Construction and evaluation of the Mandarin Chinese matrix (CMNmatrix) sentence test for the assessment of speech recognition in noise

Abstract

Objective: Development of the Mandarin Chinese matrix (CMNmatrix) sentence test for speech intelligibility measurements in noise according to the international standard procedure.

Design: A 50-word base matrix representing the distribution of phonemes and lexical tones of spoken Mandarin was established. Hundred sentences capturing all the co-articulations of two consecutive words were recorded. Word-specific speech recognition functions, speech reception thresholds (SRT: signal-to-noise ratio (SNR), that provides 50% speech intelligibility) and slopes were obtained from measurements at fixed SNRs. The speech material was homogenised in intelligibility by applying level corrections up to ± 2?dB. Subsequently, the CMNmatrix test was evaluated, the comparability of test lists was measured at two fixed SNRs. To investigate the training effect and establish the reference data, speech recognition was measured adaptively.

Study sample: Overall, the study sample contained 80 normal-hearing native Mandarin-speaking listeners.

Results: Multi-centre evaluation measurements confirmed that test lists are equivalent in intelligibility, with a mean SRT of ?10.1?±?0.1?dB SNR and a slope of 13.1?±?0.9 %/dB. The reference SRT is ?9.3?±?0.8 and ?11.2?±?1.2?dB SNR for the open- and closed-set response format, respectively.

Conclusion: The CMNmatrix test is suitable for accurate and internationally comparable speech recognition measurements in noise.     

噪声下言语识别速测表（Quick SIN）普通话版的编制

目的编制普通话版的噪声下言语识别速测表（QuickSpeech-In-Noise,Quick SIN）并进行等价性筛选。方法从嘈杂语噪声下的普通话儿童短句库中抽取90个句子组成15张噪声下旬表。每张表6句话,每句包含5个关键词,表中各句的信噪比依次为＋15,＋10,＋5,0,-5,-10dB。选择15名18～25岁听力正常人为受试者,每位受试者依次测试15张表,计算各自的信噪比损失。对15张句表的信噪比损失进行单因素方差分析,并使用TukeyHSD检验进行表间两两比较和等价性分析。结果15名受试者的信噪比损失为（0．84±1．77）dB。经统计学分析,15张句表中有12张表相互等价,表5、8、14不等价。单侧80％医学参考值范围是小于＋2．32dB,95％医学参考值范围是小于＋3。74dB。结论普通话版的Ouick SIN为临床提供了一种简单、快捷地评价患者在噪声下言语识别能力的测听方法,并为助听装置的选配提供了客观依据。     

Development of the Russian matrix sentence test

Objective: To develop the Russian matrix sentence test for speech intelligibility measurements in noise. Design: Test development included recordings, optimization of speech material, and evaluation to investigate the equivalency of the test lists and training. For each of the 500 test items, the speech intelligibility function, speech reception threshold (SRT: signal-to-noise ratio, SNR, that provides 50% speech intelligibility), and slope was obtained. The speech material was homogenized by applying level corrections. In evaluation measurements, speech intelligibility was measured at two fixed SNRs to compare list-specific intelligibility functions. To investigate the training effect and establish reference data, speech intelligibility was measured adaptively. Study sample: Overall, 77 normal-hearing native Russian listeners. Results: The optimization procedure decreased the spread in SRTs across words from 2.8 to 0.6 dB. Evaluation measurements confirmed that the 16 test lists were equivalent, with a mean SRT of ? 9.5 ± 0.2 dB and a slope of 13.8 ± 1.6%/dB. The reference SRT, ? 8.8 ± 0.8 dB for the open-set and ? 9.4 ± 0.8 dB for the closed-set format, increased slightly for noise levels above 75 dB SPL. Conclusions: The Russian matrix sentence test is suitable for accurate and reliable speech intelligibility measurements in noise.     

Talker- and language-specific effects on speech intelligibility in noise assessed with bilingual talkers: Which language is more robust against noise and reverberation?

