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The Debate Over Sensory Processing

A look at the dispute over whether sensory symptoms constitute a disorder, and whether treatment works 

Beth Arky

Writer
Child Mind Institute

Jodi and Matt were mystified. At 2, their son, Paul, was behaving in ways no parenting book had described: knocking into walls, hugging them to the point of hurting, and screaming inexplicably in restaurants. He was strangely tentative when climbing or balancing on the playground equipment. Instead, he always rushed for the swings, which he loved pushing as much as he loved being pushed in.

The couple didn't know how different their only child's behaviors were until Paul started preschool and they got to know more children and their parents. While their pediatrician dismissed their concerns, saying that kids outgrew these things, their preschool director did not: She suggested an evaluator, who said that their little boy had sensory processing disorder or, as she called it, SPD.

She explained that SPD includes being too sensitive to some stimuli, which made loud, crowded restaurants so overwhelming they triggered meltdowns, and not sensitive enough to other input and therefore craving it, which would explain the hugging and crashing into walls, as well as his love of both swinging and pushing the swings. And he had trouble with the senses that help him "know where his body is in space," which would account for the clumsiness and fear while climbing. She recommended occupational therapy (OT).

It's difficult when parents receive conflicting messages from professionals involved with their children. Jodi and Matt were confused, but their son was in distress and, at best, OT sounded benign. They decided to give it a try. The occupational therapist invited them to come see what Paul was doing in therapy—"crashing" into beanbags, swinging in a stretchy hammock, and being smooshed into a "Paul sandwich," with pillows subbing in for other fillings and bread, all to give him the input he sought and help calm him.

She urged them to try these ideas at home as part of what's called a "sensory diet" and also suggested that they read The Out-of-Sync Child, Carol Stock Kranowitz's seminal book on sensory processing problems. They recognized Paul's behaviors in the book and it all started to make sense to them. Most important, they felt they were able to do something to help their son—and that he seemed to be improving.

This family's story is a common one, says Lindsey Biel, an occupational therapist and coauthor of Raising a Sensory Smart Child. When a child is identified as having developmental delays, not speaking or walking as well as other children his age, the first thing parents often hear is SPD. "On top of confirmation of these delays, parents are given this unheard-of diagnosis of sensory processing disorder," she says.

One of the reasons it's often "unheard of" is that SPD is not included among the conditions spelled out in the Diagnostic and Statistical Manual (DSM), the guide used by psychiatrists and many other clinicians—including pediatricians, psychologists, and social workers—in diagnosis. It is occupational therapists who first theorized that sensory processing issues are a source of distress for many children, and an explanation for a lot of otherwise puzzling behaviors. And it is often OTs who identify these challenges, typically in preschool children, and who specialize in treating them. Despite an intense campaign—waged in part so that costly private treatments could be covered by insurance—it was not added as a new diagnosis in the latest edition of the diagnostic manual, the DSM-5.

What is accepted in the wider clinical community is that many children do have unusual and sometimes problematic sensory responses, including most of those kids who are eventually diagnosed with autism. Indeed, Paul was later found to be on the autism spectrum. In the latest edition of the diagnostic manual, the DSM-5, sensory problems like the ones Paul experienced are now listed as one of the criteria for an autism diagnosis. But lots of other children who are identified as having sensory issues as preschoolers are later diagnosed with ADHD—Paul's secondary diagnosis—and others with anxiety. And some are never diagnosed with any disorder in the DSM.

So while there is general agreement that some children do have serious sensory challenges, the disagreement is over whether SPD should be considered an independent disorder, how far sensory issues go in explaining behaviors, and whether the treatment occupational therapists offer for sensory issues has any effect on a child's functioning over time.

Understanding the disagreement

Dr. Michael Rosenthal, a pediatric neuropsychologist at the Child Mind Institute and the son of an occupational therapist, explains the landscape this way: On the one hand, it's clear that identifying sensory issues and working with an OT help many children become calmer and better regulated. By tuning in to a child's particular sensory profile, they can find ways to help kids cope and bring them more balance. "I've known many OTs who are really creative and 'get' kids very well," he says.

On the other hand, it's not clear how much benefit children get from the techniques and whether it's possible to generalize enough from the behavior of individual kids to consider it a coherent disorder. "The thing we don't really understand is how and if this approach works for every kid who has sensory issues," Dr. Rosenthal adds, "and where the science is in creating a specific sensory diet for a specific kid."

Dr. Catherine Lord, a leading autism expert and the director of the Center for Autism and the Developing Brain at New York-Presbyterian Hospital, argues that sensory issues are an important concern, but not a diagnosis in themselves. "I do think there's a value in attending to how a child is perceiving sensations, thinking about whether he could be uncomfortable. Where I get concerned is labeling that as a separate disorder." 

