Music to your ears? New research examines evidence of damage to your hearing

August 19, 2014

Many people listen to loud music without realizing that this can affect their hearing. This could lead to difficulties in understanding speech during age-related hearing loss which affects up to half of people over the age of 65.

New research led by the University of Leicester has examined the cellular mechanisms that underlie hearing loss and tinnitus triggered by exposure to loud sound.

It has demonstrated that physical changes in myelin itself -the coating of the carrying sound signals to the brain – affect our ability to hear.

Dr Martine Hamann, Lecturer in Neurosciences at the University of Leicester, said: "People who suffer from hearing loss have difficulties in understanding speech, particularly when the environment is noisy and when other people are talking nearby.

"Understanding speech relies on fast transmission of auditory signals. Therefore it is important to understand how the speed of signal transmission gets decreased during hearing loss. Understanding these underlying phenomena means that it could be possible to find medicines to improve auditory perception, specifically in noisy backgrounds."

The research, funded by Action on Hearing Loss, and led by Leicester, was done in collaboration with Dr Angus Brown of the University of Nottingham. The research, Computational modelling of the effects of auditory nerve dysmyelination is published in Frontiers in Neuroanatomy.

Dr Ralph Holme, Head of Biomedical Research at Action on Hearing Loss, the only UK charity dedicated to funding research into hearing loss said: "There is an urgent need for effective treatments to prevent hearing loss - a condition that affects 10 million people in the UK and all too often isolates people from friends and family. This research further increases our understanding of the biological consequences of exposure to loud noise. Knowledge that we hope will lead to effective treatments for hearing loss within a generation."

In previous research, researchers have shown that after exposure to loud sounds leading to hearing loss, the myelin coat surrounding the auditory nerve becomes thinner. An important property of auditory signal transmission consists of electrical signals "jumping" from one myelin domain to the other. Those domains, called Nodes of Ranvier, become elongated after exposure to loud sound.

Dr Hamann said: "Although we showed that transmission of auditory signals (electrical signals transmitted along the auditory nerve) was slowed down after exposure to loud sound leading to hearing loss, the question remained: Is this due to the actual change of the physical properties of the myelin or is it due to the redistribution of channels occurring subsequent to those changes?

"This work is a theoretical work whereby we tested the hypothesis that myelin was the prime reason for the decreased signal transmission. We simulated how physical changes to the myelin and/or redistribution of channels influenced the along the auditory nerve. We found that the redistribution of channels had only small effect on the conduction velocity whereas physical changes to myelin were primarily responsible for the effects."

The research has shown for the first time the closer links between a deficit in the "myelin" sheath surrounding the auditory nerve and hearing loss. "This research is innovative because data modelling (simulations) was used on previous morphological data and assessed that physical changes to the myelin coat were the principal cause of the deficit," said Dr Hamman.

"We have come closer to understanding the reasons behind deficits in auditory perception. This means that we can also get closer to target those deficits, for example by promoting myelin repair after acoustic trauma or during age related hearing loss."

Dr Hamann said the work will help prevention as well as progression into finding appropriate cures for hearing loss and possibly tinnitus developing from hearing loss.

"The sense of achievement comes from the fact that it could help ageing people to better understand their relatives on the phone," said Dr Hamann.

The next step is to test drugs that could promote myelin repair and improve hearing after .

Explore further: Tinnitus study signals new advance in understanding link between exposure to loud sounds and hearing loss

More information: Computational modelling of the effects of auditory nerve dysmyelination, Angus M. Brown and Martine Hamann, Frontiers in Neuroanatomy, 01 August 2014 | DOI: 10.3389/fnana.2014.00073

Related Stories

Tinnitus study signals new advance in understanding link between exposure to loud sounds and hearing loss

February 14, 2014
(Medical Xpress)—A research team investigating tinnitus, from the University of Leicester, has revealed new insights into the link between the exposure to loud sounds and hearing loss.

Earphones 'potentially as dangerous as noise from jet engines,' according to new study

August 29, 2012
Turning the volume up too high on your headphones can damage the coating of nerve cells, leading to temporary deafness; scientists from the University of Leicester have shown for the first time.

New study brings scientists a step closer to silencing tinnitus

June 16, 2014
New research funded by charity Action on Hearing Loss suggests that tinnitus can be eliminated by blocking signals between the ear and brain, offering hope to suffers that a cure is within reach, with prolonged exposure to ...

Twin hearing study helps discover gene that influences hearing ability

August 5, 2014
The largest ever genome wide association study on hearing ability has identified the salt-inducible kinase 3 (SIK3) gene as a key influencer in how well we can hear, particularly at high frequencies. This significant new ...

Noise-induced hearing loss alters brain responses to speech

July 31, 2014
Prolonged exposure to loud noise alters how the brain processes speech, potentially increasing the difficulty in distinguishing speech sounds, according to neuroscientists at The University of Texas at Dallas.

Smokers and passive smokers more likely to suffer hearing loss, study shows

May 29, 2014
Giving up or reducing smoking and avoiding passive exposure to tobacco smoke may reduce your risk of hearing loss, new research shows.

Recommended for you

Americans are getting more sleep

January 19, 2018
Although more than one in three Americans still don't get enough sleep, a new analysis shows first signs of success in the fight for more shut eye. According to data from 181,335 respondents aged 15 and older who participated ...

Wine is good for you—to a point

January 18, 2018
The Mediterranean diet has become synonymous with healthy eating, but there's one thing in it that stands out: It's cool to drink wine.

Sleep better, lose weight?

January 17, 2018
(HealthDay)—Sleeplessness could cost you when it's time to stand on your bathroom scale, a new British study suggests.

Who uses phone apps to track sleep habits? Mostly the healthy and wealthy in US

January 16, 2018
The profile of most Americans who use popular mobile phone apps that track sleep habits is that they are relatively affluent, claim to eat well, and say they are in good health, even if some of them tend to smoke.

Improvements in mortality rates are slowed by rise in obesity in the United States

January 15, 2018
With countless medical advances and efforts to curb smoking, one might expect that life expectancy in the United States would improve. Yet according to recent studies, there's been a reduction in the rate of improvement in ...

Can muesli help against arthritis?

January 15, 2018
It is well known that healthy eating increases a general sense of wellbeing. Researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have now discovered that a fibre-rich diet can have a positive influence ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.