澳大利亚人工耳蜗技术发展历程

澳大利亚科利耳公司是世界上生产人工耳蜗历史最长,最先生产多通道人工耳蜗的厂家,全球已有超过7万余名的使用者。澳大利亚人工耳蜗技术是基于墨尔本大学格莱姆·克拉克教授的研究。★1967年克拉克教授开始着手于单通道及多通道人工耳蜗可行性的基础研究工作。★1978年,克拉克教授为Rod Saunders植入了第一个研究用多通道人工耳蜗。★1982年,科利耳公司与澳大利亚墨尔本大学合作,率先研制出用于临床的22通道人工耳蜗-Nucleus22型人工耳蜗。★1985年澳大利亚人工耳蜗系统成为第一个通过美国食品与药物管理局许可,允许使用于成人的多通道人…     

听神经-听觉通路完整性评估的价值

人工耳蜗植入已成功地帮助许多双侧感音神经性聋患者恢复听力,据2004年Zeng[1]统计当时全球已有超过60000多名人工耳蜗使用者。我国从1995年引进国外多通道人工耳蜗以来,     

多通道人工耳蜗使用者电刺激速率辨别与声调识别的关系

目的用心理物理学的方法探讨多通道人工耳蜗使用者单个电极速率识别与声调及言语识别的关系，为国人使用多通道人工耳蜗效果的评估及汉语语音编码方案的设计提供依据。方法４例语后聋成人人工耳蜗使用者参与测试。以４个标准频率５０、１００、２００和４００Ｈｚ为基线，对４个电极对（Ｅ１，Ｅ３），（Ｅ７，Ｅ９），（Ｅ１４，Ｅ１６）和（Ｅ２０，Ｅ２２）分别用不同频率与４个基线间进行刺激率辨别测试。用２５组４个声调共计１００汉字进行声调识别测试。计算正确识别率，分析正确和错误识别的混淆矩阵，对测试材料进行基频分析。结果速率辨别阈（７５．０％正确率时）个体差异很大，从数Ｈｚ到上百Ｈｚ。统计学分析显示标准频率、电极位置和患者间差异具有显著性。声调识别正确率为４０％～８０％，阴平和上声较阳平和去声容易识别。相关分析显示在速率辨别与声调识别间表现出高度相关性。结论人工耳蜗使用者的声调识别依赖于其良好的电极速率辨别。     

人工耳蜗电极植入部位对人工耳蜗使用者言语理解影响的研究

目的:探讨人工耳蜗电极覆盖耳蜗基膜范围对汉语普通话人工耳蜗使用者的言语识别能力,特别是声调识别能力的影响.方法:使用人工耳蜗调试软件通过开启(关闭)不同电极通道设置7种测试条件,以模拟人工耳蜗电极覆盖耳蜗基膜范围的不同状态.并对各测试条件下人工耳蜗使用者元音、辅音、声调识别能力进行测试.结果:不同测试条件下元音识别平均得分56%～91%(P<0.05);辅音识别平均得分72%～85%(P<0.05);声调识别平均得分68%～81%(P>0.05).但随着人工耳蜗电极覆盖基底膜范围的扩大,人工耳蜗使用者元音、辅音成绩呈现显著性改善,声调识别成绩亦有所提高.结论:增加人工耳蜗电极覆盖基膜的范围、积极利用耳蜗各个区域有利于改善人工耳蜗使用者的言语识别能力,进而对提高人工耳蜗使用者言语交流和社会交往能力是非常重要的.     

异常耳蜗的多通道人工耳蜗埋植

本文就异常耳蜗主要是骨化和畸形耳蜗的多通道人工耳蜗埋植的术前检查、手术方法和听觉 -言语康复效果进行综述     

大鼠多通道人工耳蜗植入模型的建立

目的:建立多通道人工耳蜗植入的大鼠动物模型.方法:5只正常听力的Hooded Wister大鼠经药物致聋后,采用在前期研究中所创立的新手术步骤,在鼓阶内植入多通道电极.对双极电刺激诱发的听性脑干反应(EABRs)进行分析,对耳蜗组织学切片进行评价.结果:在电极植入后,顺利描记到正常EABRs波形,从而确认了有效的人工耳蜗功能状态.组织学观察表明,电极植入后的大鼠耳蜗内未见组织结构的严重损伤.结论:本文介绍的大鼠多通道人工耳蜗植入法有效,安全,所建立的大鼠动物模型为进行多通道人工耳蜗植入研究提供了一个新的途径;也为其他小啮齿动物(如沙鼠和小鼠)的实验性耳显微外科研究提供了思路.     

