Sensory Perception and Autism - Part 2

In the previous article in this series, Sensory Sensitivity and Autism: Part 1, we described sensory perception differences across the auditory, tactile, visual, olfactory and interoceptive sensory systems. Our Part 2 will focus on screening and measuring instruments for sensory sensitivity, synaesthesia, emotional sensitivity, sensory pleasure, and strategies for accommodating sensory sensitivity.

Screening and measuring instruments for sensory sensitivity

Winnie Dunn is the author of the Sensory Profile 2 (2014), which assesses children's sensory profiles. Catana Brown and Winnie Dunn have published the Adolescent/Adult Sensory Profile (2002). Olga Bogdashina has published the second edition of her book Sensory Perceptual Issues and Autism (2016), which includes a 140-item checklist based on the sensory profile associated with autism. We also have the Sensory Perception Quotient (SPQ) (Tavassoli et al., 2014), an instrument that measures the visual, hearing, touch, smell and taste perception of autistic adults. These are examples of the SPQ items:

• I can recognize different people by the way they smell
• I can hear electricity humming in the walls
• I can’t go out in bright sunlight without sunglasses
• I would be the first to hear if there was a fly in the room
• I can see dust particles in the air in most environments
• I would be able to hear the sound of a vacuum cleaner from any room in a two-storey building
• I would be able to hear each note in a chord even if there were ten notes
• I would be able to smell the smallest amount of burning from anywhere in the house

The Glasgow Sensory Questionnaire (Robertson and Simmons (2013) has items that measure hyper and hypo-sensory sensitivity, such as:

• Do you notice that you have hurt yourself but did not feel any pain?
• Do you react very strongly when you hear an unexpected noise?

The Interoception Sensory Questionnaire (ISQ8; Suzman et al., 2021) has eight items that explore difficulties in perceiving internal body sensations. Examples of the questions are:

• I have difficulty making sense of my body’s signals unless they are very strong
• There are times when I am only aware of changes in my body because of the reactions of other people
• I find it difficult to identify some of the signals that my body is telling me (e.g. If I’m about to faint or I’ve overexerted myself)

The screening and measuring instruments for sensory perception are not just research tools but practical aids that can be used to explore an autistic person’s sensory perception. By understanding their experience of specific sensory experiences, these tools can indicate what environmental accommodations are needed at home, school, work, and in a consulting or therapy room. This practical application empowers educators, therapists, parents, and individuals to make informed decisions and create supportive environments.

Synaesthesia

Synaesthesia is experiencing a sensation in one sensory modality that activates a sensation in another modality. The most common expression of synaesthesia is a written word, symbol, or sound that triggers the perception of a colour. For example, the letter ‘A’ evokes the colour red. Musical notes can also elicit colours, or a word elicits a specific taste, such as the word ‘parents’, creating the sensation of the taste of an apple. Synaesthesia is rare in non-autistic adults, occurring in 2-4% of the adult population, but around one in five autistic adults have synaesthesia (Baron-Cohen et al., 2013).

We have known autistic adults who have described their perception of a coloured ‘aura’ around people with the colour indicative of personality characteristics which can be used to identify people to avoid or accept.

It is important to recognise that synaesthesia is an aspect of the sensory profile associated with autism and a sign of sensory, not mental, disturbance. Some synesthetes have used this characteristic in the creative arts.

Emotional sensitivity

Our clinical experience and autobiographies confirm that autistic individuals are extremely sensitive to another person’s negative emotions, such as disappointment, anxiety or agitation. There seems to be a ‘sixth sense’ ability to perceive ‘negative vibes’; for example, an autistic person may refuse to go into a room of people, not necessarily due to auditory or visual sensitivity, but saying they ‘just feel negativity in the room’. We have found that this emotional sensitivity is often an accurate perception of the emotional ‘atmosphere’.

Emotional sensitivity may be one of the reasons why autistic individuals avoid crowds due to the risk of proximity to someone who is experiencing a negative mood and being ‘infected’ by that mood. Emotional sensitivity may also contribute to a characteristic of autism of avoiding eye contact as the eyes convey feelings (Smith, 2009).

Emotional sensitivity can occur with all expressions of autism. Robert Hughes (2003) wrote about his non-speaking autistic son, Walker, whom he described as being a “supersensitive emotional barometer who registered the true emotional pressure in the air, no matter how hard we tried to mask it”.

In his autobiography, Aaron Wahl (2019) wrote…. I perceived the feelings of others often overly clearly but could not find access to my own, which may be due to aspects of interoception associated with autism as described in part 1 of Sensory Perception and Autism.

Other autistic adults have described:

'I am able to distinguish very subtle cues that others would not see, or it might be a feeling I pick up from them.'

'There’s a kind of instant subconscious reaction to the emotional states of other people that I have understood better in myself over the years.'

Negative emotions in others can be ‘infectious’ to an autistic person. One of our clients said, 'Emotions are contagious for me. If someone approaches me for a conversation and they are full of worry, fear or anger, I find myself suddenly in the same state of emotion.'

