What is presbycusis?
Presbycusis is the loss of hearing that gradually occurs in most individuals
as they grow older. Hearing loss is a common disorder associated with aging.
About 30-35 percent of adults between the ages of 65 and 75 years have a hearing
loss. It is estimated that 40-50 percent of people 75 and older have a hearing
loss.
The loss associated with presbycusis is usually greater for high-pitched
sounds. For example, it may be difficult for someone to hear the nearby chirping
of a bird or the ringing of a telephone. However, the same person may be able to
hear clearly the low-pitched sound of a truck rumbling down the street.
There are many causes of presbycusis. Most commonly it arises from changes in
the inner ear of a person as he or she ages, but presbycusis can also result
from changes in the middle ear or from complex changes along the nerve pathways
leading to the brain. Presbycusis most often occurs in both ears, affecting them
equally. Because the process of loss is gradual, people who have presbycusis may
not realize that their hearing is diminishing.
What are the symptoms of presbycusis?
With presbycusis, sounds often seem less clear and lower in volume. This
contributes to difficulty hearing and understanding speech. Individuals with
presbycusis may experience several of the following:
- The speech of others seems mumbled or slurred.
- High-pitched sounds such as "s" and "th" are difficult to hear and tell
apart.
- Conversations are difficult to understand, especially when there is
background noise.
- A man's voice is easier to hear than the higher pitches of a woman's
voice.
- Certain sounds seem annoying or overly loud.
- Tinnitus (a ringing, roaring, or
hissing sound in one or both ears) may also occur.
What are the causes of presbycusis?
Sensorineural hearing loss is caused by
disorders of the inner ear or auditory nerve. Presbycusis is usually a
sensorineural hearing disorder. It is most commonly caused by gradual changes in
the inner ear. The cumulative effects of repeated exposure to daily traffic
sounds or construction work, noisy offices, equipment that produces noise, and
loud music can cause sensorineural hearing loss. Sensorineural hearing loss is
most often due to a loss of hair cells (sensory receptors in the inner ear).
This can occur as a result of hereditary factors as well as aging, various
health conditions, and side effects of some medicines (aspirin and certain
antibiotics).
What can be done?
Much of the hearing loss caused by noise exposure can be prevented. Awareness
of potential sources of damaging noises, such as firearms, snowmobiles, lawn
mowers, leaf blowers, woodworking machinery and loud appliances is important.
Ear plugs or special fluid-filled ear muffs can give protection and should be
worn to help avoid the possibility of damage to hearing. Excessively loud
everyday noises, both at home and at work, can pose a risk to a person's
hearing. Avoiding loud noises and reducing the amount of time one is exposed to
everyday noises may be helpful.
There are many strategies to help people with presbycusis.
Hearing aids may be recommended for some
individuals. Assistive listening devices can provide further improvement in
hearing ability in certain situations. One example of such a device is the
built-in telephone amplifier. Another example is FM systems that make sounds
clearer, with or without a hearing aid, by delivering sound waves like a radio.
Training in speechreading (using visual cues to determine what is being spoken)
can help those with presbycusis to understand better what is being said in
conversations or presentations.
How is a hearing aid selected?
Consultation with specially trained professionals who work as a team is
important for evaluation of a hearing loss and selection of appropriate
management. An otolaryngologist (ear, nose
and throat specialist) should evaluate the individual with a hearing problem to
make the diagnosis and exclude related systemic disorders that may contribute to
the problem. An audiologist is a professional who measures the hearing and
identifies the type of hearing loss. The
audiologist conducts a complete hearing evaluation and determines if a
hearing aid may be useful. The individual is counseled about how a hearing aid
may improve listening situations. Then the audiologist conducts tests to find an
appropriate aid, selecting one that maximizes a person's hearing and
understanding of speech. Most older adults with hearing loss can benefit from
using a hearing aid, although the degree of benefit may vary according to the
type and amount of hearing loss.
Communication tips
If you have a hearing loss caused by presbycusis or know someone who does,
share these tips with family members, friends, and colleagues.
- Face the person who has a hearing loss so that he or she can see your
face when you speak.
- Be sure that lighting is in front of you when you speak. This allows a
person with a hearing impairment to observe facial expressions, gestures,
and lip and body movements that provide communication clues.
- During conversations, turn off the radio or television.
- Avoid speaking while chewing food or covering your mouth with your
hands.
- Speak slightly louder than normal, but don't shout. Shouting may distort
your speech.
- Speak at your normal rate, and do not exaggerate sounds.
- Clue the person with the hearing loss about the topic of the
conversation whenever possible.
- Rephrase your statement into shorter, simpler sentences if it appears
you are not being understood.
- In restaurants and social gatherings, choose seats or conversation areas
away from crowded or noisy areas.
How does hearing work?
- The outer ear collects sound waves and works like a funnel to send them
through a narrow tube (ear canal) that leads inside the ear. At the end of
the ear canal is the eardrum (tympanic membrane).
- The tympanic membrane is a thin membrane that vibrates when sound waves
strike it. It divides the area called the outer ear from the middle ear. It
is attached to a set of three tiny bones in the middle ear.
- These bones are called the hammer (malleus), anvil (incus), and the
stirrup (stapes). The bones pass the vibrations of sound waves to a small
organ in the hearing part of the inner ear called the
cochlea, which is a coiled structure like a snail shell.
- The inner ear is filled with a thin fluid that transmits pressure
changes throughout the cochlea. Inside the cochlea are tiny hair cells that
pick up sound vibrations from the fluid and cause nerve impulses in the auditory nerve.
- The auditory nerve carries the message to the brain, where it is interpreted as sound.
Presbycusis may be caused by changes in the blood supply to the ear because
of heart disease, high blood pressure, vascular (pertaining to blood vessels)
conditions caused by diabetes, or other circulatory problems. The loss may be
mild, moderate, or severe.
Sometimes presbycusis is a conductive hearing disorder, meaning the loss of
sound sensitivity is caused by abnormalities of the outer ear and/or middle ear.
Such abnormalities may include reduced function of the tympanic membrane (the
eardrum) or reduced function of the three tiny bones in the middle ear that
carry sound waves from the tympanic membrane to the inner ear.
For more information, additional addresses and phone numbers, or a printed
list of organizations, contact:
NIDCD Information Clearinghouse
1 Communication Avenue
Bethesda, MD 20892-3456
Toll-free Voice: (800) 241.1044
Toll-free TTY: (800) 241.1055
Fax: (301) 770-8977
e-mail: nidcdinfo@nidcd.nih.gov
Source: National Institutes of Health; National Institute on Deafness and Other Communication Disorders
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 4/12/2008...#5840
