Identifying Autism Earlier
Finding simple, inexpensive ways to identify infants and young toddlers with autism spectrum disorders (ASD) is an urgent public health priority. Accurate early screening can help identify children at risk for diagnosis with ASD from variations in typical development in the first year. This can lead to intervention during the time when critical social, cognitive, and communication skills are developing and more amenable to change. In addition, finding the early signs of ASD can also give scientists important clues to the causes or basis of the disorder.
Warren, KU vice provost for research and graduate studies and professor of applied behavioral science, lead a team that, for the first time, precisely measured the impact of autism on several aspects of how children learn language with a new technology that has enormous potential for researchers, practitioners and parents published online in the November 11, 2009 Journal of Autism and Developmental Disorders.
Using the LENA™ (Language Environment Analysis) system, an automatic vocal analysis technology, the study confirmed that young children with ASD vocalize significantly less than their typically- developing peers of the same age - 29 percent less - and that these were often in the form of what the researchers called "monologues" rather than being directed to another person.
More importantly, researchers were able to document deficits in conversational turn-taking with adults - the hallmark of how we learn to communicate with others. Children with autism do this 26 percent less frequently than typical children and the exchanges are markedly shorter in duration.
The cumulative effect of this deficit is sobering. In one day, the children with autism had 146 fewer opportunities on average than typical children to learn the give and take of learning language and social and emotional development. In a year's time, that would burgeon to 53,290 fewer conversational turn-taking occurrences.
But there is some good news: the LENA system also measured why therapy may be effective. It documented that when children were in treatment, there was a sharp increase in their vocalizations and turn-taking as well as adult vocalizations to them.
Warren predicts that LENA, which allows the inexpensive collection and analysis of magnitudes of data unimagined in language research before now, could revolutionize the assessment and treatment of autism and the behavioral sciences in general.
In a study published in the March 2009 issue of Developmental Psychobiology, John Colombo, director of the Life Span Institute and professor of psychology, and Christa Anderson, doctoral student in psychology and LSI graduate research assistant, reported that the resting or "tonic" pupil size of children with Autism Spectrum Disorders (ASD) was larger than those of peers of the same mental and chronological age.
Using only pupil size, researchers were able to correctly identify which children from a group of 22 had ASD with 71 percent accuracy. The researchers believe that pupil size might be used to identify children with ASD earlier than the typical 3 years of age.
In response to a stimulus, pupil size increases (dilation) or decreases (constriction) as a result of brightness, arousal, or cognitive demand. These moment-to-moment changes are called "phasic" changes.
In this study, however, Anderson and Colombo found that the resting, or "tonic" pupil size was larger in children with ASD. Tonic pupil size is held constant by inputs from several neural systems at the level of the brainstem, the part of the brain that controls involuntary bodily functions such as heart rate and respiration.
"The fact that children with ASD have larger tonic pupil size indicates an imbalance in these systems, and further suggests that the disorder might have its origins in these lower-order brain systems," Colombo said.
Researchers have reported that people with ASD have notable differences in heart rate, respiration, blood pressure, sleep and other ANS functioning having a neurochemical or structural basis. The Anderson and Colomobo study adds atypical pupil response to this description of ASD.
Colombo said that studies like this serve two purposes. "In addition to providing us with the potential for early identification and diagnosis, they provide important clues to the nature of the disorder. This kind of information is critical to understanding what causes the disorder, and perhaps how to prevent it."