Mandarin tone perception in multiple-talker babbles and speech-shaped noise

Lexical tone recognition in multi-talker babbles and steady-state noise by Mandarin-speaking children with unilateral cochlear implants or bimodal hearing

BACKGROUND AND OBJECTIVES

Lexical tone presents challenges to cochlear implant (CI) users especially in noise conditions. Bimodal hearing utilizes residual acoustic hearing in the contralateral side and may offer benefits for tone recognition in noise. The purpose of the present study was to evaluate tone recognition in both steady-state noise and multi-talker babbles by the prelingually-deafened, Mandarin-speaking children with unilateral CIs or bimodal hearing.

METHODS

Fifty-three prelingually-deafened, Mandarin-speaking children who received CIs participated in this study. Twenty-two of them were unilateral CI users and 31 wore a hearing aid (HA) in the contralateral ear (i.e., bimodal hearing). All subjects were tested for Mandarin tone recognition in quiet and in two types of maskers: speech-spectrum-shaped noise (SSN) and two-talker babbles (TTB) at four signal-to-noise ratios (-6, 0, +6, and +12 dB).

RESULTS

While no differences existed in tone recognition in quiet between the two groups, the Bimodal group outperformed the Unilateral CI group under noise conditions. The differences between the two groups were significant at SNRs of 0, +6, and +12 dB in the SSN conditions (all p < 0.05), and at SNRs of +6 and +12 dB of TTB conditions (both p < 0.01), but not significant at other conditions (p > 0.05). The TTB exerted a greater masking effect than the SSN for tone recognition in the Unilateral CI group as well as in the Bimodal group at all SNRs tested (all p < 0.05). Among demographic or audiometric variables, only age at implantation showed a weak but significant correlation with the mean tone recognition performance under the SSN conditions (r = -0.276, p = 0.045). However, when Bonferroni correction was applied to the correlation analysis results, the weak correlation became not significant.

CONCLUSION

Prelingually-deafened children with CIs face challenges in tone perception in noisy environments, especially when the noise is fluctuating in amplitude such as the multi-talker babbles. Wearing a HA on the contralateral side when residual hearing permits is beneficial for tone recognition in noise.

Effects of absolute pitch on brain activation and functional connectivity during hearing-in-noise perception

Hearing-in-noise (HIN) ability is crucial in speech and music communication. Recent evidence suggests that absolute pitch (AP), the ability to identify isolated musical notes, is associated with HIN benefits. A theoretical account postulates a link between AP ability and neural network indices of segregation. However, how AP ability modulates the brain activation and functional connectivity underlying HIN perception remains unclear. Here we used functional magnetic resonance imaging to contrast brain responses among a sample (n = 45) comprising 15 AP musicians, 15 non-AP musicians, and 15 non-musicians in perceiving Mandarin speech and melody targets under varying signal-to-noise ratios (SNRs: No-Noise, 0, -9 dB). Results reveal that AP musicians exhibited increased activation in auditory and superior frontal regions across both HIN domains (music and speech), irrespective of noise levels. Notably, substantially higher sensorimotor activation was found in AP musicians when the target was music compared to speech. Furthermore, we examined AP effects on neural connectivity using psychophysiological interaction analysis with the auditory cortex as the seed region. AP musicians showed decreased functional connectivity with the sensorimotor and middle frontal gyrus compared to non-AP musicians. Crucially, AP differentially affected connectivity with parietal and frontal brain regions depending on the HIN domain being music or speech. These findings suggest that AP plays a critical role in HIN perception, manifested by increased activation and functional independence between auditory and sensorimotor regions for perceiving music and speech streams.

English vowel recognition in multi-talker babbles mixed with different numbers of talkersa)

The present study examined English vowel recognition in multi-talker babbles (MTBs) in 20 normal-hearing, native-English-speaking adult listeners. Twelve vowels, embedded in the h-V-d structure, were presented in MTBs consisting of 1, 2, 4, 6, 8, 10, and 12 talkers (numbers of talkers [N]) and a speech-shaped noise at signal-to-noise ratios of -12, -6, and 0 dB. Results showed that vowel recognition performance was a non-monotonic function of N when signal-to-noise ratios were less favorable. The masking effects of MTBs on vowel recognition were most similar to consonant recognition but less so to word and sentence recognition reported in previous studies.

