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

Abstract

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.

The effects of aging and hearing impairment on listening in noise

“…The inference about the effects of peripheral hearing loss is strongly supported by the efficacy of the stimulus individualization procedure: there are no significant group differences and no significant correlation between hearing thresholds and performance measures of the figure detection task, and no correlation between the current working memory indices and any of the behavioral measures. Further, the current results are fully compatible with those of prior studies showing that spectrotemporal coherence supports auditory stream segregation (better figure detection performance with higher coherence (31,(36)(37)(38)(39).…”

“…Results are suggesting that the ability to exploit sequential stimulus predictability for auditory stream segregation degrades with age (40). A recent study, however, suggested that elderly listeners can utilize predictability, albeit with a high degree of inter-individual variation(37). Further, de Kerangal and colleagues (41)also found that the ability to track sound sources based on acoustic regularities is largely preserved in old age.…”