Predictive Coding Supports Sound Source Segregation

2015 ◽  
Vol 52 ◽  
pp. S4-S5
Keyword(s):  
Sound Source ◽  
Predictive Coding ◽  
Sound Source Segregation ◽  
Source Segregation

scholarly journals Predictability-Based Source Segregation and Sensory Deviance Detection in Auditory Aging

2021 ◽  
Vol 15 ◽  
Author(s):  
Christiane R. Neubert ◽  
Alexander P. Förstel ◽  
Stefan Debener ◽  
Alexandra Bendixen
Keyword(s):  
Sound Source ◽  
Predictive Coding ◽  
Single Subject ◽  
Group Level ◽  
Sound Sources ◽  
Passive Listening ◽  
Deviance Detection ◽  
Sound Source Segregation ◽  
High Degree ◽  
Source Segregation

When multiple sound sources are present at the same time, auditory perception is often challenged with disentangling the resulting mixture and focusing attention on the target source. It has been repeatedly demonstrated that background (distractor) sound sources are easier to ignore when their spectrotemporal signature is predictable. Prior evidence suggests that this ability to exploit predictability for foreground-background segregation degrades with age. On a theoretical level, this has been related with an impairment in elderly adults’ capabilities to detect certain types of sensory deviance in unattended sound sequences. Yet the link between those two capacities, deviance detection and predictability-based sound source segregation, has not been empirically demonstrated. Here we report on a combined behavioral-EEG study investigating the ability of elderly listeners (60–75 years of age) to use predictability as a cue for sound source segregation, as well as their sensory deviance detection capacities. Listeners performed a detection task on a target stream that can only be solved when a concurrent distractor stream is successfully ignored. We contrast two conditions whose distractor streams differ in their predictability. The ability to benefit from predictability was operationalized as performance difference between the two conditions. Results show that elderly listeners can use predictability for sound source segregation at group level, yet with a high degree of inter-individual variation in this ability. In a further, passive-listening control condition, we measured correlates of deviance detection in the event-related brain potential (ERP) elicited by occasional deviations from the same spectrotemporal pattern as used for the predictable distractor sequence during the behavioral task. ERP results confirmed neural signatures of deviance detection in terms of mismatch negativity (MMN) at group level. Correlation analyses at single-subject level provide no evidence for the hypothesis that deviance detection ability (measured by MMN amplitude) is related to the ability to benefit from predictability for sound source segregation. These results are discussed in the frameworks of sensory deviance detection and predictive coding.

scholarly journals Effect of Dual-Carrier Processing on the Intelligibility of Concurrent Vocoded Sentences

2018 ◽  
Vol 61 (11) ◽  
pp. 2804-2813
Author(s):  
Frédéric Apoux ◽  
Brittney L. Carter ◽  
Eric W. Healy
Keyword(s):  
Sound Source ◽  
Speech Intelligibility ◽  
Target Sentence ◽  
Sound Sources ◽  
Single Carrier ◽  
Sound Source Segregation ◽  
Onset Asynchrony ◽  
Source Segregation ◽  
Vocoded Speech

Purpose The goal of this study was to examine the role of carrier cues in sound source segregation and the possibility to enhance the intelligibility of 2 sentences presented simultaneously. Dual-carrier (DC) processing (Apoux, Youngdahl, Yoho, & Healy, 2015) was used to introduce synthetic carrier cues in vocoded speech. Method Listeners with normal hearing heard sentences processed either with a DC or with a traditional single-carrier (SC) vocoder. One group was asked to repeat both sentences in a sentence pair (Experiment 1). The other group was asked to repeat only 1 sentence of the pair and was provided additional segregation cues involving onset asynchrony (Experiment 2). Results Both experiments showed that not only is the “target” sentence more intelligible in DC compared with SC, but the “background” sentence intelligibility is equally enhanced. The participants did not benefit from the additional segregation cues. Conclusions The data showed a clear benefit of using a distinct carrier to convey each sentence (i.e., DC processing). Accordingly, the poor speech intelligibility in noise typically observed with SC-vocoded speech may be partly attributed to the envelope of independent sound sources sharing the same carrier. Moreover, this work suggests that noise reduction may not be the only viable option to improve speech intelligibility in noise for users of cochlear implants. Alternative approaches aimed at enhancing sound source segregation such as DC processing may help to improve speech intelligibility while preserving and enhancing the background.

Sign in / Sign up

Export Citation Format

Share Document