The Science of Audiology
How Do We Hear?
Hearing depends on a series of complex steps that change sound waves in the air into electrical signals. Our auditory nerve then carries these signals to the brain.
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. These bones have also been referred to as the hammer, anvil, and stirrup, respectively.
The bones in the middle ear amplify, or increase, the sound vibrations and send them to the cochlea, a snail-shaped structure filled with fluid, in the inner ear. 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. Hair cells near the wide end of the snail-shaped cochlea detect higher-pitched sounds, such as an infant crying. Those closer to the center detect lower-pitched sounds, such as a large dog barking.
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 cells, creating an electrical signal.
The auditory nerve carries this electrical signal to the brain, which turns it into a sound that we recognize and understand.
Source: NIH Medical Arts
Since 1989, the Hearing Industries Association (HIA) has been collecting data on satisfaction with hearing instruments, new user rates by age, mental and physical health effects of hearing loss, and many others. Every three to four years, HIA commissions a detailed survey with comprehensive findings on these topics. We've put the most current findings here
Auditory Processing. What is it?
A condition where the brain is unable to process auditory information in a normal way. "The Missing Piece: Auditory Processing and Learning Difficulties!" first appeared as a blog post through the Regina Speech Centre
Dementia and Untreated Hearing Loss
Is there really a connection? The American Association of Retired Persons has put together a really good, easy-to-read article about the correlation between cognitive loss and hearing loss.
You hear your spouse breathing nearby and you instantly get angry. Your 6-year-old yawns and it triggers a fight-or-flight reaction in you. You avoid restaurants because you can’t stand the sound of chewing. Sounds other people don’t even seem to notice, drive you up a wall. You might have misophonia.
"The Misunderstood Misophonia" by Christopher Spankovich and James W. Hall III first appeared in Audiology Today in 2014 and is an excellent resource