hearing assessments and hearing aids

Question 1

what is pure tone audiometry

Answer 1

the most commonly performed test in audiology that determines hearing sensitivity at different dB and frequencies

Question 2

what frequencies are affected more by ototoxic medication

Answer 2

higher frequencies affected first

Question 3

R ear vs L ear colour and symbol in audiogram

Answer 3

R ear - red circle
L ear - blue X

Question 4

what are the different dB ranges of hearing loss (mild, moderate, severe, profound)

Answer 4

normal: -10-20 dB
mild: 20-40 dB
moderate: 40-70 dB
severe: 70-100 dB
profound: 100-120 dB

Question 5

what does a typical presbycusis audiogram look like

Answer 5

bilateral hearing loss that decreases linearly at higher frequencies (see lect)

Question 6

what is the issue with bone conduction testing

Answer 6

either ear could be generating the response and so it is difficult to tell which ear is defective -> sound emitter is usually placed behind the ear of interest to try and omit this

Question 7

what does an air-bone conduction gap on an audiogram indicate

Answer 7

conductive hearing loss - sounds can be heard at a much lower dB through bone compared to air indicating a defect in sound conduction rather than a neural problem

Question 8

what will a sensorineural hearing loss look like on an audiogram

Answer 8

hearing loss via both air and bone conduction tests -> it is the nerve that is affected so sounds are not being transmitted

Question 9

what does a mixed hearing loss appear like on an audiogram

Answer 9

bone conduction is better than air but bone is still not within the usual range

Question 10

what is masking (audiology)

Answer 10

a method employed to stop compensation by a better hearing hear when testing hearing loss - a narrowband noise is played in the good ear so that it cannot compensate for the bad ear

Question 11

what is the symbol for masking on audiogram

Answer 11

[ or ]

Question 12

what is tympanometry

Answer 12

a test that measures the change in compliance (movement) of the eardrum

Question 13

what is normal middle ear pressure

Answer 13

+50 to -50 daPa

Question 14

what is a normal ear canal volume

Answer 14

no normal volume but > 3 cm^3 usually indicates perforation, can also be increased by interventions such as grommets

Question 15

what does a peaked 0daPa tympanometry classification indicate

Answer 15

normal middle ear function - movesthe most when air pressure is equal on both sides

Question 16

what does no peak in tympanometry indicate

Answer 16

lack of movement of ear drum -> glue ear if ear canal volume is normal, gommets or perforation is large ear canal volume

Question 17

what does a peak at negative pressure in tympanometry indicate

Answer 17

eustachian tube dysfunction

Question 18

what happens to middle ear pressure in eustachian tube dysfunction

Answer 18

pressure increases due to blockage of the tube

Question 19

what are the 2 newborn baby hearing screens

Answer 19

1. well baby pathway - otoacoustic emission test (OAE) measures hair cell function in the inner ear, a sound is playedand the cochlear produces and echo
2. NICU protocol - the auditory brainstem response (ARB) is a non-invasive test that uses electrodes to measure how well sounds reach your baby’s brainstem, baby must be asleep to stop the minute changes being hidden

Question 20

why do NICU babies need a different hearing test

Answer 20

they have a higher chance of neuropathy affecting their hearing and so hearing must be tested to the level of lateral lemniscus (part of the auditory tract of the brainstem)

Question 21

what are the 3 main parts in a hearing aid

Answer 21

1. hearing aid
2. tubing
3. earmould/tip - custom made

Question 22

disadvantages of open fit hearing aids

Answer 22

1. more feedback
2. needs to be cleaned out
3. fiddly and harder to put in if poor dexterity

Question 23

disadvantages of receiver in ear canal hearing aids

Answer 23

1. infection
2. ear wax
3. water can get in and damage it

Question 24

how does anchored hearing aid work

Answer 24

sound is transmitted through the skull -> used in patients with permanent conductive hearing loss or who cannot use standard hearing aids e.g. those who have not developed an ear canal

Question 25

how does a cochlear implant work (3)

Answer 25

1. The processor (external) captures sound signals and sends them to a receiver implanted under the skin behind the ear
2. The receiver sends the signals to electrodes implanted in the cochlea
3. The signals stimulate the auditory nerve, which then directs the signals to the brain

Question 26

how do CROS hearing aids work

Answer 26

used when there is one hearing and one non-hearing hear
1. A hearing aid for the deaf ear consists of a microphone (to pick up sounds on the deaf side) and a transmitter, which transmits sounds to the other ear
2. The transmitter sends the recorded sounds through radio waves to the hearing aid in your healthy ear
3. This second part of the CROS system consists of a radio receiver for wireless communication and an amplifier, The latter amplifies the sounds received from the other side

Question 27

how can vestibular dysfunction be assessed (3)

Answer 27

1. dix-hallpike
2. gait assessment
3. calorics - pour cold/hot water in one ear in order to establish a temperature gradient from one side of the canal to the other, this should induce dizziness in the pt and nystagmus should be seen, absence of this indicates defect