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Home / AFA Balance & Hearing Institute / Hearing & hearing aids

How we hear

The human ear is a complex and amazing system. Hearing begins when sound waves are collected by the outer ear (or pinna) and are funneled down through the ear canal. At the end of the ear canal the sound waves reach the eardrum (or tympanic membrane). Behind the eardrum lies a cavity called the middle ear space.

The middle ear space contains three small bones; the malleus (aka the hammer), the incus (aka the anvil), and the stapes (aka the stirrup). When the sound waves strike the eardrum, vibrations occur which move the bones of the ossicular chain. Movement of the malleus imparts movement on the incus and movement of the incus, which imparts movement to the stapes. This middle ear process converts the sound waves from acoustic energy into mechanical energy and amplifies the intensity of the sound. The movement of the stapes then transfers this energy in a hydraulic fashion, to the fluid-filled inner ear.

The inner ear consists of the hearing organ (or cochlea) and the auditory nerve fibers which travel to the brain. The inner ear converts the hydraulic sound energy into neural impulses via the movement of tiny neural receptors within the cochlea, called hair cells. These impulses then travel to the brain where they are decoded and interpreted into our perception of sound. As long as all parts of the auditory system function correctly and the message is not distorted along the way, normal hearing can occur. As you can see however, there are many opportunities along the pathway for the signal to become degraded resulting in hearing loss.

Hearing loss

Hearing loss is much more common than most people realize. The National Institute on Deafness and Other Communication Disorders estimates that 2 to 3 out of every 1,000 children in the United States are born with a hearing loss, and 30 million Americans over the age of 12 have hearing examinations recording hearing loss in both ears—with even more that remaining undiagnosed. The sad reality about hearing loss is that although most losses can be treated, many people continue to struggle needlessly. An untreated hearing loss affects not only an individual’s quality of life, but also relationships with family, friends, and co-workers. Long-term untreated hearing loss has been shown to lead to increased stress, fatigue, depression, and social withdrawal.

The signs of hearing loss are typically very subtle and occur gradually over time, though they can also be severe and sudden. Regardless of onset, most types of hearing loss share similar indicators. If you experience any of the following, you may have hearing loss and should ask to be tested.

You may have hearing loss if you:

  • Require frequent repetition of words or sentences
  • Respond inappropriately during conversations
  • Think that other people’s voices sound muffled or that they mumble
  • Have difficulty understanding women or children’s voices
  • Have difficulty following conversations involving more than two people
  • Have difficulty hearing in noisy environments
  • Have your television or radio turned up to a loud volume
  • Need to read lips or watch people’s faces when they speak
  • Feel embarrassed, annoyed, or stressed out because you cannot understand people
  • Withdraw from social situations you once enjoyed because of communication difficulty
  • Have been exposed to loud sounds over a prolonged period of time
  • Have any of the following conditions: ringing in your ears, a family history of hearing loss, diabetes, heart disease, circulatory or thyroid problems, or take medications that can harm the ear (ototoxic drugs)