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Sensory Synaesthesia in Autism:

Updated: Jul 26, 2021

Seeing or tasting sounds, hearing colours, being touched by sights…

Alyosha was about 9 years old when he tried to account for a panic attack by saying: “I was scared. I saw a yellow ‘z-z-z’ sound.” This was confusing, until I realised he had synaesthesia.

Synaesthesia (Greek syn – ‘together’ and aesthesis – ‘perception’) or ‘cross-sensory perception’ is an involuntary physical experience when the stimulation of one sensory modality triggers a perception in one or more different senses. To translate it into plain English: synaesthetes see sounds, or smell colours, or taste shapes, or feel sounds on the skin, etc. For example, hearing certain sounds brings the perceptions of colours.

Synaesthesia is not homogenous and can manifest in different ways; in other words, there are different types, variations and forms of synaesthesia. Many synaesthetes have more than one form of synaesthesia.

Different kinds of synaesthesia are classified according to the time they occur, for example:

  • Constitutional synaesthesia (Grossenbacher 1997) starts very early in childhood, and it is constant during the lifetime. Constitutional synaesthesia is also known as developmental synaesthesia, idiopathic, or strong synaesthesia.

  • Acquired or postaccidental synaesthesia occurs during adulthood as a result of neurological dysfunction, or an accident, or disease.

According to the number of senses involved there are:

  • Two-sensory synaesthesia (when stimulation of one sense triggers the perception in a second sense). E.g., someone may complain about the sour taste of the somebody’s voice. There can be many different combinations of senses.

  • Multi-sensory synaesthesia (when more than two senses are involved). That’s when it gets really complicated. A child may experience the taste of the sound, while simultaneously seeing the colour and experiencing a tickling sensation on the skin. Some individuals seem to see not only the colours of their acoustic environment but also the density, shape and movement of sounds.

Synaesthetic experiences are involuntary; they are not just in the head, they are projected into the environment: individuals with synaesthesia actually see sounds, hear colours, etc. Interestingly, synaesthetic experience is very individual; for example, among people who see coloured sounds there is no specific colour for each sound from person to person.

One of the most common features of synaesthetes is their superior memory (due to their parallel sensations). Synaesthetes often remember the secondary perception better than the primary one. Some people may forget the name of the person they know but remember the colour, or taste, or even the temperature of the word.

The research of prevalence shows that from two to five per cent of the population have synaesthesia (Simner et al. 2006). Though the fact that synaesthesia does occur in autism is recognized, it is considered to be rare. However, the analysis of the personal accounts of autistic individuals shows that synaesthesia is not rare in this population and practically all combinations of senses have been found. Probably, the reported low incidence of synaesthesia in autism can be accounted for by the fact that because many autistic children with synaesthesia don’t realise that other people cannot, for example, hear sounds while seeing colours. To them, it’s a normal way to perceive the world. Even very articulate adults with autism find it difficult to express their experiences because they are so different from the ‘norm’. And of course, unappreciated…

In autism (among other types), quite common is the form of synaesthesia that produces tactile sensations without the individual being physically touched, for example, looking at something can bring a tactile experience. Or the other way round, when somebody looks (or stares) at them directly, they feel it on the skin. Some autistic individuals experience ‘being touched’ by sounds on their skin. Lucy Blackman (2001) calls this phenomenon ‘sound-feeling’. Often the skin sensation comes from sounds other people cannot hear. Some can be even hit by sounds. What is even more interesting, the sound can be both felt on their skin and seen by their eyes simultaneously. Too much noise creates visual chaos – making it impossible to interpret their environment and comprehend what is going on around them.

Most synaesthetes don’t complain of their condition because for them it is their normal perception of the world and they are not aware of it causing any disadvantages. Moreover, they often enjoy the colours of voices and emotions, tactile experience of music, smells of sounds and many other unusual perceptions, and think that losing their unique perception would be upsetting, like ‘losing one of the senses’.

Though it is true only if synaesthesia is unidirectional, whereas in case of ‘two-way’ .(bidirectional) synaesthesia (when, for instance, a synaesthete not only sees colours when he hears sounds, but also hears sounds whenever he sees colours), the individual really suffers from the condition and can experience stress, dizziness and information overload. Because of this, they may avoid noisy or colourful places, and may withdraw completely. And if the synaesthete has autism with other sensory problems as well (that can and must be addressed), it becomes harder to deal with sensory overload.

Some children can experience problems with the voice of their communicative partner because the voice hurts or sends flashes of colour that disrupts the understanding. Or they can be so intrigued/ fascinated by the colour and movement of the voice that they are unable to comprehend what the voice is saying and become confused and disoriented in social situations. If you suspect this is the case, talk in small ‘doses’ (1-2 sentences) and regularly pause to check if the child is ‘with you’ (following what you are talking about).

Though there may be problems, in many ways, it’s an enriched multidimensional experience of the world, leading to creativity and originality of thoughts, insights and expressions.

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