Objective: Investigate talker- and language-specific aspects of speech intelligibility in noise and reverberation using highly comparable matrix sentence tests across languages. Design: Matrix sentences spoken by German/Russian and German/Spanish bilingual talkers were recorded. These sentences were used to measure speech reception thresholds (SRTs) with native listeners in the respective languages in different listening conditions (stationary and fluctuating noise, multi-talker babble, reverberated speech-in-noise condition). Study sample: Four German/Russian and four German/Spanish bilingual talkers; 20 native German-speaking, 10 native Russian-speaking, and 10 native Spanish-speaking listeners. Results: Across-talker SRT differences of up to 6 dB were found for both groups of bilinguals. SRTs of German/Russian bilingual talkers were the same in both languages. SRTs of German/Spanish bilingual talkers were higher when they talked in Spanish than when they talked in German. The benefit from listening in the gaps was similar across all languages. The detrimental effect of reverberation was larger for Spanish than for German and Russian. Conclusions: Within the limitations set by the number and slight accentedness of talkers and other possible confounding factors, talker- and test-condition-dependent differences were isolated from the language effect: Russian and German exhibited similar intelligibility in noise and reverberation, whereas Spanish was more impaired in these situations.     

The Norwegian Hearing in Noise Test

Abstract

Objective: The Toy Discrimination Test measures children's ability to discriminate spoken words. Previous assessments of reliability tested children with normal hearing or mild hearing impairment, and most studies used a version of the test without a masking sound. We assessed test-retest reliability for children with hearing impairment using maskers of broadband noise and two-talker babble. Design: Stimuli were presented from a loudspeaker. The signal-to-noise ratio (SNR) was varied adaptively to estimate the speech-reception threshold (SRT) corresponding to 70.7% correct performance. Participants completed each masked condition twice. Study sample: Fifty-five children with permanent hearing impairment participated, aged 3.0 to 6.3 years. Thirty-four children used acoustic hearing aids; 21 children used cochlear implants. Results: For the noise masker, the within-subject standard deviation of SRTs was 2.4 dB, and the correlation between first and second SRT was + 0.73. For the babble masker, corresponding values were 2.7 dB and + 0.60. Reliability was similar for children with hearing aids and children with cochlear implants. Conclusions: The results can inform the interpretation of scores from individual children. If a child completes a condition twice in different listening situations (e.g. aided and unaided), a difference between scores ≥ 7.5 dB would be statistically significant (p <.05).     

嘈杂语噪声下普通话儿童语句测听表的标准化

目的 研究嘈杂语噪声下普通话语句识别测听材料在学龄前儿童言语测听中的效度、信度和敏感度指标,并分析年龄、性别因素对测听结果的影响.方法 招募54名北京市4～6岁听力言语正常儿童(分成4.0～、4.5～、5.0～6.0岁三组,每组18名,男女各半),应用27张中文嘈杂语噪声下普通话语句识别表,采用随机区组裂区设计,在幼儿园简易声场(本底噪声＜40 dB A)在SNR=+1、-2、-5 dB三种条件下由同一扬声器播放语句(强度固定为65 dB SPL)和噪声,由儿童复述所听到的语句,逐一计算各表的言语识别率.结果 ①多种信噪比下的识别率得分在各表之间的差异无统计学意义;②各表对学龄前儿童的识别率(performance)-信噪比(SNR)函数显示,SNR50阈值为-1.96±0.19 dB SNR,斜率为15.8%±1.1%/dB;③各表得分经"合理化的"反正弦变换,推定在95%置信度下的临界差值(critical difference,CD)为24.6%;④4～4.5岁儿童与另两组儿童之间的得分差异有统计学意义(P=0.000 000),另二组儿童之间的得分差异无统计学意义(P=0.895 199).男女之间的差异也有统计学意义(P=0.000 000).结论 ①27张中文嘈杂语噪声下的普通话语句识别表,对学龄前儿童彼此等价;②学龄前儿童50%语句识别率所对应的SNR50接近-2 dB,测试的敏感度为15.8%/dB,均低于成人水平;③男女儿童在噪声下的语句识别能力虽略有差异,但远小于信度指标所对应的24.6%的临界差值;④每表测试时间仅1.5分钟,适用于4.5岁以上的城市儿童.     

An Italian matrix sentence test for the evaluation of speech intelligibility in noise

Objective: Development of an Italian matrix sentence test for the assessment of speech intelligibility in noise. Design: The development of the test included the selection, recording, optimization with level adjustment, and evaluation of speech material. The training effect was assessed adaptively during the evaluation measurements with six lists of 20 sentences, using open- and closed-set response formats. Reference data were established for normal-hearing listeners with adaptive measurements. Equivalence of the test lists was investigated using the open-set response format at three signal-to-noise ratios (SNRs). Study sample: A total of 55 normal-hearing Italian mother-tongue listeners. Results: The evaluation measurements at fixed SNRs resulted in a mean speech reception threshold (SRT) of ? 7.3 ± 0.2 dB SNR and slope of 13.3 ± 1.2 %/dB. The major training effect of 1.5 dB was observed for the first two consecutive measurements. Mean SRTs of ? 6.7 ± 0.7 dB SNR and ? 7.4 ± 0.7 dB SNR were found from the third to the sixth adaptive measurement for open- and closed-set test response formats, respectively. Conclusions: A good agreement has been found between the SRTs and slope and those of other matrix tests. Since sentences are difficult to memorize, the Italian matrix test is suitable for repeated measurements.     

