How Loud Noise Exposure Causes Hearing Loss & Tinnitus

Exposure to noise levels greater than 110 dBs has been shown to cause both temporary and permanent hearing loss and tinnitus (ringing in the ears). However, the damage caused by this level of noise exposure can oftentimes be partially (or completely) reversed. Research led by Dr. Martine Hamann of the Department of Cell Physiology and Pharmacology at the University of Leicester has shown both how noise exposure causes hearing loss and tinnitus as well as how the body can repair itself. 

A ScienceBlog article detailing the research describes how loud noise exposure damages hearing: 

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 – i.e. 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.

In response to the research findings, Dr. Hamann notes:

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.

Researchers hope this information can be used to find potential cures to noise induced hearing loss and tinnitus.

For more information on this research and the source of this blog post, click here.



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