Sensory integration dysfunction (DSI), or as it is currently known, sensory processing disorder (SPD) is a complicated, somewhat controversial disorder of "sensory processing" - the ability to take in, filter, and respond appropriately to sensory input (touch, movement, vision, hearing, taste, and smell). Some children are felt to be "sensory-avoiding", or "sensory-defensive" - feeling bombarded by overly intense experiences of touch, lights, sound, and so on. Some children are "sensory-seeking", or "sensory under-responsive" - seeking intense stimulation, bashing and crashing around, and seeming less aware of pain and touch. Some children have trouble using sensory inputs to plan and perform gross and fine motor tasks ("dyspraxia", or motor planning disorder).

SPD is one of those diagnoses where definitive research on prevalence, validation of diagnostic tools, and effective therapy is lacking. It's especially hard to know when normal developmental, temperamental, and other individual differences in sensory responsiveness becomes a "disorder". It's underdiagnosed in many arenas, and overdiagnosed in others, just like any disorder where convenient but unvalidated checklists proliferate on the web, and where "cottage industries" marketing products and treatments are competing for your parental attention and money.

Having worked with a lot of post-institutionalized and alcohol-exposed children (two populations that are at higher risk for SPD), I am convinced that there are many such children for whom SPD is a real disorder - one that significantly impairs their function in home, social, and school environments. And I've seen children respond well to occupational therapy (OT) sensory interventions, especially functional approaches that integrate sensory work with the child's needs in motor skills and social interactions.

Even if your child's issues are more reflective of developmental immaturity or individual temperament than a definitive disorder, the sensory approaches can be fun, stimulating, and helpful with self-regulation and self-soothing. It's still hard to convince insurers and schools to fund such interventions, and depending on your situation, sensory-based therapy may not be the most pressing use of your time and money ... but here are some good resources on the topic. A lot of interventions are ones that you can do at home, and while there are scads of nifty products marketed for SPD, you can get a lot done with simple, cheap, or home-made tools and toys.