Masking (final exam) Flashcards
Define Masking
The process by which the threshold of a sound is elevated by the simultaneous introduction of another sound
The process by which the threshold of a sound is elevated by the simultaneous introduction of another sound
Masking
Is masking used in evaluation?
Yes
Is masking used in screening?
No
Why is masking used?
To prevent the non-test ear from participating in the evaluation of the test ear
Masking is only used in…
not referring to evaluation/screening
Audiometry
The amount by which the air conduction threshold exceeds the bone conduction threshold at a particular frequency in the same ear.
Air-bone gap
Explain air-bone gap
The difference between air and bone conduction thresholds.
When should you mask?
When the ABG is greater than 10 in one ear then masking is probably needed in the other ear.
What are the 3 questions audiologists ask for masking?
Is masking needed?
If so, how much masking should we use?
At what point did we put too much noise?
What is interaural attenuation?
Number of decibels lost in cross hearing
or
the loss of energy of a sound presented by AC (air conduction) or BC (bone conduction) as it travels from the test ear to the non-test ear.
What is the interaural attenuation with sura-aural headphones?
40dBHL
What is the interaural attenuation with insert earphones in low frequencies?
75dBHL
What is the interaural attenuation with insert earphones in higher frequencies?
50dBHL
What is the interaural attenuation with bone conduction?
0dBHL
T/F cross hearing is not possible with bone conduction
False, cross hearing is always possible with bone conduction because the IA is 0dBHL
When do we need to mask pure tones?
AC (air conduction) of the Test Ear minus the Interaural Attenuation is greater than or equal to the BC (bone conduction) of the Non-Test Ear.
Air-Bone Gap of the Test Ear is greater than 10dBHL
Should also look at the AC of the Test Ear and AC of the Non-Test ear to determine if the Interaural attenuation has been exceeded
Are you less likely to mask with insert earphones or supra-aural earphones? Why?
You are less likely to mask with insert earphones because they provide greater separation between the ears.
Two types of masking noise are..
speech noise and narrow band noise
Which is more effective, speech noise or narrow band noise?
Speech noise
Explain speech noise for masking
Broadband; used to mask speech stimuli; sounds like hissing
Explain narrow band noise for masking
band pass filtering of broadband noise; small band of frequencies surrounding a frequency to be masked; used to mask pure tones
What is effective masking?
Minimal amount of noise required to just mask out a signal at a given hearing level
Explain central masking
a small pure tone threshold shift occurring when masking is presented to the opposite ear.
You do not want this.
List the three masking methods
Shotgun approach, minimum noise method, plateau method.
How do you mask for speech audiometry?
compare the speech recognition threshold of the test ear to the best bone conduction threshold of the non-test ear with interaural attenuation factored in
