Dear Doctor: When our grandson learned his colors, he sang along to the music. We thought he was copying the song to learn the ABCs. This is said to be called synesthesia. How and why does it happen?
answer: Synaesthesia — a somewhat rare and highly fascinating phenomenon — is a neurological condition in which sensory inputs are cross-wired in the brain.
As a result, information normally interpreted by one sense spills out, stimulating another, unrelated sense.
This fusion of sensations has been described for centuries. The term synaesthesia dates back to the late 1800s.
In some people with this condition, sound activates the visual center of the brain. For others, colors also have tastes, tastes evoke shapes, numbers have colors, and scents can be elicited by reading the printed words.
There may be as many as 60 forms of synesthesia, depending on how the senses are combined. Estimates of the number of people who experience it in some way range from 1 he in 20,000 to 1 her in 23 him.
The audiovisual variety your grandson described is considered one of the more popular formats. The rarest — lexical-gustatory synaesthesia — makes the speaker taste what he’s saying.
Someone is born with synesthesia or develops synesthesia at an early age.
It does not affect health, is not related to any illness or disability, and is not an indication of mental illness. It suggests that you are better than others.
There is also evidence that people with this condition are often disoriented.
The cause is unknown. Since synaesthesia was first described, researchers have investigated its origins. Some believe that sensory crossover occurs due to the presence of additional neurons.
This condition has been found to occur within families. Up to 40% of people with synesthesia have a relative with synesthesia. This makes heredity and genetics more likely to play a role.
Advances in imaging technology may provide more answers in the not too distant future.
Dr. Eve Glazier and Dr. Elizabeth Ko are physicians at UCLA Health.