Lecture 17: Sound 1

Question 1

What is the connection between sound and behaviour?

Answer 1

Subconcious low level processing;

Communication; Speech carries a lot of meaning

Music; Controls emotions and evokes memories

Question 2

Describe subconscious low level processing

Answer 2

Subconcious low level processing;
but streams important information.
i.e reflexes, car horn
- Rapid warning signals
- Environmental sounds connect us with the environment, can localise it and identify it, if you have previous knowledge of it.

Creates 3d environement

Question 3

How can speech carry a lot of meaning, making hearing and communication important;

Answer 3

Context of a message

Intonation, Q or A, emotional

Can create insecurity in deaf people

Question 4

How does music influence behaviour?

Answer 4

• Melody, rhythm, beat
• Measureable physiological response: HR, level of stress hormone

“Music is the food of the brain”

Deaf people miss this

Question 5

How does hearing loss effect an individual?

Answer 5

• Essential to communication
• Critical to learning and education; Critical period in early development where hearing is essential
• Auditory system is a powerful processor; Integrating complex information in time and space
• Provides awareness of environment sounds and real world contact

Question 6

What sort of process is detecting sound in a noisy environment?

Answer 6

It is a learned process

-biarual hearing is critical for listening in background noise

reduced ability to hear in noisy situations is a sign of hearing loss especially with age (complex processes first thing to go with age)

Question 7

How many people in NZ have mod-severe hearing loss?

Answer 7

200,000

Question 8

How many people have some sort of hearing loss in NZ?

Answer 8

880,000 (13-18%)

Prevelence set to rise to 26.7% by 2025

Question 9

How does prevelence of hearing loss change with age?

Answer 9

increases rapidly beyond 55,

60% of all people over 70

However a number of children have reversible hearing loss (ear infections)

Question 10

What can cause hearing loss in children?

Answer 10

2-3/1000 children have moderate-profound hearing loss (120-280 a year)

• 50% genetic
• Associated with developmental defects
• Other 50% probably from meternal infections i.e CMV
• There is now the Newborn Screening program

Question 11

What is the biggest contributor to temporary or permanent hearing loss in children?

Answer 11

• Otitis media with effusion (glue ear)
• Infections (meningitis)
• Trauma

Question 12

What are the causes of adult hearing loss?

Answer 12

• Age (primarily)
• Noise exposure
• Genetic (loss of hearing with age)
• Trauma
• Tumours
• Ototoxicity (aminoglycoside antibiotics and cytotoxic drugs)

Question 13

How is loss of senses impacting the body?

Answer 13

hearing loss affects brain health, cognition and may cause development of dementia

Cardiovascular effect of hearing loss
Diabetes can cause hearing loss

Question 14

How does hearing loss correlate with dementia?

Answer 14

The greater the hearing loss intensity the greater the risk of developing dementia

Question 15

Describe how hearing loss is associated with AD?

Answer 15

Those with hearing loss also have greater depositis of B amyloid in the auditory cortex and substantially greater cognitive loss. (greater cell loss)

Question 16

How important is hearing with brain health?

Answer 16

Sensory input is equally important as exercise and social engagement in brain health.

Question 17

Describe the individual impacts of hearing loss;

Answer 17

• Poor speech, language and cognitive development
• Reduced literacy, learning, education and employment
• Social isolation
• Social stigmatism
• Depression
• Tinnitus

Question 18

Whats central factor may cause a hearing loss?

Answer 18

• Central deficits have major impact on perception of sound, speech and langauge
• Auditory brain is very plastic i.e cochlear implant works because of this. and brain adapts to abnormal input

Question 19

What difference in loudness can the brain detect?

Answer 19

Can detect million fold difference in sound energy i.e threshold eardrum movement is 0.3nm

but on the other hand can detect 140db jet engine performing equally as well as 10db sound hearing

Question 20

What is the decibel scale?

Answer 20

logarithmic scale that compresses sounds that can be detected into range….

i.e 0db is hearing threshold, (p0) has a pressure value

db= 2log10 (pi/po)

Question 21

At what intensity sound is harmful?

Answer 21

85db

But trade off between intensity and length of exposure

Question 22

What frequency of sounds to humans hear?

Answer 22

20-20,000hz

Question 23

How does the auditory system process sound (overview)?

Answer 23

Separates the frequencies and the power (intensity) in the ear and this is put back together in the brain to give a picture of whats happening

i.e deconstruction to process and reconstruct an image in the brain

Question 24

Whats the function of the ears in the auditory system?

Answer 24

Detects mechanical vibrations and analyses sounds frequencies and intensities.

Then sends information via auditory nerves (Cr. n 9) to the auditory centres in the brain.

Also have powerful descending regulatory pathways, regulate hair cells, allows focusing on sounds

Question 25

Describe the structure of the ear compartments;

Answer 25

Outer ear
Middle ear (estuchian tube enters)
Inner Ear (cochlear)

Question 26

Describe the cochlear divisions;

Answer 26

Cochlear and vestibular canals (balance)

Question 27

Describe the physical structures of the auditory pathway;

Answer 27

Pinna
Concha (resonator)
External auditory meatus

Tympanic membrane

Incus
Malleous
Stapes

(muscles; Tensory tympani, stapedius muscle)

Oval window (cochlea)
Tectorali membrane (organ of corti)

Round window( extends to allow pressure movements in the cochlea)

Question 28

As you move through the auditory processing cortices what happens?

Answer 28

Increasing complexity of processing and more binaural

Question 29

Give an overview of sound transduction from environment to cochlea

Answer 29

Mechanical pressure translates to volume velocity and pressure in the cochlea

Pressure waves, tympanic membrane, turned to velocity in ossicles, then to oval window which resonates and creates pressure through fluid in cochlear (this moves the tectorali membrane)