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News |  03 Sep 2012 13:53 |  By RnMTeam

Loud music on earphones can cause deafness: report

MUMBAI:  Don't forget to lower the volume if you are listening to loud music on earphones. A new study has found that playing loud music on earphones can cause deafness by having a similar effect on nerves as multiple sclerosis (MS).

Headphones on music players including mobiles, iPod and more can reach noise levels similar to those of jet engines and can damage the coating of nerve cells, leading to temporary deafness.

The research revealed that noise levels above 110 decibels strip insulation from nerve fibres carrying signals from the ear to the brain. Loss of the protective coating, called ‘myelin' disrupts electrical nerve signals. The same process, this time due to an attack from the immune system, damages nerves in the brain and results in MS. The findings have been published in the journal ‘Proceedings of the National Academy of Sciences'.

Loud noises are well known to lead to hearing problems such as temporary deafness or tinnitus (ringing in the ears). But this is the first time that scientists have been able to identify the underlying damage to nerve cells.

University of Leicester researcher department of cell physiology and pharmacology Dr Martine Hamann said, "The research allows us to understand the pathway from exposure to loud noises to hearing loss. Dissecting the cellular mechanisms underlying this condition is likely to bring a very significant healthcare benefit to a wide population. The work will help prevention as well as progression into finding appropriate cures for hearing loss."

The findings are part of the ongoing research into the effects of loud noises on a part of the brain called the dorsal cochlear nucleus, the relay that carries signals from nerve cells in the ear to the parts of the brain that decode and make sense of sounds. The scientists have also found that myelin lost as a result of noise exposure re-grows in time, allowing the hearing to recover.

"We now understand why hearing loss can be reversible in certain cases. We showed that the sheath around the auditory nerve is lost in about half of the cells we looked at, a bit like stripping the electrical cable linking an amplifier to the loudspeaker. The effect is reversible and after three months, hearing has recovered and so has the sheath around the auditory nerve," he added.