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TOPIC
1
TYPES OF HEARING
IMPAIRMENT
Types of Hearing Impairment

A loss of sensitivity

Auditory nervous system pathology
Important Terms
Time of onset



Congenital:
Acquired:
Adventitious:
present at birth
obtained after birth
acquired after birth
Important Terms
Time Course




Acute:
duration
Chronic:
Sudden:
Gradual:
time
sudden onset/short
long duration
rapid onset
changes slowly over
Important Terms
Time Course




Temporary:
Permanent:
Progressive:
Fluctuating:
time
limited duration
irreversible
advancing
changes in degree over
Important Terms
Number of Ears Involved

Unilateral:
Just one

Bilateral:
Both
Hearing Sensitivity Loss
“The ear is not as sensitive as normal in
detecting sound”
 Types:
 Conductive
 Sensorineural
 Mixed
Conductive Hearing Loss
“Caused by an abnormal reduction or
attenuation of sound as it travels from
the outer ear to the cochlea”
Conductive Hearing Loss
An audiogram of a bilateral conductive
hearing loss
Conductive Hearing Loss
Differences in the air-bone gap across
different types of hearing loss
Sensorineural Hearing Loss
“Caused by a failure in the cochlea to
transduce the sound from the middle
ear to neural impulses in the VIII
Nerve.”
Sensorineural Hearing Loss
n
Implications include:

A reduction in the sensitivity of the receptor
cells in the cochlea
A reduction in the frequency resolving power
of the cochlea
A reduction in the dynamic range of the
system


Sensorineural Hearing Loss
An audiogram of a bilateral sensorineural
hearing loss
Sensorineural Hearing Loss
Differences in the air-bone gap across
different types of hearing loss
Mixed Hearing Loss
“A loss with both a conductive and
sensorineural component.”
Mixed Hearing Loss
An audiogram of a bilateral mixed hearing
loss
Mixed Hearing Loss
Differences in the air-bone gap across
different types of hearing loss
Types of Hearing Impairment

A loss of sensitivity

Auditory nervous system pathology
Auditory Nervous System Impairment
Causes:


Disease
Disordered auditory nervous system
development
Auditory Nervous System Impairment
Kinds:


Retrocochlear disorders
Central auditory processing disorders
Auditory Nervous System Impairment
§




Auditory Characteristics:
Reduced ability to understand speech in
a noise background
Problems understanding speech with
reduced redundancy
Problems with localization and
lateralization
Problems processing normal or altered
temporal cues