Hearing And Balance

Question 1

Describe the basic anatomy of the ear.

Answer 1

Outer ear - external ear and eardrum
Middle ear - ossicles (malleus, incus stapes) and Eustachian tube
Inner ear - semi circular canals and cochlea.

Question 2

Describe the effects of age induced hearing loss (presbycusis)

Answer 2

Loss of hearing that occurs over age, generally slow

Question 3

Explain the effects of age induced hearing loss (8)

Answer 3

Difficult hearing 
Frequently asking to repeat
Frustration 
Certain sounds overly loud
Noisy areas
S or th sounds the same
Difficulty high pitch
Tinnitus

Question 4

Explain the effects of pressure changes on the middle ear and Eustachian tube.

Answer 4

Eustachian tube is normally closed but opens from time to time when we swallow, yawn or chew.

Allows air to flow into the middle ear and any mucus to flow out keeping air pressure equal either side of the eardrum.

Question 5

Explain the effects of colds; hay fever; and/or allergies on the sinuses and eustachian tubes.

Answer 5

A blocked nose or thick mucus that develops during a cold or other infections may block the Eustachian tube causing an equal pressure.

Typically, with a blocked Eustachian tube, the air pressure in the ear canal is greater than the pressure in the middle ear.

With a reduced air pressure on one side, the ear drum or tympanic membrane bulges inward, causing discomfort and in some cases extreme pain.

Question 6

Define disorientation

Answer 6

Cognitive disability in which the sense of time, direction and recognition of people and places become difficult to distinguish

Happen anytime

Question 7

Define spatial orientation

Answer 7

Spatial orientation is defined as the ability to correctly interpret the aircrafts’ attitude, altitude and/or airspeed in comparison to Earth or a point of reference

Question 8

Outline the physiology of the motion, orientation and gravitational sensory organs - semi-circular canals

Answer 8

Made of 3 canals, posterior (pitch) superior (roll) and horizontal (yaw)

Interlinked at right angles with each other and filled with liquid which shifts in relation with rotational acceleration of the body.

Question 9

Outline the physiology of the motion, orientation and gravitational sensory organs, including vestibular sacs and tubes.

Answer 9

Two otolith organs, the utricle and saccule found in the vestibular sac.

Each organ has gelatinous substances surrounding har like cells which sense linear acceleration from the movement of the substance.

The otolith organs sense both head/body tilt and longitudinal acceleration.

Question 10

Explain the interconnection between the visual and kinaesthetic senses in maintaining accurate spatial orientation.

Answer 10

Many thousands of never ending in the joints muscles and neck which generate information on movement and position

Called proprioceptors

Question 11

Explain the body’s limitations in maintaining spatial orientation when vision is adversely affected

Answer 11

False info from either sense will normally be compensated for by the other.

In the absence of normal visual inputs, as when flying in could or at night incorrect information from the. Vestibular system can lead to pilot disorientation or motion sickness.

Question 12

Explain the leans and sub-threshold stimulation

Answer 12

• a strong sensation felt by pilots as being in one attitude when all the aircraft instruments are indicating that the aircraft actually has a different altitude
• caused by slow rolling of the aircraft that’s not picked up by the semi-circular canals.

Question 13

Explain somotogravic illusions.

Answer 13

Because the otolith can’t distinguish between a rapid longitudinal acceleration and a body/head tilt backwards, a powerful but erroneous sensation of a steep climb can occur in the event of a rapid takeoff.

Question 14

Explain somotogyral illusion

Answer 14

Occurs when pilot has leans but isn’t aware, aircraft having meanwhile entered a spiral dive.

As speed builds, pilot beliefs the aircraft wings level dive and tries to pull out of the dive.

However aircraft has considerable bank applied so therefore this increases intensity of spiral dive.

Question 15

Explain cross coupled turning (Coriolis effect)

Answer 15

the result of moving the head excessively, especially during in flight turns, confusing the balance mechanism in the ears.

can produce a tumbling sensation which may lead to nausea and disorientation.

Question 16

Explain pressure vertigo

Answer 16

condition that occurs as a result of pressure differences between the ears. As aircraft climbs this higher pressure inside the eardrum can force its way out, but on descent, the higher pressure outside air cannot enter the blocked tubes leading to a pressure differential.

Pressure vertigo can occur when only one ear ‘pops’, which may cause a tumbling sensation and slight onset of vertigo

Question 17

Prevention of disorientation.