Development of Mandarin Lexical Tone Identification in Noise and Its Relation With Working Memory

PURPOSE

This study aimed to examine the developmental trajectory of Mandarin tone identification in quiet and two noisy conditions: speech-shaped noise (SSN) and multitalker babble noise. In addition, we evaluated the relationship between tonal identification development and working memory capacity.

METHOD

Ninety-three typically developing children aged 5-8 years and 23 young adults completed categorical identification of two tonal continua (Tone 1-4 and Tone 2-3) in quiet, SSN, and babble noise. Their working memory was additionally measured using auditory digit span tests. Correlation analyses between digit span scores and boundary widths were performed.

RESULTS

Six-year-old children have achieved the adultlike ability of categorical identification of Tone 1-4 continuum under both types of noise. Moreover, 6-year-old children could identify Tone 2-3 continuum as well as adults in SSN. Nonetheless, the child participants, even 8-year-olds, performed worse when tokens from Tone 2-3 continuum were masked by babble noise. Greater working memory capacity was associated with better tone identification in noise for preschoolers aged 5-6 years; however, for school-age children aged 7-8 years, such correlation only existed in Tone 2-3 continuum in SSN.

CONCLUSIONS

Lexical tone perception might take a prolonged time to achieve adultlike competence in babble noise relative to SSN. Moreover, a significant interaction between masking type and stimulus difficulty was found, as indicated by Tone 2-3 being more susceptible to interference from babble noise than Tone 1-4. Furthermore, correlations between working memory capacity and tone perception in noise varied with developmental stage, stimulus difficulty, and masking type.

Evaluating the Relative Perceptual Salience of Linguistic and Emotional Prosody in Quiet and Noisy Contexts

How people recognize linguistic and emotional prosody in different listening conditions is essential for understanding the complex interplay between social context, cognition, and communication. The perception of both lexical tones and emotional prosody depends on prosodic features including pitch, intensity, duration, and voice quality. However, it is unclear which aspect of prosody is perceptually more salient and resistant to noise. This study aimed to investigate the relative perceptual salience of emotional prosody and lexical tone recognition in quiet and in the presence of multi-talker babble noise. Forty young adults randomly sampled from a pool of native Mandarin Chinese with normal hearing listened to monosyllables either with or without background babble noise and completed two identification tasks, one for emotion recognition and the other for lexical tone recognition. Accuracy and speed were recorded and analyzed using generalized linear mixed-effects models. Compared with emotional prosody, lexical tones were more perceptually salient in multi-talker babble noise. Native Mandarin Chinese participants identified lexical tones more accurately and quickly than vocal emotions at the same signal-to-noise ratio. Acoustic and cognitive dissimilarities between linguistic prosody and emotional prosody may have led to the phenomenon, which calls for further explorations into the underlying psychobiological and neurophysiological mechanisms.

Influence of Speech Recognition Ability on Acceptable Noise Level for Mandarin (Chinese) Speakers with Normal Hearing

INTRODUCTION

Noise can induce hearing loss and reduce speech understanding. The Acceptable Noise Level (ANL) test has been widely used in audiology. However, strategies used by listeners to determine ANLs are unclear. The current study evaluated the role of speech recognition in selecting ANL and how well ANL could predict speech understanding in a noisy situation.

METHODS

Forty-five Mandarin speakers with normal hearing were tested in both ears. ANL is defined as Most Comfortable Level (MCL) minus Background Noise Level (BNL). To obtain ANL monaurally with an earphone, the study measured participants' MCL to hear a Mandarin story in quiet and the maximum BNL to tolerate while following the story. Then, based on the participant's ANL, speech recognition in noise was examined using a set of phonemic-balanced Mandarin words. The signal-to-noise ratio (SNR) was adjusted to ANL, ANL - 10 dB ("degraded noise condition"), and ANL + 10 dB ("improved noise condition").

RESULTS

The mean ANLs were 2.4 dB and 2.6 dB for the left and right ears, respectively. The mean speech recognition with SNR adjusted to ANL was relatively high for both ears (81-83% correct). Even for those ear samples with very low ANL (<0 dB), speech performance obtained at SNR = ANL was still high. The mean speech recognition obtained at SNR = ANL was 5 percentage points lower than the mean speech recognition at the improved noise condition and 14 percentage points higher than the mean speech recognition at the degraded noise condition. Speech recognition obtained at SNR = ANL and ANL - 10 dB correlated significantly with ANL.

