Earphones and headphones have become quite necessary accessories to the gadgets we carry with us. However, researchers warn that turning the volume up too high on earphones may damage nerve cells that carry signals to the brain.
University of Leicester research team led by Dr Martine Hamann found that earphones or headphones on personal music players can reach noise levels similar to those of jet engines.
Noises louder than 110 decibels are known to cause hearing problems such as temporary deafness and tinnitus (ringing in the ears), but the study for the first time observed the underlying cell damage.
Nerve cells that carry electrical signals from the ears to the brain have a coating called the myelin sheath, which helps the electrical signals travel along the cell. Exposure to loud noises – noise over 110 decibels – can strip the cells of this coating, disrupting the electrical signals. This means the nerves can no longer efficiently transmit information from the ears to the brain.
However, the coating surrounding the nerve cells can reform, letting the cells function again as normal. This means hearing loss can be temporary, and full hearing can return, according to the research study published in the Proceedings of the National Academy of Sciences.