Physiology of Hearing

Question 1

What ranges on an audiogram indicate hearing loss?

Answer 1

20 and above = normal
20-40 mild hearing loss
40-60 moderate hearing loss
70-90 severe hearing loss
90+ profound hearing loss

Question 2

Why is the external ear shaped the way it is?

Answer 2

Acts as sound receiver

Question 3

What is the ratio of the tympanic membrane to the oval window and why is this important?

Answer 3

18:1

focusses sound on a much smaller area

Question 4

The cochlea completes 2.5 turns around what structure in the centre?

Answer 4

Modiolus

Question 5

The oval and round windows move “in phase”. What is meant by this?

Answer 5

Pressure wave is transmitted from oval to basilar membrane and apex of cochlea before travelling back to round window

Question 6

What type of fluid is found in the scala vestibuli, scala tympani and scala media?

Answer 6

Scala media (endolymph) 
scala tympani and scala vestibuli (perilymph)

Question 7

What does the acronymn ECOLI stand for?

Answer 7

Eighth cranial nerve
Cochlear nucleus
(superior) Olivary complex
Lateral Lemniscus
Inferior Colliculus

sound to brain

Question 8

At what gestation can a foetus hear?

Answer 8

In utero – 18 weeks foetus can hear.

In utero – 26 week foetus will respond to sound/voice

Question 9

What has been introduced to tackle early intervention in hearing loss

Answer 9

Neonatal hearing loss screening

Question 10

Describe the aim of the cochlear implant?

Answer 10

Electrode placed in space of cochlea to initial electrical signals itself in response to the sounds

Question 11

Where is the auditory complex of the brain found?

Answer 11

superior temporal gyrus