Assessmet Of Paediattic Hearing Flashcards
What are otoacoustic emissions
-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
What is the new born hearing test called and what is it
- otoacoustic emissions test
-tests the amplification ability but not necessarily hearing
How are otoacoustic emissions screened for
-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
What is the ABR test
Auditory evoked potentials
-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)
Explain the wave form for the ABR test
- 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
What does the tympanometry test measure
-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)
What does low middle ear pressure mean
Problem (ETD) can lead to OME
What does high compliance mean on the tympanometry test
Flaccid eardrum, too high= problem
What does low compliance mean on the tympanometry test
Stiff eardrum, too low= problem
What are the three things a tympanometry test can find
- equivalent ear canal volume
-middle ear compliance
-middle ear pressure
Explain how the tympanometry test finds the ear canal volume
- 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.
Explain how the tympanometry test can find the middle ear compliance
- We can find the middle ear compliance. (The peak compliance tells us this. Subtract compliance of the air in ear canal)
Explain how the tympanometry test can find the middle ear pressure
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
What are the subjective behavioural tests
-behavioural observation audiometry
-distraction test
-visual reinforcement audiometry
-play audiometry
-McCormick toy test
What test do you use at 0-6 months old
Behavioural observation audiometry