(Masking Exam) Flashcards
masking is what? (not asking why we use it)
a way to cover up one signal from another
why do we use masking?
to make sure we are actually testing the ear we want to test
what is crossover?
sound traveling through the skull and being heard by the other ear, but at a lower intensity than the presentation in the original ear
crossover occurs via
bone conduction
why is intensity lost in crossover?
since the sound has to travel through the skull to get to the other ear
crossover occurs for who?
people with normal hearing and hearing impairments.
why don’t people with normal hearing notice crossover?
because the cross over sound is so much softer in the contra ear than the ipsi ear.
interaural means what?
between ears
if you use supra aural headphones, how much sound is attenuated as sound travels from the stimulated ear to the contra ear?
40dB in AC
when using inserts, the amount of sound attenuated when sound travels to the contra ear is ?
55dB in AC
no matter where you put the bone oscillator on your skull, it always does what?
presents the same sound intensity to both cochleas at the same time
if a person has 0dB thresholds and you present a tone at 30dB in one ear, how loud is it in the other ear? with supra aural HPs and inserts?
Supra aural HPs- -10dB Inserts- -35dB (not audible AT ALL)
supra aural HPS have a ___________ of 40dB
interaural attenuation
if you had someone with 0dB threshold and you present a tone at 70dB to one ear, the other ear will hear it at what threshold?
40dB for supra aural 15dB inserts
if a person has an ear with 80dB thresholds and 0dB thresholds in the contra ear and a 70dB tone was presented, what happens?
the originial ear does not perceive the tone, but the sound crosses over to the contra ear and that ear hears it, allowing the person to “respond” to the tone. (at 30dB for supra aural, 15dB for inserts)
if you present 20dB via a bone oscillator, what happens?
both cochleas are sent the 20dB of sound, but only the better cochlea will hear it
is there attenuation in presenting sound via BC?
no attenuation for either ear!
interaural attenuation varies depending on _________. what will we focus on and why?
varies depending on freq. we focus on 40dB for SA HPs and 55dB for inserts since this is the lowest value that all freqs. have.
what is the masking stimulus?
noise! (but there are 3 kinds of noise - white noise, narrow band noise, speech shaped noise)
what are the 3 types of masking noise?
white noise, narrow band noise, speech shaped noise
white noise is also called? what is it?
broadband noise. energy around every freq.
narrow band noise is what?
noise centered around the freq. of the test sound.
what are 2 things to know about narrow band noise? (not what it is)
-more efficient than white noise, because it centers around the freq. being tested -seems less loud to listener than white noise since it’s not encompassing as many freqs
speech shaped noise is what?
noise centered around freqs. most important for speech (500 to 2000Hz ish)
on a spectrum plot, a pure tone is _______?
energy at one freq. (one bar)
white noise that is louder than the pure tone, will show what on a spectrum plot?
will be higher in amplitude at the pure tone, but also covers the same amplitude at every single freq.
narrow band noise that is louder than a pure tone will look like what on a spectrum plot?
noise will be taller in amplitude, and surround a few freqs around the pure tone, but does not cover every freq.
Broadband noise activates ____________ whereas NBN activates _______
activates whole cochlea NBN activates cochlea around pure tone area of BM
a shadow curve is what?
an audiogram where one ear is about 40 to 55dB lower than than the other ear almost consistently across freqs.
a shadow curve is really what? (not what it looks like)
it’s showing the good ear picking up the sound presented to the bad ear, making it look like the bad ear is responding
in a shadow curve, you need to ?
mask
a square is what symbol?
left masked
a triangle is what symbol?
right masking