Sensory processing involves the ability to take in, organize and make sense of the different kinds of sensations received by the brain. It has been estimated that around 90 per cent of people with autism experience over and/or under sensitivity in at least one sense, and that this will have a significant impact on their ability to function and make sense of the world around them. The latest edition of the Diagnostic and Statistical Manual has included sensory issues in the criteria for an autism diagnosis, in order to reflect how frequently the sensory environment impacts people with ASC.
Non autistic people, on average, are good at organizing information from their senses. Their brains ”tune out” or ”filter” information so that they can focus on what is relevant in any given situation. This process is mostly done unconsciously, allowing them, for example, to carry on with their work despite the distant sound of a lawnmower or the slight smell of someone’s aftershave. According to the theory, autistic people have over connected brains, which means that the world is super intense and they are less able to adapt or become habituated to an environment over time. Every single sensory input is consciously processed, meaning that the person might experience severe distraction and anxiety. This theory also interlinks with the fact that synaesthesia, a condition where input from one sense is experienced simultaneously by another, for example seeing colour when hearing someone talk, is more common in autism.
In autism all the sensory input competes for attention, meaning that the brain is flooded with information, resulting in a state of sensory or information overload. In this state the autistic person can find it harder to focus on a relevant channel of sensory information, for example someone talking to them, because other ”background” information can interfere with their attention. I might be distracted by a baby crying, a conversation near by, or the smell of cigarette smoke. Eye contact, and even the whole face, can also be very uncomfortable because of a heightened visual sense. I find it much easier to pay attention to what someone is saying if I don’t have to simultaneously look at their face.If the other person is not aware of the autistic person’s difficulty, they might make the mistake of assuming that the autistic person is uninterested, bored, or being rude. In fact it is likely that the autistic person is trying very hard to focus, but is experiencing a lot of anxiety. Because people with ASC may have longer neural pathways to process the information, or very slow processing speed, it can take the person with ASC longer to make sense of and respond to their environment. I might need to have instructions repeated several times before being able to understand or take meaning from it, because, as highlighted in a recent cognitive assessment, my processing speed is in the extremely low range of intellectual ability, despite my extremely high verbal intelligence.
It is important to remember that each autistic person is unique in terms of their sensory profile, or what sensory differences they experience. As no two autistics are the same, one person’s sensory joy will be another’s nightmare. To reflect this diversity, sensory experiences are often categorised as either hyper or over and hypo or under sensitive, and many autistics are both hyper and hypo sensitive, sometimes even within the same sense. For example, in some contexts they might be over sensitive to noise, while they might barely register the noise on another day or context. They might even crave loud music, flashing lights and other extreme sensations, despite being oversensitive at other times. Generally speaking I am more hyper sensitive than hyposensitive, and my main sensory issue is unpredictable noise, particularly when I am trying to concentrate on another activity. In my case sensory issues heavily overlap with the other autism traits of a need for routine, predictable environments, and my intense interests. For example, I love reading to the extent that this activity dominates my life, and I have a strong need to read every morning for at least two hours. From the moment I get up I feel stressed, worrying whether or not there will be noise from the neighbours or construction work outside that might interfere with my ability to focus on the book I am currently reading and need to complete. I try and cope by playing white noise through my headphones, which helps because the noise is steady and predictable, and has the effect of muting the jarring, chaotic noise from outside. However, because my ears are so sensitive, I can still pick up this noise, such as a neighbour’s toilet flushing upstairs, water in the pipes, or random footsteps above me. Every time there is a noise I experience a painful spasm in my stomach, and I have to read the sentence all over again, as I lose all sense of meaning. Likewise, I struggle to sleep if there is any noise, no matter how gentle the noise may be, and have had to resort to sleeping with fingers in my ears because unfortunately ear plugs have not helped me. Consequently I am often at least slightly tired, which has the adverse effect of making me even more sensitive to noise, and so a vicious cycle is created.
I am also quite sensitive to light, and very bright sunshine or florescent lighting can make me more tired or overstimulated, and this can also affect my sleep if there is any light infiltration from street lights outside.
However, my hypersensitivity is not uniform because in some contexts I can endure noise without being too affected by it. I can cope with sitting in certain cafes, despite the noise from coffee machines around me, because I expect cafes to be noisy, I am in control, and there is a clear escape route. I can also cope better if my other senses are not being overwhelmed. For example, if I was standing up in a crowded room, I wold quickly become overloaded because I would have movement and touch to contend with as well as just noise. There has recently been some research carried out that has highlighted a strong link between sensory sensitivities and difficulty handling uncertainty, carried out by Pawan Sinha ,professor of vision and computational neuroscience at the Massachusetts Institute of Technology. His research showed that making the sensory environment more predictable can be as effective if not more so than simply reducing all sensory input, although of course this will vary for each individual.
With some sensory stimuli I crave stimulation because of being hyposensitive. As a child I was very hyperactive, and although as an adult I am more sedentary, I often like to jump and flap or move my body in particular ways, in order to feel alive and stimulated. Unfortunately, due to negative reactions from other people, I have learnt to repress a lot of my energy, which can result in tension and increased anxiety. As I will talk about later, I also enjoy eating and seek out strong flavours. However, other autistics might have the opposite profile and experience a lot of food aversion and consequently have quite a limited diet.
