Audiometry

Question 1

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

Answer 1

pure tone audiometry

Question 2

what is a pure tone threshold at a specific frequency

Answer 2

the decibel level at which the sound is heard 50% of the time

Question 3

what frequency range are most speech sounds in

Answer 3

500-8000Hz

Question 4

how dose pure tone audiometry work

Answer 4

A certain tone at a certain intensity and frequency is presented to the individual via both air and bone conduction. They will respond if they have heard it by pressing a button

Question 5

what do the symbols on an audiogram mean

Answer 5

right- red
left- blue

O- air conduction right
X- air conduction left

Triangle- bone conduction (can be left or right)

masking symbols
filled in O - shadow right AC
thick X - shadow left AC
[ - bone conduction masked right
] - bone conduction masked left

Question 6

why is masking done

Answer 6

to make sure it is the ear being tested that is hearing the sound

Question 7

what does a SN HL look like on an audiogram

Answer 7

no significant gap between bone and air

below 20

Question 8

what is presbycusis

Answer 8

age related hearing loss

Question 9

what can cause SN HL

Answer 9

loud sounds 
ototoxic drugs 
diseases (e.g. rubella) 
birth complications 
schwannomas
genetics

Question 10

what does a C HL look like on an audiogram

Answer 10

significant gap between air and bone conduction (bone within normal limits)

Question 11

what can cause CHL

Answer 11

ear infections
middle ear fluid (glue ear)
perforated ear drums

Question 12

what does mixed HL look like on an audiogram

Answer 12

at parts will have significant gap between B and A conduction
BUT
bone conduction thresholds are not all within normal limits

Question 13

what is the classical sign of otosclerosis

Answer 13

carharts notch at 2KHz

Question 14

what is otosclerosis

Answer 14

pathological increased bony turnover leading to sclerosis and failure of the sound conduction mechanism, due to ankylosis of the stapes footplate in the fenestra ovalis of the cochlea. This produces a slowly progressive conductive hearing impairment

Question 15

what does tympanometry test

Answer 15

the condition of the middle ear by creating variations of pressure in the ear canal
This is an objective test of middle-ear function and is not a test of hearing

It permits a distinction between sensorineural and conductive hearing loss
It can be helpful in making a diagnosis including that of:
Otitis Media by demonstrating the presence of middle ear fluid
A Tympanic Membrane Perforation by showing a large ear canal volume

Question 16

what can cause a flat tympanogram

Answer 16

glue ear, middle ear fluid

Question 17

what can cause a tympanogram that is towards the left of the axis

Answer 17

drum is moving but something is retracting it inwardly, toward middle ear space (could be negative pressure from the E. tube). Positive pressure can build up and do the reverse, pushing the drum outward. You can cause this by pinching your nostrils and exhaling with your mouth closed (Valsalva). E.g eustachian tube problems

Question 18

what does the tympanogram of a perforated ear look like

Answer 18

measure canal volume will be large (high peak)