In this project, PhD student Filip Hrnčiřík and Professor Manohar Bance explore how the fit of different cochlear implants can be improved for patients, improving a person’s listening experience and comfort.
Project start date: October 2019
Project end date: September 2023
Read about the project outcomes here.
About the project
Cochlear implants contain a long, thin, plastic (usually silicone) strip with electrodes embedded into it (called an “array”). This array is inserted into the inner ear (cochlea) through manual surgery. The electrode array stimulates the hearing nerve with electrical signals in response to sound. These signals are then transmitted along the hearing nerve to the brain.
Arrays from different cochlear implant manufacturers come in a limited number of fixed lengths and properties (such as stiffness and shape), but the size and shape of the cochlea varies a lot from person to person.
Putting the wrong array in the wrong cochlea is more likely to cause damage and destroy remaining hearing than one that fits better. This project aims to understand which cochlear implant array features are best suited to which cochlear shapes.
How it works
Filip will take detailed scans of human cochleas and document the range of variation in their shape and size, then use this information to print plastic cochlear models including both common and unusual shapes and sizes.
The research team will make their own implant arrays out of silicone, changing the shape, size, and stiffness of the arrays. They’ll then insert these arrays into human cochleas (post-mortem). By measuring the force needed to insert the array, they will calculate how much friction is generated as the array rubs against the inside of the cochlea – more friction is thought to cause more damage.
How will this research benefit people with hearing loss?
Understanding better how the anatomy of the cochlea interacts with the implant array will help surgeons select the best implant for each patient, to reduce trauma and preserve as much of their remaining natural hearing as possible.
This will improve hearing outcomes as people can hear better when they use a combination of natural and electrical hearing. The higher standard of implantation that may result from this project could lead to more people will be able to access and benefit from this life-changing technology.
What we’ve learned so far
It was found that the angle of insertion was the major factor that determined how much damaging force the cochlea experienced, rather than the shape of the cochlea or the depth of insertion.
The team also developed expertise in measuring force from implantation, which is being used to test other surgical questions, such as what is the optimum type of material for future cochlear implants.
About the researchers
Filip Hrnčiřík is a PhD student in Professor Manohar Bance’s lab at the University of Cambridge. His RNID-funded studentship began in 2019 and is funded in partnership with Cochlear Ltd.
What drove me was the gap between an extraordinary technology and the people it could help even more. Cochlear implants already transform lives, yet each insertion still carries a risk of trauma that can cost someone their residual hearing. My goal has been to close that gap, to understand the mechanics of implantation deeply enough to design electrodes and surgical approaches that preserve as much of the natural cochlea as possible.”
Professor Manohar Bance is an ear surgeon and clinician-scientist at the University of Cambridge. He is Professor of Otology at the University of Cambridge and Honorary Consultant at Addenbrooke’s Hospital.
I hope my research will improve quality of life for the millions of people with hearing and balance disorders, relieve suffering for those affected by tinnitus, and to give people with hearing loss the same opportunities that hearing people have.”