Hearing Tests

Question 1

what test is done to assess hearing loss?

Answer 1

pure tone audiometry (PTA)

Question 2

how is pure tone audiometry carried out?

Answer 2

soundproof room
transducer presents sound can be headphones/insert earphones or a bone conductor
patient presses a button when they have heard sound

Question 3

define masking

Answer 3

narrow band noise centred around the test frequency is introduced into the non-test ear which distracts this ear

Question 4

why is masking done?

Answer 4

to isolate the test ear

ensure true thresholds are obtained

Question 5

what pitch are vowels?

Answer 5

low pitch (left side of the audiogram)

Question 6

what pitch are consonants

Answer 6

high (right side of the audiogram)

Question 7

mild hearing loss

Answer 7

20-40

speech (often noticed by partners first)

Question 8

moderate hearing loss

Answer 8

40-70

Question 9

severe hearing loss

Answer 9

70-90

Question 10

profound hearing loss

Answer 10

90-120

Question 11

three types of hearing loss

Answer 11

sensorineural
conductive
mixed

Question 12

presentation of sensorineural hearing loss

Answer 12

no significant gap between air and bone conduction thresholds

Question 13

what is the cause of a permanent SNHL?

Answer 13

damage to hair cells in cochlea or hearing nerve (or both)

Question 14

is damage to the cochlea a natural part of the ageing process?

Answer 14

yes (presbycusis)

Question 15

causes of SNHL

Answer 15

presbycusis
noise exposure
ototoxic drugs e.g. gentamicin
certain infectious diseases e.g. rubella
complications at birth
benign tumour
genetic predisposition

Question 16

what does SNHL find difficult/

Answer 16

understanding speech

Question 17

is SNHL reversible?

Answer 17

no

Question 18

conductive hearing loss on an audiogram

Answer 18

significant gap between air and bone conduction thresholds where bone conduction thresholds are within normal limits

Question 19

define conductive hearing loss

Answer 19

sound is not able to pass freely into the inner ear, usually an abnormality of the outer or middle ear

Question 20

causes of CHL

Answer 20

glue ear

perforated ear drum

Question 21

mixed hearing loss presentation on audiogram

Answer 21

significant gap between air and bone conduction levels, but bone conduction is not within normal limits

Question 22

what does a mixed hearing loss tell you?

Answer 22

there is damage to both outer or middle and inner ear

Question 23

causes of mixed hearing loss

Answer 23

genetic factors
birth defects
diseases
infections
tumours/masses
head injuries

Question 24

otosclerosis presentation on PTA

Answer 24

Cahart’s notch at 2kHz

Question 25

define tympanometry

Answer 25

this is a test used to assess the condition of the middle ear by creating vibrations of pressure in the ear canal

Question 26

what does tympanometry permit

Answer 26

distinction between SNHL and CHL
OME (showing presence of middle ear fluid- flat)
tympanic membrane perforation showing a large ear canal volume