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

High quality early intervention for children with autism quickly results in costs savings

August 8, 2017
One in every 68 children in the United States has autism spectrum disorder (ASD), a neuro-developmental disorder that results in difficulty socializing and communicating needs and desires, and often is accompanied by restricted ...

Research identifies effects of cognitive behaviour therapy on parents of children with autism

August 1, 2017
Parents of children with autism experience a greater impact from their child's therapy than once thought, according to new research out of York University's Faculty of Health.

People with autism are less surprised by the unexpected

July 31, 2017
Adults with autism may overestimate the volatility of the world around them, finds a new UCL study published in Nature Neuroscience.

Late-breaking mutations may play an important role in autism

July 17, 2017
A study of nearly 6,000 families, combining three genetic sequencing technologies, finds that mutations that occur after conception play an important role in autism. A team led by investigators at Boston Children's Hospital ...

Females with autism show greater difficulty with day-to-day tasks than male counterparts

July 14, 2017
Women and girls with autism may face greater challenges with real world planning, organization and other daily living skills, according to a study published in the journal Autism Research.

Researchers investigate possible link between carnitine deficiency and autism

July 13, 2017
Researchers are always looking for new clues to the causes of autism, with special emphasis on prevention or treatment. At Baylor College of Medicine, Dr. Arthur Beaudet has been following clinical and genetic clues in patients ...

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.