Objective testing Flashcards
Part one of behavioural objective testing:
What does OAE’s stand for?
Oto-acoustic Emission
Does OAE’s test the degree of HL
No, ABR’s give you this information.
How do OAE’s probe work?
There is a probe that goes in the in the ear that has three little holes.
1 and 2) Speaker
3) microphone that picks up OAE’s when frequency bounces off the eardrum.
How many frequencies are sent from the ear to the eardrum in OAE’s?
Two frequencies are sent to the eardrum. These are separated by a specific ratio (F1 and F2 a high and low frequency separated by a 1:1 ratio).
Sent out by a 65 and 55dbspl, as a response a third tone is picked up by the microphone which originates from the cochlea. (Doesn’t bounce off the eardrum like in TM).
The OHC in the cochlear amplify these soft sounds so they can be processed to the brain.
What does an abnormality in OAE’s indicate?
That the OHC are not working as well as they should be as they can’t pick up the distortion freq sent from the cochlear.
What does ABR stand for?
Auditory brain stem response
What can ABR’s do?
It can assess the degree of HL
How does ABR work and what condition does it rely on?
It includes an electrode being stuck on the babies head and the two ears of the baby. Headphones are also places in the babies ear. Rapid tones known as busts or clicks are sent in succession to the babies ear drum. The electrodes placed on the ear are measuring the brainstem response.
Condition| Baby needs to be asleep. No other electrical waves distorting the equipment. The electrodes need to be sticky to stay put on the babies head.
What are we looking for in an ABR graigh
- That they tested at multiple frequencies.
- As you go down the latency should increase and the wave V (five) should start to not look as prominent.
- When the wave 5 response is where we would assume no more brainstem response and where the babies threshold response is.
- Wave 5 should be a large peak
What is ABR done with?
It is usually done with behavioural tests in a a battery test because ABR can tell you the degree of HL
How do you know how an OAE will look like?
The SNR should be above 6 dB in two or more octaves in frequencies 1,1.5,2,3,4Hz
Advantages of AOAE’s
- Automated
- Does not require specific professionals
- Cost effective
- Produces quick results
Disadvantages of AOAE’s
- Can be affected by fluid in the babies ear
- Baby should be quiet so also acoustic influences (baby crying, outside noise)
3.does not test beyond the cochlea
Advantages of AABR’s
More robust than AOE
Tests up to the brainstem
Does not need professionals
Gives automated response
Disadvantages
Not cost effective
Takes a long time
The child has to be asleep
Can be impacted by electrical devices
