言语编码策略升级对成年人工耳蜗使用者听觉效果影响的研究

目的　探讨言语编码策略升级对有经验人工耳蜗使用者听觉效果的影响趋势,以期为临床制定有效的人工耳蜗言语编码策略升级方案提供参考依据。方法　采用噪声下汉语普通话声调识别测试、普通话噪声下言语识别测试以及自行编制的声音质量自评问卷,对13例有经验成年人工耳蜗使用者言语编码策略升级后的声调识别能力、短句分辨能力以及声音质量和聆听感受进行3个月连续观测。以使用日常言语编码策略（即CIS+策略）的测试结果为参考值,以新言语编码策略（即精细结构编码策略）的测试 结果为目标值,分析言语编码策略升级对成年人工耳蜗使用者听觉效果的影响。结果　①声调识别能力：各测试阶段两种编码策略的声调识别测试成绩无显著差异,随着精细结构编码策略使用经验增加,测试成绩呈明显改善趋势[F（3,36）=5.201,P =0.004];②短句分辨能力：各测试阶段两种编码策略的言语识别测试成绩无显著差异,随精细结构编码策略使用经验增加,测试成绩略有提高[F（3,36）=2.450,P =0.079];③声音质量自评：更换言语编码策略对本组受试者的声音质量和聆听感受无不利影响（P =0.083）。随着精细结构编码策略使用经验增加,受试者认为声音质量更“饱满、丰富”、聆听感受更“容易、轻松”。结论　言语编程策略升级未对有经验人工耳蜗使用者的言语识别能力造成不良影响且存在潜在的改善作用。在临床工作中可参考患者主观意愿确定是否升级言语编程策略。     

Comparison of two cochlear implant coding strategies on speech perception

Objective: Assess whether differences in speech perception are observed after exclusive listening experience with high-definition continuous interleaved sampling (HDCIS) versus fine structure processing (FSP) coding strategies.

Methods: Subjects were randomly assigned at initial activation of the external speech processor to receive the HDCIS or FSP coding strategy. Frequency filter assignments were consistent across subjects. The speech perception test battery included CNC words in quiet, HINT sentences in quiet and steady noise (+10?dB SNR), AzBio sentences in quiet and a 10-talker babble (+10?dB SNR), and BKB-SIN. Assessment intervals included 1, 3, and 6 months post-activation.

Results: Data from 22 subjects (11 with HDCIS and 11 with FSP) were assessed over time. Speech perception performance was not significantly different between groups.

Discussion: Speech perception performance was not significantly different after 6 months of listening experience with the HDCIS or FSP coding strategy.     

Speech and music perception with the new fine structure speech coding strategy: preliminary results

Conclusions. Taking into account the excellent results with significant improvements in the speech tests and the very high satisfaction of the patients using the new strategy, this first implementation of a fine structure strategy could offer a new quality of hearing with cochlear implants (CIs). Objective. This study consisted of an intra-individual comparison of speech recognition, music perception and patient preference when subjects used two different speech coding strategies with a MedEl Pulsar CI: continuous interleaved sampling (CIS) and the new fine structure processing (FSP) strategy. In contrast to envelope-based strategies, the FSP strategy also delivers subtle pitch and timing differences of sound to the user and is thereby supposed to enhance speech perception in noise and increase the quality of music perception. Patients and methods. This was a prospective study assessing performance with two different speech coding strategies. The setting was a CI programme at an academic tertiary referral centre. Fourteen post-lingually deaf patients using a MedEl Pulsar CI with a mean CI experience of 0.98 years were supplied with the new FSP speech coding strategy. Subjects consecutively used the two different speech coding strategies. Speech and music tests were performed with the previously fitted CIS strategy, immediately after fitting with the new FSP strategy and 4, 8 and 12 weeks later. The main outcome measures were individual performance and subjective assessment of two different speech processors. Results. Speech and music test scores improved statistically significantly after conversion from CIS to FSP strategy. Twelve of 14 patients preferred the new FSP speech processing strategy over the CIS strategy.     

Fine Structure Processing improves speech perception as well as objective and subjective benefits in pediatric MED-EL COMBI 40+ users

Objectives

Presently, there are only few studies examining the benefits of fine structure information in coding strategies. Against this background, this study aims to assess the objective and subjective performance of children experienced with the C40+ cochlear implant using the CIS+ coding strategy who were upgraded to the OPUS 2 processor using FSP and HDCIS.

