New research confirms that individuals with an autism spectrum disorder (ASD) often have significant sensory deficits that influence social interactions.
Investigators determined the brains of individuals with ASD appear to lack feedback loops that help to process tactile information. This faulty processing results in social challenges.
Belgium researchers explain that many individuals with ASD are over- or undersensitive to sensory information. Some feel overwhelmed by busy environments such as supermarkets, others are less sensitive to pain, or dislike being touched.
Prior research has found that the severity of daily social difficulties of individuals with ASD is strongly related to the extent to which they are sensitive to touch. In fact, the sensory challenges impact function more so visual or auditory sensitivities.
To determine why this is the case, doctoral researcher Eliane Deschrijver and her colleagues investigated how the brain of individuals with and without ASD uses own touch to understand touch sensations in the actions of others.
Prof. Marcel Brass clarifies: We think that the human brain uses the own sense of touch to distinguish one’s self from others.
For example, when I perform an action that leads to a tactile sensation, for instance by making a grasping movement, I expect to feel a tactile sensation that corresponds to this.
If my own touch tells me something else, the tactile sensation will probably belong to the other person, and not to me. The brain can thus effectively understand others by signaling tactile sensations that do not correspond to the own sense of touch.”
In a series of experiments with electro-encephalography (EEG) conducted at Ghent University, the scientists showed that the brain activity of adults with ASD differs from that of adults without ASD while processing touch.
The research showed that the human brain of individuals without ASD indicated very quickly when a tactile sensation does not correspond to the own sense of touch.
This means that the human brain is able to signal that a tactile sensation of a finger that touches a surface does not correspond to own touch.
Investigators discovered a different pattern in the brain of adults with ASD, however.
Their brain signaled to a much lesser extent when the external touch sensation did not correspond to their own touch.
Those individuals that experienced stronger sensory difficulties showed a stronger disturbance of the neural process, while they were also the ones that experienced more severe social difficulties.
“It is to my knowledge the first time that a relationship could be identified between the way individuals with ASD process tactile information in their brain, and their daily social difficulties.
The findings can yield a novel and crucial link between sensory and social difficulties within the autism spectrum”, concludes Eliane Deschrijver.
“These findings primarily lead to a better understanding of the complex disorder, and of associated difficulties. It is yet too early to conclude on the impact on interventions.
If the results can be confirmed in future studies of other groups with ASD, such as (young) children, they could provide a target for optimizing treatment”, explain Dr Wiersema, Deschrijver’s doctoral chair.
Research findings appear in the journal Social, Cognitive and Affective Neuroscience.
Source: Ghent University/Alphagalileo
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