Pitch perception and frequency-following responses elicited by lexical-tone chimeras

Objective: Previous research has shown the usefulness of utilizing auditory chimeras in assessing a listener’s perception of the envelope and fine structure for an acoustic stimulus. However, research comparing and contrasting behavioral and electrophysiological responses to this stimulus type is scarce. Design: Two sets of chimeric stimuli were constructed by interchanging the envelopes and fine-structures of the rising/yi²/and falling/yi⁴/Mandarin pitch contours that were filtered through 1, 2, 4, 8, 16, 32, and 64 frequency banks. Behavioral pitch-perception tasks were administered through a two-alternative, forced-choice paradigm. Electrophysiological responses were measured through scalp-recorded frequency-following responses (FFRs) to the lexical-tone chimeras. Study sample: Twenty American and twenty Chinese adults were recruited. Results: A two-way analysis of variance showed significance (p?<?0.05) within and across the filter bank and language background factors for the behavioral measurements, while the frequency-following response demonstrated a significance only across the filter banks. Conclusions: Perceptual importance of envelope cues increases starting from 16 filter banks, while the FFR accuracy and magnitude decreases with increasing number of filter banks. These results can be useful in assessing experience-dependent neuroplasticity and in designing speech processing strategies for cochlear-implant users who speak tonal or non-tonal languages around the globe.     

The effect of non-native and non-regional speech testing on a multi-lingual population

Objective: This study was conducted to evaluate the speech perception of Malaysian Chinese adults using the Taiwanese Mandarin HINT (MHINT-T) and the Malay HINT (MyHINT). Design: The MHINT-T and the MyHINT were presented in quiet and noise (front, right and left) conditions under headphones. Results for the two tests were compared with each other and with the norms for each test. Study sample: Malaysian Chinese native speakers of Mandarin (N?=?58), 18–31 years of age with normal hearing. Results: On average, subjects demonstrated poorer speech perception ability than the normative samples for these tests. Repeated measures ANOVA showed that speech reception thresholds (SRTs) were slightly poorer on the MHINT-T than on the MyHINT for all test conditions. However, normalized SRTs were poorer by 0.6 standard deviations for MyHINT as compared with MHINT-T. Conclusions: MyHINT and MHINT-T can be used as norm-referenced speech perception measures for Mandarin-speaking Chinese in Malaysia.     

Continuous improvement in Mandarin lexical tone perception as the number of channels increased: a simulation study of cochlear implant

CONCLUSION: With reference to English phoneme recognition, where performance usually does not improve after six or eight channels in cochlear implants (CIs), increasing total channel numbers continuously improved perception of Mandarin tones. OBJECTIVE: To test our hypothesis that current CI strategies might be modified to improve Mandarin lexical tonal perception. MATERIALS AND METHODS: Lexical tonal perception tests using 48 monosyllables in Mandarin Chinese were conducted in 32 native Mandarin speakers with normal hearing. The performance of tonal perception was compared among the controlled factors, which were total channel number, number of channels allocated to the F0 spectrum, and whether there were spectral shifts in the electrode configuration. The experimental condition that preserves fine structure was used as a comparison. RESULTS: The signal processing strategy using 16 channels--which is technically possible with current CI devices--produced better tonal perception than those using 12 or 8 channels. Increasing the number of fundamental channels did not improve tonal perception, and spectral shifts did not change tonal perception. An experimental condition (FiC12) that preserves the fine structure produced significantly better overall scores for tone perception than other experimental conditions with envelope strategies.     

Factors affecting the Mandarin dichotic digits test

Abstract

Objective: Data with regard to the Mandarin dichotic digits test (DDT) are limited, with conflicting results reported between the Mandarin and English DDTs. The current study examined factors that might affect the performance in the Mandarin DDT.

Design: The digits were arranged in 3 sets of 20 dichotic pairs; each set comprised 2, 3 or 4 digits in a pair.

Study sample: Forty-one young, native Mandarin speakers with normal hearing were tested; 30 of them were right-handed and 11 left-handed. Six participants repeated the test.

