Light Could Bring Music to Deaf People

by Lisa Zyga

Scientists have accidentally discovered that infrared light can stimulate neurons in the inner ear like sound waves do. While trying to "weld" nerves with heat from a laser, surgeons found that the light could stimulate the ear nerves extremely precisely. A research team led by Claus-Peter Richter at Northwestern University in Chicago decided to explore this idea further.

Infrared light from the LED of an XBox 360 remote control.Laser light stimulation can target the nerves with high precision because the light doesn’t spread. On the other hand, electrical stimulation (the mechanism behind conventional hearing aids) cannot achieve such precise stimulation because tissue conducts electricity, causing electrical signals to spread and interfere with each other.

Electrical hearing aids use about 20 electrodes to target nerves, and are good enough to allow deaf children to develop speech skills similar to those of hearing children. However, deaf people using the hearing aids can’t hear tonal variations as well, making it difficult for them to enjoy music or communicate in a noisy environment.

By increasing the number of points of stimulation, infrared lasers could be a step toward enabling deaf people to listen to music and complex sounds more fully.

The scientists don’t know exactly how light stimulates the neurons, but they think the accompanying heat may play a role. They plan to investigate the long-term effects of heating neurons in the near future.

Via: New Scientist

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