Genes influence autistic people’s reactivity to sights, sounds and other sensory cues, whereas environmental factors shape their tendency to notice and seek out such stimuli, a new study in twins suggests.
Sensory issues, such as hypersensitivity to noise or an impulse to touch certain textures, are common in autism, affecting 69 to 95 percent of autistic people. Yet the factors underlying these traits are still poorly understood.
The new study reveals specific kinds of sensory alterations that occur in people with autism and begins to disentangle the roles that genes and environment may play in how these traits manifest.
“It [gives] us a clue of where to look,” says lead investigator Janina Neufeld, assistant professor of women’s and children’s health at the Karolinska Institute in Stockholm, Sweden. “It tells us maybe it’s worthwhile to look more into the genes of sensory sensitivity.”
Altered sensory processing affects some autistic people on a daily basis, says David Simmons, lecturer in psychology at the University of Glasgow in Scotland, who was not involved in the study. “It can be really disabling in some cases.”
The new work paves the way for identifying stimuli that autistic people may be particularly sensitive to, Simmons says. It also helps researchers and clinicians understand what treatment can and cannot change about how people with autism process these cues.
Although the study helps clarify how genes and environment could influence sensory differences, it leaves some questions unanswered, Neufeld says.
For example, the study found a negative association between autism traits and sensation-seeking behaviors — an unexpected result because it is well established that many people with autism engage in such behaviors, Simmons says.
Another outstanding question is what kinds of genetic and environmental factors are driving these results, says Teresa Tavassoli, associate professor of psychology at the University of Reading in the United Kingdom, who was not involved in the study.
Neufeld says she and her colleagues plan to collaborate with geneticists to try to zoom in on particular genes that may drive hyperreactivity in autism. They would also like to learn more about what environments elicit aversive behaviors and make it difficult for people with autism to function, she says, particularly in settings such as schools.
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Source: Spectrum News