Investigations

Question 1

what is the first line investigation for hearing loss?

Answer 1

pure tone audiometry (PTA)

Question 2

how is pure tone audiometry carried out?

Answer 2

soundproof room with sound produced via headphones/earphones (air conduction) or bone conductor (bone conduction)
patient presses a button when sound is heard

Question 3

what is masking?

Answer 3

technique used in PTA to isolate the test ear

narrow band noise played in non-test ear

Question 4

pitch of vowels

Answer 4

low

Question 5

pitch of consonants

Answer 5

high

Question 6

mild hearing loss result on PTA

Answer 6

20-40

Question 7

moderate hearing loss result on PTA

Answer 7

40-70

Question 8

severe hearing loss result on PTA

Answer 8

70-90

Question 9

profound hearing loss result on PTA

Answer 9

90-120

Question 10

SNHL result on audiogram

Answer 10

no significant gap between air and bone conduction thresholds

Question 11

what causes permanent SNHL?

Answer 11

damage to hair cells and/or hearing nerve

Question 12

what naturally happens to the cochlea in ageing?

Answer 12

it is damaged

Question 13

causes of SNHL

Answer 13

exposure to loud sounds
ototoxic drugs
infections (rubella)
complications at birth
tumour of auditory nerve (vestibular schwannoma)
genetics

Question 14

what do people with SNHL struggle to understand?

Answer 14

speech

Question 15

is SNHL reversible?

Answer 15

no

Question 16

CHL result on audiogram

Answer 16

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

Question 17

what causes CHL?

Answer 17

sound cannot pass into the inner ear due to abnormalities with the middle and external ear e.g. infection

Question 18

what is mixed hearing loss result on audiogram?

Answer 18

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

Question 19

causes of mixed hearing loss

Answer 19

genetics

birth defects

Question 20

what is tympanometry used for?

Answer 20

test condition of the middle ear by creating pressures in ear canal

Question 21

why is tympanometry helpful in OME?

Answer 21

demonstrates presence of middle ear fluid and tympani membrane perforation by showing a large ear canal volume