An overview on informational masking

In noisy environments, two types of masking including energetic masking (EM) and informational masking (IM) occur. EM results from the spectral overlap of the target and maskers on the basilar membrane, while IM occurs at higher level. This paper aimed to review the concept of IM in terms of historical perspective and definitions, the important cues for releasing from it, age-related effects and its neural basis.

The data from psychoacoustic, behavioral, and neuro-imaging studies were reviewed and discussed in order to provide an overall image of IM. According to these studies, it seems that perceptual segregation between the target and maskers is the most important cues for releasing from IM. This process takes place simply and without any effort in adults with normal hearing; however, it does not occur easily in children, elderly people and those with impaired hearing. Moreover, it seems that both top-down and bottom-up processing are involved in IM formation.

Since IM leads to failure in selection of auditory objects and prevents the individual from auditory scene analysis, understanding the IM concept leads to a better knowledge of speech perception in noise.