Autism and Sensory Processing

autism sensory processing


So, what is sensory processing?

Sensory processing is our ability to combine and understand information coming in from our senses. Our brain continuously receives information from all of our senses. Our brain then filters through this information in order to decide which information is important to attend to and which isn’t. Sensory processing is an automatic process. The purpose of this process is to enable us to be able to attend, organise and move our bodies and manage our emotions as efficiently as possible. Autism can cause a more varied experience of sensory processing.

It is common for autistic individuals to report difficulty tolerating every day sensations such as smells, background noise, or the sensation of clothes. We think autistic individuals may not have the same ability to filter through and get used to the information the brain is receiving. If this filtering isn’t happening efficiently, the brain can be flooded with sensory information which can make it difficult for the person to attend to other things in the environment (e.g. someone talking to them) and can be overwhelming emotionally too. 


How is sensitivity to the sensory environment recognized in an Autism diagnosis ?

Within the DSM-5 criteria for Autism, sensory processing differences known as hypo or hyper sensitivity are categorised under section B “restrictive, repetitive patterns of behaviour”.  Whilst this does reference the sensory processing difficulties somewhat in terms of engaging in self-regulatory behaviours/’stimming’ (see below), it doesn’t, in my opinion, reflect the impact that sensory processing difficulties can have on an autistic individual’s participation in every day activities. It has been my experience, that the most commonly reported explanation that autistic individuals give for having difficulty participating in every day activities, school life or social situations are sensory processing difficulties/sensitivities and a difficulty tolerating the sensory aspect of an environment.   


How does an Occupational Therapist gain an understanding of their client’s sensory needs?

The most commonly used standardised assessments that Occupational therapists use to evaluate an  individual’s sensory needs are; The Sensory Processing Measure (SPM-2 and/or The Sensory Profile (Sensory Profile 2 These measures assess whether an individual’s sensory preferences (likes and dislikes) are within the average range when compared against a standardised norm. The questionnaires also provide information on the extent to which any sensory  processing difficulties are interfering with every day activities and behaviour and whether the individual may be more/hyper sensitive or less/hypo sensitive to sensory input than average . 


What is “sensory overload”?

The purpose of our sensory processing is to keep us calm but alert in relation to what is going on in our environment. If individuals are not able to filter through the  sensory information in their environment it can be more difficult to  remain calm or alert. This build up of sensory information is referred to as sensory overload. This can feel different for different people. An individual experiencing sensory overload may become irritable, anxious, upset or even completely shut down in their attempt to regulate their sensory environment. 


What is meant by the term hyposensitivity?

It’s common knowledge that autistic people can be “hypersensitive” to their sensory environment, which means that there is more sensory information in their environment than they can process at that time. However, autism can also mean the exact opposite for some people’s sensory processing in the form of hyposensitivity.  Hyposensitive people are less responsive to the sensory input in the environment. They may need to intensify their sensory stimulation rather than reduce or avoid it. Busier, noisy or bright environments are actually what these individuals may seek out in order to focus or remain calm. 


What happens in our body when we are stressed?

Our bodies have a number of automatic reactions that occur when faced with a potentially threatening or dangerous situation. These reactions are called our ‘fight or flight’ reaction and are built into our bodies to enable us to escape quickly should that be necessary. Part of this ‘fight or flight’ reaction is that our senses become heightened or more sensitive. This begins with our ear drums changing shape to allow in lower frequency sounds that we would usually filter out.  Our eyes also become more alert and also scan the environment more frequently and rapidly. At a physiological level, our heart might begin to race, and our breathing might become quicker which pumps oxygen to our muscles so we are ready to run. Sometimes however, the ‘threat’ is not a physical one i.e. we are not actually in physical danger, rather we experience a psychological stress such as receiving unexpected bad news, having an exam or test or a falling out with a friend. But the reaction in our body can be the same . Alongside the emotional upset, we will become more sensitive to sensation. For example, if we are feeling stressed and someone touches us we may jump because we have become more sensitive to sensory input. This in turn can make us more emotionally upset so it can become a cycle of sensory sensitivity and stress. 

