ASD, ADHD

February 17, 2012
(Medical Xpress) -- Many children with an autism spectrum disorder (ASD) can benefit from medication for related disorders such as attention-deficit/hyperactivity disorder (ADHD).

Recommended for you

New autism study a "shocking wake-up call" for society, say academics

October 23, 2017
People who show characteristics of autism are more at risk of attempting suicide, according to a Coventry University study whose results are being presented to a United States federal advisory committee tomorrow.

Signaling pathway may be key to why autism is more common in boys

October 17, 2017
Researchers aiming to understand why autism spectrum disorders (ASD) are more common in boys have discovered differences in a brain signaling pathway involved in reward learning and motivation that make male mice more vulnerable ...

Whole genome sequencing identifies new genetic signature for autism

October 12, 2017
Autism has genetic roots, but most cases can't be explained by current genetic tests.

Mum's immune response could trigger social deficits for kids with autism

October 10, 2017
The retrospective cohort study of 220 Australian children, conducted between 2011-2014, indicates that a "an immune-mediated subtype" of autism driven by the body's inflammatory and immunological systems may be pivotal, according ...

Largest study to date reveals gender-specific risk of autism occurrence among siblings

September 25, 2017
Having one child with autism is a well-known risk factor for having another one with the same disorder, but whether and how a sibling's gender influences this risk has remained largely unknown.

Faulty cell signaling derails cerebral cortex development, could it lead to autism?

September 20, 2017
As the embryonic brain develops, an incredibly complex cascade of cellular events occur, starting with progenitors - the originating cells that generate neurons and spur proper cortex development. If this cascade malfunctions ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.