Deciphering Sounds Through Skin Vibrations

How deaf people can substitute touch for hearing

One of the brain’s most awe-inspiring abilities is sensory substitution which is the process of converting one sensory modality into another whenever there is a deficiency. For example, people that are blind often have better hearing than people who are not blind. Another example of sensory substitution is sound-to-touch. Deaf people are able to communicate visually with sign language, but this requires one’s visual attention. Our sense of hearing is important for grabbing our attention of events happening outside of our visual field (for example a smoke alarm or oncoming car).

This is where sound-to-touch devices come in and a new study in the Journal of Neuroscience has demonstrated how deaf people can use a wrist-worn device to decipher not only different sounds, but different words all-together.

The device works by using a microphone to listen to sounds and convert them to vibrations on the wrist. The frequency of the sound (i.e., high or low pitch) is mapped onto different areas of the wrist. The device cleverly uses a well-known sensory illusion in which two areas of the wrist are stimulated with vibrations, but the person senses only one vibration.

“We stimulate these illusion locations by turning on two motors, one on either side of the illusion location, at specific amplitudes such that the wearer feels as if a single point somewhere between the two motors is vibrating”

Through repeated use, the wearers are able to learn the vibration patterns that different sounds make. For example:

The mapping of different sounds into the activation of four vibration motors

Interestingly, after one month of use, some of the participants could discriminate the difference between very similar words like “house” and “mouse.”

The study also showed that younger participants were better at learning to use the device, possibly because of their increased potential for neuroplasticity.

This kind of neuroscience research is incredibly important from an accessibility standpoint and also demonstrates how we can use technology to tap into our brain’s already amazing capability to overcome handicaps which might lower one’s quality of life.

Have a great week and stay warm!

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