SYNESTHESIA

SYNESTHESIA, AUTISM, SAVANT SYNDROME.

Is there a relationship?

By Lirio S. Covey, Ph.D.

Do you feel sounds and taste shapes? Do you smell songs or hear flavors?

No, you may not be hallucinating; you could be truly experiencing this phenomenon of simultaneously felt multiple experiences. You could be a synesthete, someone with synesthesia!

Synesthesia is a neurological condition wherein perception of one sensory modality produces simultaneous awareness of one or more other sensory modalities. For example, hearing music can stimulate a sense of sweetness or the feel of a tickle on a body part. Or when reading letters of the alphabet, each letter is viewed in color, varying from one letter to another. Or hearing a certain word triggers the taste of a favored drink.

Why is this of interest to autism?

The estimated prevalence of synesthesia in the general population is 2-4%; among autistic persons, the estimated prevalence of synesthesia is much higher – about 20%. Considered distinct conditions, yet commonalities between autism and synesthesia have been noted. They share similar traits such as heightened sensory sensitivity and attention to detail and, like autism, synesthesia is viewed as biological in origin and unlearned.

Why is this of special interest to autism?

Synesthesia has been speculated to be among features of the savant syndrome, which in turn has been seen among some, but not exclusively, persons with autism. The savant syndrome can be described as possessing an exceptional ability in a particular field, for example, extraordinary talents or skills in music, painting, sculpture, and mathematical calculations, memory, in the context of overall handicap, usually intellectual disability.

Does the savant visual artist see not only shapes and colors but also feel tingling in his/her skin? Does the savant pianist hear the music, feel the keys, and enjoy scents as she plays? Does the superbly skilled woodworker who feels the shape and grains of the wood, also hear music and smell aroma in the music? Could this richness wrought by experiencing multiple sensations underlie the savant’s exceptional and unique abilities? And do such synesthetic qualities mark savants?

What might the commonality of synesthesia and its possible link to savant status as well as autism imply for understanding and managing autism? As noted earlier, while a higher than expected prevalence of synesthesia has been seen with autism, those synesthetic traits are present only in a subset (about 20%) of persons with autism. Thus, could the co-presence of synesthesia, with or without savant status, and autism identify a subset of persons on the autism spectrum.

Implications?

If there is such a subset, what other observable or underlying neurobiology traits characterize that subset? How could recognition and comprehension of such a subset impact the management of autistic persons, especially those with extraordinary (aka savant) qualities. Such knowledge and subsequent practice could optimize the positive abilities of this unusual subset of autistic persons who have synesthetic qualities. This would be a welcome departure from one-size-fits-all, under-nourishing formative methods that fail to optimize exceptional talent.

In addition, greater understanding of the behavioral and neurobiological linkages between autism and synesthesia could be productive towards optimizing the positive abilities and traits, not only of a select subtype, but also of others in the larger population of persons with autism.

References:

Van Leeuwen T, Van Lier R. Spectrum/ Autism Research News, June 16, 2020.

Harrison JE & Baron-Cohen S (Eds) 1996. Synesthesia: Classic and contemporary readings. Cambridge, MA: Blackwell.