Results using the OPAL strategy in Mandarin speaking cochlear implant recipients

Abstract

Objective: To evaluate the effectiveness of an experimental pitch-coding strategy for improving recognition of Mandarin lexical tone in cochlear implant (CI) recipients. Design: Adult CI recipients were tested on recognition of Mandarin tones in quiet and speech-shaped noise at a signal-to-noise ratio of?+10?dB; Mandarin sentence speech-reception threshold (SRT) in speech-shaped noise; and pitch discrimination of synthetic complex-harmonic tones in quiet. Two versions of the experimental strategy were examined: (OPAL) linear (1:1) mapping of fundamental frequency (F0) to the coded modulation rate; and (OPAL+) transposed mapping of high F0s to a lower coded rate. Outcomes were compared to results using the clinical ACE? strategy. Study sample: Five Mandarin speaking users of Nucleus® cochlear implants. Results: A small but significant benefit in recognition of lexical tones was observed using OPAL compared to ACE in noise, but not in quiet, and not for OPAL+?compared to ACE or OPAL in quiet or noise. Sentence SRTs were significantly better using OPAL+?and comparable using OPAL to those using ACE. No differences in pitch discrimination thresholds were observed across strategies. Conclusions: OPAL can provide benefits to Mandarin lexical tone recognition in moderately noisy conditions and preserve perception of Mandarin sentences in challenging noise conditions.     

普通话快速噪声下言语测听材料的等价性评估

目的开发一套标准的普通话版快速噪声下言语测听材料,评估依据听力学要求和语言学特征选取的300个语句材料的等价性,并获得其在50%正确识别时所对应的信噪比(记为SNR-50)的正常值。方法首先将这些语句材料按照数字化录制原则录制为女声音频材料,背景噪声为4人同时谈话的言语噪声。言语声和噪声混合在一起。选取30例正常受试者,采用听说复述方式,分别在+6、+3、0、-3、-6 dB信噪比条件下测试。对测试所得结果使用SPSS17.0统计软件进行数据分析和强度-识别率函数曲线的拟合。结果 300个语句在噪声环境下测试结果分析显示,斜率和阈值不呈正态分布。剔除斜率过大(>0.72)的语句,及曲线拟合相关系数过小(r<0.7)的语句,精选出等价性较好的78句。后者呈正态分布。结论经过对300个语句的等价性评估,经过严格的筛选及精细调整,最终保留的78个语句在正常人中的等价性较好,下一步可进行这些语句复测信度的测试。     

Development of a Dutch matrix sentence test to assess speech intelligibility in noise

Abstract

Objective: A Dutch matrix sentence test was developed and evaluated. A matrix test is a speech-in-noise test based on a closed speech corpus of sentences derived from words from fixed categories. An example is “Mark gives five large flowers.” Design: This report consists of the development of the speech test and a multi-center evaluation. Study sample: Forty-five normal-hearing participants. Results: The developed matrix test has a speech reception threshold in stationary noise of ? 8.4 dB with an inter-list standard deviation of 0.2 dB. The slope of the intelligibility function is 10.2 %/dB and this is slightly lower than that of similar tests in other languages (12.6 to 17.1 %/dB). Conclusions: The matrix test is now also available in Dutch and can be used in both Flanders and the Netherlands.     

Development of a Danish speech intelligibility test

A Danish speech intelligibility test for assessing the speech recognition threshold in noise (SRT_N) has been developed. The test consists of 180 sentences distributed in 18 phonetically balanced lists. The sentences are based on an open word-set and represent everyday language. The sentences were equalized with respect to intelligibility to ensure uniform SRT_N assessments with all lists. In contrast to several previously developed tests such as the hearing in noise test (HINT) where the equalization is based on scored (objective) measures of word intelligibility, the present test used an equalization method based on subjective assessments of the sentences. The new equalization method is shown to create lists with less variance between the SRT_Ns than the traditional method. The number of sentence levels included in the SRT_N calculation was also evaluated and differs from previous tests. The test was verified with 14 normal-hearing listeners; the overall SRT_N lies at a signal-to-noise ratio of ?3.15 dB with a standard deviation of 1.0 dB. The list-SRT_Ns deviate less than 0.5 dB from the overall mean.     

