This is a PhD studentship being carried out by Dominika Behounek in the laboratory of Dr Ben Lineton at the University of Southampton. Her project started in June 2015 and will finish in November 2018.
"This work could lead to the development of a more effective diagnostic test for auditory neuropathy, which can detect the underlying cause – this will help in developing more targeted treatments."
Auditory neuropathy spectrum disorder occurs when sound enters the inner ear normally but the transmission of signals from the inner ear to the brain is impaired. Health professionals currently diagnose it by measuring the auditory brainstem response (that is, the detection of a sound in the hearing part of the brain) alongside otoacoustic emissions (the ‘echo’ that a healthy inner ear gives in response to detecting a sound). An absent or very abnormal auditory brainstem response reading, together with a normal or near-normal otoacoustic emissions measurement, signifies auditory neuropathy. It has been estimated that between 0.5 and 15% of cases of sensorineural hearing loss involve auditory neuropathy to some degree.
There are several potential causes of auditory neuropathy spectrum disorder, such as problems within the hair cells themselves, meaning they cannot transmit information about sound, problems at the connection between the hair cell and the auditory nerve, so that the nerve is unable to pick up sound information, or problems within the auditory nerve itself.
Many uncertainties remain around the underlying causes and diagnostic techniques for auditory neuropathy. It is important to be able to diagnose the cause, as this is likely to determine the success of any subsequent management of the condition.
Dominika is investigating the use of electrocochleography as a technique for the diagnosis of auditory neuropathy. Electrocochleography can tell the difference between problems within the hair cells, preventing them from passing on sound information, and problems within the auditory nerve.
In addition, Dominika will also attempt to build computer models of the different kinds of problems that can cause auditory neuropathy.
If the cause of someone's auditory neuropathy can be accurately diagnosed, subsequent treatment can be directed towards the cause and, therefore, may be more successful. For example, it is likely that the outcomes for people with auditory neuropathy who receive cochlear implants will depend on the particular underlying cause.