Interacoustics affinity 2.0 - Page 150

Affinity
2.0
Additional Information Page 140
Recommendations
• Be aware that patients require proper instructions before audiometry with masking is undertaken.
The switching on and off of the masking noise may be uncomfortable to some patients and cause
them to become more fatigued. In some cases (when testing young children, some elderly patients
or difficult to test patients), it is recommended not to use masking because confusion about the
application of masking noise may lead to false responses.
• When measuring the second test ear, more information becomes available and it is not guaranteed
that the earlier measurements are still correct. By measuring the best ear first and completing air
conduction on both ears before measuring bone conduction, most errors can be avoided.
• Be careful when storing thresholds where masking was not possible. Masking not possible means
that the risk for crossover hearing is high. In these cases it is recommended to store a no-response
at the loudest intensity where masking was still possible (by pressing the N key).
Additional information
The masking help calculates answers to the following questions.
• Is masking required?
• Is the masking level too low?
• Is the masking level too high?
• Is masking impossible?
Terminology
AC AC test ear
AC
c AC contra
BC BC test ear
BC
c BC contra
IaA Minimum interaural attenuation
IaA
c Minimum interaural attenuation contra transducer
Dial Dial setting test ear
Dial
c Dial setting contra (masking level)
Is masking required?
Masking is recommended when the presentation at the test ear leads to a response due to detection by the
contralateral ear, or in a formula:
Dial – IaA ≥ lowest of AC
c and BCc
Is the masking level too low?
The applied masking level is too low when the applied masking level does not match the intensity at which
the test signal is heard in the contralateral ear, or in a formula:
Dial
c – (ACc – BCc) < Dial – IaA
Is the masking level too high?
The applied masking level is too high when the masking level is so loud that it potentially is heard by the test
ear, or in a formula:
Dial
c – IaAc ≥ Dial – (AC – BC)
Is masking impossible?
Masking is not possible when the needed masking level results in overmasking at the same time:
Dial + (AC
c – BCc) – IaA ≥ Dial – (AC – BC) + IaAc
or when the needed masking level is higher than the maximum level of the masking transducer:
Dial + (AC
c – BCc) – IaA > maximum available Dialc