A person is considered legally deaf when speech sounds of 82dB or less cannot be heard Typical speech occurs at about 60 dB Agerelated hearing loss results from a variety of factors including poor ID: 935644
Download Presentation The PPT/PDF document "HEARING ABNORMALITIES Hearing loss arise..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
HEARING ABNORMALITIES
Slide2Hearing loss arises from a wide variety of causes and affects nearly 30 million Americans (NIDCD, 2006).
A
person is considered legally deaf when speech sounds of 82dB or less cannot be heard.
Typical
speech occurs at about 60 dB.
Age-related hearing loss results from a variety of factors, including poor
circulation
to the inner ear or the cumulative effects of a lifetime of exposure to loud noise.
After
the age of 30, most people cannot hear frequencies above 15,000Hz.
After
the age of 50, most people can
’
t hear sounds above 12,000Hz, and people over 70 have difficulty with sounds over 6,000 Hz.
Because
speech normally ranges up to 8,000 Hz, many elderly people begin to have difficulty understanding the speech of others.
Slide3Teens who frequent concerts and clubs are much more likely to report hearing problems
Earbud
devices, such as those used by the popular iPod, boost signals 6 to 9dB and tend to be used for long periods due to their convenience.
Experts recommend using such devices for no more than an hour per day at no more than 60 percent of their maximum volume to avoid hearing loss
Everyday
noises from vehicles, machinery, and appliances can also contribute to hearing loss.
Slide4Conduction loss
Hearing
loss resulting from problems in the outer or middle ear is referred to as conduction loss.
Conduction
loss can result from a buildup of wax in the ear canal, infections of the middle ear, and a disease known as
otosclerosis
.
Most
cases of
otosclerosis
occur when the stapes (stirrup) becomes immobilized by a buildup of abnormal bone at its base.
People
with conduction loss can be helped by use of a
hearing
aid, which acts by amplifying sound signals
Slide5Hearing
loss also occurs due to damage to the inner ear, the auditory pathways, or the auditory cortex.
Medications
, such as quinine and antibiotics, damage hair cells in sensitive individuals.
Nicotine
produces hearing loss by reducing blood supply to the
ear
For
people with cochlear or brainstem damage, implants can restore the ability to process speech
sounds
Slide6Auditory defects may be either partial or complete.
Auditory
defects are of two types:
1
. Conduction deafness
2
. Nerve deafness.
CONDUCTION DEAFNESS
Conduction deafness is the type of deafness that occurs due to impairment in transmission.
It
normally caused by disease in the middle ear.
If
any disease or damage to the eardrum or the
ossicles
has occurred, conduction deafness takes place, but the transducer in the inner ear will be normal.
This
particular type of deafness can be corrected by surgery designed to free the movement of the
ossicles
or by repairing the damaged eardrum or
ossicles
.
It
can also be corrected by using an hearing aid
.
Slide7NERVE DEAFNESS
Nerve deafness is the deafness caused by damage of any structure in cochlea, such as hair cell, organ of
Corti
, basilar membrane or cochlear duct or the lesion in the auditory pathway.
It
is caused by a disease or degeneration of the auditory nerve or the
haircells
connected to the nerve.
Sometimes
these deafness will be restricted to a particular frequency of sound.
In
some cases only the path of the auditory nerve involved in the transmission of the particular frequencies is damaged, but in some cases the whole auditory nerve is damaged leading to complete deafness.
Nerve
deafness cannot be corrected because the auditory nerve will not regenerate once it has been damaged.