Masking Level Difference (Mld) - Interacoustics Affinity 2.0 Additional Information

Should you wish to edit your speech score af ter it has been assigned you can right click on the word, and it
will allow you to re-score it as shown below.
This f eature can be used during testing or af ter the test has completed.
5) Should you wish to choose where to begin your speech testing then you can click on the designated
wavef ile ahead of starting the test. Clicking on it will highlight it with a bolder outline. The material will
then play f rom her on clicking the 'play' icon.
1.7.6

Masking level difference (MLD)

Masking Level Dif f erence ref ers to the improvement in detecting a tone or speech in noise when the phase
of the tone or the noise is reversed by 180 degrees. It aims to assess central auditory f unction and is
specif ically sensitive to brainstem lesions, but peripheral changes (like a hearing loss) may also af f ect the
MLD.
The MLD is a low f requency phenomenon, related to the auditory system's ability to perceive dif f erences in
timing of a sound reaching the two ears. This helps to localize low f requency sounds that reach the ears at
dif f erent times due to the longer wave length.
The MLD is usually ref erred to as the dif f erence of improvement, in dB, between a "homophasic" (in-phase)
condition and an "antiphasic" (out of phase) condition. Homophilic means that both the signal and the noise
are in phase with each other when reaching the two ears. Antiphase means that either the signal or the
noise (not both) is out of phase with each other when reaching the two ears. The three test conditions f or
the MLD in the AC40 are:
SoNo: Signal and Noise are IN PHASE when reaching the two ears. (Homophasic condition)
•
SπNo: Signal is OUT OF PHASE, noise is IN PHASE when reaching the two ears (Antiphasic
•
condition)
SoNπ: Signal is IN PHASE, noise is OUT OF PHASE when reaching the two ears (Antiphasic
•
condition)
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MLD requires an additional software license and is only available as an additional feature for the Affinity
D-0004576-Q – 2022/05
Affinity/Equinox2.0 – Additional Information
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2.0 2.0
/Equinox
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