UCLA: Using functional magnetic resonance imaging, UCLA researchers have shown for the first time that children with autism spectrum disorder who are overly sensitive to sensory stimuli have brains that react differently from those of their peers who don’t respond as severely to noises, visual stimulation and physical contact.
The findings could lead to the development of interventions to help
the more than half of individuals with autism who have very strong
negative responses to sensory stimuli, a condition called sensory
over-responsivity. Interventions for this condition could significantly
improve the lives of children with this form of autism and their
families, said Shulamite Green, the study’s first author and a
postdoctoral fellow in the Semel Institute for Neuroscience and Human
Behavior at UCLA.
“This condition is distressing and impairing for individuals on the
autism spectrum, as well as for their parents, who often feel confined
to their homes because it’s too difficult to take their children out
shopping, to the movies or to a restaurant,” Green said. “Our research
provides new insights into the brain differences that may cause sensory
over-responsivity, which helps us understand how to treat it — from
simple interventions like limiting exposure to multiple sensory stimuli
to more complex interventions like cognitive-behavioral therapy.”
The study was published online today by the peer-reviewed journal JAMA Psychiatry.
Autism spectrum disorder can cause significant social, communication
and behavioral challenges. The Centers for Disease Control estimates
that about 1 in 68 children have autism, which is almost five times as
common in boys as in girls.
Green said research on sensory over-responsivity, and particularly
brain imaging research, is still very new, and sensory symptoms were
only recently added to the diagnostic criteria for autism.
“One surprise finding was the large differences in brain response
between youth with autism who have sensory over-responsivity and those
who do not,” said Mirella Dapretto, the study’s senior author and a
professor of psychiatry and biobehavioral sciences at the Semel
Institute. “Youth with autism who do not have sensory over-responsivity
have brain responses to sensory stimuli much more similar to their
counterparts without autism, and we showed that there may be a
compensatory mechanism in the brain helping them regulate their
For the study, the UCLA team imaged brain responses to auditory and
tactile stimuli in young people between the ages of 9 and 17, some with
autism and some without. During imaging, each of the study’s
participants was exposed to three kinds of sensory stimuli — hearing
loud environment noises such as traffic, being rubbed on the inner arm
with a scratchy wood fabric or experiencing both the auditory and
tactile stimuli simultaneously.
The team found that study participants with autism and sensory
over-responsivity had stronger brain responses to the sensory stimuli in
brain areas that process sensory information, as well as in the
amygdala, an area involved in attention, response to threat and
The brain responses were even more severe when participants with
autism and sensory over-responsivity were exposed to the auditory and
tactile stimuli simultaneously. They also found that all study
participants showed a similar initial brain response to the stimuli, but
youth with autism and sensory over-responsivity took much more time to
get used to the stimuli — and to reduce their brain response — than
children with autism but not sensory over-responsivity.
Green said that those children may be compensating through strong
brain connectivity between their prefrontal cortex and amygdala. The
prefrontal cortex, Green said, is helping to regulate the strong
response of the amygdala.
“We don’t have many good treatments for sensory over-responsivity,
but our results suggest that an effective treatment might focus on
creating coping skills to deal with stimulating environments rather than
focusing on changing sensory processing,” Green said. “I also think
parents and others working with kids with autism need to be aware of
their sensory environments.”
The UCLA team has received a grant from the Simons Foundation to
continue to study how youths with autism and sensory over-responsivity
process sensory stimulation. They hope to better characterize the
neurobiology of the brain’s reaction.
This work was supported by grants from the National Institute of
Child Health and Human Development, the National Institute of Mental
Health and the National Center for Research Resources, as well as a
National Research Service Award predoctoral fellowship (F31