Lexical tone recognition in noise in normal-hearing children and prelingually deafened children with cochlear implants

Abstract

Objective: The purpose of the present study was to investigate Mandarin tone recognition in background noise in children with cochlear implants (CIs), and to examine the potential factors contributing to their performance. Design: Tone recognition was tested using a two-alternative forced-choice paradigm in various signal-to-noise ratio (SNR) conditions (i.e. quiet,?+12,?+6, 0, and ?6?dB). Linear correlation analysis was performed to examine possible relationships between the tone-recognition performance of the CI children and the demographic factors. Study sample: Sixty-six prelingually deafened children with CIs and 52 normal-hearing (NH) children as controls participated in the study. Results: Children with CIs showed an overall poorer tone-recognition performance and were more susceptible to noise than their NH peers. Tone confusions between Mandarin tone 2 and tone 3 were most prominent in both CI and NH children except for in the poorest SNR conditions. Age at implantation was significantly correlated with tone-recognition performance of the CI children in noise. Conclusions: There is a marked deficit in tone recognition in prelingually deafened children with CIs, particularly in noise listening conditions. While factors that contribute to the large individual differences are still elusive, early implantation could be beneficial to tone development in pediatric CI users.     

Development and evaluation of the Turkish matrix sentence test

Objectives: The Turkish matrix sentence test, TURMatrix, was developed for precise, internationally comparable speech intelligibility testing. Design: The TURMatrix comprises a base matrix of ten well-known Turkish names, numbers, adjectives, objects, verbs, from which syntactically fixed sentences were randomly composed. Test conduction may be in an open-set (standard), or closed-set response format. Homogeneity in intelligibility of the test material was optimized by applying level adaptations (maximal ± 3 dB) based on word-specific speech reception thresholds (SRTs). Test list equivalence was verified and reference values were determined. Study sample: Thirty-eight native listeners of Turkish with normal hearing. Results: After training, mean SRT and slope of the final test lists were ? 8.3 ± 0.2 dB SNR and 14.1 ± 1.0%/dB, respectively (fixed SNR measurements; inter-list variability). For adaptive measurements, average across listeners was ? 7.2 ± 0.7 dB SNR in the open-set and ? 7.9 ± 0.7 dB SNR in the closed-set response format. Mean SRT for adaptive measurements in the open-set response format in quiet was 20.3 ± 4.1 dB. Individual SRTs in quiet correlated more closely with audiograms than with SRTs in noise. Conclusions: The TURMatrix was developed according to European standards and provides reliable speech intelligibility measurements in noise and quiet.     

Callsign Acquisition Test (CAT): speech intelligibility in noise

OBJECTIVE: The study was designed to assess the effects of noise on the intelligibility of speech elements used in the Callsign Acquisition Test (CAT), developed by the U.S. Army Research Laboratory. The CAT consists of 126 test items, or callsigns, each of which is made up of a two-syllable word selected from the 18-item military alphabet (Alpha-Zulu) followed by a one-syllable number (all numbers from 1 to 8, excluding 7). DESIGN: The CAT items were mixed with one of three different types of background noises (pink noise, white noise, and multitalker babble) and presented to 18 listeners. Speech-to-noise ratio for all three noises and the overall level of pink noise were varied in two separate experiments to determine how these variables affected speech intelligibility of the CAT items pronounced by a male talker. CONCLUSIONS: Test results demonstrate speech-to-noise ratio has a significant effect on speech intelligibility of the CAT items under all conditions. Pink noise generated the lowest speech intelligibility scores followed by multitalker babble and then white noise. A change in the overall level of pink noise had only small effect on CAT intelligibility.     

Speech intelligibility of virtual humans

Abstract

The speech intelligibility benefit of visual speech cues during oral communication is well-established. Therefore, an ecologically valid approach of auditory assessment should include the processing of both auditory and visual speech cues. This study describes the development and evaluation of a virtual human speaker designed to present speech auditory-visually. A male and female virtual human speaker were created and evaluated in two experiments: a visual-only speech reading test of words and sentences and an auditory-visual speech intelligibility sentence test. A group of five hearing, skilled speech reading adults participated in the speech reading test whereas a group of young normal-hearing participants (N?=?35) was recruited for the intelligibility test. Skilled speech readers correctly identified 57 to 67% of the words and sentences uttered by the virtual speakers. The presence of the virtual speaker improved the speech intelligibility of sentences in noise by 1.5 to 2?dB. These results demonstrate the potential applicability of virtual humans in future auditory-visual speech assessment paradigms.     

