Neuroscientists receive funding to understand how different forms of hearing loss in adults develop and whether they can be slowed or halted.
Professor Karen Steel, Professor of Sensory Function at the Institute of Psychiatry, Psychology & Neuroscience, has been awarded £1.3m by the Biotechnology and Biological Sciences Research Council (BBSRC) to investigate the biological mechanisms of hearing loss in adults.
More than 50 percent of adults in the UK over the age of 55 are affected by hearing loss. Hearing loss is a progressive, complex disease, which for some people can result in complete loss of hearing.
The underlying biology of hearing loss in adults are not always the same. Sometimes the connections between sensory hair cells in the inner ear and the neurons that send auditory signals to the brain are lost or damaged. Sometimes a part of the inner ear called the stria vascularis, which acts like a battery to maintain the electrochemical balance needed for hearing, stops working normally.
As hearing loss progresses, more parts of the hearing system can become affected. If hair cells are lost or damaged beyond repair, they are never replaced and the ear loses its ability to detect sound naturally.
To help combat hearing loss people are offered hearing aids or cochlear implants. Hearing aids can amplify sounds, boosting audio signals, whereas cochlear implants bypass hair cells and directly stimulate the auditory nerve using electrical signals. Neither can replace normal hearing or stop the disease process from affecting more parts of the hearing system, so are an aid rather than a cure.
Professor Steel's group wants to find ways of stopping hearing loss as it progresses. They think that looking at which part of the hearing system is first affected may provide a clue to how the disease may progress and what treatments might work, and when.
Professor Karen Steel, Professor of Sensory Function said:
"Adult-onset hearing loss manifests differently in different people. Different parts of the inner ear can be affected. Our goal is to understand the many mechanisms involved and to develop a set of non-invasive tests that can predict the main part of the inner ear that is affected."
The researchers believe that these tests may reveal potential opportunities for slowing or stopping the disease that would not be possible without understanding what type of hearing loss someone has.
"We aim to detect subsets of people with hearing loss due to stria vascularis dysfunction, but who have functional sensory hair cells. If the hair cells are still intact, there is a window of opportunity to boost stria vascularis function before the hair cells are lost," added Professor Steel.
Professor Steel and her team will also study what structures change in the inner ear after exposure to excessive noise over a period of days to weeks. Using the same diagnostic tests, the team will characterise how the response of the inner ear changes after noise exposure. They will combine this with microscopy to look for underlying cellular changes in the ear.
While the initial study will be focused on understanding and characterising the underlying biology in mice, the researchers have designed the diagnostic tests to be easily translatable to humans.
Ultimately, we aim to shift the field from the current state of resignation among healthcare providers that hearing loss is an inevitable part of growing older to a future where diagnostic tools are widely available to identify these critical windows of opportunity and treatments are developed that are specific to the part of the ear affected.
Professor Karen Steel, Professor of Sensory Function, Institute of Psychiatry, Psychology & Neuroscience.