For autistic individuals who tend to be naturally more sensitive to sensory input, minimising other stressors in the environment or routine is as important as sensory calming activities in preventing sensory overload.  

What is a sensory diet?

A “ sensory diet” is a term commonly used to describe a plan or programme of sensory activities interspaced over the course of the day to support an individual’s sensory system to help maintain a calm and alert state. For example, an individual might take a walk in the morning, carry a weighted bakcpack to school, do chair push ups or jumping jacks as a movement break in school, wear ear defenders at break time, use a fidget to help concentration in the afternoon and listen to music to wind down after school. An occupational therapist can help you/your child choose suitable activities through talking through the results of sensory questionnaires and your sensory likes and dislikes. Sometimes it can be a matter of ‘trial and error’ too. A good place to start is thinking about sensory strategies/tools you may already be using as a clue to what your sensory system needs. 


What is meant by the term “self-regulation”?

Self-regulation is something that we all do in one way or another. It refers to using activities or behaviours to maintain a calm and alert state to help us manage the changing demands we experience in our environment. If we feel ourselves becoming anxious, irritated or overwhelmed we may take some deep breaths, have a cup of tea, play with a pet, turn to a hobby such art or writing or take a break from the environment.  Similarly, if we feel ourselves getting distracted, bored or fidgety, we might stretch or go for a walk if possible, fidget, take a cold drink listen to loud music. All these activities could be considered self regulation strategies as they help us to return to a calm and alert state. Although similar, self-regulation is different to a sensory diet in that it is more intuitive i.e. depends on the person noticing when their body needs more or less sensory input rather than a planned schedule of sensory breaks. 


What is meant by the term “stimming”?

Understanding stimming is crucial to encouraging coping strategies related to autism and sensory processing. Self stimulatory behaviours or “stimming” is a type of self-regulatory behaviour which often involves repetitive behaviours, movements or noises. This may involve hopping from one foot to the other, repeating a word or phrase or flapping hands for example. It is important to remember that while this behaviour may seem ‘unusual’ this behaviour is very important to the individual and serves a purpose for them in relation to regulating their emotions, environment and behaviour. 

What should I do if my child uses harmful self-regulatory behaviours?

While self-regulatory behaviours are necessary and helpful for individuals to manage their environment, this does not always mean that people adopt safe behaviours when self-regulating. It can be difficult if your child chooses to adopt harmful self-regulatory behaviours such as nail biting or more harmful behaviours like hair pulling or even banging their head. In these cases, it is important that you work at finding your child a replacement behaviour for this self-regulation.  Notice what it is that the self-regulation is providing them from a sensory perspective. For example, with hair pulling it is the sensation to the scalp or fingers they find regulating. Then try and find a suitable replacement activity that matches the sensory need, so with hair pulling you may try a fidget or perhaps a head massage instead. This may involve a certain amount of trial and error to replace the pre-existing behaviours. With younger children particularly, you may also need to positively reenforce use of the new tool/strategy e.g. a sticker or reward chart until they get used to it. With patience and cooperation between yourself and your child can work towards finding a positive way for them to self-regulate without causing themselves or anyone else harm. 

How has the COVID-19 pandemic had an effect on our sensory environment?

The COVID-19 pandemic has been challenging in many ways for everyone, posing particular difficulties for autistic people. The change in routine and move to on-line learning has been particularly difficult for those autistic individuals who need a consistent routine to feel safe. Also, the change in sensory environments with the use of masks, hand sanitisers and strong cleaning products continues to pose an additional challenge to autistic individuals with sensory sensitivities. However, on the other hand, some autistic individuals report that the move to online or remote learning, working or shopping has been beneficial as they can be removed from busy, noisy environments they are typically faced  with in schools, workplaces and community spaces. 

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