It is interesting that, like many health issues, no one knows where sensory processing disorder comes from. There is some suggestion of it being hereditary and I almost laugh out loud at the irony. Of course, each and everyone of us carries around a list of sensory issues. Experiences we'd rather not (ever) have and things we'd really, really like to happen every second of every day. The difference between us and my son is that we (mostly) know how to handle our own issues.
In the interest of fair play I thought I'd share a couple off my list:
1. I really care about how what I am holding feels. This manifests in a few ways. One is silverware. In the days before I got rid of all the mismatched pieces of silverware and bought a set I actually liked I regularly got up from the table and exchanged my fork or spoon if it was the "wrong" one(and most of them were.) No way would I suffer through dinner with an offensive piece of flatware. Also, I don't ever, ever, ever want to touch a smooshy banana. Ever.
You can see this sensory issue in my choice of pens, cars (the steering wheel and gear shift), fabrics, yarns and crafting tools.
2. I'm sensitive to sound. If things are too loud I literally cannot see. You will never find me in the car with the radio blaring. In fact, until very recently you would almost never even find the radio on in the car. Silence is so much more enjoyable to me than additional auditory input that I regularly work in silence and have not one song on a device to listen too. I occasionally choose a CD to listen to in the car and recently started listening to the radio when traveling alone just to make sure the outside world is still there. (I am married to a musician and feel lucky that he is so respectful of this.)
We all have a few (or ten) of these kinds of things. It is amazing how well we all navigate the world with them. I'm not surprised that many children aren't able to figure out how to deal with them. One of the things I read was that we all used to get a lot more sensory input in our daily lives that was calming. Chopping wood, working in a garden, carrying water and other heavy items, working with and around fire were parts of normal life for thousands of years. Now we schedule one weekend a year where we go camping, buy all our foods in grocery stores and have indoor plumbing (thanks goodness!) It is a drastically different life than our ancestors lived. We are trying to remember this when Emerson is flooding the floor in the bathroom to play in water or taking all his clothes off in a winter storm to snuggle into a fuzzy blanket.