I remember the day I knew our daughter had a problem. We were rushing to an appointment, walking along a crowded sidewalk on a humid summer day. I was cautioning Elisabeth about something, dragging her behind me the way you sometimes do with an almost-four-year-old.

There was a lot of activity around us, the traffic was loud and smelled of exhaust, a kid on a bike was blowing a whistle, and the storefronts were bursting with bright vegetables and flowers. Suddenly, my daughter stopped in her tracks and screamed. A long, loud scream of agony — not like a tantrum, but a storm of frustration — prompting everyone around us to turn and glare. Later, when I asked her why she screamed, she said she didn’t know, she couldn’t help it.

I puzzled over that scream for a long time. I’d had other hints — for example, she was terrified of walking barefoot in grass, had an obsession with swinging, outright disliked crowds, and hated washing her hair — but I chalked these up to developmental angst.

I knew almost nothing about sensory integration (referred to as SI) except the phrase. Only when Elisabeth was finally evaluated by an occupational therapist trained in sensory integration did I begin to understand her perplexing behaviors.

So, What is Sensory Integration?

Sensory integration is the process by which information from our senses (touch, sight, hearing, taste, smell, as well as balance) is interpreted by the brain so that we can respond appropriately to our environment. A child with good SI automatically filters the important from the unimportant stimuli in order to make her way through the world.

At school, she sits comfortably at her desk without needing to think about maintaining her posture; she can pay attention to the teacher and filter out the noise of the other classes passing by in the hallway on their way to lunch. On the street, she ignores the booming car radios and honking horns, and the itch of her wool sweater, but attends to the sound of the bus turning the corner, “telling” her to wait before crossing the street.

For some children with sensory integration dysfunction, information reaching the senses often feels like an assault of competing stimuli — as when three children are telling you conflicting stories about who had the toy, and the phone starts ringing, and you suddenly remember the cake in the oven, which is burning, and did I mention the itchy rash on your legs?

For others, outside stimuli are dulled, as if a shade has been pulled over the environment, muting sights, sounds, and touch. These children need extra stimulation to arouse themselves — similar to craving the jolt of a wake-up shower after a sleepless night. These are the kids who love to spin and swing upside down. Most children with SI dysfunction display elements of both extremes, suffering overload at some times, seeking stimulation at others.

A child playing in a sandbox can ignore the sweat trickling down her face and neck because she loves to play in the sandbox, and there’s enough of a warm breeze to cool her off a little. A child with SI dysfunction cannot ignore anything — the sweat is distracting and irritating, and the wind just makes it worse, not better.

Lacking an inner ability to cope with these irritations, she may kick the sand in frustration and lash out at her playmates, ruining her playtime and her entire afternoon. The bad feelings will stay with her long after the physical triggers are gone. Children with SI dysfunction can be frustrating to parents and teachers, but their behavior is most frustrating to the children themselves. A. Jean Ayres, the occupational therapist who first described SI dysfunction (over 40 years ago), likened it to “a traffic jam in the brain.”

Who’s at Risk for Sensory Integration Dysfunction?

Most people develop normal sensory functioning, but some experts believe that the process goes awry in as many as 10 percent of children. Although the causes are unclear and may be genetic in many cases, there are extrinsic factors that are identified as putting children at particular risk.

These include maternal deprivation, premature birth, prenatal malnutrition, and early institutional care. Repeated ear infections before age 2 also appear to heighten the risk for sensory difficulties. Bundling, minimal handling, and propping bottles for feeding deprive the infant of the kinds of stimulation that promote integration of the senses. These factors may explain why the incidence of SI is higher among adopted children — even those who came to their families immediately after birth.

Diagnosing SI Dysfunction

Once you recognize the possibility of SI dysfunction in your child, the next step is to locate a knowledgeable professional, usually a trained occupational therapist, to evaluate him. Many kids with SI never receive an accurate diagnosis. SI dysfunction can resemble other problems, and can be misdiagnosed as attention deficit hyperactivity disorder, as a learning disability, and even as pervasive developmental disorder.

For other children, the symptoms are so subtle, and so similar to developmental behaviors, that they can be mistaken for mere personality idiosyncrasies. Friends and family may, with all good intentions, say, “She’s just a late bloomer. Uncle Fred was always a sensitive child, and look how successful he is.” Our first pediatrician suggested that Elisabeth’s resistance (to put it mildly) to haircutting and shampooing was probably a good thing — one of many factors that make her a unique individual.

Another barrier to diagnosis is the nature of the disorder itself. Many children with SI dysfunction are very smart. The strategies they develop to cope — the social withdrawal, the ways they find to avoid certain activities and textures — can be ingenious. Some children have a small degree of dysfunction but crave the kinds of activities that restore their ability to cope and even to excel. Thus, they find their own antidote and may not need diagnosis or formal treatment.

I know a boy who is always more attentive and cooperative in class after swinging upside down on the monkey bars during recess. My own daughter is usually more easygoing after swimming for half an hour or so. Swinging and swimming are activities that regulate the brain pathways responsible for integrating many of the senses.

What’s the Treatment?

The earlier SI dysfunction is recognized and treated, the better. When our daughter was diagnosed, I was anxious to start treatment, but also nervous about it. Treatment, developed by A. Jean Ayres in the 1960’s and considered unorthodox at the time, consists of a unique set of activities that help retrain the senses. The little I knew about it was baffling. But after seeing them in action, the strategies made complete sense.

The basis of the therapy is a varied sensory “diet,” to stimulate all the senses. Since each child has his or her own sensory strengths and weaknesses, the sessions are tailored to the child, and change as she or he progresses.

Elisabeth spent a lot of time swinging — sitting up, lying on her stomach, on her back, and on a trapeze. She was encouraged to touch lots of different textures, she searched for buried “treasure” in containers of Play Doh, poured uncooked beans and dried peas from one container to another, finger-painted on mirrors with shaving cream, carried big jars of sand up a slanted surface, somersaulted down an incline, and jumped into huge beanbags.

We started new activities for a few minutes at a time. Once she overcame her initial fears and aversions, Elisabeth began to seek out the kinds of activities that helped her — some of the very ones she had avoided. Within about a month, she seemed less fearful in the world, more cooperative, and physically stronger. She started to make friends on the playground, her general play was more organized, and she stuck with activities for longer periods of time.

One of the biggest challenges for me has been to understand that some of Elisabeth’s behaviors — irritability, avoidance, and social withdrawal — are coping mechanisms for SI dysfunction. These behaviors aren’t really a choice for Elisabeth or other children like her — they can’t help or stop themselves until they are taught strategies that will let them cope. After several years of occupational therapy, Elisabeth knows when she needs to remove herself and regroup. Our biggest conflicts of late have occurred when I’ve failed to respect her new self-awareness.

SI treatment is not a panacea and certainly not a quick fix. Although some children need less therapy than others, for many it’s a years-long proposition. Elisabeth still sometimes yells when I wash her hair, but she doesn’t scream. She fusses about waistbands that aren’t exactly right, but says it’s okay, “I’ll get used to it.” Best of all, she is making her way in the world, has lots of good friends, and is thriving at school and at home.