Aging Effect on Mandarin Chinese Vowel and Tone Identification in Six-Talker Babble

Purpose The purpose of this study was to measure Mandarin Chinese vowel-plus-tone identification in quiet and noise for younger and older listeners. Method Two types of noise served as the masker, namely, six-talker babble and babble-modulated noise, at two signal-to-noise ratios (SNRs) of −4 and −8 dB. Fourteen listeners from both age groups were recruited, and three sets of data analyses were conducted: the identification of vowel plus tone, the identification of vowel, and the identification of tone. Results Younger listeners outperformed older listeners in all listening conditions, whereas the younger–older listener difference became greater in noise than in quiet, indicating a more detrimental effect of noise for older listeners than for younger listeners. In addition, vowel identification showed slightly better scores than tone identification in noise, suggesting that noise appeared to affect tone perception more negatively than vowel perception in Mandarin Chinese. At −4 dB SNR, there was a significantly greater amount of informational masking (IM) and a greater amount of energetic masking (EM) for older listeners than for younger listeners. At −8 dB SNR, there was a greater amount of EM for older listeners than for younger listeners but with no group difference in the amount of IM. Conclusion These results suggest that older listeners received a more negative impact of noise for Mandarin Chinese phonemic and tone recognition and had a larger amount of IM or EM from competing speech noise than younger listeners, depending on the SNR.

Infants' Preference for Child-Directed Speech Over Time-Reversed Speech in On-Channel and Off-Channel Masking

Purpose This study aims to examine the development of auditory selective attention to speech in noise by examining the ability of infants to prefer child-directed speech (CDS) over time-reversed speech (TRS) presented in “on-channel” and “off-channel” noise. Method A total of 32 infants participated in the study. Sixteen typically developing infants were tested at 7 and 11 months of age using the central fixation procedure with CDS and TRS in two types of noise at +10 dB signal-to-noise ratio. One type of noise was an “on-channel” masker with a spectrum overlapping that of the CDS (energetic masking), and the second was an “off-channel” masker with frequencies that were outside the spectrum of the CDS (distractive masking). An additional group of sixteen 11-month-old infants were tested in quiet and served as controls for the “off-frequency” masker condition. Results Infants preferred CDS over TRS in both age groups, but this preference was more pronounced with “off-channel” masker regardless of age. Also, older infants demonstrated longer looking time for the target stimuli when presented with an “off-channel” masker compared to the “on-channel” masker. Looking time in quiet was similar to looking time in the “off-channel” condition, and looking time for CDS was longer in quiet compared to the “on-channel” condition. Conclusions These findings support the notion that (a) infants as young as 7 months of age are already showing preference for speech in noise, regardless of type of masker; (b) by 11 months of age, listening with the “off-channel” condition did not yield different results than in quiet. Thus, by 11 months of age, infants' cognitive–attentional abilities may be more developed.

Auditory cortex is susceptible to lexical influence as revealed by informational vs. energetic masking of speech categorization

ABSTRACTSpeech perception requires the grouping of acoustic information into meaningful phonetic units via the process of categorical perception (CP). Environmental masking influences speech perception and CP. However, it remains unclear at which stage of processing (encoding, decision, or both) masking affects listeners’ categorization of speech signals. The purpose of this study was to determine whether linguistic interference influences the early acoustic-phonetic conversion process inherent to CP. To this end, we measured source level, event related brain potentials (ERPs) from auditory cortex (AC) and inferior frontal gyrus (IFG) as listeners rapidly categorized speech sounds along a /da/ to /ga/ continuum presented in three listening conditions: quiet, and in the presence of forward (informational masker) and time-reversed (energetic masker) 2-talker babble noise. Maskers were matched in overall SNR and spectral content and thus varied only in their degree of linguistic interference (i.e., informational masking). We hypothesized a differential effect of informational versus energetic masking on behavioral and neural categorization responses, where we predicted increased activation of frontal regions when disambiguating speech from noise, especially during lexical-informational maskers. We found (1) informational masking weakens behavioral speech phoneme identification above and beyond energetic masking; (2) low-level AC activity not only codes speech categories but is susceptible to higher-order lexical interference; (3) identifying speech amidst noise recruits a cross hemispheric circuit (ACleft → IFGright) whose engagement varies according to task difficulty. These findings provide corroborating evidence for top-down influences on the early acoustic-phonetic analysis of speech through a coordinated interplay between frontotemporal brain areas.