Methods

In this prospective study, 60 children with more than 3.5 years of experience with the C40+ cochlear implant were upgraded to the OPUS 2 processor and fit and tested with HDCIS (Interval I). After 3 months of experience with HDCIS, they were fit with the FSP coding strategy (Interval II) and tested with all strategies (FSP, HDCIS, CIS+). After an additional 3-4 months, they were assessed on all three strategies and asked to choose their take-home strategy (Interval III). The children were tested using the Adaptive Auditory Speech Test which measures speech reception threshold (SRT) in quiet and noise at each test interval. The children were also asked to rate on a Visual Analogue Scale their satisfaction and coding strategy preference when listening to speech and a pop song. However, since not all tests could be performed at one single visit, some children were not able complete all tests at all intervals.

Results

At the study endpoint, speech in quiet showed a significant difference in SRT of 1.0 dB between FSP and HDCIS, with FSP performing better. FSP proved a better strategy compared with CIS+, showing lower SRT results of 5.2 dB. Speech in noise tests showed FSP to be significantly better than CIS+ by 0.7 dB, and HDCIS to be significantly better than CIS+ by 0.8 dB. Both satisfaction and coding strategy preference ratings also revealed that FSP and HDCIS strategies were better than CIS+ strategy when listening to speech and music. FSP was better than HDCIS when listening to speech.

Conclusions

This study demonstrates that long-term pediatric users of the COMBI 40+ are able to upgrade to a newer processor and coding strategy without compromising their listening performance and even improving their performance with FSP after a short time of experience.     

Tone identification in Mandarin-speaking children with profound hearing impairment

ObjectivesLittle is known about the tone identification ability of Mandarin-speaking children with profound hearing impairment (HI) and fitted with hearing aids (HAs). The present study aimed to evaluate the Mandarin tone identification ability in children with profound HI and fitted with HAs, and explore the effects of hearing thresholds, the age of first HA fitting and the duration of HA use on Mandarin tone identification ability.MethodsSubjects were Mandarin-speaking children aged 5;4–12;6 years with profound HI (n = 41). The Mandarin Tone Identification Test was administered in five test conditions: in −10, −5, 0 and 5 dB signal-to-noise ratios (S/Ns) and quiet. Hearing aids were in the usual user's settings, optimized for the best speech reception, and the volume was set to comfortable listening level.ResultsTwo-way repeated measures ANOVA showed significant effects of test conditions and tone contrasts in Mandarin tone identification. Post-hoc pairwise comparisons showed significant difference in performance among the five test conditions. Results also indicated that, among the six tone contrasts, the Tone 1/Tone 2 and Tone 2/Tone 3 contrasts were the most difficult tone contrasts in quiet. No significant difference in performance was found among the six tone contrasts in noise. Pearson product-moment correlation showed that the age of first HA fitting, the duration of HA use, aided and unaided average thresholds as well as the aided hearing thresholds in the low frequency region were not significantly correlated with tone identification ability in the five test conditions.ConclusionsConsistent with previous findings, the Tone 1/Tone 2 and Tone 2/Tone 3 contrasts were the most difficult to identify in quiet; but the presence of noise resulted in these tone contrasts being equally difficult. Findings also suggest that the tone identification ability of children with profound HI needs to be improved. Although the age of first HA fitting and the duration of HA use were not significantly correlated with tone identification performance in children with profound HI, this finding does not preclude the importance of early HA fitting.     

Speech and music perception with the new fine structure speech coding strategy: preliminary results

CONCLUSIONS: Taking into account the excellent results with significant improvements in the speech tests and the very high satisfaction of the patients using the new strategy, this first implementation of a fine structure strategy could offer a new quality of hearing with cochlear implants (CIs). OBJECTIVE: This study consisted of an intra-individual comparison of speech recognition, music perception and patient preference when subjects used two different speech coding strategies with a MedEl Pulsar CI: continuous interleaved sampling (CIS) and the new fine structure processing (FSP) strategy. In contrast to envelope-based strategies, the FSP strategy also delivers subtle pitch and timing differences of sound to the user and is thereby supposed to enhance speech perception in noise and increase the quality of music perception. PATIENTS AND METHODS: This was a prospective study assessing performance with two different speech coding strategies. The setting was a CI programme at an academic tertiary referral centre. Fourteen post-lingually deaf patients using a MedEl Pulsar CI with a mean CI experience of 0.98 years were supplied with the new FSP speech coding strategy. Subjects consecutively used the two different speech coding strategies. Speech and music tests were performed with the previously fitted CIS strategy, immediately after fitting with the new FSP strategy and 4, 8 and 12 weeks later. The main outcome measures were individual performance and subjective assessment of two different speech processors. RESULTS: Speech and music test scores improved statistically significantly after conversion from CIS to FSP strategy. Twelve of 14 patients preferred the new FSP speech processing strategy over the CIS strategy.     