CONCLUSION

Speech recognition in noise appears to play an important role for listeners with normal hearing in deciding their ANLs. Additionally, ANL can predict speech performance (r-squared = 53-61%) in the degraded noise condition.

Age-Related Differences of Mandarin Tone and Consonant Aspiration Perception in Babble Noise

PURPOSE

This study investigated the categorical perception of Mandarin tones and consonant aspiration contrasts in babble noise among adults and adolescents aged 12-14 years, and explored the association between working memory and categorical perception.

METHOD

Twenty-four adults and 20 adolescents with Mandarin as their native language were recruited. Their performances of phonemic identification and discrimination in babble noise and quiet conditions, digit span tasks, and nonword repetition were assessed.

RESULTS

Results indicated that, firstly, in the noise condition, both adults and adolescents showed wider boundary widths and lower between-category accuracies when perceiving aspiration of consonants than in the quiet condition, and the categorical boundary of tone perception in adolescents showed a transitional tendency toward Tone 1. Secondly, discrimination of consonant aspiration in adolescents needed to be further developed. Lastly, the accuracy of nonword repetition in adolescents was lower than that in adults, and adults with better auditory verbal working memory had better performance on tone perception.

CONCLUSIONS

Our results provided evidence that tone perception is acquired easier than consonant aspiration perception, and tone perception is more robust and less susceptible to noise interference. Categorical perception performance relates to the capacity and utilization of auditory verbal working memory in some ways.

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.

Effects of Adaptive Non-linear Frequency Compression in Hearing Aids on Mandarin Speech and Sound-Quality Perception

Objective

This study was aimed at examining the effects of an adaptive non-linear frequency compression algorithm implemented in hearing aids (i.e., SoundRecover2, or SR2) at different parameter settings and auditory acclimatization on speech and sound-quality perception in native Mandarin-speaking adult listeners with sensorineural hearing loss.

Design

Data consisted of participants’ unaided and aided hearing thresholds, Mandarin consonant and vowel recognition in quiet, and sentence recognition in noise, as well as sound-quality ratings through five sessions in a 12-week period with three SR2 settings (i.e., SR2 off, SR2 default, and SR2 strong).

Study Sample

Twenty-nine native Mandarin-speaking adults aged 37–76 years old with symmetric sloping moderate-to-profound sensorineural hearing loss were recruited. They were all fitted bilaterally with Phonak Naida V90-SP BTE hearing aids with hard ear-molds.

Results

The participants demonstrated a significant improvement of aided hearing in detecting high frequency sounds at 8 kHz. For consonant recognition and overall sound-quality rating, the participants performed significantly better with the SR2 default setting than the other two settings. No significant differences were found in vowel and sentence recognition among the three SR2 settings. Test session was a significant factor that contributed to the participants’ performance in all speech and sound-quality perception tests. Specifically, the participants benefited from a longer duration of hearing aid use.

Conclusion

Findings from this study suggested possible perceptual benefit from the adaptive non-linear frequency compression algorithm for native Mandarin-speaking adults with moderate-to-profound hearing loss. Periods of acclimatization should be taken for better performance in novel technologies in hearing aids.

Aging Effects on Categorical Perception of Mandarin Lexical Tones in Noise

Purpose The purpose of this study was to examine the aging effects on the categorical perception (CP) of Mandarin lexical Tones 1-4 and Tones 1-2 in noise. It also investigated whether listeners' categorical tone perception in noise correlated with their general tone identification of 20 natural vowel-plus-tone signals in noise. Method Twelve younger and 12 older listeners with normal hearing were recruited in both tone identification and discrimination tasks in a CP paradigm where fundamental frequency contours of target stimuli varied systematically from the flat tone (Tone 1) to the rising/falling tones (Tones 2/4). Both tasks were conducted in quiet and noise with signal-to-noise ratios set at -5 and -10 dB, respectively, and general tone identification of natural speech signals was also tested in noise conditions. Results Compared with younger listeners, older listeners had shallower identification slopes and smaller discrimination peakedness in Tones 1-2/4 perception in all listening conditions, except for Tones 1-4 perception in quiet where no group differences were found. Meanwhile, noise affected Tones 1-2/4 perception: The signal-to-noise ratio condition at -10 dB brought shallower slope in Tones 1-2/4 identification and less peakedness in Tones 1-4 discrimination for both listener groups. Older listeners' CP in noise, the identification slopes in particular, positively correlated with their general tone identification in noise, but such correlations were partially missing for younger listeners. Conclusions Both aging and the presence of speech-shaped noise significantly reduced the CP of Mandarin Tones 1-2/4. Listeners' Mandarin tone recognition may be related to their CP of Mandarin tones.