Lipreading in Noise: Cross-Modal Analysis of the Target-Masker Linguistic Similarity Hypothesis

The linguistic similarity hypothesis states that it is more difficult to segregate target and masker speech when they are linguistically similar (Brouwer et al., 2012). This may be the result of energetic masking (interference at the auditory periphery) and/or informational masking (cognitive interference). To provide a rigorous test of the hypothesis and investigate how informational masking interferes with speech identification in the absence of energetic masking, we presented target speech visually and masking babble auditorily. Participants completed an English lipreading task in silence, speech-shaped noise, semantically anomalous English, semantically meaningful English, Dutch, and Mandarin two-talker babble. Results showed that speech maskers interfere with lipreading more than stationary noise, and that maskers that are the same language as the target speech provide more interference than different-language maskers. However, the study found no evidence that a masker that is similar to the English target speech (Dutch) provides more masking than one that is less similar (Mandarin). These results provide some cross-modal support for the linguistic similarity hypothesis, but suggest that the theory should be further specified to address the conditions under which languages that differ in their similarity to the target speech should provide different levels of masking.

An overview on informational masking

Background and Aim: In noisy environments, two types of masking including energetic mask­ing (EM) and informational masking (IM) occur. EM results from the spectral overlap of the target and maskers on the basilar membrane, while IM occurs at higher level. This paper aimed to rev­iew the concept of IM in terms of historical perspective and definitions, the important cues for releasing from it, age-related effects and its neural basis. Recent Findings: The data from psychoacoustic, behavioral, and neuro-imaging studies were revi­ewed and discussed in order to provide an overall image of IM. According to these studies, it seems that perceptual segregation between the target and maskers is the most important cues for relea­sing from IM. This process takes place simply and without any effort in adults with normal hearing; however, it does not occur easily in chil­dren, elderly people and those with impaired hearing. Moreover, it seems that both top-down and bottom-up processing are involved in IM for­mation. Conclusion: Since IM leads to failure in selec­tion of auditory objects and prevents the indivi­dual from auditory scene analysis, understanding the IM concept leads to a better knowledge of speech perception in noise. Keywords: Informational masking; perceptual masking; energetic masking

The Effect of Talker and Listener Depressive Symptoms on Speech Intelligibility

Purpose This study examined the effect of depressive symptoms on production and perception of conversational and clear speech (CS) sentences. Method Five talkers each with high-depressive (HD) and low-depressive (LD) symptoms read sentences in conversational and clear speaking style. Acoustic measures of speaking rate, mean fundamental frequency (F0; Hz), F0 range (Hz), and energy in the 1–3 kHz range (dB) were obtained. Thirty-two young adult participants (15 HD, 16 LD) heard these conversational and clear sentences mixed with energetic masking (speech-shaped noise) at −5 dB SPL signal-to-noise ratio. Another group of 39 young adult participants (18 HD, 19 LD) heard the same sentences mixed with informational masking (one-talker competing speech) at −12 dB SPL signal-to-noise ratio. The key word correct score was obtained. Results CS was characterized by a decreased speaking rate, increased F0 mean and range, and increased energy in the 1–3 kHz range. Talkers with HD symptoms produced these modifications significantly less compared to talkers with LD symptoms. When listening to speech in energetic masking (speech-shaped noise), listeners with both HD and LD symptoms benefited less from the CS produced by HD talkers. Listeners with HD symptoms performed significantly worse than listeners with LD symptoms when listening to speech in informational masking (one-talker competing speech). Conclusions Results provide evidence that depressive symptoms impact intelligibility and have the potential to aid in clinical decision making for individuals with depression.

Speech perception with temporally patterned noise maskers.

In the real world, speech perception frequently occurs under adverse listening conditions. Laboratory studies have identified distinct phenomena associated with more or less constant sources of noise (energetic masking), and competing verbal information (informational masking). One issue complicating direct comparisons between them is that common paradigms for studying energetic and informational masking di↵er along many dimensions, in particular, informational masking is almost always measured using linguistically meaningful information. We have developed a paradigm that uses temporally patterned noise, with the goal of comparing energetic and informational masking under more comparable conditions. We hypothesized that listeners would be able to take advantage of the structure in the masking noise, providing a processing advantage over energetic masking. The initial experiment provides strong evidence for this hypothesis, but conceptual replications did not produce the same pattern of results – at least with respect to measures of central tendency. A direct replication of the first experiment did not replicate the large di↵erences in the means but a final experiment strengthening the e↵ect did. Interestingly, however, exploratory analyses across all five experiments reveal robust evidence that patterned noise conditions produce increased individual variability. Further, we observed strong correlations, specifically between the patterned conditions. We attribute these findings to as yet unidentified cognitive ability di↵erences allowing some participants to benefit from the use of additional temporal information while others are hurt by the addition of unusable distracting information. Hypothesized predictive measures of task performance, such as working memory, inhibitory control, and musical experience did not correlate with performance, however.