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.     

Short-term study of the effect of speech coding strategy on the auditory performance of pre- and post-lingually deafened adults implanted with the Clarion CII®

Objective The auditory performance of cochlear implantees is linked to numerous variables, such as audiological characteristics, age and type of speech coding strategy. In recent years, many different ways of processing sounds have been developed, with possible implications for auditory performance. The purpose of this study was to evaluate the intra-individual differences of patients for speech perception tasks in quiet and in noise as a result of switching from a standard strategy [Continuous Interleaved Sampling (CIS)/Simultaneous Analog Strategy (SAS)] to Hi-Resolution (HiRes).

Material and Methods A total of 14 post-lingual adults implanted with the Clarion CII® were selected for trials. At switch-on, six patients chose a CIS strategy and eight an SAS strategy. After an average period of 9.3 months, all patients were switched over to HiRes. All patients were tested (open-set mode) with bisyllabic words and sentences, in both quiet and noise [speech/noise ratio (SNR)=+10]. Testing was carried out after an initial period with the CIS/SAS strategy and 3 months after switching over to HiRes.

Results After switch-over a significant improvement was seen for both speech in quiet (words +25.2%, sentences +10.8%) and speech in noise (words 44.8%, sentences 45.4%).

Conclusion Despite individual differences, all patients improved their performance with HiRes use, the greatest improvements being seen under unfavourable listening conditions (SNR=+10). Subjective improvements in speech discrimination and overall sound quality perception were reported even after the first week of HiRes use.     

Clinical Trial Results with the MED-EL Fine Structure Processing Coding Strategy in Experienced Cochlear Implant Users

Objectives: To assess the subjective and objective performance of the new fine structure processing strategy (FSP) compared to the previous generation coding strategies CIS+ and HDCIS. Methods: Forty-six adults with a minimum of 6 months of cochlear implant experience were included. CIS+, HDCIS and FSP were compared in speech perception tests in noise, pitch scaling and questionnaires. The randomized tests were performed acutely (interval 1) and again after 3 months of FSP experience (interval 3). The subjective evaluation included questionnaire 1 at intervals 1 and 3, and questionnaire 2 at interval 2, 1 month after interval 1. Results: Comparison between FSP and CIS+ showed that FSP performed at least as well as CIS+ in all speech perception tests, and outperformed CIS+ in vowel and monosyllabic word discrimination. Comparison between FSP and HDCIS showed that both performed equally well in all speech perception tests. Pitch scaling showed that FSP performed at least as well as HDCIS. With FSP, sound quality was at least as good and often better than with HDCIS. Conclusions: Results indicate that FSP performs better than CIS+ in vowel and monosyllabic word understanding. Subjective evaluation demonstrates strong user preferences for FSP when listening to speech and music.     

The characteristics of monosyllable recognition in Mandarin-speaking patients with auditory neuropathy

Abstract

Background: A set of Chinese Mandarin monosyllable test lists has been widely used in clinical diagnosis, while the performance of the Mandarin-speaking patients with auditory neuropathy (AN) in the monosyllable tests was still unknown.

Objectives: To analyze the characteristics of monosyllable recognition in Mandarin-speaking patients with AN.

Materials and methods: Nineteen Mandarin-speaking patients diagnosed with AN were recruited to obtain the performance-intensity (P-I) functions. They were divided into two paired groups according to two conditions: (1) the rising-slope (RS) and the non-rising-slope pattern (NRS) group for the audiogram; or (2) the male and the female group for gender.

Results: The performance at 20 and 30?dB SL showed negative correlation with the pure tone-averaged thresholds of 0.5, 1.0, 2.0 and 4.0?kHz (4FA). We found significant differences between the P-I functions of the RS and the NRS group, and surprisingly found that between the male and female as well although there was no difference in 4FA between the paired groups. A notable rollover phenomenon in P-I functions was detected in each group.

