Abstract
Our ability to listen selectively to single sound sources in complex auditory environments is termed “auditory stream segregation.”This ability is affected by peripheral disorders such as hearing loss, as well as plasticity in central processing such as occurs with musical training. Brain plasticity induced by musical training can enhance the ability to segregate sound, leading to improvements in a variety of auditory abilities. The melody segregation ability of 12 cochlear-implant recipients was tested using a new method to determine the perceptual distance needed to segregate a simple 4-note melody from a background of interleaved random-pitch distractor notes. In experiment 1, participants rated the difficulty of segregating the melody from distracter notes. Four physical properties of the distracter notes were changed. In experiment 2, listeners were asked to rate the dissimilarity between melody patterns whose notes differed on the four physical properties simultaneously. Multidimensional scaling analysis transformed the dissimilarity ratings into perceptual distances. Regression between physical and perceptual cues then derived the minimal perceptual distance needed to segregate the melody. The most efficient streaming cue for CI users was loudness. For the normal hearing listeners without musical backgrounds, a greater difference on the perceptual dimension correlated to the temporal envelope is needed for stream segregation in CI users. No differences in streaming efficiency were found between the perceptual dimensions linked to the F0 and the spectral envelope. Combined with our previous results in normally-hearing musicians and non-musicians, the results show that differences in training as well as differences in peripheral auditory processing (hearing impairment and the use of a hearing device) influences the way that listeners use different acoustic cues for segregating interleaved musical streams.
Highlights
The perception and enjoyment of music engages complex brain networks (Zatorre et al, 2007) and recent evidence highlights the importance of top-down processes as well as stimulus-driven processes (Tervaniemi et al, 2009; Strait et al, 2010)
In order to test the statistical significance of each acoustic parameter on the difficulty ratings, a generalized linear model (GLM) was used
Based on the slopes of the functions relating physical parameter changes with perceptual difference ratings found through the multidimensional scaling analysis (MDS) analysis in Experiment 2, the results of Experiment 1 were re-scaled into perceptual distance units on the x-axis (Figure 5)
Summary
The perception and enjoyment of music engages complex brain networks (Zatorre et al, 2007) and recent evidence highlights the importance of top-down processes as well as stimulus-driven processes (Tervaniemi et al, 2009; Strait et al, 2010). Music practice has been shown to induce changes in the structure and function of the brain pathways that process sound and leads to improved performance on perceptual tasks (for example Musacchia et al, 2007). Two experiments will compare the ability to segregate auditory streams between a group of cochlear implant users and a group of normal hearing listeners. In a typical auditory streaming experiment (Bregman, 1990), listeners are exposed to a sequence of alternating high and low notes—the sounds may be grouped together and perceived as coming from a single source (termed fusion), or perceived as streams from separate sources (termed fission). According to the “Peripheral Channeling” theory, hearing impaired listeners should show a reduced ability to stream
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