From a parent's point of view, it's hard to understand why it matters whether SPD is considered a legitimate diagnosis by clinicians who go by the DSM. But from a clinical point of view, diagnoses are essential. They drive treatment, by helping clinicians understand the symptoms they are seeing and how best to respond to them. The mental health establishment doesn't acknowledge SPD as a distinct disorder because it isn't convinced that SPD is the best possible way to understand, and approach, those symptoms. And it's dissatisfied with evidence that the treatment gets real, measurable results.

"The debate is not about the importance and quality of work that OTs are involved in—we know that OTs help many children," says Dr. Matthew Cruger, a clinical psychgologist and the director of the Child Mind Institute's Learning and Development Center. "It is about whether we have acquired sufficient scientific evidence to conclude two things: Are kids who show these behaviors consistently and meaningfully different from typical kids, and are there specific treatments for this problem?"  

"In the sensory integration world, I think there are too many assumptions about cause and effect," adds Dr. Dominick Auciello, another neuropsychologist at CMI. "The explanations seem logical," he says, "but they are not based in careful study about whether that logic is actually true." Dr. Auciello offers an example: Consider the OTs' claim that kids hug other kids excessively because they are seeking deep pressure. It's an interesting theory, he says, but "there are other equally feasible hypotheses, such as if a child is impulsive, has autism, is inattentive to social cues, has trouble internalizing verbal social rules, has seen modeling of inappropriate behavior, or lacks a sense of social boundaries."

Dr. Rosenthal adds that identifying what's causing a particular behavior can be especially difficult in children who have complex issues, as many children with sensory challenges do. Take a child with autism who is averse to the feeling of water on his face. "We don't know where these things came from," he says. "There may be certain kids who come out sensory reactive from the womb and some who develop it from experience. A child could have a very early encounter that's negative—a mini trauma—that sticks in his mind, and he generalizes and avoids those things in the future. If an experience is powerful and reinforced, it can become just as powerful as an organic issue." Is it a sensory issue, then, or is it anxiety?

So while there are anecdotal accounts that kids respond to sensory work, skeptics point to a lack of research that clarifies how and how much they work to improve a child's functioning. "Any studies are poorly constructed, too small of a sample size, or show that the treatment actually did not work," Dr. Auciello says. He also worries that the interventions may actually reinforce the symptoms: "For example," he says, "if a child has a meltdown and is then allowed to go to the sensory gym to help him 'regulate,' you may actually be rewarding the meltdown."


The research outlook may be brightening, however. In 2007, a team led by Lucy Jane Miller, director of the STAR (Sensory Therapies and Research) Center, released  a randomized controlled pilot study of the effects of sensory integration treatment. Though the sample was tiny—24 children, just 8 of whom received the treatment—and it showed significant improvement in functioning only in three of six measures, its authors concluded that the study did validate a model for how researchers can identify homogenous groups of subjects. This is an important step for enhancing the reliability of a future study. Indeed, in a paper out this week from the University of California, San Francisco, researchers claim to have done just that—identify a group of kids with pure SPD—and found that their brains are in fact different from controls in key sensory areas.

Of course, researching the brain biology of a disorder without a codified diagnosis—and that so often overlaps with other neurodevelopmental conditions—isn't a risk-free proposition; investigators screened out kids with ADHD diagnoses, but many had high scores on scales for ADHD symptoms, so the study could be interpreted to show more about ADHD than SPD. But investigations like this can shed light on the sensory symptomology that all clinicians and researchers agree, at minimum, is present in many kids on the autism spectrum or with ADHD, as well as others, and help lay groundwork for future efforts.

Separating sensory issues from other disorders

But studies like UCSF's may do nothing to dull the disagreement, precisely because of the ambiguity in symptoms that can characterize several diagnoses. Some believers in SPD claim that common symptoms that are attributed to other disorders that are in the DSM-5, including autism, ADHD, and anxiety disorders, may actually stem from sensory challenges.

Marcus Jarrow, an OT and clinical director of the SMILE Center, which offers a sensory gym and other therapies, posits that autism is essentially an extreme case of SPD. He quotes the late Dr. Stanley Greenspan, a child psychiatrist who did seminal work on developmental disorders. "Dr. Greenspan once said something along the lines of 'every child on the spectrum has sensory processing dysfunction, but not every child with SPD is on the spectrum. When the sensory processing issues become severe enough to impact relatedness, engagement and the child's ability to interact with the world around them, then the child is on the spectrum,' " Jarrow says.  

