Listening with Two Ears – New Insights and Perspectives in Binaural Research

Abstract

Hearing is dependent on neural processing of acoustic cues obtained by the left and right ears. Neural signals driven by the two ears are integrated at multiple levels of the central auditory system, which enables animals including humans to perform various functions including localization of a sound source. A natural listening environment typically contains sounds from multiple sources. These sounds can have different spectral and temporal features and occur at either the same or different time. Integration can happen among neural signals elicited by the same or different sounds. The way of integration can greatly affect how individual sounds are sensed and perceived. Functions such as auditory grouping and stream segregation, which are central to establishing coherent auditory images in a complex listening environment, are highly dependent on the way of integration. Binaural hearing is complicated by individual differences and developmental changes in head and pinna shape/size as binaural cues can be affected by these differences and changes. Furthermore, neural processing of binaural cues can be influenced by hearing impairments and the use of hearing aids and cochlear implants. These factors likely require a listener to optimize the use of binaural cues through learning and to use plastic changes in the nervous system to perform the optimization. Great strides have been made in understanding binaural processing in normal and impaired auditory systems. This Research Topic aims to highlight some of the latest findings in the following areas: 1) Animal behavioral and human psychoacoustical studies of binaural hearing; 2) Neural encoding and processing of binaural cues and structural as well as neurophysiological bases of such encoding and processing; 3) Contribution of binaural neural processing to auditory functions such as sound-source localization, binaural fusion, binaural interference, spatial release from masking, auditory grouping, and auditory stream segregation; 4) Computational models of binaural processing; 5) Learning and plastic changes in binaural processing following hearing loss or alterations of acoustic environment and structural as well as physiological bases of these behavioral changes; 6) Clinical aspects of binaural processing including application of processing strategies, including research on the benefits of bilateral cochlear implantation, and the neural correlates thereof.