Conclusions: The monosyllable recognition scores of Mandarin-speaking AN patients showed numerous particular characteristics reflected by P-I functions. Acquiring the complete P-I functions at multiple presentation levels and the rollover index may give us more information about the diagnosis and prognosis.     

Implementation and preliminary evaluation of ‘C-tone’: A novel algorithm to improve lexical tone recognition in Mandarin-speaking cochlear implant users

Objectives: Because of limited spectral resolution, Mandarin-speaking cochlear implant (CI) users have difficulty perceiving fundamental frequency (F0) cues that are important to lexical tone recognition. To improve Mandarin tone recognition in CI users, we implemented and evaluated a novel real-time algorithm (C-tone) to enhance the amplitude contour, which is strongly correlated with the F0 contour.

Methods: The C-tone algorithm was implemented in clinical processors and evaluated in eight users of the Nurotron NSP-60 CI system. Subjects were given 2 weeks of experience with C-tone. Recognition of Chinese tones, monosyllables, and disyllables in quiet was measured with and without the C-tone algorithm. Subjective quality ratings were also obtained for C-tone.

Results: After 2 weeks of experience with C-tone, there were small but significant improvements in recognition of lexical tones, monosyllables, and disyllables (P?Discussion: The real-time C-tone algorithm provided small but significant improvements for speech performance in quiet with no change in sound quality. Pre-processing algorithms to reduce noise and better real-time F0 extraction would improve the benefits of C-tone in complex listening environments.

Conclusions: Chinese CI users’ speech recognition in quiet can be significantly improved by modifying the amplitude contour to better resemble the F0 contour.     

Effect of spatial separation and noise type on sentence recognition by Mandarin-speaking cochlear implant users

Objectives: To investigate the effects of spatial separation and noise type on sentence recognition by unilateral Mandarin-speaking cochlear implant (CI) users and normal-hearing (NH) listeners.

Method: Twenty-two unilateral Mandarin-speaking CI users and six NH listeners participated in this study. Speech reception thresholds were measured for three noise types (steady state noise, speech babble, and music). Sentences from the Mandarin Speech Perception test were presented directly in front of the listener (0°). Noise was presented from one of the five speaker locations: ?90°, ?45°, 0°,?+45°, and?+90°.

Results: Overall, CI performance was significantly poorer than NH performance for all spatial separation and noise type conditions. NH listeners performed best with music and poorest with steady noise. CI users performed best with steady noise, and poorest with babble. Performance was significantly affected by noise location and noise type. There was no significant difference in head shadow effects among the different noise types for CI users.

Conclusions: Performance was much poorer in CI than in NH listeners for all noise types and spatial separations. Noise type differently affected unilateral CI users and NH listeners. The limited spectral resolution in CI users did not appear to affect head shadow.     

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.     

普通话单音节测听表在人工耳蜗植入者中的初步应用

目的采用新编普通话单音节测听表,评估人工耳蜗植入者的言语识别能力。方法选取8名语前聋儿童（甲组）及13名语后聋（乙组）人工耳蜗植入者作为研究对象,男12名,女9名。甲组植入年龄为1．6～11．9岁（中位数2．7岁）,使用年限〉3．4年。乙组植入年龄为3．2～30．9岁（中位数12．0岁）,使用年限〉0．7年以上。在声场中测试人工耳蜗日常使用状态下的啭音听阈,并55dB SPL言语强度下的单音节识别率。部分受试者还接受了65、80dB SPL言语强度下单音节识别率的测试。结果甲乙2组受试者的0．5、1、2、4kHz四频率平均（4 Frequency Average,4FA）声场啭音听阈分别为32．5±3．4dB HL、35．9±4．9dB HL,t检验显示P=0．1046。甲乙2组受试者55dB SPL下的单音节识别率分别为56．8±9．0％、31．41±7．1％,t检验显示P=0．001。结论新编普通话单音节测听表,可有效地用来评价人工耳蜗植入者的言语识别能力。使用年限较短的语后聋患者的单音节识别率尚不及使用年限较长的语前聋儿童。人工耳蜗植入者的单音节识别率一言语声强（Performance—Intensity,P—I）函数曲线较正常成人平均右移30dB以上,提示人工耳蜗使用者的言语听力补偿水平较正常人仍有差距。     

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).     

