Tinnitus: Loud Sounds & Hearing Loss
A research team at the University of Leicester in the UK investigated tinnitus, a condition in which there is the perception of sound such as ringing in the ears even though there is no actual sound. The team discovered new insights into the link between the exposure to loud sounds and hearing loss associated with tinnituts.
Their study, published in February 2014 in the jouranl Neuroscience, explans how damage to myelin, a protection sheet around cells, alters the transmission of auditory signals occurring during hearing loss.
The three-year study, derived from a PhD studentship funded by Action on Hearing Loss, was led by Dr Martine Hamann, Lecturer in Neurosciences at the University's Department of Cell Physiology and Pharmacology.
A release from the university quotes Dr Hamann as saying, "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 being able 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 aging population and the increasing impact of recreational and workplace noise,” she said. "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 Hamann's team at the University of Leicester included Thomas Tagoe who performed all the electrophysiological experiments, Matt Barker and Natalie Allcock who performed the electron microscopy and the imaging experiments. Andrew Jones, a project student in the lab performed computer modeling.
Dr Ralph Holme Action on Hearing Loss' Head of Biomedical Research said, ''We know that exposure to loud noise can lead to hearing loss. Protecting your ears should always be the first line of defense, 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."