An ENT specialist astonished me last week. We were discussing Cochlear Implants and I asked him what my hearing would be like after implantation. His answer: “What is hearing?” It all set me thinking about what we think we hear, and the difference between hearing and listening.
When returning home I started researching the topic. Hearing is defined as the faculty or sense by which sound is perceived. This definition does not say anything about what we hear, it merely describes hearing as perception. Digging further, I discovered that sound waves enter the ear canal and make the ear drum vibrate. These vibrations move a tiny chain of bones called ossicles. These bones are located in the middle ear and each have their own names: the malleus, incus, and stapes, which is the last bone in the chain. As vibrations hit the stapes, it knocks on the membrane window of the cochlea and makes fluid in the cochlea move. The fluid movement triggers a response in the auditory nerve, which sends signals to the auditory center in your brain stem.
In normal hearing, our hearing center in the brain can detect a sound’s location, its loudness, and pitch. Complex sounds are separated into tones that we’ve learned to understand as speech or music. Further, our brains discriminate relevant sounds from background noise and filter unwanted noise. Sound is processed in different regions of the auditory cortex on both sides of the brainstem. However, for most people, the left side is specialized for perceiving and producing speech.
Something goes awry for those of us with hearing loss. Our brains, for reasons yet to be discovered, do not discriminate sounds from background noise as they do in normal hearing. One theory says that that hearing loss occurs when hair cells in the cochlea die off, thus interrupting the normal hearing path, resulting in sensorineural hearing loss, one of the common types of hearing loss. As hearing loss progresses from moderate to severe to profound, we lose our ability to hear sounds in the high frequency ranges. This makes speech sound garbled resulting in the cocktail party effect, the inability to hear in noisy environments.
All this set me wondering if we are able to train our brains to hear. I’ve worked with a speech therapist who would answer that questions with a very loud yes. My speech therapist had me download apps on my IPad. These were fun little games, mostly designed for children. There is one I use regularly: Sounds TSW. This App provides a series of environmental, nature, musical, and every day sounds such as a tea kettle, a door slamming shut, and a printer printing. There are several ways to use the app. One is to listen blindly to the sound and then click on a picture of what you heard.
Working with these sounds, regularly helps keep one’s brain sharp. I was using this app this morning and because I’m losing the ability to hear high frequency sounds, I noticed I couldn’t hear water running, but I did hear the deep sound of a frog croaking. This is important information to pass along to your hearing specialist, particularly when you notice an inability to hear a sound that you could previously.
There are many similar apps, some for word recognition, some that help you discriminate between minimal pairs. Words such as cake, take, lake and sake, all sound alike in rapid speech. Using apps or simply listening to sounds, allows your brain to stay tuned to sounds and goes a long way in helping to keep your hearing sharp.