Speech perception in noise: Masking and unmasking

Speech perception is essential for daily communication. Background noise or concurrent talkers, on the other hand, can make it challenging for listeners to track the target speech (i.e., cocktail party problem). The present study reviews and compares existing findings on speech perception and unmasking in cocktail party listening environments in English and Mandarin Chinese. The review starts with an introduction section followed by related concepts of auditory masking. The next two sections review factors that release speech perception from masking in English and Mandarin Chinese, respectively. The last section presents an overall summary of the findings with comparisons between the two languages. Future research directions with respect to the difference in literature on the reviewed topic between the two languages are also discussed.

Bimodal benefits in Mandarin-speaking cochlear implant users for music perception and tone recognition

BACKGROUND

Cochlear implant (CI) users have difficulty appreciating music and perceiving lexical tones in Mandarin Chinese. Wearing a hearing aid (HA) in the contralateral ear for bimodal hearing may provide additional benefits.

OBJECTIVES

To measure the bimodal benefits of music perception and tone recognition and to investigate the relationship between the two in Mandarin-speaking bimodal CI subjects.

MATERIALS AND METHODS

Sixteen Mandarin-speaking bimodal CI subjects (aged between 16 and 49 years) participated in the study. Music perception (pitch discrimination, melody discrimination and instrument identification) and lexical tone recognition were tested with electric stimulation (CI alone) or bimodal stimulation (CI + HA).

RESULTS

Subjects showed a significant bimodal benefit in tone recognition in quiet and noise, and in all music perception tests. The bimodal benefit for tone recognition in noise was significantly correlated with that of pitch discrimination thresholds and instrument identification scores.

CONCLUSION

Mandarin-speaking bimodal CI users achieved better music perception and tone recognition ability with CI + HA than with CI alone. The bimodal benefit of tone recognition was significantly correlated with that of music perception.

Increased Right Frontal Brain Activity During the Mandarin Hearing-in-Noise Test

Purpose

Previous studies have revealed increased frontal brain activation during speech comprehension in background noise. Few, however, used tonal languages. The normal pattern of brain activation during a challenging speech-in-nose task using a tonal language remains unclear. The Mandarin Hearing-in-Noise Test (HINT) is a well-established test for assessing the ability to interpret speech in background noise. The current study used Mandarin HINT (MHINT) sentences and functional magnetic resonance imaging (fMRI) to assess brain activation with MHINT sentences.

Methods

Thirty native Mandarin-speaking subjects with normal peripheral hearing were recruited. Functional MRI was performed while subjects were presented with either HINT “clear” sentences with low-level background noise [signal-to-noise ratio (SNR) = +3 dB] or “noisy” sentences with high-level background noise (SNR = −5 dB). Subjects were instructed to answer with a button press whether a visually presented target word was included in the sentence. Brain activation between noisy and clear sentences was compared. Activation in each condition was also compared to a resting, no sentence presentation, condition.

Results

Noisy sentence comprehension showed increased activity in areas associated with tone processing and working memory, including the right superior and middle frontal gyri [Brodmann Areas (BAs) 46, 10]. Reduced activity with noisy sentences was seen in auditory, language, memory and somatosensory areas, including the bilateral superior and middle temporal gyri, left Heschl’s gyrus (BAs 21, 22), right temporal pole (BA 38), bilateral amygdala-hippocampus junction, and parahippocampal gyrus (BAs 28, 35), left inferior parietal lobule extending to left postcentral gyrus (BAs 2, 40), and left putamen.

Conclusion

Increased frontal activation in the right hemisphere occurred when comprehending noisy spoken sentences in Mandarin. Compared to studies using non-tonal languages, this activation was strongly right-sided and involved subregions not previously reported. These findings may reflect additional effort in lexical tone perception in this tonal language. Additionally, this continuous fMRI protocol may offer a time-efficient way to assess group differences in brain activation with a challenging speech-in-noise task.