The Self Defense Mechanism Of The Ear

Our ears have a built in self defense mechanism (to protect against really loud sounds) contained in the middle ear. They are muscles known as the stapedius and the tensor tympani. When a loud sound enters the ear these muscles retract the ossicular chain preventing the transmission of much of the sound energy from entering the cochlea. However, when we are exposed to prolonged loud noise (in a factory, loud music, riding a motorcycle, etc.) these two little muscles will fatigue in as little as 7 minutes. When this happens the ossicular chain is lowered back into position allowing all of the sound energy to enter the cochlea where it can damage the “hair cells” contained in the organ of Corti.

The “hair cells” most affected by prolonged loud noise are those which respond to high frequency sounds. If you lose enough of these “hair cells” you will no longer be able to hear high frequency sounds as well as you once did. This loss of “hair cells” is commonly referred to as nerve deafness . To protect your ears from the occasional exposure to loud noise (rock concert, etc.) the use of some form of protection is recommended. There are several brands of single use, disposable ear plugs available which are inexpensive and comfortable and will attenuate the level of sound entering the ear down to a safe level.