Absolutely everything we do is based on how our senses detect, our brain interprets and our muscles respond to our environment. If there is a problem anywhere in this system, the result can be frustrating and exhausting to the child and family. This is called Sensory Processing Disorder.
Sensory integration is the brain’s ability to take in information from our senses, organize it and make an appropriate response. We are all bombared daily with a variety of sensations, both from outside and inside our bodies. Stimulation comes through our senses of sight, touch, hearing, taste, and smell, while from inside our bodies we are also receiving ongoing information on where our bodies are in space and how we are moving through the senses of proprioception (from muscles and joints) and vestibular(from the inner ear).
The end result of all the senses working together is coordinated, appropriate movements and responses. If messages are not being identified by the sensory system, or the brain gets confused on what to do about it, or if the brain cannot tell your muscles how to respond, then tasks will be harder than expected. A gentle touch of comfort may be registered as a harmful intrusion of space. Many times there is an over-reaction to a stimulus which seems irrational. Some children are fearful just to be picked up, or have their feet off the ground. Climbing is far from their idea of fun. On the other end of the spectrum, a child may fall hard or get a bleeding cut, yet not seem to even notice. Obviously, safety can be a concern as well as simply being able to be a part of family and community life without feeling threatened or scared. If you feel you, your child, or someone you care for may have difficulties with sensory integration, possibly Sensory Processing Disorder, then occupational therapy may be needed. Treatment is actually fun for the child!
Another good resource is the Sensory Processing Disorder Foundation.