As clinicians, we help an autistic person create a mental barrier, such as using the metaphor of imagining a forcefield, putting on a suit of armor, using a shield for protection or putting up an umbrella to keep ‘dry’ from a downpour of emotions. We also encourage autistic people to explain their sensitivity to someone’s negative mood and that the reason for their temporary withdrawal or avoidance of them is a coping mechanism due to emotional sensitivity and not a rejection of them as a person.

Dr Stephen Porges (2017) coined the term neuroception to refer to the primitive neurocircuitry we all have as human beings that help us to detect threat and danger. Neuroception is pre-conscious, so at first, we may not even be aware that our bodies are getting ready for fight, flight or freeze. Autistic people are more susceptible to both experiencing trauma, including trauma from daily exposure to feeling different/defective and experiencing exclusion, and developing post-traumatic psychological symptoms, for example, hypervigilance, distrust of others, nightmares etc. Autistic emotional sensitivity describes contagion of negative affective states from other people, such as stress and anger, rather than positive affective states such as joy and excitement. It is possible that, due to different wiring, extremely high levels of anxiety and/or trauma, an autistic person has highly attuned or very sensitive neuroception, which explains their high levels of sensitivity to other people’s emotions.

Sensory pleasure

Some sensory experiences can be extremely pleasurable, calming or fascinating for an autistic person (Smith & Sharp, 2013). These sensory pleasures are one of the positive aspects of autism. There can be a fascination with order and symmetry, such as train tracks and the ‘sleepers’ between the tracks, picket fences, streetlights and telegraph poles, creating a sense of well-being due to the consistency and predictability. Visual acuity can lead to a fascination with the perception of details, for example, in the structure of a feather, being mesmerised by watching the spinning drum of a front-loading washing machine or appreciating the various tones of yellow in a garment or painting. Heightened auditory perception can lead to appreciating complex music, which can also positively affect mood. Olfactory and oral sensitivity can make some foods extremely enjoyable, such as appreciating the quality of handmade Belgian chocolate or French champagne.

Unfortunately, enjoyment can lead to being ‘stuck in the moment,’ as described by a participant in the Smith and Sharp study: “I don’t know how long I was there, but I remember the car behind me beeping and people shouting at me as I watched the traffic lights change over and over… I was intrigued.”

Strategies for accommodating sensory sensitivity

Sensory integration therapy (SIT) was originally developed by occupational therapist A. Jean Ayres in the 1970s to help children with sensory-processing difficulties. The sensory-based interventions provide sensory activities or experiences to help children improve internal sensory processing and self-regulation and develop adaptive functioning skills. The programme has successfully been used with autistic children and is recognised as an evidence-based practice (Schoen et al., 2018).

Autistic children and adults also benefit from strategies discovered by parents or autistic people themselves. Auditory sensitivity can be reduced by wearing ear plugs, noise-attenuating or industrial headphones, or background music. Some sounds can be avoided, such as vacuuming when an autistic child is at school.

Sensitivity to the type and intensity of illumination can be reduced by wearing sunglasses when outdoors, a baseball cap, hat, or visor for bright downlights, or replacing fluorescent with incandescent lighting.

The sensory world can be frightening for an autistic child, and some autistic children have discovered that being mesmerised by a repetitive action or sensation can be a coping or escape mechanism. Temple Grandin explained that when she was a child:

“Intensely preoccupied with the movement of the spinning coin or lid, I saw nothing or heard nothing. People around me were transparent and no sound intruded on my fixation. It was as if I was deaf. Even a sudden loud noise didn’t startle me from my world. But when I was in the world of people, I was extremely sensitive to noise”

‘Stimming’ may have beneficial effects in reducing sensory sensitivity, which has recently been confirmed by research on repetitive behaviour. (Charlton et al., 2021; Nwaordu and Charlton, 2023)

In our conversations with autistic adults Autistic who have sensory sensitivity, they have explained that the sensory experience is less distressing if they can control the initiation and intensity of the experience. The experience is not a surprise, and they have the means of ending the sensory experience.

Finally, we know that sensory sensitivity and anxiety co-regulate each other. Increasing anxiety increases sensory sensitivity and vice versa. Programmes to reduce anxiety will increase the tolerance of sensory sensitivity, and a reduction in sensory sensitivity will reduce anxiety.

References

Baron-Cohen et al. (2013) Autism 4

Bogdashina, O (2016). Sensory Perceptual Issues in Autism and Asperger Syndrome. London, Jessica Kingsley Publishers

Brown, C & Dunn W. (2002). The Adolescent/Adult Sensory Profile Pearson Assessments

Charlton et al. (2021). Research in ASD 89 101864

Dunn W. (2014). Sensory Profile 2 Pearson Assessments

Hughes R (2003). Running with Walker Jessica Kingsley Publishers

Nwaordu and Charlton (2023) Journal of Autism and Developmental Disabilities 53

Robertson and Simmons (2013) Journal of Autism and Developmental Disorders 43

Schoen et al (2018) Autism Research 12

Smith, A. (2009) The Psychological Record 59 489-510

Smith and Sharp (2013) Journal of Autism and Developmental Disorders 43

Suzman et al. (2021) Molecular Autism 12:42

Tavassoli et al. (2014) Molecular Autism 5:29

Wahl A. (2019) Ein tor zu eurer welt KNAUR