Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
What are the two basic concepts of masking?
|
1. masking occurs when an unwanted sound causes a wanted sound to be inaudible.
2. masking is required to keep a better ear busy while testing a poorer ear. The poorer ear receives the tone while the better ear hears a controlled masking noise. |
|
|
What is the test ear (TE)?
|
The ear currently being tested.
|
|
|
What is the non-test ear (NTE)?
|
The ear not currently being tested?
|
|
|
Why is masking necessary?
|
While performing an audiometric evaluation, it is common to find that the sound being presented to one ear is actually being heard by the other ear.
|
|
|
What does proper masking ensure?
|
The proper use of masking during clinical audiometry ensures the clinician that the test results reflect the performance of the test ear only.
|
|
|
What is cross hearing?
|
The sound being presented to one ear is actually being heard by the other ear. This can occur during air conduction or bone conduction testing.
|
|
|
Why is the understanding of cross hearing so important?
|
If the clinician is unaware of this concept, then they may report thresholds for the TE that are in fact the thresholds of the NTE instead. This can lead to very erroneous results.
|
|
|
What is a shadow curve or mirror audiogram?
|
Where the thresholds obtained are not the true thresholds. The point where the crossover occurs is being recorded instead.
|
|
|
What is interaural attenuation (IA)?
|
It refers to the loss of the acoustic energy of a sound as it travels from TE, across the head, to the NTE.
As the stimulus travels from one side of the head to the other, some energy is lost in transmission. |
|
|
Is IA the same for each frequency and for each patient?
|
No - IA varies with frequency and individual patients.
|
|
|
What is the rule established by convention for interaural attenuation?
|
1. IA for air conduction using supra aural headphones - 40 dB
2. IA for air conduction using insert headphones - 70 dB 3. IA for bone conduction - 0 dB |
|
|
What is the formula for whether or not masking is needed in air conduction?
|
AC (te) - IA > or = BC (nte)
The level of the tone in the test ear (TE) by air conduction, minus the IA, is equal to or higher than the BC threshold of the non-test ear (NTE). |
|
|
What is the formula for whether or not masking is needed in bone conduction?
|
ABG(te) > 10 dB
Cross hearing can be suspected whenever there is an air bone gap in the test ear greater the 10 dB. |
|
|
What is central masking?
|
1. It has been shown that a small shift is seen in the threshold of a pure tone when a masking noise is introduced into the opposite ear.
2. This increased shift averages about 5 dB. 3. It is believed that the elevation of threshold is produced by inhibition that is sent down from the auditory centers in the brain/ |
