Chapter 6 - Ear, Hearing & Balance

Question 1

Ossicles

Answer 1

Malleus - Hammer
Incus - Anvil
Stapes - Stirrup

Question 2

Human Hearing Range

Answer 2

20 - 20 000 Hz

Question 3

Most Annoying Sound

Answer 3

High Pitch - Intermitent

Question 4

NIHL Source / Factors (3)

Answer 4

Noise Induced Hearing Loss
> 90 dB 8h+
> 120 dB sudden
-> Permanent Damage

Depends on:

• Frequency
• Duration
• Intensity

Question 5

dB Levels

Answer 5

120 Disconfort
140 Pain
160 Ear drum rupture

Question 6

Hearing Loss (HL) (3)

Answer 6

Presbycusis - old age, high frequency degrade first
Tinnitus - constant pitch
Conductive HL:
  - damaged ossicles / cochlea
  - wax buildup
  - ruptured ear drum

Question 7

Vestibular System & Analysis

Answer 7

Semi-circular canals in cochlea (90deg from each other)
- hair in liquid sense yaw, pitch, roll

Otoliths
- Utricle, Saccule sense linear aceleration

Cerebellum - Brain part analyses vestibular data

Question 8

Vestibular Illusions List and General Reasons

Answer 8

Detects change in movement only
Assumes 1g = gravity
Sensory threshold

Somatogravic Illusions
Somatogyral Illusions
Spatial Disorientation
Coriolis Spatial Disorientation
Vertigo

Question 9

Somatogravic Illusions

Answer 9

Linear acceleration illusion
Tilting head back = accelerate
Tilting head forward = deccelerate

Question 10

Somatogyral Illusions

Answer 10

Angular acceleration illusion

Habituation to a steady turn. When level again, impression of turning the other way.

Question 11

Spatial Disorientation

Answer 11

False impression of attitude because of:
  - IMC
  - aerobatics
  - head movements
70% visual reference used for spatial orientation

Question 12

Coriolis Spatial Disorientation

Answer 12

2+ semi-circular canals stimulated -> vertigo

Question 13

Vertigo / Factors (3) / Solutions (3)

Answer 13

Contradictory Vestibular information

• alcohol
• smoking
• drugs
• min head movement
• rely instruments IMC
• rely instruments VMC