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Unit 10: Speech and Hearing Impaired: Definition, Types, Characteristics

loss such that they cannot benefit from amplification, while hard of hearing is used for those with Notes
mild to sever hearing loss but who can benefit from amplification.

10.5 Different Types of Hearing Impairment
There are different types of hearing loss, depending on which part of the hearing pathway is affected.
A specialist will always try to localize where in the hearing pathway the problem lays, so as to be
able to classify the hearing loss as belonging to one of the following groups. This is most important in
determining the appropriate treatment. There are following types of hearing impairment.
• Conductive hearing loss
• Sensorineural hearing loss
• Central hearing loss
• Functional hearing loss
• Mixed hearing loss
10.5.1 Conductive Hearing Loss
Conductive hearing loss is due to any condition that interferes with the transmission of sound through
the outer and middle ear to the inner ear. This type of hearing loss can be successfully treated in most
cases.
In cases of conductive hearing loss, sound waves are not transmitted effectively to the inner ear
because of some interference in:
• The external ear canal
• The mobility of the eardrum (problems with the mobility of the eardrum are often caused by
accumulation of fluid in the eustachian tube, the tube that connects the middle ear to the back of
the throat)
• The three tiny bones inside the middle ear
• The middle-ear cavity
• The openings into the inner ear
• The eustachian tube
Modern techniques make it possible to cure or at least improve the vast majority of cases involving
problems with the outer or middle ear. Even if people with conductive hearing loss are not improved
medically or surgically, they stand to benefit greatly from a hearing aid, because what they need
most is amplification.
10.5.2 Sensorineural Hearing Loss
In sensorineural hearing loss, the damage lies in the inner ear, the acoustic nerve, or both. Most
physicians call this condition "nerve deafness."
The hair cells in the large end of the cochlea respond to very high-pitched sounds, and those in the
small end (and throughout much of the rest of the cochlea) respond to low-pitched sounds. These hair
cells, and the nerve that connects them to the brain, are susceptible to damage from a variety of causes.
• The term "sensory" hearing loss is applied when the damage is in the inner ear. Common
synonyms are "cochlear" or "inner-ear" hearing loss.
• "Neural" hearing loss is the correct term to use when the damage is in the acoustic nerve,
anywhere between its fibers at the base of the hair cells and the relay stations in the brain (the
auditory nuclei). Other common names for this type of loss are "nerve deafness" and
"retrocochlear" hearing loss.
Sensorineural hearing loss is one of the most challenging problems in medicine. A large variety of
hearing impairments fall under this category. Although the chances for restoring a sensorineural
hearing loss are slim, a small number of cases can be treated, and some people experience dramatic
improvements as a result. However, a great need for further research in this area still exists.

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