Answer 17

• don’t fly an aircraft based on the ‘seat of your pants’ - e.g. what you think the aircraft is doing
• in periods of reduced visibility or at night, transition to scanning the instruments early (as required)
• fly at night and with instruments often to keep proficient
• use and trust your instruments

Question 18

Explain the effects of a positive and negative acceleration on the circulatory system.

Answer 18

Positive G - the blood pressure in the head may fall to a point where blood supply to the eyes and brain ceases

Negative G - blood is forced upwards and can cause much greater discomfort than positive G, upward movement of blood can overload the heart, slowing it.

Question 19

Explain the effects of positive and negative accelerations on vision

Answer 19

Positive G - visual acuity is reduced and therefore loss of peripheral vision with a retention of central vision (tunnel) prolonged acceleration above 5 can cause blackout

Negative G - blood is forced to head and eyelids. Bloood laden eyelids can come into visual field causing vision to be red. Redout

Question 20

Explain the effects of positive and negative accelerations on consciousness

Answer 20

Positive G - +5 to +6g pilot may become unconscious. Due to blood being drained away form the brain and therefore also oxygen from the brain causing a type of hypoxia.

Negative G - if heart rate is slowed down to far this could lead to heart stopping

Question 21

Causes and symptoms of blackout

Answer 21

• exposure to + 5g due to blood draining from head
• pilot will experience grey or tunnel vision first but continued exposure will lead to complex loss of vision. hearing is unaffected until unconscious.

Question 22

Red out causes and systems

Answer 22

• Exposure to -2.5G or greater or blood is forced to the head and eyelids.
• Blood laden eyelids can come into the visual field causing vision to appear read.

Question 23

Explain the causes of motion sickness

Answer 23

A normal response of healthy individuals when exposed to a flight environment characterised by unfamiliar motion

Question 24

Explain how motion sickness can be prevented

Answer 24

Not flying with fatigue, after alcohol, drugs, medications, under stress or illness.

Repeated exposure to flight environment will usually decrease an individuals susceptibility.

Question 25

Explain how motion sickness can be treated (5)

Answer 25

• Open all air vents
• Loosen clothing
• Use supplemental oxygen if available
• Focus on a point in the distance
• Avoid unnecessary head movements.

Question 26

Causes of flight anxiety.

Answer 26

Develop fears as they mature and life seems to be more precious or bad previous experiences of flight.

Concerns regarding weather or fears.

Question 27

Signs of flight anxiety (5)

Answer 27

• Muscle tension; tremors
• heavy, laboured breathing
• heart palpitations, chest pain
• abdominal & intestinal discomfort
• sweating, weakness, dizzy, prickly sensations, Dry mouth, flushed or pale face

Question 28

Explain How flight anxiety be prevented (4)

Answer 28

• Attend a course and education
• Learn how they fly
• Learn how airliners are flown in practice
• skydive

Question 29

What does the cochlea do?

Answer 29

Connected to the cochlear nerve, transmitting sound via neurological signals to the brain to produce the sound that is heard

Question 30

34.20.10/46.20.6 The various levels of noise in decibels at which various grades of hearing protection are required

Answer 30

Over 115dbA - seek expert advise

110-115 - grade 5 earmuffs
104-109 - grade 4
98-103 - grade 3
92-97 - grade 2
86-91 -  grade 1
85 and below - non needed

Question 31

34.20.14/46.20.10 The action threshold for hearing protection

Answer 31

The action level for hearing protection is a level of noise exposure above which active steps should be taken in order to avoid the harmful effects of the noise on hearing

Question 32

34.20.12/46.20.8 Noise levels at which hearing damage may occur

Answer 32

Temporary hearing impairment: steady noise over 90 dB over a short time (even several hours)

• Permanent hearing damage: noise over 90 dB for 8 hours or more per day for several years
• Immediate hearing loss: a sudden noise of 140 dB – 150 dB

Question 33

c) G-LOC (gravity induced loss of consciousness)

Answer 33

Caused by prolonged exposure to +5 – 6g

• The pilot will lose consciousness until the amount of g-force is reduced.
• Recovery will be delayed by the fact that the blood has concentrated in the lower limbs where it does not readily return for re-circulation.
• Pilots of aircraft required to carry out high G manoeuvres wear special G suits which resist the pooling of blood.

Question 34

Physiology of the ear

Answer 34

The ear has two functions: Performing Hearing and sensing Balance/Acceleration

●Sound waves travel through the ear canal and vibrate the air drum - this vibration transfers to the ossicles which in turn vibrates the cochlea. This causes fluid inside the cochlea to move which produces electrical signals that are transmitted to the brain.

●The signals are then processed and perceived as sound

Question 35

How much protection do earmuffs and earplugs give you

Answer 35

10-15db