We know that sound can cause damage to the ear but, how does it happen. As a follow up to our article “Noise Induced Hearing Loss” we wanted to cover this topic. The most best way to understand sound can damage hearing is to know how hearing works.
Hearing is a series of events that change change sound waves in the air to electrical impulses. These impulses are then picked up by our auditory nerve and sent to the brain. There are several complex steps involved in this process. Again thanks to the NIDCD we have a pretty good description of these processes.
HOW SOUND WORKS
- Sound waves enter the outer ear and travel through a narrow passageway called the ear canal, which leads to the eardrum.
- The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear. These bones are called the malleus, incus, and stapes.
- The bones in the middle ear couple the sound vibrations from the air to fluid vibrations in the cochlea of the inner ear, which is shaped like a snail and filled with fluid. An elastic partition runs from the beginning to the end of the cochlea, splitting it into an upper and lower part. This partition is called the basilar membrane because it serves as the base, or ground floor, on which key hearing structures sit.
- Once the vibrations cause the fluid inside the cochlea to ripple, a traveling wave forms along the basilar membrane. Hair cells—sensory cells sitting on top of the basilar membrane—ride the wave.
- As the hair cells move up and down, microscopic hair-like projections (known as stereocilia) that perch on top of the hair cells bump against an overlying structure and bend. Bending causes pore-like channels, which are at the tips of the stereocilia, to open up. When that happens, chemicals rush into the cell, creating an electrical signal.
- The auditory nerve carries this electrical signal to the brain, which translates it into a sound that we recognize and understand.
Unfortunately, unlike birds and reptiles, as these hair cells die they do not grow back. Once they are gone they are gone. To prevent this make sure you are always conscious of the sounds in your environment and use hearing protection when necessary.
If you feel like you are experiencing a hearing loss Schmidt’s Optical and Hearing™ would be happy to provide you with a FREE comprehensive hearing screening by our Board Certified Licensed Hearing Aid Specialist. Call us today at 772-286-43247 to schedule!!!