Human beings are gifted with five senses that allow us to interact with the world. The sense of sound, in particular, can imbue a certain serenity. Think of the barely perceptible hiss beneath the harmony-layered music of The Beatles, “Rubber Soul” playing from a phonograph. The same sense, with the blare of a siren or a clap of thunder, can bring one to the peak of alertness. The ear, like a microphone, allows us to perceive these sounds, but it’s the hearing center of the brain that interprets them.
As Tesla would note, our bodies use electricity to relay this information. Vibrations from the middle ear, or eardrum, pick up these sounds that are converted into electrical impulses and sent to the brain. These sound waves are transmitted by the cochlear nerve, or simply acoustic nerve, to the cochlear nucleus in the brainstem. This hearing center contains one cochlear nucleus for each ear, left and right, just like a stereo system. Here, these bundles of electricity are separated from each other based on pitch. The acoustic nerve, acting like a highway, also relays information back to the inner ear to aid in filtering out background noise while protecting from potential damage from loud noises.
When hearing loss occurs, doctors will typically attribute this to problems with the inner ear. Common causes of hearing loss are frequent exposure to loud noises, such as motorcycle riding or loud music; changes in the cells or nerves of the inner ear; and ear infections or even wax build up.
Some hearing impediments in the elderly may not be related to the workings of the ear itself but are instead caused by the slow deterioration of an aging brain. Recent studies have found increasing evidence of feedback and timing issues of sounds processed by the brain. When this neural hearing center is compromised, the ear becomes unable to filter out background noise and can be left unprotected from damaging loud noises. When the timing or meter of sound is obscured by the brain, words can often sound blurred together, making consonants indistinguishable and minor pauses imperceptible. Many people find themselves raising their voices to elderly people with auditory afflictions, which is often accompanied by a sensitivity to loudness, doing more harm than good. Speaking softly, yet slowing one’s speech for clarity can be much more effective without the potential of exasperating the problem.
As the acoustic nerve intimately connects the brain stem and the ear, deciphering the exact cause of an issue is often troublesome. Researchers may be closer to isolating hearing loss that is caused by the brain, but repairing or reversing damage to the brain’s hearing center is another story entirely.