Study links Synaesthesia to Autism

A condition where people experience a mixing of the senses, such as tasting words, has been linked with autism.

Research suggests synaesthesia is nearly three times as common in adults with autism spectrum disorder than in the general population.

The two conditions may share common features such as unusual wiring of the brain, say UK scientists.

The study helps understanding of how people with autism experience life, says the National Autistic Society.

Synaesthesia is a condition where one sense automatically triggers another. Some people experience tastes when they read or hear words, some perceive numbers as shapes, others see colours when they hear music.

People with synaesthesia might say: "The letter q is dark brown," or: "The word 'hello' tastes like coffee," for example. People with the condition [autism] can find everyday life confusing or even frightening so research like this, which helps us to understand more about how they experience the world, is valuable” 

Carol Povey, National Autistic Society

Following anecdotal evidence of links between synaesthesia and Asperger's syndrome, researchers at the Autism Research Centre at Cambridge University set out to test the idea.

More than 200 study participants - 164 adults diagnosed with high-functioning autism or Asperger's syndrome, and 97 adults without autism - were asked to fill in questionnaires to measure synaesthesia and autism traits.

The study found one in five adults with autism spectrum conditions - a range of related developmental disorders, including autism and Asperger's syndrome - had synaesthesia compared with about 7% of people with no signs of the disorders.

Prof Simon Baron-Cohen, who led the research, told reporters: "Synaesthesia involves a mixing of the senses and it's a very subjective private experience, so the only way we know it's happening is if you ask people to report on their experiences.

"And what this new study has done is ask people whether they experience synaesthesia, for example where a sound triggers the experience of colour or a taste triggers the experience of colour, and finding that these unusual experiences are actually much more common in autism than we previously knew."

The research, to be published in the journal Molecular Autism, suggests that while the two conditions might appear distinct, there could actually be some underlying similarities in brain connectivity.

More information: Is synaesthesia more common in autism? Authors: Simon Baron-Cohen, Donielle Johnson, Julian Asher, Sally Wheelwright, Simon E Fisher, Peter K Gregersen, Carrie Allison. In Molecular Autism (November 1st, 2013). www.molecularautism.com/content/4/1/40

Olivier Messiaen: Synaesthesia - Music and Colours

Olivier Messiaen (1908 – 1992)



Messiaen was a French composer, organist and ornithologist, widely regarded as a major composer of the 20th century.

Messiaen was gifted with Synaesthesia, whereby he perceived colours when he heard sounds and musical chords. He cited the importance and relevance of using these colour combinations in his compositional process.

His music is rhythmically complex (he was interested in rhythms from ancient Greek and from Hindu sources); harmonically and melodically it is based on modes of limited transposition, which he abstracted from his early compositions and improvisations.

Many of his compositions depict what he termed "the marvellous aspects of the faith", and drew on his deeply held Roman Catholicism.

Messiaen was deemed as 'a bit eccentric' and he had a particular fascination for birdsongs; he believed birds to be the greatest musicians and considered himself as much an ornithologist as a composer.

He notated bird songs worldwide and incorporated birdsong transcriptions into most of his music.

His innovative use of colour, his conception of the relationship between time and music, his use of birdsong and his desire to express religious ideas are among features that make Messiaen's music distinctive.

Dyslexia:Synesthesia can improve Memory, Reading and Spelling

We investigated whether functional brain networks are different in coloured-hearing synaesthetes compared with non-synaesthetes.

Based on resting state electroencephalographic (EEG) activity, graph-theoretical analysis was applied to functional connectivity data obtained from different frequency bands (theta, alpha1, alpha2, and beta) of 12 coloured-hearing synaesthetes and 13 non-synaesthetes.

The analysis of functional connectivity was based on estimated intra-cerebral sources of brain activation using standardized low-resolution electrical tomography.

These intra-cerebral sources of brain activity were subjected to graph-theoretical analysis yielding measures representing small-world network characteristics (cluster coefficients and path length).

In addition, brain regions with strong interconnections were identified (so-called hubs), and the interconnectedness of these hubs were quantified using degree as a measure of connectedness.

Our analysis was guided by the two-stage model proposed by Hubbard and Ramachandran (2005).

In this model, the parietal lobe is thought to play a pivotal role in binding together the synaesthetic perceptions (hyperbinding).

In addition, we hypothesized that the auditory cortex and the fusiform gyrus would qualify as strong hubs in synaesthetes.

Although synaesthetes and non-synaesthetes demonstrated a similar small-world network topology, the parietal lobe turned out to be a stronger hub in synaesthetes than in non-synaesthetes supporting the two-stage model.

The auditory cortex was also identified as a strong hub in these coloured-hearing synaesthetes (for the alpha2 band).

Thus, our a priori hypotheses receive strong support. Several additional hubs (for which no a priori hypothesis has been formulated) were found to be different in terms of the degree measure in synaesthetes, with synaesthetes demonstrating stronger degree measures indicating stronger interconnectedness.

These hubs were found in brain areas known to be involved in controlling memory processes (alpha1: hippocampus and retrosplenial area), executive functions (alpha1 and alpha2: ventrolateral prefrontal cortex; theta: inferior frontal cortex), and the generation of perceptions (theta: extrastriate cortex; beta: subcentral area).

Taken together this graph-theoretical analysis of the resting state EEG supports the two-stage model in demonstrating that the left-sided parietal lobe is a strong hub region, which is stronger functionally interconnected in synaesthetes than in non-synaesthetes.

The right-sided auditory cortex is also a strong hub supporting the idea that coloured-hearing synaesthetes demonstrate a specific auditory cortex.

A further important point is that these hub regions are even differently operating at rest supporting the idea that these hub characteristics are predetermining factors of coloured-hearing synaesthesia.

The DOI Paper: DOI: 10.1111/j.1748-6653.2011.02004.x

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Brain-hacking art: Getting your wires crossed

What's the colour of a trumpet blast? David Hockney, Wassily Kandinsky and other synaesthetes could tell you

LETTERS, words, numbers, sounds, touch, pain and smell all trigger flashes of colour in Carol Steen's mind. The New York-based artist first discovered she could paint her synaesthetic visions after a visit to her acupuncturist.

"Each time a needle went in a colour flashed in front of my eyes," she recalls. "When all the needles were in it was like watching a movie. I rushed home and realised I could recall enough to paint a part of what I had seen."

Other synaesthetic artists include David Hockney and Wassily Kandinsky, who painted the piece below, entitled Blue. There is still some speculation over whether Kandinsky actually had synaesthesia or was simply influenced by reports of the phenomenon in other people.

But to Christopher Tyler of the Smith-Kettlewell Brain Imaging Center in San Francisco, who has analysed Kandinsky's work, it is obvious.

"It's very explicit in his work and his writings. He went to a performance of Wagner's music and then wrote about how vivid the visual impressions of the horns were and the colour that the music evoked in his mind. That's synaesthesia," he says.

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