Audiometry

Question 1

When is pure tone audiometry used?

Answer 1

First test carried out to assess the nature and degree of hearing loss in adults and young children

Question 2

What is the pure tone threshold?

Answer 2

Decibel level at which the sound is perceived 50% of the time

Question 3

What does air conduction test?

Answer 3

Entire auditory pathway

Question 4

What does bone conduction test?

Answer 4

Stimulates the cochlea directly

Question 5

What does the O on the audiogram mean?

Answer 5

Air conduction

Question 6

What does red on the audiogram mean?

Answer 6

Right ear

Question 7

What does blue on the audiogram mean?

Answer 7

Left ear

Question 8

What does the X on the audiogram mean?

Answer 8

Air Conduction

Question 9

What does the triangle on the audiogram mean?

Answer 9

Bone conduction

Question 10

Why is masking used in audiometry?

Answer 10

To isolate the test ear and ensure that results obtained are true thresholds

Question 11

What are the consequences of not maskin?

Answer 11

An inaccurate measure of threshold
Incorrect diagnosis
May lead to inappropriate intervention
Difficult in later interpreting results

Question 12

What are the different types of hearing loss?

Answer 12

Sensorineural hearing loss
Conductive hearing loss
Mixed hearing loss

Question 13

What will a sensorineural hearing loss look like on audiogram?

Answer 13

No significant gap between air and bone conduction thresholds

Question 14

How does a sensorineural hearing loss occur?

Answer 14

Result of damage to the hair cells within the cochlea or the cochlear nerve

Question 15

What is presbycusis?

Answer 15

Are related sensorineural hearing loss

Question 16

What can cause SNHL?

Answer 16

Presbycusis 
Loud sounds
Ototoxic drugs: gentamicin, cisplatin, vincristine
Rubella
Complications at birth 
Vestibular schwannoma
Genetic predisposition

Question 17

What will a conductive hearing loss look like on audiogram?

Answer 17

Significant gap between air and bone conduction thresholds with bone conduction being at normal limits

Question 18

What can cause a conductive hearing loss?

Answer 18

Ear infections
Otitis media with effusion
Perforated ear drum

Question 19

What will a mixed hearing loss look like on an audiogram?

Answer 19

At parts there is a significant gap between air and bone conduction thresholds but bone conduction thresholds are not at all within normal limits
Combination of conductive and sensorineural hearing loss, which means there is damage in both the outer or middle ear and in the inner ear

Question 20

What can cause a mixed hearing loss?

Answer 20

Genetic 
Birth defects
Diseases
Infections
Tumours
Masses 
Head injuries
Otosclerosis

Question 21

What will otosclerosis classically show on audiogram?

Answer 21

Carhart’s notch at 2KHz

Question 22

What is tympanometry?

Answer 22

Used to test the condition of the middle ear by creating variations of pressure in the ear canal

Question 23

What can tympanometry be useful in making a diagnosis of?

Answer 23

Otitis media by demonstrating the presence of middle ear fluid
TM perforation by showing a large ear canal volume

Question 24

What is a type A tympanogram?

Answer 24

Normal eustachian tube function

Eardrum is moving normally with a pressure change

Question 25

What is a type B tympanogram?

Answer 25

Restricted movement of the drum (likely fluid, but can be ossification of the malleus, incus and stapes)

Question 26

What is a type C tympanogram?

Answer 26

Drum is moving but something is retracting it inwards towards the middle ear space. Eustachian problems, nasal tumours etc that are preventing normal equalisation

Question 27

What is a type Ad tympanogram?

Answer 27

Pressure is fine but the ossicles are moving too much allowing too much movement of the ear drum

Question 28

What is a type As tympanogram?

Answer 28

Eardrum has retracted back onto the ossicles, ossified ossicles