As briefly mentioned, sensory issues can be experienced differently even within the same person, depending on different factors, such as tiredness, the weather, location, and the degree of predictability and familiarity. So, for example, because visiting the clothing store H&M every Monday was part of my routine for several months, I could endure what might appear to be a very unfriendly autistic environment. I could endure the harsh lighting and noise better in this environment because I was in control, and I was completely focused on looking at all the clothes, which had become one of my interests. In another context, for example if that was my work environment or living quarters, I would very likely meltdown and not be able to function at all. Therefore, if there is order within the sensory experience, it is possible that the autistic person will be more comfortable than if the sensory world is unpredictable and not connected to their interests.It is impossible to generalise about what might work for all autistic people because we’re individuals and we can also change over time.
While there are exceptions, the sensory profile of non autistic people is usually fairly balanced and it is unlikely that their senses will cause them any major difficulty. Conversely it is common for autistic people to experience super intensity in at least one sense, and in some cases nearly all the senses are affected.
Recently it has been theorised in the Intense World Theory of autism, coined in 2007 by the neuroscientists Kamila and Henry Markram, that autism is the consequence of a supercharged brain that makes the world painfully intense and the behaviours an autistic might engage in, such as withdrawing from social contact, are coping strategies for avoiding the intense feelings. The theory suggests that autism is first and foremost a sensory processing difference, and that the social difficulties are not primary but secondary. The theory makes a lot of sense to me because I do see, hear, feel, think and remember too much, too deeply, and because of the rush of information I can’t prioritise it and struggle to relate to the world and people because I’m in a constant state of anxiety. Far from it being the case that most autistics are oblivious to other people and are disconnected from the world, it is likely that they are too aware of their environment and the feelings of other people but struggle to comprehend the information, and so everything around them is experienced as chaotic and impenetrable noise. The intense world theory also suggests that behaviours such as rocking and other repetitive movements that some autistic people engage in help to bring some degree of safety and calm to the person’s anxiety filled life, by providing the person with a sense of control and order. I feel much less anxious when I am allowed to rock or pace, and it’s important that people don’t judge this behaviour negatively because this can encourage the autistic to mask or hide their coping strategies, resulting in even more anxiety. The intense world theory argues that autism is essentially and inner experience of chronic anxiety, which may be visible or invisible, depending on what strategies the person has developed to deal with their discomfort.
Although we often speak about sensory difficulties in autism, it is important to understand that the sensory world can also be experienced positively. For example, in moments where the visual sense is hypersensitive,the autistic person might be moved to a state of euphoric joy when they look at a perfect picture or piece of architecture. For example, I often visit the small town of Arundel, which has several antique parlors. The beauty of the varied objects in the room was overwhelming and intoxicating, but I also felt a rush of positive energy and joy in the face of such perfection. I also have synaesthesia, the sensory mingling which I touched on earlier. In my case this means that days of the week, months of the year, words, and numbers are all intensely coloured and are felt as having spatial locations, and this partly explains my intense love of words and reading. My need for taste stimulation ties into my strong interest in food, nutrition, and cooking. I love eating good food at particular times of the day, and the sensations are extremely comforting and bring great satisfaction to my life.
In terms of strategies for helping the autistic person, first of all think about methods of communication. For example, meeting in person might be too overstimulating, and so they might prefer phone or email contact. Others, however, might hate speaking on the phone because of the ringing sound, or they might not like email because of the distracting light from the computer. Get to know the person and find out what works best for them.
Think about how your environment might impact the autistic person. Myself and many other autistic people struggle to concentrate in noisy environments. When I attended an autism event this year, I became very distracted when the lady sitting behind me kept moving about, and I had to constantly ask the speaker to repeat what they were saying, before I finally decided to move seats. And at a tea room I regularly visit, I sometimes find the pendulum lights very distracting and this means I have to look down or close my eyes, if I cannot move elsewhere. Bear in mind that noise, light or smells that might not affect a non autistic person can be torture for an autistic, so think about how much perfume you are wearing, how, how cluttered the room is, the acoustics, whether or not there are any distracting patterns on the walls or carpet, or whether the person might be distracted by the fan or electrical equipment. You could get creative and think about any positive sensory experiences that might help that person to concentrate, such as allowing them sensory breaks where they can jump up and down, if they crave movement stimulation, or they might find that listening to extremely loud rock music helps them to filter out distractions.
Sensory overload can sometimes get so intense that the person meltsdown. In this scenario the best thing you can do is to remain calm, find out if you can relocate elsewhere, and talk quietly and slowly. Relaxation tools such as stress balls, high intensity exercise (if they are hposensitive and crave input), reading, or sitting in a quiet and dark room for a while, depending on the person, could help.
To round up, in autism sensory issues can significantly impact upon a person’s life, often negatively but sometimes positively as well. Autistic people can struggle to pay attention, learn and socialise in situations that do not take into account their sensory needs. By trying as much as possible to make the environment as friendly as possible for that particular individual, you can make a world of difference in that person’s life and their ability to function in this very confusing world.