Importance of binaural hearing.

An essential task for the central auditory pathways is to parse the auditory messages sent by the two cochleae into auditory objects, the segregation and localisation of which constitute an important means of separating target signals from noise and competing sources. When hearing losses are too asymmetric, the patients face a situation in which the monaural exploitation of sound messages significantly lessens their performance compared to what it should be in a binaural situation. Rehabilitation procedures must aim at restoring as many binaural advantages as possible. These advantages encompass binaural redundancy, head shadow effect and binaural release from masking, the principles and requirements of which make up the topic of this short review. Notwithstanding the complete understanding of their neuronal mechanisms, empirical data show that binaural advantages can be restored even in situations in which faultless symmetry is inaccessible.