Results: The prevalence of ceiling effect in recognition score decreased systematically as the digit-pair length increased. At digit sets of 3-pair and 4-pair, the right-handed group showed a significant higher recognition score at right ear than left ear, while the left-handed group reversed the performance. The score difference between ears is significantly different between the right- and left-handed groups. The retest of the Mandarin DDT was reliable.

Conclusions: For the right-handed group, a right-ear advantage can exist in the Mandarin DDT at a longer digit-pair length, similar to what was reported in the English DDT. Moreover, for the left-handed group, the attended right hemisphere in processing the tonal digits can result in a left-ear advantage.     

Production of Mandarin Tone by Adults and Children with Normal Hearing: Significance for Children with Cochlear Implants

Mandarin Chinese is a tone language in which pitch variations are used to change the meanings of words. This study focused on the production of the four tones of Mandarin by adults and eight-year-old children with normal hearing, who spoke Mandarin as their first language. All speakers were recorded producing the tones in the syllable [ma]. Analysis of the speakers' productions of the four tones in [ma] showed that all of the children were able to produce the appropriate tonal contrasts. Some differences between the children and adult speakers were found in the duration of the tones. These data represent a benchmark against which the speech of children with implants can be compared.     

Contributions of language and memory demands to verbal memory performance in language-learning disabilities

The purpose of this study is to investigate the performance of adults with language-based learning disorders (L/LD) and normal language controls on verbal short-term and verbal working memory tasks. Eighteen adults with L/LD and 18 normal language controls were compared on verbal short-term memory and verbal working memory tasks under low, moderate, and high linguistic processing loads. Results indicate no significant group differences on all verbal short-term memory tasks and verbal working memory tasks with low and moderate language loads. Statistically significant group differences were found on the most taxing condition, the verbal working memory task involving high language processing load. The L/LD group performed significantly worse than the control group on both the processing and storage components of this task. These results support the limited capacity hypothesis for adults with L/LD. Rather than presenting with a uniform impairment in verbal memory, they exhibit verbal memory deficits only when their capacity limitations are exceeded under relatively high combined memory and language processing demands.Educational Objectives: The reader will (1) understand the relationship between increased linguistic demands and working memory, and (2) learn about working memory skills in adults with language learning disorders.     

Production of Mandarin tone by adults and children with normal hearing: significance for children with cochlear implants

Mandarin Chinese is a tone language in which pitch variations are used to change the meanings of words. This study focused on the production of the four tones of Mandarin by adults and eight-year-old children with normal hearing, who spoke Mandarin as their first language. All speakers were recorded producing the tones in the syllable [ma]. Analysis of the speakers' productions of the four tones in [ma] showed that all of the children were able to produce the appropriate tonal contrasts. Some differences between the children and adult speakers were found in the duration of the tones. These data represent a benchmark against which the speech of children with implants can be compared.     

时域和频域信息对汉语普通话声调识别的影响

目的通过探讨时域和频域信息对听力正常人声调识别的影响,试图为人工耳蜗汉语言语编码策略的编制提供理论依据.方法共有13名听力正常人参加本次研究,均以普通话作为日常交流方式.测试材料使用美国Ohio大学提供的声调识别测试系统.测试系统包含10组测试词.每组测试词的声、韵母相同而声调不同.将上述测试词录制成原始声音文件.采用声码器技术处理录制的原始声音.将决定时域信息的低通滤波器的截止频率设为1、2、4、8、16、32、64、128、256和512 Hz,共10种;将决定频域信息的通道数设为1、2、4、6、8、12、16和20,共8种.经不同的排列组合,共产生6400个处理后的声音文件.测试在标准隔声室内进行.测试声音通过扬声器发出,强度为65 dB SPL.声音的发出和成绩的记录均由Matlab软件自动完成.结果听力正常人的声调识别得分随着低通滤波的截止频率和通道数的增加而增加.当低通滤波的截止频率在2 Hz以下时,是否增加通道数对声调识别得分基本没有影响.当通道数在2以下时,是否增加低通滤波的截止频率对声调识别得分基本没有影响.结论听力正常人的声调识别与时域和频域信息均相关.时域信息和频域信息在听力正常人的声调识别中的作用是协同的.     

