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
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.
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.
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.
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.