Impaired processing of binaural temporal cues to auditory scene analysis in schizophrenia

It is well established that individuals with schizophrenia demonstrate alterations in auditory perception beginning at the very earliest stages of information processing. However, it is not clear how these impairments in basic information processing translate into high-order cognitive deficits. Auditory scene analysis allows listeners to group auditory information into meaningful objects, and as such provides an important link between low-level auditory processing and higher cognitive abilities. In the present study we investigated whether low-level impairments in the processing of binaural temporal information impact upon auditory scene analysis ability. Binaural temporal processing ability was investigated in 19 individuals with schizophrenia and 19 matched controls. Individuals with schizophrenia showed impaired binaural temporal processing ability on an inter-aural time difference (ITD) discrimination task. In addition, patients demonstrated impairment in two measures of auditory scene analysis. Specifically, patients had reduced ability to use binaural temporal cues to extract signal from noise in a masking level difference paradigm, and to separate the location of a source sound in the presence of an echo in the precedence effect paradigm. These findings demonstrate that individuals with schizophrenia have impairments in the accuracy with which simple binaural temporal information is encoded in the auditory system, and furthermore, this impairment has functional consequences in terms of the use of these cues to extract information in complex auditory environments.