If know anything about the five senses you will know of sight, smell, taste, touch and hearing. Those are the basics and what we know of on the surface. But how much are we really affected?
In autism, some senses are turned up too high and thus are too intense at times to endure. Others are turned down too low and may endanger the person affected. For example, pain sensory too low can affect reasoning on dangerous situations.
Before I get to that really cool word up there, let me touch on the basics for a recap of how they can affect us.
Sight: Sensitivity to lights (including flashing ones) and brightness are commonplace. Flashing lights or too many fast moving objects in the area can also cause too much stimulation. If something moves close to the face goes past fast it can cause flinching. Some may get stimulation they like. My son flies toys past his eyes all the time for "movie-like" effects close up. Too many moving objects like bodies in a crowd or a thousand tennis balls being dropped at once can cause the eyes to try and focus in several places as once. As you can imagine that doesn't work out well. It's a natural tendency of the autistic brain to lack filters for several or certain senses causing an intake overload.
Hearing: I've mentioned before how painful high pitched noises can be. I don't just mean aggravating with chills up the spine. I mean you may as well have plunged a fistfull of hypodermic needles into my ears. But this can go the other way too. Some of us like a sound so much that we'll over use it. Some kids like the sound of their own voice at various pitches and will make all sorts of cooing and varied noises just to hear themselves. Again, multiple noises can short circuit a person with too much stimulation. The ears and the sensory intake may lack the ability to sort multiple sounds at times.
Touch: I've seen few sensory stimulants work on autistics like the sense of touch. Textures and temperatures work together to either provide a calm or repellent effect. A heightened sense of touch can make something as menial as bumps on a wall an object of fascination. It can also make a seam in clothing completely unbearable.
Smell: Odors can thrill or gag a person. Too high of sensory can make even a pleasant smell impossible to tolerate. Too low and you may not realize your dinner is burning.
Taste: There are three senses that work in the mouth at once and they make taste what it is. Smell and touch work with taste for a multi-sensory experience. This makes for picky eaters and even eating disorders. As it is, digestion in the mouth changes the taste and textures of some foods and can affect just how much it's tolerated.
Now for how they all work with that word; proprioception. Our proprioceptive sense are how our body and other senses work with the work around us and out internal being. So we can break it down to two ways this works; internally and externally.
Internal examples would be the feeling of a full stomach, muscle cramps, the need to go to the bathroom, and anything else our internal organs need to tell us. Yes, those are part of our senses and they can be affected by autism. This is why something as simple as mild hunger can be totally intolerable to some autistics.
External examples are spatial. Spatial senses tell us where our arms and legs are as we move around. If those senses are not working properly, you get someone like me. I hit my arms, hands, knees and feet on doorways and walls. I overshoot when reaching for doorknobs and jam my fingers. Spatial sense is important. Your sense of balance also works into this and bridges the gap from internal to external.
You know that feeling you get when dropping through the air suddenly? That's a proprioceptive sense. Kids who enjoy that feeling may jump off of things a lot.
The feeling of having lots of pressure on your body from blankets (as many autistics seem to like with weighted blankets) is a proprioceptive sense.
This is why understanding of sensory can be such a distinct key to understanding your child or family member who as ASD at any degree. I've found that sensory response is usually the first thing to check when it comes to the behaviors or reactions of any person with autism. It's amazing to think how some things most take for granted can have such a profound (or lack of) effect.
I hope this gives you a deeper insight to sensory disorders.