T/F Human ears are not acoustically isolated
True
T/F Tones presented via air conduction to one ear can be loud enough to stimulate the opposite ear via bone conduction
True
Crossover hearing
When a tone is presented to one ear at a given level and it is heard at a lower level in the opposite ear
the decrease in the level of an acoustic signal as it passes from one ear to the cochlea of the opposite ear
Interaural Attentuation
Transducers
Supra-aural (TDH) and insert earphones
Anytime the air conduction threshold in one ear differs from the air or bone conduction threshold in the other ear by a minimum of _____ dB when using supra-aural headphones, crossover may have occurred.
40 dB
Anytime the air conduction threshold in one ear differs from the air or bone conduction threshold in the other ear by a minimum of _____ dB when using insert earphones, crossover may have occurred.
70 dB
Interaural attenuation for bone conduction is _____ dB.
0 dB
We can assume the patient hears the tone from bone conduction in the ____ cochlea.
Better
______ allows us to acoustically isolate the test ear.
Masking
The noise is heard in the ________ ear.
The tone is heard in the ________ ear.
Non-test/Test
Noise elevates the threshold in the non-test ear and ________ it from the test.
eliminates
________ noises are introduced to the non-test ear.
Narrow-band noises
T/F Speech shaped noise is used to mask speech stimuli.
True
How to confirm crossover
- Determine if the threshold in the test ear was the result of a crossover (40 dB difference for TDH headphones; 70 dB difference for insert earphones)
- Present narrow-band noise to non-test ear at a level 5-10 dB above the threshold in that ear
- Test the threshold of the test ear again (if it increases by 5-10 dB, the original threshold was the result of cross hearing)