Development of the Listening in Spatialized Noise-Sentences Test (LISN-S)

OBJECTIVE: The goals of this research were to develop and evaluate a new version of the Listening in Spatialized Noise Test (LISN; Cameron Dillon & Newall, 2006a) by incorporating a simplified and more objective response protocol to make the test suitable for assessing the ability of children as young as 5 yr to understand speech in background noise. The LISN-Sentences test (LISN-S; Cameron & Dillon, Reference Note 1) produces a three-dimensional auditory environment under headphones and is presented by using a personal computer. A simple repetition response protocol is used to determine speech reception thresholds (SRTs) for sentences presented in competing speech under various conditions. In four LISN-S conditions, the maskers are manipulated with respect to location (0 degrees versus +/-90 degrees azimuth) and vocal quality of the speaker(s) of the stories (same as, or different than, the speaker of the target sentences). Performance is measured as two SRT measures and three "advantage" measures. These advantage measures represent the benefit in decibels gained when either talker, spatial, or both talker and spatial cues combined, are incorporated in the maskers. This use of difference scores minimizes the effects of between-listener variation in factors such as linguistic skills and general cognitive ability on LISN-S performance. DESIGN: An initial experiment was conducted to determine the relative intelligibility of the sentences used in the test. Up to 30 sentences were presented adaptively to 24 children ages 8 to 9 yr to estimate the SRT (eSRT). Fifty sentences each were then presented at each participant's eSRT, eSRT +2 dB, and eSRT -2 dB. Psychometric functions were fitted and the sentences were adjusted in amplitude for equal intelligibility. After adjustment, intelligibility increased across sentences by approximately 17% for each 1 dB increase in signal-to-noise ratio (SNR). A second experiment was conducted to gather normative data on the LISN-S from 82 children with normal hearing, ages 5 to 11 yr. RESULTS: For the 82 children in the normative data study, regression analysis showed that there was a strong trend of decreasing SRT and increasing advantage as age increased across all LISN-S performance measures. Analysis of variance revealed that significant differences in performance were most pronounced between the 5-yr-olds and the other age groups on the LISN-S measures that assess the ability to use spatial cues to understand speech in background noise, suggesting that binaural processing skills are still developing at age 5 yr. Inter-participant variation in performance on the various SRT and advantage measures was minimal for all groups, including the 5- and 6-yr-olds who exhibited standard deviations ranging from only 1.0 dB to 1.8 dB across measures. The intra-participant standard error ranged from 0.6 dB to 2.0 dB across age groups and conditions. Total time taken to administer all four LISN-S conditions was on average 12 minutes. CONCLUSIONS: The LISN-S provides a quick, objective method of measuring a child's ability to understand speech in background noise. The small degree of inter- and intra-participant variation in the 5- and 6-yr-old children suggests that the test is capable of assessing auditory processing in this age group. However, because there appears to be a strong developmental curve in binaural processing skills in the 5-yr-olds, it is suggested that the LISN-S be used clinically with children from 6 yr of age. Cut-off scores, calculated as 2 standard deviations below the mean adjusted for age, were calculated for each performance measure for children ages 6 to 11 yr. These scores, which represent the level below which performance on the LISN-S is considered to be outside normal limits, will be used to in future studies with children with suspected central auditory processing disorder.     

Avoiding disconnection: An evaluation of telephone options for cochlear implant users

Objective: The primary aim of this study was to evaluate the effect of coupling method on telephone-based speech recognition and perceived listening difficulty in noise for cochlear implant (CI) users. A secondary aim was to evaluate potential impacts of additional processing modifications within coupling conditions, such as activating noise reducing algorithms or muting environmental microphones.

Design: Hochmair–Schulz–Moser sentences were bandpass-filtered (300–3400?Hz) and presented unilaterally either via telephone handset or advanced wireless streaming device in a background of cafeteria babble (signal-to-noise ratio =15?dB). Sentence recognition was scored at the word level and perceived listening difficulty was assessed via visual-analogue scale for each of five test conditions. Study sample: Twenty native German-speaking CI users participated. Results: Repeated measures analysis of variance revealed coupling via advanced streaming significantly improved sentence recognition and reduced listening difficulty, when compared to either telecoil or acoustic coupling configurations. In addition, program modifications further increased benefit within a coupling condition. CI users who exhibited the most difficulty during basic acoustic coupling were most likely to benefit from advanced wireless streaming. Conclusion: CI users have several options for improving speech recognition and decreasing listening difficulty over the telephone when listening in noisy environments.     

