Using infrared light to help deaf people hear and blind people see

Researchers are improving cochlear implants and vision with infrared light.
Written by Boonsri Dickinson, Contributing Editor

Normally, implants use electrical signals to help people hear and see.

However, University of Utah bioengineer Richard Rabbitt has discovered a different way to activate cells. Rabbitt figured out how to use infrared light to send signals to the brain. Instead of using electrical signals, pulses of invisible wavelengths activate nearby nerve cells and communicate with the brain.

In the lab, researchers were able to make heart cells in rats beat again and make inner-ear cells of toadfish send signals the brain.

The researchers see this type of therapy working in the following situations:

  • to restore balance as we age
  • to provide artificial vision in patients with retinitis pigmentosa
  • to treat people with Parkinson's disease

If the future, if cochlear implants use infrared light instead of the traditional electrical signals, the devices could help people hear a much wider range of sounds.

Compared to electrical-based implants, optical devices would work better with the body. The main challenge is getting the devices to run on a small power supply and light source.

In current devices, electrical signals spread through tissues. At times, this can be quite limiting. For instance, the electrical signals are transmitted through eight electrodes in the inner ear, where vibrations send signals to the brain. This means only eight frequencies of sound can be heard.

But the infrared signal is different because it is more focused. Like a laser pointer, the pulses are delivered at a different wavelength to activate heart and ear cells.

Rabbitt said in a statement:

"A healthy adult can hear more than 3,000 different frequencies. With optical stimulation, there's a possibility of hearing hundreds or thousands of frequencies instead of eight. Perhaps someday an optical cochlear implant will allow deaf people to once again enjoy music and hear all the nuances in sound that a hearing person would enjoy."

It will be interesting to see if and how this discovery is used to improve implants in the near future.

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