When to Mask - Air Conduction


1)Which air-conduction thresholds should be masked?  Unless otherwise noted, for all of the questions in this tutorial, please consider when masking is needed in two cases:
    A)  When using insert earphones and assuming the minimum interaural attenuation value is 50 dB
    B)  When using supra-aural earphones and assuming the minimum interaural attenuation value is 40 dB.

 


2) When is air-conduction masking needed in this case?





3) When is air-conduction masking required?


4)  When is air-conduction  masking needed?  Consider this two different ways:
    A)  If the left ear has a sensorineural loss
    B)  If the left ear has a flat tympogram, and the patient history suggests that the left ear loss is purely conductive.

   


5) Is masking needed for air-conduction?


6) Is air-conduction masking required:
    A)  If the left ear loss is sensorineural (e.g. a type A tympanogram is found and acoustic reflexes are present in the probe left conditions)

    B)  If the left ear loss is conductive (e.g. flat tymp and absent reflexes)


7) Is air-conduction masking required?


8) Is masking required for air conduction testing?


9) If, on conducting unmasked bone conduction on the right ear, the following bone conduction thresholds are found, do you need to mask any of the left ear air-conduction thresholds?



10) When is air-conduction masking needed in this case?


11) Bone conduction masking is required if the unmasked thresholds suggest an air-bone gap in the test ear.  Clinically significant air-bone gaps are larger than 10 dB; therefore, masking is needed if the air-bone gap is 15 or greater in the test ear. 

Often, unmasked testing  is conducted just once, since the signal can cross to the non-test ear with little to no attenuation.  In that case, when to mask is decided by whether there is a 15 dB or more difference between each air conduction threshold and the unmasked threshold.

In this audiogram, which bone conduction thresholds should be masked?


12) Which bone-conduction thresholds require masking?


13) When is masking needed?


14) Is masking needed?  Insert earphones were used for AC testing.


15)Is masking needed?
 


16) Is masking needed?  TDH earphones used.


17) Is masking required?  TDH earphones.


18) Is masking required?

Is there any more information that you want before answering this question?


19) Is masking needed?


20)  Assuming TDH earphones, when is masking needed?


21) Is masking needed?  TDH earphones.


22) Is masking needed?  TDH earphones.


23) Is masking needed?   Insert earphones.


Copyright (c) 2001, AuDStudent.com
Content by Teri Hamill, Ph.D., Nova Southeastern University, (c) 2005, rev 2007 (c)