Quiz 2 Flashcards
Masking
a procedure audiologists use while testing to separate the two ears acoustically
Test ear
Ear currently being tested
Non-test ear
one not being tested
How to separate the ears?
Covering one and then testing the other to determine if it is normal or impaired
The amount of masking noise required depends on the amount of signal that may crossover
Noise is introduced to the non-test ear while the test ear is evaluated with a tone
How do you indicate that the hearing thresholds were obtained?
Masked threshold symbols
Cross-Hearing
Differences at the same frequency between the 2 ears
the patient will respond to the test stimuli before their true threshold has been reached
Interaural Attenuation
the amount of sound intensity that is reduced when crossing from the test ear to the non test ear
reduces crossover
Supra Aural Headphones
average IA values across all frequencies for air conduction tend to be around 60-40 dB
Interaural Attenuation for Bone Conduction
Adult skulls are fused at the cranial structures
If you vibrate any part of the head equal vibrations will transmit to the entire head bone and cochlea
Almost no IA in BC testing
Masking for Air Conduction
General Rule: compare the air conduction thresholds of the test ear with the bone conduction thresholds of the non test ear
When should you mask?
Super aural headphones: if the difference between the non test ear BC and test ear AC thresholds is 40 dB or more
Insert Headphones: if the difference is 60 dB or more between the non-test BC and test ear AC thresholds
What is the difference between the bone conduction theshold vs air conduction threshold?
Air bone gap
Occlusion Effect
During bone conduction testing only
Occurs when the occluded ear canal traps the BC signal energy
Bone conduction masking requires a correction factor for the occlusion effect
Overmasking
When the masking noise is so intense in the masked ear that it crosses the skull and produces an undesired masking of the test signal in the ear
Undermasking
The assumption that the threshold of the tone in the test ear has not been reached and that both the tone and noise are heard by the non test ear
Central Masking
the belief that the elevation of threshold is produced by inhibition that is sent down from the auditory centers in the brain
Masking Dilemma
not finding the masking plateau
occurs when the hearing loss causes the masking levels presented in the non-test ear to cross over to the test ear and elevates the threshold
solution: use insert earphones
Immittance
used as an all-encompassing term to describe measurements made of tympanic membrane impedance, compliance, or admittance
also known as “middle ear measurements” or impedance audiometry
