One theory regarding autism is that many of the symptoms are the result of problems in the brain integrating language and the senses.
“Researchers know that autism is a complex brain disorder that affects the way the brain uses or transmits information. Studies have implicated several causes for the disorder but still more investigation is needed. Studies have found abnormalities in several parts of the brain that are believed to have occurred during fetal development.” http://medical-dictionary.thefreedictionary.com/Autism 5/28/14
One thought has been that the right and left hemispheres of the brain aren’t communicating the same as in typically developing brains, but we don’t really know. However, what I have noticed working with children and adults with Asperger’s syndrome is that even though many can create mental images when reading, some don’t use those images when writing or planning. They can use a skill in one area, but not transfer that skill to another. The pieces are often there, but as the complexity of the task increases the skill is not integrated. Why?