Tone perception in Mandarin-speaking children with cochlear implants

Abstract

Objective: To evaluate the effects of implant age and duration of implantation on development of Mandarin tone perception in paediatric cochlear implant recipients. Design: Retrospective cross-sectional evaluation of tone perception, as assessed with the Mandarin Early Speech Perception test at 3, 6, 12, 24, 36 and 48 months after activation. Study sample: A total of 143 subjects, 60 girls and 83 boys unilaterally implanted at 1–4 years of age comprised the sample. All the subjects were implanted with devices from one of three manufacturers. Results: Regardless of implant age, approximately 80% of the subjects obtained overall tone discrimination scores significantly above chance by 4 years after implantation, and average discrimination accuracy increased from approximately 68% to 79%. Acoustically distinct tones 1 and 4 were discriminated and recognised more accurately, while less distinct tones 2 and 3 were discriminated and recognised less accurately. Large individual differences in performance were evident. Conclusions: Most Mandarin-speaking paediatric CI recipients discriminate tones above chance at 5 years of age with accuracy comparable to that of children with normal hearing at 2 years of age. Modest benefits of early implantation are evident.     

Assessment of Mandarin-speaking pediatric cochlear implant recipients with the Mandarin Early Speech Perception (MESP) test

Objective

The primary purpose of the current study was to evaluate the Mandarin Early Speech Perception (MESP) test for use in objective outcome assessment of pediatric CI recipients in China. Although almost 5000 pediatric CIs have been implanted in China, very little is known about the speech perception abilities of these recipients, in large part because of the previous unavailability of objective outcome assessment tools for Mandarin-speaking children.

Method

The Mandarin Early Speech Perception (MESP) test was administered to 25 pediatric Mandarin-speaking cochlear implant (CI) recipients implanted under the age of 10 years at West China Hospital of Sichuan University.

Results

Data from 22 children reaching MESP Categories 3 (Spondee Perception), 5 (Consonant Perception), and 6 (Tone Perception) were analyzed. The 5 children reaching Category 6 were significantly younger at implantation than children reaching the other two categories. Comparison of MESP scores for CI recipients and normally hearing children revealed that scores for the majority of CI recipients reaching Categories 3 and 5 fell within the range of normal performance, while scores for all CI recipients reaching Category 6 exceeded the average normal performance. MESP scores for Mandarin-speaking CI recipients and ESP scores for English-speaking CI recipients [1] fell on a common trajectory that, after slightly more than 3 years of age, exceeded the ceiling defined by the first four categories common to both tests. After 4 years of age, most Mandarin-speaking had reached Category 6.

Conclusions

These results provide preliminary validation of the MESP test for use in evaluation of Mandarin-speaking pediatric CI recipients. Use of objective outcome assessment tools such as the MESP following early cochlear implantation can be used to document the progress of CI recipients and identify those recipients who may need additional rehabilitative intervention.     

Perception and production of lexical tones by 3-year-old, Mandarin-speaking children.

The present study investigated 3-year-old children's perception and production of Mandarin lexical tones in monosyllabic words. Thirteen 3-year-old, Mandarin-speaking children participated in the study. Tone perception was examined by a picture-pointing task, and tone production was investigated by picture naming. To compare children's productions with the adult forms, 4 mothers of the children were asked to say the same set of words to their children in a picture-reading activity. The children's and mothers' productions were low-pass filtered at 500 Hz and 400 Hz, respectively, to eliminate segmental information. Ten Mandarin-speaking judges identified the productions of tones from the filtered speech. Adult productions were more accurately identified than productions of the children. The children perceived the level, rising, and falling tones with relatively high accuracy. The dipping tone posed the greatest difficulty for the children in both perception and production.     

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.     

Parameter selection and programming recommendations for the ACE and CIS speech-processing strategies in the Nucleus 24 cochlear implant system

Abstract

This study evaluated a range of programming parameters available for the ACE and CIS speech-processing strategies in the Nucleus 24 cochlear implant system. Specifically, the effect on speech perception of adjustments to the number of channels and the stimulation rate in the CIS strategy, and the effect of adjustments to the number of maxima in the ACE strategy were investigated in a group of adult subjects. Based on these findings, and the results of a previous study (Vandali et al., 2000), a number of recommendations for programming were identified that could improve efficiency in the clinical setting where time may be limited. The results suggest that speech perception benefits may be maximized for an individual cochlear implant recipient through concentration on selection of the appropriate stimulation rate. When using the CIS strategy, the number of channels should also be optimized. Adjustment to the number of maxima in the ACE strategy was found to be less likely to provide improvements in speech recognition for a given individual when the number of maxima parameter is set to eight or 12.