Dr Martine Hamann

Dr Martine Hamann

Leicester research reveals why hearing loss is correlated with auditory signals failing to get transmitted along the auditory nerve.

A research team from the University of Leicester investigating tinnitus has found new insights into the link between the exposure to loud sounds and hearing loss. Their study, published in the February 12 edition of Journal of Neuroscience helps to explain how damage to myelin— a protection sheet around cells— alters the transmission of auditory signals occurring during hearing loss.

The 3-year study was derived from a PhD studentship funded by Action on Hearing Loss. It was led by Dr Martine Hamann, lecturer in Neurosciences at the University’s Department of Cell Physiology and Pharmacology.

“A previous publication has shown that exposure to loud sound damages the myelin which is the protection sheet around cells,” says Dr Hamann. “We have now shown the closer links between a deficit in the ‘myelin’ sheath surrounding the auditory nerve and hearing loss. It becomes obvious why hearing loss is correlated with auditory signals failing to get transmitted along the auditory nerve.

“Understanding cellular mechanisms behind hearing loss and tinnitus allows for developing strategies to prevent or alleviate the symptoms of deafness or tinnitus—for example by using specific drug therapies,” continues Dr Hamann. “This new study is particularly important because it allows us to understand the pathway from exposure to loud sound leading to the hearing loss. We now have a better idea about the mechanisms behind the auditory signals failing to get transmitted accurately from the cochlea to the brain. Consequently, targeting myelin and promoting its repair after exposure to loud sound could be proven effective in noise induced hearing loss.”

She added that getting to dissect the cellular mechanisms underlying hearing loss is likely to bring a very significant healthcare benefit to a wide population: “Understanding mechanisms responsible for hearing loss represents a significant unmet need that is likely to increase as the incidence of the disorder increases due to an ageing population and the increasing impact of recreational and workplace noise.

“I am very excited by this research,” added Dr Hamann. “The work will help prevention as well as progression into finding appropriate cures for hearing loss and possibly tinnitus developing from hearing loss.”

Dr Hamann’s team at the University of Leicester included Thomas Tagoe who performed all the electrophysiological experiments, and Matt Barker and Natalie Allcock who performed the electron microscopy and the imaging experiments. Andrew Jones, a project student in the lab performed computer modelling.

Source: University of Leicester