OBJECTIVES:Sensory over-responsivity (SOR), defined as a negative
response to or avoidance of sensory stimuli, is both highly prevalent
and extremely impairing in youth with autism spectrum disorders (ASD),
yet little is known about the neurological bases of SOR. This study
aimed to examine the functional neural correlates of SOR by comparing
brain responses to sensory stimuli in youth with and without ASD.
METHOD:A total of 25 high-functioning youth with ASD and 25 age- and
IQ-equivalent typically developing (TD) youth were presented with
mildly aversive auditory and visual stimuli during a functional
magnetic resonance imaging (fMRI) scan. Parents provided ratings of
children's SOR and anxiety symptom severity.
RESULTS:Compared to TD participants, ASD participants displayed
greater activation in primary sensory cortical areas as well as
amygdala, hippocampus, and orbital-frontal cortex. In both groups, the
level of activity in these areas was positively correlated with level
of SOR severity as rated by parents, over and above behavioral ratings
of anxiety.
CONCLUSIONS:This study demonstrates that youth with ASD show neural
hyper-responsivity to sensory stimuli, and that behavioral symptoms of
SOR may be related to both heightened responsivity in primary sensory
regions as well as areas related to emotion processing and regulation.
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