普通话噪声下言语测试在方言人群中的应用

目的:使用普通话版噪声下言语测试材料(mandarinhearinginnoisetest,MHINT),得到听力正常不同方言人群的MHINT测试结果。方法:选择听力正常、母语非普通话受试者82名完成MHINT测试。结果进行统计学分析,并与母语普通话结果进行比较。结果:得到母语非普通话82名受试者的328个结果。母语非普通话受试者和母语普通话受试者之间在安静环境,噪声方位0°、90°、270°的测试结果均差异有统计学意义(均P<0.01);母语非普通话高学历受试者与母语非普通话低学历受试者之间结果差异有统计学意义(P<0.01)。母语非普通话受试者按年龄、讲普通话时间等因素之间测试结果差异无统计学意义(P>0.05)。结论:母语非普通话人群进行MHINT测试,与母语普通话人群相比需要更高的言语信号声和信噪比。影响MHINT测试结果的因素有受试者母语是否为普通话以及受试者的文化水平。     

Development of equally intelligible Telugu sentence-lists to test speech recognition in noise

Objective: To develop sentence lists in the Telugu language for the assessment of speech recognition threshold (SRT) in the presence of background noise through identification of the mean signal-to-noise ratio required to attain a 50% sentence recognition score (SRTn). Design: This study was conducted in three phases. The first phase involved the selection and recording of Telugu sentences. In the second phase, 20 lists, each consisting of 10 sentences with equal intelligibility, were formulated using a numerical optimisation procedure. In the third phase, the SRTn of the developed lists was estimated using adaptive procedures on individuals with normal hearing. Study sample: A total of 68 native Telugu speakers with normal hearing participated in the study. Of these, 18 (including the speakers) performed on various subjective measures in first phase, 20 performed on sentence/word recognition in noise for second phase and 30 participated in the list equivalency procedures in third phase. Results: In all, 15 lists of comparable difficulty were formulated as test material. The mean SRTn across these lists corresponded to ?2.74 (SD?=?0.21). Conclusions: The developed sentence lists provided a valid and reliable tool to measure SRTn in Telugu native speakers.     

The perception of FM sweeps by Chinese and English listeners

Frequency-modulated (FM) signals are an integral acoustic component of ecologically natural sounds and are analyzed effectively in the auditory systems of humans and animals. Linearly frequency-modulated tone sweeps were used here to evaluate two questions. First, how rapid a sweep can listeners accurately perceive? Second, is there an effect of native language insofar as the language (phonology) is differentially associated with processing of FM signals? Speakers of English and Mandarin Chinese were tested to evaluate whether being a speaker of a tone language altered the perceptual identification of non-speech tone sweeps. In two psychophysical studies, we demonstrate that Chinese subjects perform better than English subjects in FM direction identification, but not in an FM discrimination task, in which English and Chinese speakers show similar detection thresholds of approximately 20 ms duration. We suggest that the better FM direction identification in Chinese subjects is related to their experience with FM direction analysis in the tone-language environment, even though supra-segmental tonal variation occurs over a longer time scale. Furthermore, the observed common discrimination temporal threshold across two language groups supports the conjecture that processing auditory signals at durations of approximately 20 ms constitutes a fundamental auditory perceptual threshold.     

Categorical perception of lexical tones in native Mandarin-speaking listeners with sensorineural hearing loss

Background: Categorical perception (CP) of lexical tones was examined in normal hearing (NH) people, but it was unclear whether lexical tones can be perceived categorically in sensorineural hearing loss (SNHL) people.

Objectives: To explore the characteristic of lexical tone perception in native Mandarin speakers with SNHL.

Materials and methods: Three types of continuum (Tone1/Tone2, Tone1/Tone4 and Tone2/Tone3) were constructed and each of them includes 15 stimuli which were resynthesized by applying the pitch-synchronous overlap and add (PSOLA) method implemented in Praat to the same Mandarin syllable, /a/, with a high-level tone produced by a female speaker. Forty native Mandarin NH speakers and 23 native Mandarin speakers with mild to moderate SNHL were recruited. A two alternative-forced-choice identification task was used to acquire the tonal perceptual data.

