Until then, I'd never heard of DSI (the preferred abbreviation, to distinguish it from SIDS, the acronym for sudden infant death syndrome). But I quickly got a crash course in the subject. According to experts, DSI is a neurological disorder marked by difficulty tolerating, detecting, or processing sensory information. Children with DSI may be overresponsive or underresponsive to sensory messages. And because certain senses provide information about movement, balance, and body position, some kids have motor-planning problems.
Sound lofty and abstract? Bringing it to playground level makes DSI heartbreakingly real. In a quiet corner is the super-sensitive child in an agony of overstimulation. She recoils from new experiences, loud noises, and rigorous games that most young children relish. For her, a hug feels threatening; even the seams in her socks can bother her. Elsewhere, the child with an underreactive system may look like a high-energy bully, touching other children too often and too hard. "Some of these kids are running all over the place or twirling in circles. They sometimes look like they're driven by a motor," says Lucy Jane Miller, Ph.D., an occupational therapist (OT) and executive director of the KID Foundation, a Littleton, CO-based advocacy group for children with sensory integration difficulties. (That's why DSI is often mistaken for attention deficit hyperactivity disorder.) But this whirling dervish isn't having fun -- he's seeking the sensation his underresponsive system craves. Finally, there is the clumsy child. His motor-planning problems, which affect fine- and gross-motor skills, make coloring, climbing, or playing games like Simon Says a challenge.
Identified in the 1960s, DSI is just now attracting attention. "It's becoming a popular diagnosis," observes Lauren Robertson, an OT in New York City who fields daily calls about DSI. Traffic to the Web site for the KID Foundation (www.sinetwork.org) is on the rise.
DSI's leap into the limelight can be attributed in large measure to the 1998 publication of Carol Stock Kranowitz's The Out-of-Sync Child: Recognizing and Coping With Sensory Integration Dysfunction, which has sold 250,000 copies. Concurrently, a small but growing body of research is lending credibility to the diagnosis and shedding light on a hidden disorder that, untreated, can have a lasting impact on a child's life. Imagine how difficult it is to pay attention in school when you can't resist the urge to bump into other children to satisfy your body's drive for sensory input or, conversely, when you're so sensitive that you're aware of the way your chair feels against your body. That's not to overlook the frustration of the child who has trouble using a pencil or cutting out simple shapes with a pair of scissors.
"Kids with DSI have a hard time functioning. Even if they look fine and have superior intelligence, they may be awkward and clumsy, fearful and withdrawn, or hostile and aggressive," says Kranowitz, a former preschool teacher in Bethesda, MD. "We get all our information from the senses, so if any one of them is impaired, it has a domino effect."
While DSI is drawing attention, questions about the condition abound. Dr. Miller is quick to point out that parents of kids with DSI are in no way culpable for their child's sensory problems. But just what causes DSI remains unclear. It's been associated with a traumatic or premature birth; the bright lights and beeping machines in neonatal intensive care units may overwhelm underdeveloped sensory systems, as could painful post-delivery procedures.
But it may also be in the DNA. In many of Dr. Miller's cases that don't involve birth trauma, she has found that one parent experiences sensory sensitivity, suggesting a genetic component. Some believe that unidentified environmental toxins may play a role. The condition's prevalence is similarly murky. Dr. Miller conducted a pilot study of kindergartners in a Colorado public school district and estimated that at least 5% of the kids had significant sensory problems.
DSI can be diagnosed as early as infancy by an occupational therapist with expertise in sensory integration assessment. But most kids with DSI aren't identified until they start having trouble in school, if they get diagnosed at all. "Many doctors aren't aware to look for it, and many preschool teachers don't know about it," says Larry B. Silver, M.D., a child psychiatrist in Rockville, MD, and a former acting director of the National Institute of Mental Health. And neither do parents. They think their baby is colicky or fussy. As the child grows older, he may be described as quirky, difficult, or klutzy.
Even as a baby, Laura Campbell (not her real name) was extremely sensitive to noise. "If I vacuumed or used a blender, she practically jumped out of her skin," remembers her mother, Karen, a New York City art teacher. But she wanted to touch everything -- including strangers' clothing on the subway. Though a bright and physically active child, Laura didn't take her first steps until she was 17 months old and had trouble with fine-motor skills. When Laura's preschool teacher and the school psychologist suggested she be evaluated, Karen finally got an explanation for Laura's behavior: DSI.
With therapy, Laura, now 6, is better able to tolerate loud noises and relate to others. But she's still struggling, and the problem is taking a psychological toll. "She trips over people because she has poor motor planning, and because she doesn't understand physical boundaries, other kids find her intrusive and reject her," says Karen. "It's painful. She has an awareness that there's something not right about the way she does things and her self-esteem is starting to suffer."