How understanding sensory differences can help parents support autistic children

Sensory processing disorder has been estimated to occur in as much as 90% of children with autism, compared to occurring in an estimated 5-17% of the general population. 

Some symptoms of autism may result from early differences in sensory development, according to Carissa Cascio, senior scientist at the Kansas Center for Autism Research and Training, who helped develop the “cascading effects model” to help explain this effect. 

Sensory processing disorder is a broad term to describe challenges associated with the intake of sensory signals from the environment and how they are integrated with each other to inform behavior, Cascio explained. 

“It's an umbrella term that can describe a lot of different things, much like autism,” she said. “A lot of times, this shows up as hypersensitivity,” Cascio said. 

The cascading effects model focuses on how these sensory inputs create differences in children’s behavior compared to their neurotypical peers. It explains that early differences in how a child senses the world can set off a chain reaction and, over time, gradually shape the way they explore, learn, and connect with others. 

Research on autism in children has usually looked more at attention or social cognition. But Cascio said these complex behaviors depend on a great deal of sensory processing, a process that begins as early as in utero.  

“My colleagues and I work under this assumption or premise that if you have differences in these very basic sensory processes —just how information is getting in and being analyzed by the brain — that those would probably cascade to influence more complex behaviors as they develop,” she added. 

For example, a boy who can't filter out uncomfortable background noises might avoid noisy areas of the playground. He develops a pattern of playing alone, which reduces interactions with peers. Over time, he fails to develop the same social skills, impacting his confidence and patterns of communication. 

In another example, a girl who is averse to certain smells and textures resists trying a new food. This sensory input shapes her eating habits, limiting willingness to try new foods and increasing the stress around eating. The pattern of behavior shapes her diet, making it harder to try new foods. She may even find it difficult to eat while sitting next to someone eating certain foods. 

There are others beyond the five senses of taste, touch, sight, smell, and sound, such as the senses of balance and body awareness, that make an impact on sensory input. “So, for example, with kids who are always climbing or swinging or jumping, it can seem like they never get enough stimulation to their joints and muscles,” Cascio said.  

Differences in processing sensory information can lead to behavior that can be upsetting to parents, educators, and providers. But understanding the impact of sensory difference may help better support autistic individuals. 

“If there's something different about the way I'm processing my parents' voices or their touch, then that is, over time, going to impact how much I interact with them, and the quality of those interactions and that over time, sort of compounds.” 

For example, if parents realized their child's negative reaction to being cuddled isn’t a rejection of them, they can find ways to communicate affection, reducing stress for everyone. 

It's important to realize these experiences are difficult for the autistic individual as well. 

“One of the things that drove me to this area to begin with, was that it is something that people talk about,” Cascio said. “A lot of people on the spectrum talk about their sensory sensitivities and how limiting that can be in them living the lives that they want to live. That definitely inspired me to want to look at it more.” 

Autistic individuals are more likely to have overlapping clinical conditions in addition to sensory processing disorder, such as attention deficit disorder, depression, anxiety, obsessive compulsive disorder, and seizures.  

There’s a lot that scientists still don't know about why, but research is pointing to a complex combination of genetic and environmental factors.  

"A lot of the genes that we identified for autism are ones that affect neurodevelopment globally,” Cascio said. 

The cascading effects model is an emerging framework for understanding early sensory differences that may shape autism behavior, and more research is needed. But as scientists work to connect the pieces of how autism works, understanding sensory differences can help provide better support for autistic individuals 

"This is all theoretical,” Cascio said. “It's not something that we've been able to definitively test yet, but it is a theory for how sensory processing differences could be a foundational property that that impacts a lot of the behaviors that we use to diagnose autism.”

Read a Q&A with Carissa Cascio based on the conversation used for this article.