Jarrow argues that sensory-based work is the key to getting children on the spectrum engaged socially. "In my experience, it is often in response to appropriately applied sensory-based strategies that children on the spectrum demonstrate their initial, or most consistent and meaningful, engagement," he says. "If a child cannot appropriately register and interpret the sensory information from their worlds, they will tune it out.  Try making sense of an especially long foreign film with no subtitles while bombs are going off outside your window."

But he doesn't just work with kids on the spectrum. "I see sensory processing issues as the root of much of the 'hyperactivity' and 'attention' difficulties we observe these days. If a child has somatosensory issues and can't get comfortable in their seat for more than a few seconds, that child will clearly present with increased activity levels and certainly have a difficult time paying attention," he says, adding, "I firmly believe that a lot of children diagnosed with ADHD and treated with meds could otherwise respond very well to sensory integration treatment."

As an example, he cites a 6-year-old boy who came to his clinic, after his mother said she had been pressured by his school to have him evaluated—and medicated—for ADHD.  "After a summer of pretty intensive sensory integration treatment with great home carryover," Jarrow said, "he went back to school in September and meds were never brought up again. I'm not trying to imply in any way that SI can prevent every kid out there from going on medication, but it certainly can help."

"To say any child has a disorder," responds Dr. Cruger, "you have to answer if the condition exists to scientific standards.  And if you can meet that threshold of empirical evidence, then you begin to see how effective the treatments are for alleviating that condition. Therefore, it is worth noting that there are not scientific studies that support Jarrow's claim that a child with ADHD could be better treated by OT than medication, but there have been hundreds of studies examining the diagnosis of ADHD and the use of medication to treat the symptoms of ADHD in these children—generally showing medication to be a safe and effective treatment of the symptoms of this disorder, though not a cure for the condition."

"In addition," Dr. Cruger says, "neuroscientific studies, including CT scans and MRI studies, have seen volumetric differences between typically developing youngsters and children diagnosed with ADHD—not in those somatosensory regions, but in frontal lobe regions noted to be essential for the inhibition of impulses."

Skepticism over what treatment does

One of the most hot-button aspects of the SPD debate is this claim, of Jarrow and others, that sensory-based protocols, used correctly, can actually "rewire" the brain, allowing for more optimal regulation. Skeptics agree that kids can change, but argue that what's being called sensory rewiring may really just be behavioral training.

Dr. Rosenthal gives an example: "Take a kid who's behaviorally out of control. Let's say he spends several days a week working with an OT in a sensory gym, and he gets himself under control. And the effect seems to improve his self-regulation over time. Something's happening in the brain, maybe some neuronal patterns or some axons wiring together, creating better regulation in brain. Is it sensory rewiring of some kind or learning a new calming method?"

The challenge, he adds, is to isolate the component of therapy that's actually helping the child.

The SPD Foundation, which campaigned unsuccessfully to have the disorder listed as a separate diagnosis on the DSM-5, is doing its own ongoing research through its SPD Scientific Working Group. Two researchers at Virginia Commonwealth University are now testing the short-term effects of sensory-based therapy in improving attention and functional performance in children ages 6 to 10 with typical development, ADHD, and autism.

As research struggles to catch up with practice, more OTs and clinicians are open to working together to benefit kids. In fact, Biel just completed a book, Sensory Processing Challenges: Effective Clinical Work with Kids & Teens, that's intended for mental health clinicians so that they can become more knowledgeable about how sensory challenges affect their clients. She also teamed up in 2009 with Dr. Fernette Eide, a neurologist, and husband Dr. Brock Eide, a primary care physician, to present the Sensory Processing Master Class webinar to teach parents and professionals how to help children with "attention, learning, motor skills and social/emotional issues."  

Dr. Fernette Eide says the continuing controversy over SPD is unfortunate because kids with sensory processing problems would benefit most from a "team approach with close coordination among psychiatrists, psychologists, and other professionals."

While the American Academy of Pediatrics stated in 2012 that there is not support for SPD as a diagnosable condition, the group did acknowledge the existence of sensory-based challenges and the fact that a lot of children are receiving therapies related to them, although they cautioned that there was limited data on the use of these therapies or their effectiveness.  Because of this, the AAP recommends that pediatricians help parents find ways of measuring therapy outcomes by creating pre-and post-behavior rating scales as well as explicit treatment goals, such as the ability to focus, tolerate foods, and be in a loud room.

Four years after Paul began OT, he's still at it, along with physical and speech therapy and a social skills group. Given all that, plus the fact that her son has matured and can express himself more verbally, it's hard for Jodi to say with any certainty that the sensory diet has "rewired his brain." All she knows is that when he gets "the sillies" and can't sit still, she will pull out one of her sensory techniques such as jumping on the bed to provide him with the input he craves. She, and many other parents like her, aren't waiting for a study to try to help their kids.

Published: July 10, 2013

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