How can cochlear implants be improved

Researchers improve implant for deaf people

Status: 08/24/2016 12:10 p.m. | archive

In the 1970s, Nikolaus März from Hanover lost his hearing in a car accident. The shoemaker was deaf for two decades until he could hear again for the first time in the 1990s - thanks to a so-called cochlear implant. It all sounded wrong, he says, "but it was a great pleasure to hear."

Electrodes stimulate the cochlea

The external unit of a cochlear system is clipped behind the ear.

Cochlear implants have been around for 30 years. A small microphone is connected to the hearing via control electronics and electrodes. More precisely, a fine wire leads to the cochlea, the place in the ear where sound waves are normally converted into nerve impulses. Here the electrodes send electrical impulses. The cochlea is stimulated and sends signals to the brain.

The tissue will scar over time

In practice, however, there is always a problem: The tissue around the wire and the electrodes becomes scarred. That is why Nikolaus März's hearing sensitivity has decreased over the years. Despite the implant, he still has to read his lips.

New surgical method minimizes scarring

But this is exactly what is to be prevented with a new surgical method: with the use of the body's own precursor cells, comparable to stem cells, explains Athanasia Warnecke from the ENT clinic at the Hannover Medical School (MHH). This could replace submerged cells in the ear, says Warnecke: "The precursor cells produce growth and other factors that protect the nerve cells on the one hand and can prevent the inflammatory processes that result from the operation and the introduction of the electrode on the other."

Precursor cells from the body's own bone marrow

This is to prevent scarring. Specifically, bone marrow fluid is taken during the operation, from which the cells are processed in a centrifuge. "All of this takes place directly in the operating room," explains Warnecke, because it reduces the risk of infection.

The electrode of the cochlear implant is dipped into the liquid obtained during the operation and coated with the body's own cells. A hole is then drilled in the skull to put the wire back into the ear. "The coating reduces the foreign body reaction and the implant can function much better. That means that the interaction between the implant and the body's own tissue is significantly improved," says Warnecke.

"A process that is unique in the world"

The scientists at the MHH have been researching the new process for more than five and a half years. It is a globally unique procedure, reports Thomas Lenarz, director of the ENT clinic: "At the MHH there is a definite focus on regenerative medicine, the use of stem cells and other processes to restore tissue, and ultimately organs. That is why it does it makes sense that we combine these possibilities when it comes to restoring the function of hearing. "

Study phase is coming up

It remains to be seen whether the implant will really work longer and better than before. Because there are no long-term studies with this new method. In six weeks, when everything has healed, Nikolaus March may be able to report whether he can now hear better again.

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NDR Info | Radio visit | 08/24/2016 | 9:20 am