It's ironic that there are still physicians who don't believe sensory integration problems exist in children, but that's only because the research hasn't caught up to clinical practice. Only recently have new research technologies been able to quantitate events like brain reorganization or motor imagery. In this new work too, virtual reality was needed to test individual contributions of visual and sensory input.
The link below takes you to a PubMed abstract (sorry, full article not free online yet) from April 2005 Nature Neuroscience basic research article showing that the brain uses different strategies and not just sensory inputs to determine how to guide the hand to its correct target. It makes different predictions or adjustments depending on the nature of this task.
Clinically this is probably why children with sensory integration or processing problems (seen in a wide variety of conditions involving brain recovery) need sensory-motor repetitions in specific activities (for instance, writing by hand, throwing a ball, catching a ball, protective reflexes) before improvements in real life activities are seen.
Flexible Strategies for Sensory Integration