Module 9 D: Bone conduction hearing

Question 1

Sound travels in the ear canal as pressure waves. It’s transduced into mechanical energy by the middle ear and then to pressure waves in fluid in the cochlea. The pressure waves defect the sterocilia on the inner haircells, which then send a signal to the auditory nerve that sound is present. Because the cochlea is encased in hard bone (temporal bone) sound can also produce pressure waves in the fluid of the cohlea by vibrating the skull. When this occurs, it is called ?

Answer 1

Bone conduction hearing..

Question 2

Audiologist use bone conduction to test if the problem is in the cochlea, middle or outer ear. There are two methods they use. What are they and explain:

Answer 2

Air conduction (AC) Sound waves transmitted through the air to the auditory system
Bone conduction (BC) sound waves are transmitted through the skull directly to the fluids in the cohlea. 

AC and BC result in the same cochlear activity.

Question 3

When the skull vibrates, it does not vibrate as a single unit. It vibrates in:

a) nodes
b) lateral movements
c) circular vibrations

Answer 3

a) nodes

Question 4

A node is a:

a) Circular movement
b) lateral movement
c) vibrations as a unit

Answer 4

c) vibrations as a unit

Question 5

Low freuqencies causes the skulls to vibrate as a

Answer 5

unit

Question 6

Mid frequencies causes the skull to vibrate in ?

Answer 6

Two nodes–both moving from front to back in opposite directions

Question 7

High freuquencies causes the skull to vibrate ?

LOOK AT NODES PICTURE

Answer 7

with four nodes–both moving front to back and the sides move laterally in and out.

Question 8

There are three modes of Bone conduction(BC) . They include:

Answer 8

Compressional BC
Inertial BC
Osseoptympanic BC

Question 9

Which two BC’s take a more dominant role in the lower freuqencies?

Answer 9

Inertial BC

Osseoptympanic BC

Question 10

Which one of the three modes of bone conduction does the bones of the skull contract and expand the bony shell of the cochlea, creating pressure waves in the cochlear fluids?

Answer 10

Compressional Bone conduction

Question 11

Which one of the the three bone conduction modes is active at all frequencies but dominates the higher frequencys the most?

Answer 11

Compressional Bone conduction

Question 12

When the skull vibrates it forces the ossicles to vibrate as well. But the movement of the ossicles lags in time behind the rest of the skull . What mode of bone conduction is this?

Answer 12

Inertial Bone Conduction

Question 13

The bony wall of the ear canal compresses and expands the space in the ear canal picked up by the tympanic membrane and transmitted to the cochlea via the normal AC pathway. This is essentiall “bone conduction” through air conduction. This mode of bone conduction is called?

Answer 13

Osseotympanic Bone conduction

Question 14

When the ear canal is occluded (PLUGGED UP) , low frequency radiations cannot escape and are conducted through the middle ear. This is called:

a) Occlusion Effect
b) Compressional Effect
c) Inertial Effect
d) Osseoptympanic Effect

Answer 14

A) Occlusion Effect

Question 15

In bone conduction hearing, sound by passes the peripheral auditory system and stimulates the auditory nerve directly: True or False

Answer 15

False

Question 16

The type of bone conduction due to sound being created in the ear canal by the compression and expansion of the ear canal is called______

a) compressional bone conduction
b) natural bone conduction
c) inertial bone conduction
d) The Occlusion effect
c) Osseotympanic bone conduction

Answer 16

c) inertial bone conduction

Question 17

What is it called when sound cannot escape the ear canal during bone conduction, and gets directed back into the auditory system, increasing the level of sound?

a) compressional bone conduction
b) natural bone conduction
c) inertial bone conduction
d) The Occlusion effect
c) Osseotympanic bone conduction

Answer 17

d) The Occlusion effect