|Study Provides Evidence That Autism Affects Functioning of
Previous View Held Autism Limited to Communication, Social Behavior, and Reasoning
A recent study provides evidence that autism affects the functioning of virtually
the entire brain, and is not limited to the brain areas involved with social
interactions, communication behaviors, and reasoning abilities, as had been previously
thought. The study, conducted by scientists in a research network supported by
the National Institutes of Health (NIH), found that autism also affects a broad
array of skills and abilities, including those involved with sensory perception,
movement, and memory.
The findings, appearing in the August Child Neuropsychology, strongly
suggest that autism is a disorder in which the various parts of the brain have
difficulty working together to accomplish complex tasks.
The study was conducted by researchers in the Collaborative Program of Excellence
in Autism (CPEA), a research network funded by two components of the NIH, the
National Institute of Child Health and Human Development and the National Institute
on Deafness and Other Communication Disorders.
“These findings suggest that further understanding of autism will likely come
not from the study of factors affecting one brain area or system, but from studying
factors affecting many systems,” said the director of NICHD, Duane Alexander,
People with autism tend to display 3 characteristic behaviors, which are the
basis of the diagnosis of autism, explained the study’s senior author, Nancy
Minshew, M.D., Professor of Psychiatry and Neurology at the University of Pittsburgh
School of Medicine. These behaviors involve difficulty interacting socially,
problems with verbal and non-verbal communications, and repetitive behaviors
or narrow, obsessive interests. Traditionally, Dr. Minshew said, researchers
studying autism have concentrated on these behavioral areas.
Within the last 20 years, however, researchers began studying other aspects
of thinking and brain functioning in autism, discovering that people with autism
have difficulty in many other areas, including balance, movement, memory, and
visual perception skills.
In the current study, Dr. Minshew and her colleagues administered a comprehensive
array of neuropsychological tests to a group of children with autism. The researchers
tested 56 autistic children, and compared their responses to those of 56 children
who did not have autism. The children with autism were classified as having higher
functioning autism — an I.Q. of 80 or above, and the ability to speak, read, and
write. All of the children in the study ranged in age from 8 to 15 years. The
purpose of the test array, Dr. Minshew said, was to determine whether there were
any patterns in mental functioning unique to autism.
“We set out to find commonalities across a broad range of measures, so that
we could make inferences about what’s going on in the brain,” Dr. Minshew said.
The researchers found that, across the entire series of tests, the children
with autism performed as well as — and in some instances even better than — the other
children on measures of basic functioning. Uniformly, however, they had trouble
with complex tasks.
For example, regarding visual and spatial skills, the children with autism
were very good at finding small objects in a cluttered visual field, on tasks
like finding Waldo in the “Where’s Waldo” picture books series. However, when
asked to perform a complex task, like telling the difference between the faces
of similar looking people, they had great difficulty.
Although their memory for the detail in a story was phenomenal, the children
with autism had great difficulty comprehending the story. Many were highly proficient
at spelling and had a good command of grammar, but had difficulty understanding
complex figures of speech, like idioms and metaphors.
“We see this with our patients,” Dr. Minshew said. “If you use an expression
like ‘hop to it,’ a child with autism may literally hop.”
Other complex tasks were also difficult for them. The children with autism either
had poor handwriting, or wrote very slowly. Many had difficulty tying their shoes
and with using scissors.
“These findings show that you can’t compartmentalize autism under three basic
areas,” Dr. Minshew said. “It’s much more complex than that.”
Dr. Minshew explained that the major implication of the finding is that when
seeking to understand autism, researchers need to look for a cause or causes
that affect multiple brain areas, rather than limiting their search to brain
areas dealing with the three characteristic behaviors involving social interactions,
communication, and repetitive behaviors or obsessive interests.
“Our paper strongly suggests that autism is not primarily a disorder of social
interaction, but a global disorder affecting how the brain processes the information
it receives — especially when the information becomes complicated.”
In previous research with an imaging technology known as functional magnetic
resonance imaging, or fMRI, Dr. Minshew and her coworkers determined that adults
with autism have abnormalities in the neurological wiring through which brain
areas communicate. In those studies, the researchers found that people with autism
had difficulty performing certain complex tasks that involved brain areas working
together. (This research is described in previous releases, http://www.nichd.nih.gov/new/releases/final_autism.cfm,
Dr. Minshew said that such abnormalities in brain circuitry provide the most
likely explanation for why the children with autism in the current study have
difficulty with complex tasks that require coordination among brain regions but
do well on tasks that require only one region of the brain at a time.
The researchers undertook the current study as a follow up to an earlier study
they did of adults with autism. The researchers studied children to determine
if the features of autism were consistent throughout life, or changed as people
with autism grow older. For the most part, the current study revealed that both
adults and children with autism experience the same kinds of difficulties with
One difference is that adults with autism appear to score higher on tests involving
sensory interpretation than do children with autism. Such tests would involve
identifying a number traced on a finger tip, or identifying an object placed
in one’s hand without looking at it. Dr. Minshew said that as people with autism
grow older, they may have less sensory difficulty than they did as children.
Still, adults with autism fare much worse on tests of complex language and reasoning
than do other adults. This gap in complex language and reasoning ability between
the two groups is not as pronounced when children with autism are compared to
other children. This is because children’s brains have not yet developed these
skills, Dr. Minshew said. However, the gap widens with time. As typical children
get older, they develop these higher order language and reasoning skills while
adolescents and adults with autism do not.
The NICHD sponsors research on development, before and after birth; maternal,
child, and family health; reproductive biology and population issues; and medical
rehabilitation. For more information, visit the Institute’s Web site at http://www.nichd.nih.gov/.
The National Institutes of Health (NIH) — The Nation's Medical Research
Agency — includes 27 Institutes and Centers and is a component of
the U.S. Department of Health and Human Services. It is the primary federal
agency for conducting and supporting basic, clinical and translational medical
research, and it investigates the causes, treatments, and cures for both common
and rare diseases. For more information about NIH and its programs, visit www.nih.gov.