Assessmet Of Paediattic Hearing

Question 1

What are otoacoustic emissions

Answer 1

-sounds that can be recorded in the ear canal that are produced within the cochlea
-the amplification process within the cochlea involves active movement of the outer hair cells

Question 2

What is the new born hearing test called and what is it

Answer 2

• otoacoustic emissions test
  -tests the amplification ability but not necessarily hearing

Question 3

How are otoacoustic emissions screened for

Answer 3

-TEOAES
-quick, easy and non invasive
-can be undertaken while infant is asleep
-the equipment is portable and many manufacturers have produced hand held screeners

Question 4

What is the ABR test
Auditory evoked potentials

Answer 4

-as nerves fire there is voltage changes
-electrodes are attached to the head and sound is played through headphones
-auditory brain stem response ABR (brain stem measurement)

Question 5

Explain the wave form for the ABR test

Answer 5

• Amplitude of response decreased and latency increases as stimulus intensity is lowered.
• Threshold is the lowest stimulus intensity which elicits a detectable response (subjective decision)
• Not essential to identify all wave components only wave V as it is the most robust and stable component of the ABR.
• Start at relatively loud stimulus but not too loud as to wake baby if have normal hearing.
• Always get repeats near threshold
• Obtain a baseline to prove threshold

Question 6

What does the tympanometry test measure

Answer 6

-test of middle ear function
-measures the stiffness of the middle ear
-also find the air pressure in the middle ear space (and the ear canal volume)

Question 7

What does low middle ear pressure mean

Answer 7

Problem (ETD) can lead to OME

Question 8

What does high compliance mean on the tympanometry test

Answer 8

Flaccid eardrum, too high= problem

Question 9

What does low compliance mean on the tympanometry test

Answer 9

Stiff eardrum, too low= problem

Question 10

What are the three things a tympanometry test can find

Answer 10

• equivalent ear canal volume
  -middle ear compliance
  -middle ear pressure

Question 11

Explain how the tympanometry test finds the ear canal volume

Answer 11

• Can find the equivalent ear canal volume (at the positive pressure level the middle esr is stiff and the compliance measured is just due to the volume of air in the ear canal.

Question 12

Explain how the tympanometry test can find the middle ear compliance

Answer 12

• We can find the middle ear compliance. (The peak compliance tells us this. Subtract compliance of the air in ear canal)

Question 13

Explain how the tympanometry test can find the middle ear pressure

Answer 13

We can find the middle ear pressure (the maximum compliance occurs when the pressure in the ear canal Is equal to the pressure in the middle ear space

Question 14

What are the subjective behavioural tests

Answer 14

-behavioural observation audiometry
-distraction test
-visual reinforcement audiometry
-play audiometry
-McCormick toy test

Question 15

What test do you use at 0-6 months old

Answer 15

Behavioural observation audiometry

Question 16

What test do you use at 6-12 months old

Answer 16

Distraction test

Question 17

What test do you use at 6-36 months old

Answer 17

Visual reinforcement audiometry

Question 18

What test do you use at 30-36 months old

Answer 18

Play audiometry

Question 19

What test do you use 18-24 months old

Answer 19

McCormick toy test

Question 20

Behavioural observation audiometry

Answer 20

• 0-6 months: behavioural observation auditometry
• Baby observed in a quiet state during the presence of sounds.
• Highly subjective
• Basic
• Shows responsiveness to sounds at particular measured levels.
• Often a test of last resort

Question 21

Distraction test

Answer 21

6-12 months: distraction test
- Was used by health visitors as infant hearing screening test now used as a test of last resort.
- Based on the principle that an infant will turn to locate a sound source involuntarily.

Question 22

Visual reinforcement audiometry

Answer 22

6-36 months: visual reinforcement audiometry
- Wildly used in hospital based clinics, test of choice for this group.
- Based on principle that child will turn to a sound stimuli involunatryily but this response is reinforced in order for it to be repeated, using a visual reward.

Question 23

Play audiometry

Answer 23

30-36+ months: play audiometry
- Children can wait for a sound and then respond with some play activity.
- Child can be conditioned to the task with little or no verbal instruction.
- Game activity should be simple and demonstrate by a tester eg man in the boat.
- Principles:
- Stage 1 (conditioning): sound + guidance and praise = response (classical conditioning)
- Stage 2 (testing): sound= response. Reinforced by social praise (operant conditioning)

Question 24

McCormick toy test

Answer 24

18-24+ months: McCormick toy test
- Speech recognition test for children
- High face validity, often welcomed by parents and confirms other testing (demonstrates hearing loss to parents)
- Most common for young children: identification of toys in response to ‘show me the…’
- Live voice or fully automated