We have completed maintenance on DiscoverMagazine.com and action may be required on your account. Learn More

Cochlear Implant Plus Gene Therapy Could Restore Hearing to the Deaf

By Breanna Draxler
Apr 23, 2014 10:38 PMNov 19, 2019 9:39 PM


Sign up for our email newsletter for the latest science news

Cochlear implants have restored hearing to many deaf people, but they haven't advanced much since they were unveiled in the 1970s. That may be set to change with an exciting new advance, not in the technology of the device itself, but rather in using gene therapy to increase the device's effectiveness. Today researchers announced that they've been able to restore tonal hearing in guinea pigs with the new method of gene delivery.

Cochlear Implants, Then and Now

Cochlear implants, or "bionic ears," work by stimulating the auditory nerve to restore a rudimentary kind of hearing. This works pretty well, but the gap between the electrodes and the degenerating nerve is pretty big, which makes communication difficult. And even the state-of-the-art implants only have 22 electrodes, enabling them to hear 22 different tones. They can't, for example, distinguish between the soft buzz of a clarinet and the shrill sound of a flute. Teams of researchers have tried to improve upon the implants over the last decade by trying to focus the electrical currents more narrowly, to stimulate a smaller, more pitch-specific area of the nerve, or to use drugs that improve the communication between the electrodes and the neurons. But this new method, reported

today in Science Translational Medicine, has a distinct advantage: it actually encouraged the regrowth of the auditory nerve. This decreased the gap between the nerve and the cochlear implant, and improved communication between the two.

Image credit: Science Translational Medicine

Bionic Guinea Pigs

The team implanted "bionic ears" in deaf guinea pigs, whose auditory systems are very similar to humans'. With the device, then, they delivered DNA that coded for a protein called brain-derived neruotrophic factor (BDNF), which encourages nerves to grow. The DNA was taken up by cells in the cochlea and, after two weeks, the nerves had grown significantly toward the electrodes. When the guinea pigs' hearing was tested they found that animals that were once completely deaf had their hearing restored to almost normal levels. It's unclear, however, whether the treatment will work long-term: neuron production in the guinea pigs dropped off six weeks after the gene therapy. Researchers are also unsure whether tones heard after this treatment accurately reflect how they sound with normal hearing. The technique is very close to being ready for human trials, where some of these questions should be answered. If it proves successful in clinical trials, the technique of combining gene therapy with device could also be used for other implants like retinal prosthesis and deep brain stimulation.

Top image credit: Elizabeth Hoffmann/Shutterstock

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.