Hearing #1

Question 1

Hearing is essential to enriching _______, and critical to _______ and ________, for children there is a very sensitive period where good hearing is essential

Answer 1

Hearing is essential to enriching communication, and critical to learning and educational development, for children there is a very sensitive period where good hearing is essential.

If the hearing issue is not picked up early ⇒ learning difficulties.

Question 2

The auditory system is a powerful ______?

Answer 2

Processor; integrates complex info in space and time and creates a 3D image of the spatial auditory movement around you.

Question 3

Can we ‘turn off’ sound around us? Why?

Answer 3

No, the awareness of environmental sounds provides ‘real world contact’ that we cannot turn off, but we can tune in and out

This is for safety to allow us to move in the world around us.

Question 4

Detection of sounds in a noisy environment is a _____ process, and what type of hearing is critical to this?

Answer 4

Learned process, which requires ‘binaural hearing’ to do this. This is why loss of listening ability in background noise is an early sign of hearing loss, more common with elderly. (especially in classroms for kids)

Question 5

How does the auditory system detect movement?

Answer 5

Via spatial hearing abilities, (animals can use this to find prey, or navigate in the dark). By using the reflections of sound waves you can detect and navigate your environment.

Bats do this far more effectively then humans

Question 6

What two auditory issues have a really high prevalence in the community?

Answer 6

• Deafness
• Tinnitus

Question 7

Whats Hearing Loss like in NZ

Answer 7

• Around 200,000 NZ people have mod-severe hearing loss
• Prevelance increases with age >55yr, 60% of those >70yr
• There’s a high prevelance of temp. hearing loss in kids, during the formative period of learning.

Question 8

What are the statistics of hearing loss in NZ children, what are the causes and what are we doing to fix this?

Answer 8

• Around 2-3/1000 kids mod-severe hearing loss
• ~50% genetic cause
• Often middle ear infection; glue ear, otitis media w effusion etc
• meningitis (less common with vaccines)
• trauma

The ‘Newborn Hearing Screening Programme’ has been introduced that checks babys between 3-7days old in order to catch issues early

Question 9

What are the main causes of hearing loss in NZ adults

Answer 9

• Age-related
• Noise Exposure: this is the most modifiable factor!
• Genetic
• Trauma: blow to the ear
• Tumour: acoustic neuromas
• Ototoxic drugs: aminoglycoside ABs, cytotoxic drugs

Question 10

What’s the individual impact of hearing impairment?

Answer 10

• Poor speech, language and cognitive skill development
• Reduced learning, eeducation and employment
• Social isolation ⇒ increased risk of depression
• Societal Stigma
• Tinnitus: ringing in ears, indication of injury

Question 11

Common co-morbidities of hearing loss?

Answer 11

Question 12

How does hearing loss affect healthy aging?

Answer 12

• Stops people being socially engaged
• People don’t utilize health resources due to social stigmitization and accessibility

Question 13

The auditory system breaks apart sound into fragments and then puts it back together. Where does the outer canal sit?

Answer 13

Sitting in the temporal bone is the outer ear canal (pinna +concha).

Question 14

Where’s the middle ear, what does it contain and what does it do?

Answer 14

About 2.5cm into the temporal bone is the ‘middle ear’ a cavity. (12mmx6mm)

Inside are small bones which will take sound from the ear drum across to the inner ear (just a series of tubes)

Question 15

What is the cochlea?

Answer 15

Snail-shell shaped (for maximising space) series of tubes in the middle ear, next to the vestibular system, which shares al the same system.

Inside the cochlea is the organ or corti which contains all the sensory cells.

Question 16

How is the peripheral ear connected to the central brain?

Answer 16

The inner ear (peripheral) is connected to the brain (central) via CN 8 (cochlear nerve) via a series of pathways and nuclei to the primary auditory cortex in a hierachical way(via frequency and intensity of signal)

Question 17

Overview on how the ear works

Answer 17

1. Air goes down the aircanal and causes the air drum membrane to vibrate.
2. This causes the tiny ossicle bones; malleus, incus and stapes of the air-filled middle ear to move also and knocks on the membrane of the inner air
3. This causes fluid movement in the inner air, moving the sensory hair cells that are connected to nerve fibres, stimulating them

Question 18

The Outer Ear function

Answer 18

• “collects” sound
• Protects the middle ear
• Important for sound localisation
• Skin lining contains cerumen glands → wax!
• Canal is self cleansing

Question 19

Why is it bad to use cotton buds in your ears?

Answer 19

Because you will distrupt the natural skin migration of the ‘epithelial conveyor belt’ → excess skin debris in canal

• Canal skin shed from the surface, and pushed out of canal
• Growth starts at centre of eardrum and moves along the canal
• similar speed to fingernail growth

Question 20

Why do we have ear wax/cerumen?

Answer 20

• Produced from sebaceous and sweat glands in the outer 1/3 of the canal
• 2 types: wet (caucasians and africans) and dry (asians)
• Helps cleaning and lubrication
• Repels water
• Traps dust and debris (with hairs also)
• Carried out by epithelial migration.

Question 21

When can ear wax be a bad thing?

Answer 21

Build up → occluded canal → conductive hearing loss

• Worse in the elderly
• Biggest cause of hearing loss

Question 22

How should we be cleaning our ears then?

Answer 22

• Via a professional with a microscope!

Question 23

How is the middle ear organised and held together?

Answer 23

Starts at the tymphatic membrane, then held to 3 ossicle bones the malleus, incus and stapes.

These bones are held very tightly together and suspended by ligaments. They have very tight synovial joints (and contain a little marrow).

The head of the ossicles is above the eardrum.

Question 24

What bones are what behind the eardrum?

Also what sensory structure is also running with these bones?

Answer 24

Chorda Tympani: branch of the facial nerve that originates from the taste buds in the front of the tongue, runs through the middle ear, and carries taste messages to the brain.

Question 25

Whats the purpose of a Eustachian Tube?

Answer 25

* Drains the middle ear to the nasopharynx (back of throat). * Needed as middle ear mucosa creates mucus (cilliation assists the drainage) Flatter tract in infants → uppertract resp infections * Maintains air pressure across the ear drum (stopping rupture)

Question 26

What is 'Otitis Media'?

Answer 26

Infections of the middle ear, "glue ear", where it is full of pus and debris, can be very painful.