Autism 101: Sensory differences with autism

A huge part of how we interact with the world around us is based on the senses. There are sensory differences with autism that make up an important part of the diagnostic criteria. Not everyone with autism has the same sensory experiences of the world, but there are similarities in our sensory processing and the way this differs from the general population.

Unless we talk about these differences, it can be difficult for both autistic and non-autistic people to understand how others experience the world. Therefore, in this post I will provide an introduction to sensory processing and what this can be like for autistic people.

What is meant by sensory experiences?

We each have a sensory processing system in the body that helps us understand information from the world around us. How our individual sensory processing system works determines how we perceive the world, and how we interact with it. You might not realise, but this system is working hard with everything you do. Here’s an example:

I often bend down to cuddle my dog Maggie and never give it much thought. But a number of sensory processes and experiences are taking place. First, I see and/or hear her approach. I notice the familiar black and white fluffball that is my dog, and I recognise the tapping of her paws on the floor. When I bend down to her level, I need to make sure there is enough space and to be able to keep my balance. I reach out to touch her and notice that her fur has a soft and wavy texture. Sometimes I give her a kiss on the head and pick up her familiar scent which I think smells like biscuits. I notice the sound of her sniffing, or the happy little noises she makes. I have a positive association with these sensory experiences and so I usually feel happy and calm and will seek them out on a regular basis. And I’ll stop there before this turns into another Maggie appreciation post!

So, how do autistic people’s sensory experiences differ?

There are sensory differences with autism which means that autistic people can be hyper- or hyposensitive when it comes to the senses.

Hypersensitivity refers to what happens when the awareness and experiences of stimuli are increased. For example, a person may become distressed by loud noises or bright lights.

Hyposensitivity refers to what happens when the awareness and experiences of stimuli are decreased. This, for example, could mean the person does not react to stimuli others would react to, such as touching a hot pan. They may be able to tolerate strong and powerful flavours and may seek this out in preference to foods they would experience as bland.

What are the 7 senses?

For each sense there is an associated organ in the body that sends information to the brain to help us process and understand the world around us. It is important to note that information relating to each sense can be more complex than you might think. For example, touch consists of a number of sensations including pressure, temperature, pain and texture.

There are five main senses you are probably familiar with: sight, sound, smell, taste and touch. The two you might not be so familiar with are vestibular and proprioception.

Vestibular

The inner ear interprets the body’s position and movement and adjusts balance and direction accordingly. This supports you to move and position yourself safely and effectively. If an individual is hypo- or hypersensitive then balance will be affected. Those experiencing hypersensitivity may struggle to tolerate quick movements and could feel disorientated if, for example, jumping and leaving the ground. Those with hyposensitivity, on the other hand, may gain pleasure from the feeling of movement and may not experience dizziness or nausea from activities such as spinning or swinging (Bogdashina, 2016).

Proprioception

Proprioception refers to a person’s awareness of where their body is positioned in space and how much room it takes up. It also refers to how much force is being applied to the body. If people are hypo- or hypersensitive to this sense it will impact their coordination and how they interact with the world around them. Similar differences are seen with proprioception regardless of whether this difference is hypo- or hypersensitivity.

Difficulties with fine motor skills (precise movements) are related to proprioception and this can impact a person’s ability to carry out day-to-day tasks such as writing or using cutlery. Poor gross motor skills (movements using larger muscles in the body) impact on coordination of the body in larger movements such as dancing or running. A person may also have difficulty with placing objects or avoiding objects when moving (Bogdashina, 2016).

Examples of different sensory experiences:

Here are some examples of sensory differences with autism and how a person might experience sensory input differently depending on whether they are hyper- or hyposensitive.

Sense	Hypersensitivity	Hyposensitivity
Sight	May not be able to tolerate bright lights or certain colours or patterns.	May be attracted to light, bright colours or certain shapes. May move objects in front of their eyes.
Sound	Particular sounds may be too loud or painful to tolerate. May hear noises others do not and may have difficulty processing competing noises.	May seek sounds (eg putting ear against electrical equipment) and may create sounds such as vocalisations or tapping.
Smell	May not be able to tolerate certain smells and may find unfamiliar smells distressing.	May seek out strong smells and may smell items to process and understand them.
Taste	May have a limited diet of foods they can eat. May also have a sensitive gag reflex.	May put objects to their mouth to process them. May seek out stronger tasting foods.
Touch	May not be able to tolerate certain types of touch, eg light touch, particular textures, or unexpected touch. May not be able to tolerate wearing particular clothes depending on the texture and fit.	May not be able to feel light touch, pain or extremes of temperature. May try to experience touch through seeking deep pressure (eg tight hugs) or banging their head against something.
Vestibular	May have difficulty changing direction when moving or walking on uneven surfaces. May feel dizzy or disoriented after activities that require a quick change in the body’s position such as jumping or turning.	Enjoying the feeling of movement from activities such as spinning or rocking back and forth.

Proprioception – Similar differences are seen with proprioception regardless of whether the person is hypo- or hypersensitive. Examples of these differences are that the person: may have difficulty manipulating small objects (eg fastening buttons); may appear uncoordinated and may tire easily when standing; may bump into items when moving and trip or fall easily; or may lean against things or people to support themselves.

Final thoughts

The sensory processing system is complex and is something probably not given much thought by those whose sensory experiences are more like the majority of the population. However, I hope this post serves as a useful introduction to sensory processing and what it means to have sensory differences.

In a future post I will be further exploring what it is like to live with sensory differences, including what happens when sensory input becomes too much and sensory overload is experienced.