Speech audiometry in noise: Development of the French-language VRB (vocale rapide dans le bruit) test

IntroductionUnderstanding speech in noise is a major challenge for most hearing-impaired subjects, with or without hearing aids. To overcome the weaknesses of French-language speech-in-noise tests, we developed a new instrument, with a balanced mix of difficulty of the speech material.Material and methodsThe speech material comprised 127 sentences taken from the “Marginal Benefit from Acoustic Amplification” (MBAA) corpus, each including 3 keywords. The noise was created using the “onde vocale globale” (global vocal wave: OVG), described by Dodelé. The 127 speech/noise pairs were recorded individually after root-mean-square equalization. The first experiment, on 10 normal-hearing adults, determined the signal-to-noise ratio (SNR) associated with 50% correct keyword identification in each sentence (SNR-50), using an ascending method with noise level set at 73 dB SPL. Relative levels between sentences and noise were then adjusted sentence by sentence to achieve an SNR-50 of 0 dB. The second experiment, with 12 normal-hearing adults, validated the equalization of sentence difficulty.ResultsMean SNR-50 was −6.64 dB (σ = 1.47). Mean adjusted SNR-50 was 0.08 dB (σ = 0.55). Mean psychometric curve slope was 19.3%/dB, with low standard deviations, testifying to the sensitivity of the speech material.ConclusionThe VRB (vocale rapide dans le bruit: rapid speech in noise) test is based on sentences from the MBAA corpus with background noise based on the OVG at different signal-to-noise ratios. The test is feasible and able to detect slight variations in speech-in-noise performance between subjects.     

Design,optimization and evaluation of a Danish sentence test in noise

The Danish sentence test DANTALE II was developed in analogy to the Swedish sentence test by Hagerman and the German Oldenburg sentence test as a new Danish sentence test in noise to determine the speech reception threshold in noise (SRT, i.e. the signal-to-noise ratio (SNR) that yields 500% intelligibility). Each sentence is generated by a random combination of the alternatives of a base list. This base list consists of 10 sentences with the same syntactical structure (name, verb, numeral, adjective, object). The test sentences were recorded and segmented in such a way that the coarticulation effects were taken into account in order to achieve a high perceived sound quality of the resynthesized sentences: 100 sentences were recorded, each coarticulation between each word and the 10 possible following word alternatives were recorded, and the correct coarticulation was used to generate the test sentences. Word-specific speech recognition curves were measured for each recorded word to optimize the homogeneity of the speech material and the measurement accuracy. Level corrections of particular words and a careful selection of the test lists produced a noticeable reduction in the variation in the distribution of word-specific SRT (standard deviation 1.75 dB instead of 3.78 dB). Therefore, the slope of the total intelligibility function was expected to increase from 8.30%/dB (raw test material) to 13.2%/dB (after modification). These theoretical expectations were evaluated by independent measurements with normal-hearing subjects, and, for the most part, confirmed. The reference data for the DANTALE II are: SRT=-8.43 dB SNR; slope at SRT, s50 = 13.2%/dB. The training effect was 2.2 dB and could be reduced to less than 1 dB if two training lists of 20 sentences were performed prior to data collection.     

Validation of list equivalency for Mandarin speech materials to use with cochlear implant listeners

Abstract

Objectives: Speech materials validated with normal-hearing listeners may not be appropriate for clinical assessment of cochlear implant (CI) users. The aim of this study was to validate list equivalency of the Mandarin Speech Perception (MSP) sentences, disyllables, and monosyllables in Mandarin-speaking CI patients. Design: Recognition of MSP sentences, disyllables, and monosyllables each were measured for all 10 lists. Study sample: 67 adult and 32 pediatric Mandarin-speaking CI users. Results: There was no significant difference between adult and pediatric subject groups for all test materials. Significant differences were observed among lists within each test. After removing one or two lists within each test, no significant differences were observed among the remaining lists. While there was equal variance among lists within a given test, the variance was larger for children than for adults, and increased from monosyllables to disyllables to sentences. Conclusions: Some adjustment to test lists previously validated with CI simulations was needed to create perceptually equivalent lists for real CI users, suggesting that test materials should be validated in the targeted population. Differences in mean scores and variance across test materials suggest that CI users may differ in their ability to make use of contextual cues available in sentences and disyllables.