A string quartet sits on the stage ready to play. Enjoyment of the concert depends upon many things: the skill of the musicians, the quality of their instruments, and the acoustics of the performance area. A small boxy room will distort the sound even of virtuosi, and detract from the listening experience.
Hearing Aid Acoustics
A hearing aid's components are like musical instruments. Although quality is essential, the very finest components may not be needed for an enjoyable listening experience. Besides the components, some consideration should be given to their acoustic surroundings. Just as room acoustics are important to the enjoyment of a concert, ear acoustics are critical to the usefulness of a hearing aid.
Low Frequencies Are Absorbed; High Frequencies Are Reflected
What sounds come through the walls of an apartment? The base beat; the low frequencies. High frequencies are reflected off the walls and back into the room from which the music arises.
A portion of all sounds are transferred through the walls and a portion is reflected. But as the frequency is increased, less sound passes through the wall and more is reflected back into the room.
Put your fingers in your ears. Does it change your voice? Of course, it does. You've changed the acoustics of your ear canal.
Hearing Loss: A Fact of Life
The National Institutes of Health estimate that one-third of Americans will experience hearing problems by the time they reach age 65. Heredity and the chronic exposure to noise in an industrialized society are the main contributors to the loss over time. Presbycusis is a term attributed to this age-related hearing loss.
Hearing Aids Change the Ear's Acoustics
Hearing aids do more than amplify sound; they change the acoustics of your outer ear. No matter what style of aid is chosen (with the exception of bone conduction aids or cochlear implants for the profoundly hard of hearing), something goes into the ear canal. Because acoustics are affected in complex ways, multiple “fittings” may be needed to get optimal performance out of a hearing aid.
BTE, ITE, ITC, and CIC Hearing Aids
An individual's hearing loss may affect only the high frequencies, or it can affect a broad range of frequencies. The loss may be mild, moderate, or profound. Behind-the-ear (BTE), and the various types of in-the-ear (ITE) devices offer a range of choices for the hearing aid user. These styles have different acoustical properties, which sould be considered in their selection. Some types of hearing loss may be well served by in-the-ear aids; other types, by behind-the-ear aids. The goal of this article is to raise awareness that the acoustics of a hearing aid may be critical for customer satisfaction. A skilled audiologist or other hearing aid professional can help sort out the benefit of various types of aids for each individual patient.
Talk With Your Doctor
In very rare cases, a hearing loss can be symptomatic of something more serious. It is always advisable to mention your hearing difficulties to your primary care physician or ENT specialist.
Sources
- Staff, Hearing Loss, MayoClinic.com.
- Anonymous, Presbycusis, National Institute on Deafness and Other Communication Disorders.
- Anonymous, Types of Hearing Aids, Food and Drug Administration, updated 10/20/2009.
Richard Walloch - Don't believe me because of my education or professional experience. Believe me because of the evidence and arguments I advance.
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