Regenerating Hearing? Yep, AB’s Working on It.

The kind of work the team is doing right now has never been done before. Can you tell us a little about it?

PB: Yes. I’m very excited about the work we’re doing together with The University of Nottingham, Guy’s and St Thomas’ Hospitals and Rinri Therapeutics (a spin-out from the University of Sheffield). For the first time ever, we’re able to observe and record the inner workings of the cochlea, our hearing organ, frequently enough to learn how it behaves and changes on a daily basis. 

The cochlea is a tiny, intricate structure the size of an eraser on the end of a pencil. It is encased deep in the densest bone in the human body, so it’s been very hard to access and learn about. But with the information we’re now able to capture about the cochlea and the structures inside, the possibilities are limitless.
 

How has this been made possible?

PB: Well, this takes us back to the beginning of AB, when we were designing our first cochlear implants in 1991. Unlike what had been done before, we wanted to a create a system with an electrical pathway that goes both ways. In other words, we wanted to not only send a signal into the cochlea, we also wanted to be able to get information back, information that would let us know that the system is working. 

This is the beginning of the technology that, today, allows hearing care professionals to perform impedance tests, which check the integrity of the electrodes every time a cochlear implant recipient goes in for a check-up. But we only perform such tests in CI patients maybe once every six months. We have no idea how the cochlea is doing in between. 

Clinically, the AIM system provides valuable information to the surgeon performing CI implantation, and also to the audiologists working with the patient afterwards. But for our research purposes, it is also the perfect tool to monitor a person’s cochlear status easily and frequently. 

How’s the study going so far?

We started the study in October, 2020. It involves participants who are adult CI recipients, who use the AIM tablet to measure their electrode impedances twice a day, every day, as well as electrophysiological measures once a week. Participants are also asked to log their general health status during the same time period. We started with study participants who have had an implant for longer than a year because we expected that at that point post-implantation, there wouldn’t be much variation in the day-to-day measurement results. But we were surprised to find that while this is true for some participants, others have had results that fluctuate widely. 

That just shows us that there is so much that we don’t know about the workings of our inner ear. What’s causing these fluctuations? What are the interactions between different body states such as hormonal and stress level changes and cochlear health? Discovering these unexpected fluctuations is the first step that will lead us to learn more. 

In the next phase of the study, we will be following the same procedure, but with participants who have  just been implanted. So we expect to see eye-opening results from that study group as well. 
 

What kind of research and real world applications do you think the results of your study will lead to?

PB: I think the opportunities are limitless! With the AIM system, we can collect so much information about the cochlea—the excitability of the auditory nerve, the status of the hair cells and basilar membrane, the effects of abnormalities, etc. 

And that knowledge can help us develop a deeper understanding of how we hear, why we don’t hear, and how we can hear again. This can help with the development of therapeutic treatments to reverse hearing loss, and even regenerative cell therapies to treat deafness, such as those being developed by Rinri Therapeutics. I think it is this prospect which makes this study extraordinary, and particularly exciting.