scriptautistic:

If you know a bit about autism, or have been following this blog for some time, you must be aware that one of the autistic traits which has the most consequences on our daily lives is our sensory differences. They have an impact on all spheres of our lives: on what we can and cannot do, on where we can and cannot go, on what we can eat, wear, listen to, on our ways to feel good and on what makes us feel bad.

Such a wide subject definitely warrants a masterpost. So, here we go!

First, let’s take a look at the human sensory system, to understand the different areas in which there can be differences. It’s actually more complicated than the traditional five senses! Our sensory system is divided into three parts:

• Exteroception : sensing what comes from the environment outside your body.
• Interoception : sensing the internal physiological condition of your body
• Proprioception : sensing the position your limbs and body are in

These three main areas encompass different senses (note that this is one model and others exist):

• Exteroception: sight, hearing, smell, taste, touch, but also thermoception (sensation of heat/cold) and nociception (sensation of pain)
• Interoception: nociception (internal pain), feelings of hunger, lack of oxygen, thirst, need to pee, as well as monitoring of the respiratory rate and heart rate.
• Proprioception: the kinesthetic sense (knowledge of the movement and relative positions of your body parts) and the vestibular sense (knowledge of body movement, direction and acceleration)

For all of these senses, autistic people can have them work typically, be hyposensitive (less sensitive than most people), be hypersensitive (more sensitive than most people) or have sensory processing differences which do not fall under the hypo/hyper system.

The clinical term which encompasses these differences is “Sensory Processing Disorder”. One can have SPD without being autistic, but all or almost all autistic people have SPD.

It should be noted, however, that some autistic people don’t like to think of it as a disorder and prefer simply talking about sensory processing differences.

Something very important to understand is that hypersensitivity and hyposensitivity CAN coexist in any one person’s sensory system. For example, they might be hypersensitive to smell and hyposensitive to touch. They can also be hyper/hypo sensitive to only one aspect of one sense (for instance, pressure or texture or bright lights or sweet tastes). They can also be sometimes hyposensitive to something, and sometimes hypersensitive to it.

Being hypersensitive to a stimulus and being exposed to it can cause what is called “sensory overload”, which usually translates to pain, discomfort, and impaired cognitive functions (in other words, trouble thinking properly). If pushed further (very intense stimuli or very long exposition), it can lead to a shutdown or meltdown.

Being hyposensitive to something and lacking stimulation can translate to restlessness, discomfort, and even pain, as well as an intense craving for the stimuli.

Here are some examples of what hypersensitivity to different senses can translate to, on a behavioral and subjective level:

• Sight: The person wears sunglasses, maybe even indoors. They avoid places with fluorescent lightning, blinking lightning or too bright lightning. They dislike looking at brightly colored surfaces. They may have trouble with visually cluttered spaces, such as crowds and supermarkets. They may find any kind of flickering or movement around them painful to see.

• Hearing: They may hear sounds no one else can hear (and some have been tested to hear outside the normal human range). They may have to wear headphones/ear defenders in noisy places. They may avoid crowds and events with lots of people/loud music/shouting. They may have difficulty with the noise of the vacuum, of the construction work on the other side of the street, of the clock ticking in the next room. They may develop tinnitus eventually.

• Smell: They’ll probably dislike places with strong smells such as perfume shops, farms, or crowded public transportation. They may need to wash themselves, their clothes and their sheet very often to keep body odors to a minimum. They may not tolerate scented soap, shampoo or deodorant (and it’s sometimes difficult to find an unscented one!). They may struggle with the smell of food in general, or with particular smells.
  
  
• Taste: They may be very picky eaters, only tolerating a couple of very bland-tasting food such as mashed potatoes or pasta. They may have difficulty having diverse enough diets with all the nutrients they need. They may always eat the exact same thing.

• Touch: They may have trouble finding clothing with a texture that they can tolerate. They may need to cut all the tags off their clothing. They may absolutely hate anyone touching them. They may be ok with firm touch, but find light brushy touches painful. They may have trouble wearing specific items of clothing, such as socks/shoes, headphones or hats. They may hate people touching their hair, or find brushing their hair very difficult. They may find brushing their teeth nearly impossible because of the scratching sensation. They may have trouble with the texture of many foods, and be a picky eater because of that.
  
  
• Thermoception: They may be very sensitive to cold, and always wearing loads of clothing and turning the heating up even when other people don’t think it’s that cold. They may be very sensitive to heat, finding summer very hard to cope with, especially if they don’t have access to AC. They may be hyper-aware of tiny changes in temperature, feeling cold when it is dropping and hot when it is rising regardless of the actual temperature.

• Nociception: They may be more sensitive to pain than most people, and find very painful what most people would shrug off. (They’re not being a drama queen! They really do feel more pain!)

• Vestibular sense: They may get motion sickness very easily.

And here are some examples for hyposensitivity:

• Sight: The person may have trouble finding things in visually crowded environments. They may enjoy looking at bright colored lights or at objects in motion (spinning top/twirling fingers…)

• Hearing: They may not notice being called or being talked to, especially when focused. They may enjoy listening to very loud music, singing, or making lots of noises.

• Smell: They may not notice smells which other people do. They may enjoy strong smells such as perfume, essential oils or body odor. They may enjoy sniffing a favorite blanket, a significant other, a pet, or anything they like.

• Taste: They may be able to ingest an impressive amount of spicy food, and may crave strong tasting food (pepper, lemon, salt, sugar…).

• Touch: They may love rubbing/touching favorite textures, rubbing their hands together… They may love and crave deep pressure, such as having heavy weights on top of them.

• Thermoception: They may be outside in winter with just a T-shirt, or not be bothered by the heat in summer and even wear a sweater. They may enjoy touching very hot things such as radiators or very hot water, or very cold things like ice cubes or snow.

• Nociception: They may be less sensitive to pain than most people and not notice it when they’ve been hurt.
  
  
• Vestibular sense: They may love roller coasters, boat rides when there’s a lot of waves… They may never get motion sickness of any sort. They may spend time rocking or like to chill upside down.

• Kinesthetic sense: They may be very clumsy since they have a poor sense of the position of their body in space. They may stumble a lot and be generally bad at sports. They may have trouble with fine motor skills such as handwriting or sewing. They may enjoy doing repetitive motions such as hand flapping.
  
  
• Interoception: They may have trouble noticing  when they are hungry, thirsty, tired, or when they need to go to the bathroom. They may need to set alarms or to have self-care at set times as part of their routine.

These are of course only examples and hyper or hyposensitivity can express themselves in as many ways are there are people who experience them.

Here are some examples of other sensory differences autistic people can experience:

• Synesthesia seems more frequent among autistic people than in the general population. It is defined as a transfer from one sensory modality to another: for example, seeing sounds or hearing tastes. It can also mean associating colors or personalities to numbers/letters. In autistic people specifically, it can be a very positive thing (you can now stim with two senses at the same time!) or something painful (these bright lights are awful, well now they’re harsh noises too).

• We often struggle with processing sensory information, especially speech, which can mean we can have a lot of trouble understanding what people say, might take a lot of time to process speech (which results in conversations such as” “Hey, will you get me this thing please?” “What?” “I said, will-” “Oh yeah, sure”), and might need subtitles to be able to understand movies. Processing information from two different senses at a time can also be difficult, which often translates as “I can either look at the images or understand what’s being said”. This is one of the causes of our struggle with eye contact.

That’s all for today. We hope this helped. We are currently preparing a masterpost on stimming which will be quite related to this one. Happy writing!