Lecture - Hearing Loss In The Community

Question 1

Audiometry

Answer 1

• measurement of hearing
• dBHL based on normal hearing
• 20 dBHL is a tenfold change in sound pressure levels

Question 2

Normal audiogram

Answer 2

• less than 30 dBHL loss

Question 3

Mild hearing loss

Answer 3

• 30-45 dBHL loss
• unable to hear a whisper
• difficulty hearing a background noise

Question 4

Moderate hearing loss

Answer 4

• 50-65 dHBL loss
• hear conversational voice like a whisper
• corrected by a hearing aid

Question 5

Severe hearing loss

Answer 5

• 70-85 dBHL loss

- unable to hear conversational voice at all without a hearing aid

Question 6

Profound hearing loss

Answer 6

• 90 dHBL loss or greater

- unable to hear clearly even using a hearing aid

Question 7

Rinne’s test

Answer 7

• test for conductive hearing loss
• 512 Hz tuning fork pressed against mastoid and then 1 cm away from ear
• if can hear the sound better when pressed against bone - conductive hearing loss

Question 8

Weber’s test

Answer 8

• tuning fork in midline of forehead

- if can hear better on one side - sensory hearing loss on the other side

Question 9

Common causes of a conductive hearing loss

Answer 9

• Wax
• perforted TM (trauma or infection)
• otisis media with effusion
• dislocation of ossicles
• otosclerosis

Question 10

TM perforations

Answer 10

• trauma: can repair on its own
• infection: cannot clear unless infection is clear
• small holes cause no hearing loss
• total loss of pars tensa leads to a 60dBHL loss

Question 11

Otitis media with effusion

Answer 11

• effusion in the middle ear
• poor eustachain tube function
• usually resolves when permanent teeth appear and ET function improves
• present at some time 20% of children
• mild conductive hearing loss
• difficulty hearing in class
• poor concentration and school performance
• can lose one year in academic performance

Question 12

Grommets indication

Answer 12

• No: intermittent episode, intermittent ear infections, intermittent periods of hearing loss, dizziness
• yes: constant for at least 3 months with associated loss of hearing

Question 13

Cholesteatoma and complications

Answer 13

• growth of skin inside the ear
• causes erosion of bone
• hearing loss due to erosion of ossicles
• vertigo due to thinning of wall of inner ear
• labyrinthitis
• facial palsy
• meningitis
• brain abcess
• treatment is surgical

Question 14

Otosclerosis

Answer 14

• stapes bone becomes fixed by abnormal bone growth

- stapedectomy surgery

Question 15

Hearing devices for conductive hearing loss

Answer 15

• conventional hering aids
• bone conductor hearing aids
• bone anchored hearing aids: skull bone, skin and subcutaneous tissue, implanted titanium fdixture, titanium abutment
• bonebridge
• for patients suffering from conductive or mixed hearing loss due to chronic otitis media, congenital atresia or external otitis

Question 16

Seonsory hearing loss

Answer 16

• loss of hair cells within the inner ear

causes:
1) congenital: genetic, intrauterine viral illness, ototoxic medication, birth problems (jaundice, anoxia, prematurity)
2) Acquired: infection, trauma, noice, ototoxic medication (gentamicin/codeine), meniere’s disease, autoimmune disorder, late onset genetic, presbyacusis

Question 17

Problems with children with profound hearing loss

Answer 17

• no useable speech development
• poor language
• lack of educational opportunities
• loss of employment opportunities

Question 18

Incidence of hearing loss in children

Answer 18

• approximately 0.9/1000 live births

- further 0.5/1000 deafened during childhood

Question 19

Ancient methods for hearing loss in children

Answer 19

• auditory oral: teaching the child by lip reading to say the speech sounds not heard
• total communication: a forlorn attempt to increase language by combining signed english with other methods of communication such as speech
• Auslan: a system of signs which does not follow the rules of spoken language

Question 20

Cochlear implant

Answer 20

• directly stimulates surviving spiral ganglion cells
• straight incision immediately behind the ear about 4-7 cm in length
• incision: the younger the child the easier to make a shorter incision as the skin is so elastic
• adults, especially men, may require a longer incision as the periosteum is difficult to lift
• about 60 children a year in NSW need cochlear implant

Question 21

Adults with hearing loss issues

Answer 21

• loss of ease of communication
• loss of self esteem
• withdrawal from social situations
• loss of employment

Question 22

If a deaf children receives a cochlear implant before the age of 18 months and has no other disability, what percentage learn to communicate using speech and receive regular schooling?

Answer 22

• 100 %
• because of neural plasticity
• early detection of hearing loss via SWISH - Automated Auditory Brainstem REsponse (AABR)
• if a child fails SWISH - referred for diangostic testing