Results: All tone perception curves owns the characteristic of CP in SNHL subjects. All tone perception curves were S-shape in SNHL subjects same as those in NH subjects. No significant difference of each continuum was observed between SNHL and NH.

Conclusions: CP of lexical tone perception could be observed in native Mandarin speakers with mild to moderate SNHL. The slight damage in the peripheral auditory system did not change characteristic of lexical tone perception.     

The strengths and weaknesses in verbal short-term memory and visual working memory in children with hearing impairment and additional language learning difficulties

Objectives

To compare verbal short-term memory and visual working memory abilities of six children with congenital hearing-impairment identified as having significant language learning difficulties with normative data from typically hearing children using standardized memory assessments.

Methods

Six children with hearing loss aged 8–15 years were assessed on measures of verbal short-term memory (Non-word and word recall) and visual working memory annually over a two year period. All children had cognitive abilities within normal limits and used spoken language as the primary mode of communication. The language assessment scores at the beginning of the study revealed that all six participants exhibited delays of two years or more on standardized assessments of receptive and expressive vocabulary and spoken language.

Results

The children with hearing-impairment scores were significantly higher on the non-word recall task than the “real” word recall task. They also exhibited significantly higher scores on visual working memory than those of the age-matched sample from the standardized memory assessment.

Conclusions

Each of the six participants in this study displayed the same pattern of strengths and weaknesses in verbal short-term memory and visual working memory despite their very different chronological ages. The children’s poor ability to recall single syllable words in relation to non-words is a clinical indicator of their difficulties in verbal short-term memory. However, the children with hearing-impairment do not display generalized processing difficulties and indeed demonstrate strengths in visual working memory. The poor ability to recall words, in combination with difficulties with early word learning may be indicators of children with hearing-impairment who will struggle to develop spoken language equal to that of their normally hearing peers. This early identification has the potential to allow for target specific intervention that may remediate their difficulties.     

Development of a corpus of Mandarin sentences in babble with homogeneity optimized via psychometric evaluation

Abstract

Objective: To develop a corpus of sentences in babble noise that is suitable for Mandarin-speaking children. Two experiments were conducted with specific aims of (1) developing sentence material that is grammatically and semantically within the linguistic abilities of children; and (2) improving the efficiency of the test by equalizing the relative intelligibility of individual items in sentences. Design and Study sample: Sentences were extracted from spoken material of Chinese children aged between 4 and 5 years of age. The sentences were tested for intelligibility in a four-talker babble by 96 adult native speakers of Mandarin. Psychometric functions were generated, and used for adjusting signal-to-noise ratios of individual items by varying the level of the time-locked babble to equate intelligibility of the target speech. These adjusted stimuli were tested for intelligibility using a different group of 64 adult listeners. Results: The signal-to-noise ratio for 50% correct was not different before and after adjustments (? 6.1 dB and ? 6.0 dB, respectively). However, there was a significant reduction in standard deviation from 2.3 dB before adjustment to 1.1 dB after adjustment (p < 0.05). Conclusions: The experiments established a corpus of Mandarin BKB-like sentences with four-talker babble as competing noise, in which the test items’ homogeneity was optimized via psychometric evaluation (HOPE).     

Robust relationship between reading span and speech recognition in noise

Objective: Working memory refers to a cognitive system that manages information processing and temporary storage. Recent work has demonstrated that individual differences in working memory capacity measured using a reading span task are related to ability to recognize speech in noise. In this project, we investigated whether the specific implementation of the reading span task influenced the strength of the relationship between working memory capacity and speech recognition. Design: The relationship between speech recognition and working memory capacity was examined for two different working memory tests that varied in approach, using a within-subject design. Data consisted of audiometric results along with the two different working memory tests; one speech-in-noise test; and a reading comprehension test. Study sample: The test group included 94 older adults with varying hearing loss and 30 younger adults with normal hearing. Results: Listeners with poorer working memory capacity had more difficulty understanding speech in noise after accounting for age and degree of hearing loss. That relationship did not differ significantly between the two different implementations of reading span. Conclusions: Our findings suggest that different implementations of a verbal reading span task do not affect the strength of the relationship between working memory capacity and speech recognition.     

