I first learned about SPD when I was in college, studying to be a Certified Occupational Therapy Assistant. I was fascinated by it. Years later, SPD would become a reality for me. My son was diagnosed with Autism right after he turned 3 (he is 6 now). I have to say I was in denial until right before this point. I started to "see" it when he was almost 3, and got him in for an evaluation shortly afterwards. Usually, children with Autism also have SPD, but they are two separate disorders. There are a lot of people with SPD who do not have Autism.
He lacks stability in his muscles and trunk (proprioceptive dysfunction), so he prefers to play while lying on the floor with this head on the ground. Proprioception is the sense of where your body is in space. There are receptors in the joins, muscles and tendons that help us with this. Children who have proprioceptive dysfunction may lack stability like my son. They may be clumsy and trip and fall a lot, they may not know how much pressure to put on things, so when they color it might be too light, or they may break the crayon because they push too hard. Sometimes my son will hang on things, trying to get that proprioceptive feedback in his joints. The photos above and below are showing how he is seeking that feedback by pushing his head into the ground/couch. He is also supporting himself in the above photo. Two birds with one stone :)
His biggest difficulty with SPD is tactile. We live in Utah, where it is cold half the year. He loves to wear shorts and short sleeves. Getting him to wear pants has been very difficult. He just doesn't like the feeling of them on his legs. We have made a lot of progress with this, but in the past we would deal with meltdowns almost every morning getting dressed. I used to have to hide his shorts because he wouldn't wear anything else. People probably thought I was a negligent mom for sometimes sending him to school in shorts and with no coat on. It just wasn't worth the fight sometimes. He does so much better wearing pants now, but he does roll his pant legs up sometimes to have the feeling of shorts. Long sleeve shirts and coats are the same story. Some kids prefer to have their body covered up. They don't like the feeling of the shorts or short sleeved shirts rubbing on their skin, and that might cause a meltdown. Some kids like to have their clothes tight and others like them loose. I remember one time he had a very long meltdown and I couldn't figure out what the problem was. I finally found that he had a string hanging from the waistband of his pants and he just couldn't take it anymore. Below is a photo of one of his many meltdowns.
The last thing I will talk about is the auditory sense, or the sense of hearing. Lots of kids with SPD hear things differently. They may hear sounds louder or they may not even hear them. The 4th of July that my son was 3 was probably one of the hardest days of my life. We went to a parade, and it was so loud. He kept covering his ears and screaming. The photo below shows him "shut down". He was trying to protect himself from all the stimulation he was getting. He came home and threw up. We weren't sure if he was getting sick or what the problem was, but now we know that his system had just had too much (he has done it since after movies as well). THEN, we went to fireworks later that night. Worst. experience. ever. I still break down in tears thinking about it. I took him and hid in the restroom, but he was still hysterical. We had parked too far away for me to take him to the car. He has since done much better with fireworks, but we have had to work hard and be prepared (parking close, noise cancelling headphones). Movies are also difficult for him. He would much rather not go, and we haven't taken him to a movie for a couple years.
He is an amazing little boy, and I can truly say he one of my heroes. I am so proud of all that he has accomplished and know that he will do great things.
This is just a basic overview of SPD and how it presents in my son. If this is something you are interested in learning more about, please feel free to ask me any questions.
A good website to learn more: www.sensory-processing-disorder.com/
Some of my favorite books on SPD:
Sensational Kids by Lucy Jane Miller
The Out of Sync Child by Carol Kranowitz
The Out of Sync Child Has Fun by Carol Kranowitz