Overcoming the Limits of Cochlear Implants: Helping Stimulate the Auditory Nerve

Researchers at the Technische Universitaete Muenchen (TUM) are working on developing a better cochlear implant in order to improve functional hearing and speech learning for deaf children and adults.

In the United States alone, it's estimated that about 2 to 3 out of every 1,000 children are born deaf or hard-of-hearing, and nine out of every 10 children who are born deaf are born to parents who can hear according to the National Institute on Deafness and Other Communication Disorders (NICDC). The organization also adds that men are more likely than women to be or become deaf, and approximately 17 percent of the American population has reported some sort of hearing loss due to numerous factors. 

Yet for many born without certain hearing problems, the understanding and development of language can be greatly harmed.

As intact learning is a prerequisite for learning to speak, children who are born deaf should be fitted with cochlear implants as early as possible--a tool that consists of a speech processor and a transmitter coil worn behind the ear that directly stimulates the auditory nerve via an electrode with up to 22 contacts.

The researchers note that they hope to develop a perfect interplay of sound between both ears with advances to the implant. As it stands now, since the ears are located a few centimeters apart, this can delay sound heard by a very slight amount of time (a few millionths of a second.) However, it is enough to make a distinction. 

"Getting implants to operate more precisely will require strategies that are better geared to the information processing of the neuronal circuits in the brain. The prerequisite for this is a better understanding of the auditory system," said Professor Werner Hemmert, director of the Department for Bio-Inspired Information Processing, at the TUM Institute of Medical Engineering (IMETUM), via a press release.

Fortunately, based on the researchers findings, they've successfully built a computer model of acoustic coding for the inner ear and the neuronal information that's processed by the brain stem.

In other words, this new model will help researchers better determine how to create coding strategies that can be tested in experiments of deaf individuals.

"Many ideas can now be tested significantly faster. Then only the most promising processes need to be evaluated in cumbersome patient trials," Hemmert said, via the release. "The new models thus have the potential to significantly reduce development cycles. "In this way, patients will benefit from better devices sooner."

More information regarding the study can be found here.