web analytics

Cool New Ear Implants Enable Deaf Gerbils To “Hear” Light

Grisha Bruev/Shutterstock

Grisha Bruev/Shutterstock

At present, an experimental technique has been successful in restoring some sense of hearing to deaf gerbils by application of  light. Although it is just the start of a proof-of-concept study, it does make it hopeful that one day doctors could use a similar method for treatment of hearing loss in humans.

There are now nearly 360 million people suffering from a form of disabling hearing impairment, which is regarded as the most common type, known as sensorineural hearing loss (SNHL). This is caused by damage to the cochlea, the fluid-filled inner part of the ear that somewhat looks similar to a snail’s shell.

For the time being,, SNHL patients receive the treatment through cochlear implants. These approach is involved in electrical currents stimulating the auditory nerve in a direct way, jumping over any parts of the inner ear that have been damaged. However, this method of cochlear implants has some disadvantage, because their sound resolution is poor, thus making patients find difficulty in separating background noise from conversation in the foreground.

To address such issue, German researchers turned to a field of research known as optogenetics, which is targeted at application of light to control cells in living tissue. Having finished  preliminary studies in mice and rats, they tested this method with adult Mongolian gerbils, whose auditory pathways resemble those of humans rather than other rodents. Their reseach results have been released in the journal Science Translational Medicine.

At the first stage, the hearing of the gerbils were intact, and they were trained to complete the shuttle box test. This involved having the critters placed inside a box being separated in two by an obstacle. The gerbil then had to jump over the obstacle whenever they heard a particular sound – if they did not jump, they would be hurt by a mild electric shock.

Then came the treatment. With the help of a virus, the researchers had a light-detecting gene inserted into the gerbils’ cochleas.After that, they implanted optical fibers that could be turned on and off to send light signals to the inner ear. When they completed the shuttle box test post-surgery, the gerbils responded to the light signals as if they were sounds, which would indicate clearly that gerbils could “hear” the light signals. This was confirmed when some gerbils were deafened. The deaf gerbils no longer responded to the sound but they continued to jump across the obstacle when the light signals were activated.

Even though such technique is quite successful with gerbils, there is still is a long way to go before it could be actually used with humans, because scientists haven’t yet been capable of  finding a way to recreate different sounds. Hypothetically, however, compared with current treatment, this method would have the potential to stimulate cells in a more precise way.

As Tobias Moser, study author and professor of auditory neuroscience at the University Medical Center Goettingen said, since light could be better confined than electrical current, it was expected that the number of independent frequency channels would be greater in the optical CI. And it would offer more frequency resolution of sound coding enabling the user to better separate similar sounds, understand speech in the noise, and appreciate melodies.

You May Also Like:

The Irish Rugby Team Has Exceptional Guts
Sleep Deprivation Might Give You False Memories!
Novel Drug Delivery Capsule May Substitute Injections
UNC Scientists Discover How a Single Genetic Mutation Can Cause Autism