This is a PhD studentship being carried out by Hannah Guest, in the laboratory of Professor Chris Plack at the University of Manchester. Hannah started work in October 2014 and will finish in March 2018.
Audiologists use standard tests to diagnose hearing loss. Using the results, they can then prescribe the right hearing aids.
But, at the moment, these tests only measure the quietest sound you can hear – your ‘hearing thresholds’. So, when some people complain of having substantial difficulty understanding speech in noisy environments – but the audiologist's tests show normal results – we say they have ‘hidden hearing loss'.
The reasons for this hidden hearing loss are unclear, and there are no clinical management guidelines. Usually, people are simply discharged from audiology services.
Recently, scientists working with animals have found that substantial damage can occur to the auditory nerve without changes in hearing thresholds. This damage is not detectable using standard hearing tests, and may account for some cases of hidden hearing loss.
Hannah is testing the idea that hidden hearing loss is caused by damage to the auditory nerve. She'll compare measures of auditory nerve function in people with hidden hearing loss with those for people with normal hearing. This will enable her to determine whether our hunch is right – that auditory nerve damage is definitely related to difficulties with understanding speech in background noise.
Hannah's research will help us to determine whether hidden hearing loss is caused by auditory nerve damage. Right now, there are no clinical management guidelines for this kind of hearing loss so treatment is limited to counselling or advice on communication 'tactics'. We hope that Hannah's work will lead to a diagnostic test for hidden hearing loss and, eventually, to the development of effective treatments.