Download Conductive hearing loss

INTRODUCTION TO
AUDIOLOGY (SPHS 1100)
WEEK 4 POWER POINT
TOPICS
 TYPES OF HEARING LOSS
 CAUSES OF HEARING LOSS
 DEGREE OF HEARING LOSS
 AUDIOGRAM
GOALS and OBJECTIVES
GOAL
Learner will understand the different topics related to
Audiology
OBJECTIVES
 TLW identify the causes of hearing loss. (cognitive)
 TLW differentiate types of hearing loss. (cognitive)
TYPES OF HEARING LOSS
The type of hearing loss depends up on where in the ear
problem occur. The three main types are
 Conductive hearing loss.
 Sensorineural hearing loss.
 Mixed hearing loss
TYPES OF HEARING LOSS
TYPES OF HEARING LOSS
Conductive hearing loss
 A problem in the outer or middle ear causes
conductive hearing loss.
 A decrease in strength of a sound is called
attenuation.
 Conductive hearing loss involves reduction in sound
level, or the ability to hear faint sounds.
 Persons with conductive hearing loss find that their
sensitivity to sounds that are introduced by air
conduction is impaired by such a blockage.
TYPES OF HEARING LOSS
 If the sound is introduced by bone conduction, it
passes the obstacle and goes directly to the
sensorineural mechanism.
 The inner ear and other sensorineural structures will be
unimpaired and hearing by bone conduction will be
normal.
 This occurs when sound is not able to reach cochlea.
This is due to malformation of ear canal.
 This problem can be fixed through simple surgical
procedures.
TYPES OF HEARING LOSS
Sensorineural hearing loss
 A problem in the inner ear can cause sensorineural
hearing loss .
 It is also known as nerve-related hearing loss as the
damaged nerves in the inner ear can cause the loss.
 These losses cannot be fixed through surgical
procedures.
 Sensorineural hearing loss involves reduction in sound
level, inability to hear sounds and also affects speech
understanding .
TYPES OF HEARING LOSS
Mixed hearing loss
 Hearing loss which is caused by combination of
conductive and sensorineural hearing loss.
 The problem might be both in the outer or middle ear
and in the inner ear.
CAUSES OF HEARING LOSS
Causes of conductive hearing loss
 Malformation of outer ear, ear canal or middle ear
structures.
 Problems associated with middle ear pathology such
as fluid in the middle ear from colds and allergies
 Poor Eustachian tube function
 Ear infection, perforated eardrum and benign tumors.
 Impacted earwax
 Foreign body in the ear
 Otosclerosis which is abnormal growth of bone of the
middle ear
CAUSES OF HEARING LOSS
Causes of sensorineural hearing loss
There are two types of causes
 Prenatal or Perinatal causes
 Postnatal causes
CAUSES OF HEARING LOSS
PRENATAL OR PERINATAL CAUSES
 Infections such as rubella, herpes, toxoplasmosis,
syphilis and cytomegalovirus.
 Hearing loss that runs in family.
 Asphyxia or lack of oxygen at birth.
 Birth weight of less than 1500 grams.
 Defects of head and neck.
CAUSES OF HEARING LOSS
POSTNATAL CAUSES
 Exposure to loud noise.
 Bacterial Meningitis
 Ototoxicity caused by exposure to drugs
 Physical damage to head or ear
 Hearing loss due to aging which is called as
presbycusis
Other descriptors associated
with hearing loss
Bilateral
 Hearing loss in both ears.
Unilateral
 Hearing loss in one ear and normal in other ear.
Symmetrical
 In symmetrical hearing loss the degree and
configuration are similar in both ears.
Asymmetrical
 In asymmetrical hearing loss the degree and
configuration are different in both ears.
Other descriptors associated
with hearing loss
Progressive versus sudden
 In progressive hearing loss the loss becomes worse
over time where as in sudden the loss happens
quickly.
Fluctuating versus stable
 Fluctuating hearing loss changes over time,
sometimes getting better sometimes getting worse.
Stable hearing loss does not change over time and
remains the same.
Degree of hearing loss
Degree of hearing loss refers to severity of hearing loss.
According to Clark J.G. (1981) the degree of hearing loss
is classified as
 Normal- -10 to 15 dBHL
 Slight – 16 to 25 dBHL
 Mild- 26 to 40 dBHL
 Moderate- 41 to 55 dbHL
 Moderately severe- 56 to 70 dBHL
 Severe- 71 to 90 dBHL
 Profound- 91+ dBHL
AUDIOGRAM
 An audiogram is a graph illustrating a person’s usable
hearing and the amount of hearing loss that an
individual has for each ear.
 The frequency or pitch of the sound is referred to in
Hertz.
 The intensity or loudness of sound is measured in
decibels.
Example of Audiograms with
different degree of hearing loss
References
 Images
 http://www.dallashear.com/types-of-hearing-loss.html
 http://www.bcchildrens.ca/Services/ClinicalDiagnosti
cFamilyServices/Audiology/Forfamilies/readaudiogra
m.htm