New understanding of cause of hearing loss and tinnitus

New research carried out by scientists at the University of Leicester has led to a better understanding of the link between exposure to loud sounds and hearing loss.

The study provides evidence on how damage to myelin, which is an insulating and protective layer around nerve fibres, alters the transmission of auditory signals occurring during hearing loss.

The three-year study was 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.

Dr Hamann said: "A previous publication has shown that exposure to loud sound damages the myelin which is the protection sheet around cells. 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.

"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."

Dr Hamann added that getting to dissect the cellular mechanisms underlying hearing loss is likely to bring a very significant healthcare benefit to a wide population.

She said: "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. The work will help prevention as well as progression into finding appropriate cures for hearing loss and possibly tinnitus developing from hearing loss."

Dr Ralph Holme Action on Hearing Loss' Head of Biomedical Research says: ''We know that exposure to loud noise can lead to hearing loss. Protecting your ears should always be the first line of defence, but medical treatments to combat unavoidable or accidental exposure to noise are also urgently needed. The research we have been funding at University of Leicester makes an important contribution to increasing our understanding of how noise damages the hearing system - knowledge we hope will ultimately lead to medical treatments for this common type of hearing loss."

Their study was published in the journal Neuroscience.

Relating to the sense of hearing. Full medical glossary
The basic unit of all living organisms. Full medical glossary
Spiral shaped organ situated in the labyrinth of the inner ear. Full medical glossary
The number of new episodes of a condition arising in a certain group of people over a specified period of time. Full medical glossary
Bundle of fibres that carries information in the form of electrical impulses. Full medical glossary
A ringing, hissing, buzzing or other noise heard in the ear when there is no such noise in the environment. Full medical glossary