I’ve referenced sensory overload and sensory processing differences here before, but haven’t really explained them.
Sensory Processing Disorder is very common in autistic people (there is a long list of different disorders and conditions that are comorbid with ASD); however, as with many conditions comorbid to ASD, the comorbidity rate is not known. A meta analysis (which basically takes lots of other research papers and evaluates the overall conclusion, how reliable the other papers are, etc) concluded that autistic people are significantly more likely to have sensory modulation issues than control groups.
Basically, many autistic people experience the world differently. We integrate and modulate sensory input differently to non-autistic people.
For example, at a pub my Dad was explaining this to my friend, and was explaining that whilst they could block out the loud environment around them to focus on the conversation (which I still don’t entirely believe because it sounds impossible to me), I could not. As the NAS says, autistic people often take in too much information.
I can’t listen to what someone’s telling me in a restaurant, for example, because I can hear their voice as loudly as I can hear a couple chatting behind us, as loudly as the cutlery clicking at another table, and as loudly as the music restaurants play for ‘ambience’. I have to focus extremely hard to even hear what they are saying and translate it into something I can understand.
Often, I mishear someone and repeat what they say back to them (phrasing it differently so they cannot tell that’s what I’m doing) to make sure I heard correctly. Now whilst this can be pretty funny sometimes (some of my misunderstandings are pretty out there), it makes it very hard for me to focus on what someone’s saying and understand them. People get annoyed when you ask them to repeat themselves more than once (usually they take offence and think you’re suggesting they’re mumbling, or tell you ‘just listen!’), I generally give up after asking once, and mimic whatever facial expression they’re making so they believe I’ve heard them.
This can make it even harder to keep up in conversations. And if multiple conversations are going on at once, I will not be able to keep up, and will likely panic and possibly shut/meltdown if forced to try. Because I’m already hearing everything, I’ve got it all going into my head, and it takes energy just to cope with the overload of information. Picking out the necessary parts, and trying to figure out what someone is saying, is also pretty tiring. But doing all of that, whilst trying to answer 2 conversations at once? Impossible. This is why I need questions once at a time, and I need time to process them.
So, people with sensory processing disorder will get the sensory input the same as everyone else, but often we cannot filter out most of it like others. And often this sensory input will affect us in different ways. For example, when I cover my ears when an ambulance passes, it’s because the siren hurts my ears. I don’t mean that it makes me uncomfortable, I mean I experience physical pain, like someone stabbed my ear.
This is true for the other senses. But people can be hypo- and/or hyper-sensitive. Basically, some senses may take in all of the information, and cause you to feel overwhelmed and overloaded (for me, this includes touch, taste, sight, and sound). But other senses may not register as much (for me, smell). Usually, I’m not sensitive to smell, and can’t smell things that others can. Smells often confuse me because they are often too vague and faint to identify.
You can be hyper-sensitive and hypo-sensitive to the same sense. I am hyper-sensitive to light touch, but hypo-sensitive to deep pressure and firm touch. I’ve also heard that people with autism tend to be hypo- or hyper-sensitive to pain. I could believe that, because stubbing my toe has me hugging my foot and unable to move for up to 10 or so minutes, and I’ll often be in pain for a while after. But being hit isn’t really painful. It’s deep pressure, not sharp pain.
There is also sensory seeking. Some people stim or seek sensory input because their bodies are craving it (I think, correct me if I’m wrong). For me, sitting completely still feels like a build up of energy underneath my skin, and it can hurt. I cannot sit still most of the time, and have to be moving even slightly (often rocking side to side, fidgeting with my hands). Sometimes, randomly, this energy fluctuates. Sometimes I have no need to move (it’s rare though), and sometimes I desperately need to move. If I’m unable to move in the way my body is craving, it can feel similar to sensory overload, because you’re getting all of these cues from your body that you’re unable to act upon. Sometimes it’s very hard to figure out how you need to move, as well. I remember that I’ve sat in class before, experiencing this sudden wave of energy, and I try stimming subtly to get rid of it (kicking my leg, rocking, etc). This often isn’t enough, and I can get panicky because I cannot figure out how to move in a way to get rid of the energy.
Now, when you’re able to stim freely, it’s awesome. The energy is great, and it makes you super happy (probably endorphins like from exercise?). My body is different to non-autistic people, and I need to move differently. I process the world differently, and cope with it differently.
What I find odd is that others have difficulty understanding this. Ever since you are little, you’re told how the majority of people experience things, and expected to respond in the same way. This is confusing for people who don’t experience the world the same way. I would try to figure out how non-autistic people experienced the world so I could understand why they reacted certain ways. I still get surprised when I realise or remember that someone is experiencing something differently to me, but I accept that. Non-autistic people seem to struggle with this, with grasping that others can have a completely different way of experiencing the world. I guess many haven’t really been forced to consider it before, like many autistic people have.