Autism, Brain Overgrowth, and Pruning

For many families that have children with autism, they live in a frustrating fog of uncertainty.  They don't know what "causes" autism, nor do they know what people are doing about it.  In fact, as with the case of my wife and I, many have no clue what autism is until faced with the challenges and joys of having a child with autism.  My first question was what caused it, and then what I could do about it.  

Well, recently (within the last 12 months), a study was completed and presented to the neuropsychological community that suggests an overgrowth of brain neurons could contribute to autistic behavior.  Basically, this is what happens from birth to age 6:  A child's brain will grow a lot of neurons that are randomly connected.  This allows the brain to absorb and record a lot of information at a very young age.  Once that information starts to process, children begin to go through a "pruning" process, which is accelerated at age six.  This pruning process removes many of the random neurons in the brain, leaving those that have developed.  

But with some autistic children, the brain tends to "overgrow", developing more random neurons than most "normal" children.  This means they are processing more information from visual, tactile, auditory, olfactory or gastronomical inputs.  Often this input is so overwhelming that they need to "unplug".  This presents the bulk of autistic behavior.  Your face is too detailed for them to take in, so they can't look you in the eye.  They get overwhelmed with the sights, sounds, and smells in a store, so they need to cling to you or start to scream.  Often they will just lay down on the floor to try to get sense of their surroundings, or focus on one object very intently, trying to block everything else out.  

If that were not enough, children with autism tend to either have a delayed pruning period, or do not prune at all.  Those children with more severe autism would most likely fall within this group, with Asperger's children having an overgrowth in the brain, and those with PDD will have a delayed pruning period.  At least, that makes the most sense to me.  It will be interesting to see if that is confirmed with subsequent studies.  

So what does this mean to the parent that is uncertain?  It means that there is hope!  Children with autism can "rewire" their brain by going through intensive training.  Going through tasks at each step, each sub-task, each skill that is required to complete the entire task.  As such, even if pruning is delayed or fails to happen, the neurons can be directed and merged into those tasks, allowing the autistic child to operate at a more functional level.  

For a more detailed explanation of the Pruning portion of the neurological studies on Autism, check out this article I have on my website from the Department of Neuropsychiatry, University of South Carolina, as published in the Brain and Development, The Official Journal of the Japanese Society of Child Neurology.  It outlines the impact of pruning, and the discoveries found in classic autistic children.