Although many people like to turn their headphones up as loud as they can after having a bad day or to get their mind off things bothering them, experts from the University of Leicester have shown evidence for the first time that turning the volume on your headphones up too high can damage the coating of nerve cells, eventually causing temporary deafness.
According to the researchers, the noise levels similar to those of jet levels can be heard on earphones or headphones on personal music players if they are turned up loud enough.
Scientists have known that temporary deafness and tinnitus (a condition that presents itself as a noise such as ringing or buzzing in the ears) can be caused by noises louder than 110 decibels. This study, published in the Proceedings of the National Academy of Sciences, is the first to examine how those noises cause underlying cell damage.
Dr. Martine Hamann, of the Department of Cell Physiologu and Pharmacology, lead author and researcher at the University of Leicester, explained:
“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 myelin sheath is a coating found on nerve cells that carry electrical signals from the ears to the brain, which helps the electrical signals travel along the cell.
The cells become stripped of this coating with exposure to loud noises (noise over 100 decibels), which stops the electrical signals and no longer allows information to be successfully transmitted from the ears to the brain.
Fortunately, full hearing can return when the coating surrounding the nerve cells reform and allows the cells to function normally again. This means that hearing loss is sometimes only temporary.
The study is important, according to Dr. Hamann, because it explains why in certain cases, hearing loss can be reversible. He continued:
“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.”
Research is still being conducted on the effects of loud noises on a part of the brain referred to as 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.
Written by Sarah Glynn