Research: Sensory Overresponsivity in Children with Autism
JAMA Psychiatry published research on the neurobiological basis of sensory overresponsivity (an extreme negative reaction to sensory stimuli) in youth with autism. Since more than half of youth with autism spectrum disorders (ASDs) have sensory overresponsivity (SOR) the researchers wanted to use functional magnetic resonance imaging to investigate the differences in brain responses, habituation, and connectivity during exposure to mildly aversive sensory stimuli in 19 youth with ASDs and SOR compared with youth with ASDs without SOR and compared with typically developing control subjects. The mean age in both groups was 14 years and the majority in both groups (16 of 19 each) were male.
The results indicated the following:
1. compared with neurotypical control participants, participants with ASDs displayed stronger activation in primary sensory cortices and the amygdala. This activity was positively correlated with SOR symptoms after controlling for anxiety.
2. participants with ASD with SOR subgroup had decreased neural habituation to stimuli in sensory cortices and the amygdala compared with groups without SOR.
3. Youth with ASD without SOR showed a pattern of amygdala downregulation, with negative connectivity between the amygdala and orbitofrontal cortex.
The researchers determined that “youth with ASD and SOR show sensorilimbic hyperresponsivity to mildly aversive tactile and auditory stimuli, particularly to multiple modalities presented simultaneously, and show that this hyperresponsivity is due to failure to habituate”. The subset of youth with ASD without SOR were able to regulate their responses through prefrontal downregulation of amygdala activity. The researchers recommend that intervention should include minimizing exposure to multiple sensory modalities and building coping strategies for regulating emotional response to stimuli.
Reference: Green SA, Hernandez L, Tottenham N, Krasileva K, Bookheimer SY, Dapretto M. Neurobiology of Sensory Overresponsivity in Youth With Autism Spectrum Disorders. JAMA Psychiatry. Published online June 10, 2015. doi:10.1001/jamapsychiatry.2015.0737.
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