[055] Sensory Demonstrations

Question 1

Sensorineural hearing loss is caused by problems in which areas?

Answer 1

Cochlea, auditory nerve or higher up in brain

Question 2

Conductive hearing loss is caused by problems in which areas?

Answer 2

Caused by problems in outer or middle ear

Question 3

Why does conductive hearing loss make an ear more sensitive to bone-conducted sound

Answer 3

• bone-conducted sound will be unable to escape from inner ear, which enhances its effect (middle ear allows sound to both enter and exit inner ear)
• ambient background noise will be much quieter because it is unable to enter ear via air-conduction
• over time, inner ear may upregulate its sensitivity to sound to compensate for lack of air-conducted sound

Question 4

What does the term “hearing threshold” refer to

Answer 4

Quietest sound that can be heard for a particular frequency in a particular ear

Question 5

What is meant by “dynamic range of ear”

Answer 5

Difference between quietest sound you can hear and loudest you can comfortably hear

Question 6

What does a threshold of 0dB HL on a clinical audiogram indicate of a patient’s hearing?

Answer 6

Person has perfectly average hearing (no better, no worse)

• clinical audiogram uses average human hearing as baseline

Question 7

Audiogram including frequency and hearing level of common sounds and syllables

Answer 7

Question 8

Levels of hearing loss, classifying according to magnitude of hearing level

Answer 8

Mild 20-40 dB HL
Moderate 40-70
Severe 70-90
Profound 90-100

Question 9

What is presbycusis
And what are the characteristics of its audiogram

Answer 9

Age-related high-frequency loss

Characterised by bilateral hearing loss above 200 Hz

• on standard audiogram, presents as downward sloping line that indicates impaired hearing at higher frequency sounds

Question 10

How does noise damage hearing loss look like on audiogram

Answer 10

Hearing loss at specific frequency
Eg rifle shooters, specific loss of sensitivity in only one ear

Question 11

What is Ménière’s disease

Answer 11

Hearing loss at Low frequency

Question 12

How do you distinguish between conductive and sensorineural hearing loss on an audiogram

Answer 12

Conductive hearing loss: patient more sensitive to bone-conducted sound than air-conducted sound
Air-conduction </= bone-conduction

Normal outer/ middle ear function when air-conduction > bone-conduction

Question 13

How does the brain adapt to hearing loss?

Answer 13

1. Learn to rely more on intact sensory inputs
   - eg sight and touch
2. Learn to use abnormal sensory inputs
   - eg cochlear implants

Question 14

What is the McGurk effect?

Answer 14

Result of sensory integration

Eg where lip-reading doesnt just change your understanding of what is said, but can actually change what you hear

Question 15

What is tinnitus

Answer 15

Perception of a phantom sound without a corresponding acoustic stimulus

• can be tone-like (beeping, whistling) or noise-like (hissing, roaring)
• can be perceived in one ear, both ears or in the head

Question 16

Prevalence of Tinnitus

Answer 16

Tinnitus in general: 5-10% of population (some of the time)

Troublesome tinnitus: 1-2% of population
(Troublesome tinnitus — stimulus affecting daily life)

Question 17

Causes of tinnitus
Subjective vs objective tinnitus

Answer 17

Objective tinnitus:

Question 18

What are some examples of different types of hearing loss

Answer 18

• presbycusis
• noise damage
• Ménière’s disease
• sensorineural or conductive hearing loss