Gene therapy could lead to better, light-based cochlear implants

(Bjorn Knetsch CC BY 2.0)

Cochlear implants can help people who are deaf and hard of hearing perceive sound, but they could potentially be improved by using light instead of electricity to stimulate nerves in the cochlea, a cavity inside the ear.

Unlike hearing aids, which amplify sounds, cochlear implants use electrical signals to skip over damaged parts of the ear and directly stimulate the auditory nerve. According to New Scientist, these implants are able to distinguish between about a dozen sound frequencies, while a normal ear can differentiate between 2,000 different frequencies. It’s difficult to add more frequencies in cochlear implants as electricity can also travel through live tissue, causing frequencies to blend into each other, New Scientist reported.

Enter Tobias Moser and his team at the University Medical Center Göttingen in Germany, who are working on using light, which doesn’t travel through tissue, to stimulate the nerve. The device uses tiny light-emitting devices, or LEDs, and requires gene therapy that makes nerves sensitive to light. The team introduced a gene into deaf rats that made their auditory nerves more sensitive to light and were able to restore hearing with a 10-channel implant, New Scientist reported. They plan to create an implant with 100 channels.

This approach has been previously shown to work with a one-channel implant in mice. However, it’s still “some years away” from human testing, as the team needs to ensure safety and reliability and find a way to make the LEDs last longer. This light-based take on cochlear implants has the potential to improve the quality of life of people who are deaf and hard of hearing, including musicians and people who need to communicate in noisy places.

Meanwhile, other industry players are developing alternatives to traditional cochlear implants. In 2015, Medtronic ($MDT) bought Sophono for an undisclosed amount, which makes a magnetic hearing implant. It has a processor that transmits audio vibrations through the skin and into the bone, where it is sensed by the cochlea.

- here's the New Scientist story

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