In this project, Dr Stuart Johnson at the University of Sheffield investigates how loud noise exposure might affect the development of age-related hearing loss.
Project start date: April 2022
Project end date: September 2025
About the project
Sound is detected by extremely sensitive sensory cells called hair cells. These cells translate sound information into an electric signal that they then send to the auditory nerve thanks to specialised structures called synapses. Hair cells and their synapses are damaged by both noise exposure and ageing.
In this project, researchers will investigate whether damage caused by loud noise exposure is the same as the damage that normally occurs with ageing, or if it is different. This will help to explain whether damage from loud noise exposure worsens age-related hearing loss or makes it develop earlier.
How it works
Researchers will use a technique called ‘electrophysiology’ to measure the tiny electrical currents produced by hair cells. They will also measure hearing in mice using the same techniques as those used to test hearing in people. Finally, they will use ‘electron microscopy’ to provide a visual understanding of the structure and molecules present in the hair cells.
How will this research benefit people at risk of hearing loss?
Our sense of hearing is susceptible to damage caused by loud noise or ageing. Both factors can cause hearing loss severe enough to affect communication, leading to isolation and depression. Despite the prevalence of hearing loss, we still do not have effective treatments. This is in part due to our lack of understanding of the full range of underlying causes.
This study will improve our understanding of why we lose our hearing after noise exposure and during ageing. The long-term goal is to develop effective treatments to either prevent hearing loss or restore hearing.
What we’ve learned so far
This project found two targets of damaging noise exposure:
- A protein called KCNQ4
- The outer hair cells – the ear’s natural sound amplifiers
By identifying these two targets, they have opened the door to new treatments: protecting the KCNQ4 channels or the outer hair cells after a concert or workplace noise exposure, may prevent ‘hidden’ damage from becoming permanent.
The research also provides a crucial distinction between noise-induced and age-related hearing loss: damage to outer hair cells is unique to noise-induced hearing loss. This finding provides a path for differential diagnosis and targeted therapy.
About the researcher
Dr Stuart Johnson is a lecturer in the School of Biosciences and part of the Hearing Research Group at the University of Sheffield.
I am fascinated by the intricate mechanisms of hearing in the mammalian cochlea. I find it incredible how the auditory system has evolved such elaborate structures and specialised cell types to enable a sense of hearing…
The opportunity to investigate the mechanisms underlying the function and dysfunction of the cochlea and to identify potential targets to improve hearing loss therapies is what motivates and inspires me every day.”