Quantification of the effects of Mandarin dialect differences on the use of norm-referenced speech perception tests

Objective: Determine the effects of Chinese dialects on results for the Mandarin HINT recorded with a talker speaking Standard Mandarin (Putonghua). Design: Normally-hearing subjects with different dialect exposure histories and usage preferences were administered the Mandarin HINT, and results were compared with published norms. Additional published measures of the intelligibility and mutual intelligibility of Chinese dialects were used to identify dialects for which Putonghua is highly intelligible. Study sample: One sample (N = 19) was exposed to a variety of dialects throughout China during childhood, and used Putonghua as adults. A second sample (N = 22) was exposed to Sichuanhua (the dialect found in Sichuan province) during childhood, and used Sichuanhua as adults. Results: The average difference in SRTs for the Putonghua and Sichuanhua groups was 0.66 dB, with the Sichuanhua group's SRTs slightly higher. Means for neither group fell outside the confidence intervals for the norms. Putonghua is intelligible for 98% of Sichuanhua dialect users, and for over 90% of the users of two-thirds of the remaining Chinese regional dialects. Conclusions: Norm-referenced speech perception tests, such as the Mandarin HINT, can be used with speakers of Chinese regional dialects for whom Putonghua is highly intelligible. Small differences in dialect-specific norms are not clinically significant.     

Visuospatial immediate memory in specific language impairment.

PURPOSE: Investigations of the cognitive processes underlying specific language impairment (SLI) have implicated deficits in verbal short-term and working memory and in particular the storage and processing of phonological information. This study investigated short-term and working memory for visuospatial material for a group of children with SLI, to test whether the verbal memory impairments already established extend to the visuospatial domain. METHOD: Fifteen children with SLI and control groups of children matched on chronological age and language age completed tests of visuospatial short-term and working memory. RESULTS: The SLI group performed comparably with age-matched control children on all measures and at a higher level than the language-age control group on several measures. CONCLUSIONS: The visuospatial short-term and working memory abilities were at age-appropriate levels in this SLI group. This contrasts markedly with their impairments on tests of verbal short-term and working memory.     

Tone in Thai alaryngeal speech

The perception and production of linguistic tone was investigated in utterances spoken by Thai alaryngeal speakers. Thai is a tone language with five phonemic tones. High-quality tape recordings of five monosyllabic words produced by 2 esophageal, 1 electrolaryngeal, and 5 normal, native Thai speakers were subjected to perceptual and acoustic analysis. Results from the phonemic identification tests indicated that tones produced by alaryngeal speakers were not only perceived at much lower levels of accuracy than those produced by normal speakers, but the patterns of tonal confusions for alaryngeal speakers were also dissimilar to those for normal speakers. Results from fundamental frequency (Fo) analysis revealed that the performance deficit of alaryngeal speakers could be related to specific characteristics of their Fo contours. Findings are interpreted to highlight the importance of (a) language, (b) type of prosody, (c) form of alaryngeal speech, and (d) Fo level and direction on linguistic assessments of Fo control in alaryngeal speech.     

Perception of pitch contours in single words in alaryngeal speech.

The perception and production of pitch contours were investigated in single words produced by two groups of alaryngeal speakers: tracheo-oesophageal (TE) and oesophageal (E) speakers. High quality tape-recordings of three tonal patterns by four oesophageal and eight tracheo-oesophageal speakers in monosyllabic words were judged by a group of six speech and language therapy listeners. The results indicated that tonal patterns can be produced with a relatively high level of reliability for both speaker groups. Some individual speakers from both groups approached predicted normal levels. These findings emphasise the importance of providing the opportunity for patients to acquire either of these speech modes in alaryngeal rehabilitation, rather than simply being provided with an artificial larynx, particularly in countries where tone languages are used. The high variability between groups also suggests that other variables apart from alaryngeal speech mode may be relevant in determining ability to signal tonal patterns.