Relationship between Speech Perception in Noise and Phonemic Restoration of Speech in Noise in Individuals with Normal Hearing

Abstract

Background and Objectives: Top-down restoration of distorted speech, tapped as phonemic restoration of speech in noise, maybe a useful tool to understand robustness of perception in adverse listening situations. However, the relationship between phonemic restoration and speech perception in noise is not empirically clear.Subjects and Methods: 20 adults (40-55 years) with normal audiometric findings were part of the study. Sentence perception in noise performance was studied with various signal-to-noise ratios (SNRs) to estimate the SNR with 50% score. Performance was also measured for sentences interrupted with silence and for those interrupted by speech noise at -10, -5, 0, and 5 dB SNRs. The performance score in the noise interruption condition was subtracted by quiet interruption condition to determine the phonemic restoration magnitude.Results: Fairly robust improvements in speech intelligibility was found when the sentences were interrupted with speech noise instead of silence. Improvement with increasing noise levels was non-monotonic and reached a maximum at -10 dB SNR. Significant correlation between speech perception in noise performance and phonemic restoration of sentences interrupted with -10 dB SNR speech noise was found.Conclusions: It is possible that perception of speech in noise is associated with top-down processing of speech, tapped as phonemic restoration of interrupted speech. More research with a larger sample size is indicated since the restoration is affected by the type of speech material and noise used, age, working memory, and linguistic proficiency, and has a large individual variability.

The impact of language background and listening-in-noise on the phonemic restoration effect

“…Studies that have measured the PR benefit separately for each participant often show a range of performance. For example, Jaekel, et al (2018) showed PR benefit measured in RAUs ranging from -22 to +28 for young adults and from -17 to +47 for older adults, Vijaysarathy & Barman (2020) report PR benefit ranging from -1 to +12 keywords (out of 40) for 40-55 year-old adults, and Bologna, et al (2018) report PR benefit ranging from 1 to 12 keywords (out of 76) for young adults. These findings suggest that the use of restoration by any given individual may depend critically on a variety of cognitive, perceptual, and linguistic factors.…”

“…In the second task, listeners heard sentences that were interrupted every 333 ms and either left silent or replaced with speech-shaped noise; they measured the degree to which participants showed better performance in the filled vs. unfilled condition (PR benefit). They found that the PR benefit was not consistent across individuals, such that only some participants consistently showed it, but that individuals who showed better listening in continuous noise also showed a greater PR benefit (Vijaysarathy & Barman 2020). This supports the idea that speech perception in continuous noise and the PR effect have similar underlying mechanisms.…”

“…Recent research has found a relationship between an individual's ability to comprehend speech in continuous noise and the degree of PR benefit they experience. Vijaysarathy & Barman (2020) presented 40 -55-year-old English monolinguals with two listening tasks. In one task, they assessed the signal-noise-ratio (SNR) at which each participant showed 50% accuracy in sentence repetition (SNR-50).…”

“…However, the ability to comprehend speech in background noise correlates with individual differences in linguistic and cognitive skills as well, and it is possible that one of these factors is driving the correlation found in Vijaysarathy and Barman (2020). For example, perhaps individuals who could comprehend sentences at higher levels of background noise could do so because they were more efficiently able to access their linguistic knowledge, which also aided phonemic restoration.…”

“…One goal of the current study, then, is to test the relationship between the PR effect and listening-in-noise in a different listener population (bilinguals) and using different stimuli. This will allow us to better understand if the relationship found in Vijaysarathy and Barman (2020) is due to low-level perceptual abilities alone or if it is further driven by cognitive and linguistic factors that vary across individuals.…”