语后聋多通道人工耳蜗使用者的普通话言语识别

普通话是我国的规范语言,其语音学特点有别于西方语系,特别是声调[1] 。人工耳蜗植入作为治疗重度感音性聋的最重要手段,目前多为基于西方语系设计的国外产品,能否充分地体现汉语、特别是汉语普通话的语音学特点,一直备受关注。我国多通道人工耳蜗使用者、特别是更具代表性的语后聋使用者的普通话言语识别状况,目前仅报道5例[2 ,3 ] 。一、研究对象2 0 0 2年9月～2 0 0 3年3月间,随访北京协和医院语后聋多通道人工耳蜗植入者中志愿参加并能配合言语识别测试者共14例,其中男8例,女6例;脑膜炎后聋伴耳蜗骨化、腮腺炎后聋、大前庭导水管综合征…     

再次人工耳蜗植入术

人工耳蜗植入（cochlear implantation,CI）已经成为治疗双侧重度感音性聋的常规方法。虽然人工耳蜗产品质量有很好的治疗保证,但我国95％以上的人工耳蜗使用者为儿童,很难保证终身使用,多数儿童使用者可能在一生中至少更换一次人工耳蜗。所以进一步探讨手术技术,减少再次植入的困难很有必要。     

语后聋多通道人工耳蜗使用者的普通话言语识别

普通话是我国的规范语言，其语音学特点有别于西方语系，特别是声调。人工耳蜗植入作为治疗重度感音性聋的最重要手段，目前多为基于西方语系设计的国外产品，能否充分地体现汉语、特别是汉语普通话的语音学特点，一直备受关注。我国多通道人工耳蜗使用者、特别是更具代表性的语后聋使用者的普通话言语识别状况，目前仅报道5例。     

语后聋Nucleus人工耳蜗使用者的声调识别

目的 评估语后聋Nucleus人工耳蜗使用者的普通话声调识别水平，探讨其影响因素。方法应用(MACC)材科及北京协和医院耳蜗中心自编（声调测试）材科，评估14例语后聋Nucleus人工耳蜗使用者的普通话声调识别能力，其中使用Nucleus24型Sprint产品ACE方案者11例，Nucleus22型MSP产品MPEAK方案者3例。结果所有植入者的普通话声调识别率均高于机会水平，其中2例Nucleus24型Sprint产品使用者可达到100％。结论Nucleus人工耳蜗语后聋使用者可以获得较好的普通话声调识别．Nucleus24型Sprint产品可为部分植入者提供充分的声调信息。     

Effects of speech processing strategy on Chinese tone recognition by nucleus-24 cochlear implant users

OBJECTIVE: To evaluate the effects of speech processing strategy on Chinese tone recognition by Nucleus-24 cochlear implant users. METHODS: Recognition of Chinese tones was measured with the spectral peak (SPEAK), advanced combination encoders (ACE), and continuous interleaved sampling (CIS) strategies in nine Nucleus-24 cochlear implant users. Recognition of Chinese sentences was also measured with the ACE strategy (1200 pulse-per-sec on each electrode). As the stimulation rate in the SPEAK processor is fixed at 250 pulses per sec per electrode (ppspe), only one stimulation rate was tested with the SPEAK processor. Three stimulation rates (900, 1200, and 1800 ppspe) were tested in the ACE processing conditions. Four stimulation rates (1200, 1800, 2400, and 3600 ppspe) were tested in the CIS processing conditions. Because the number of stimulating electrodes determines the stimulation rate in CIS processors, the number of electrodes was reduced from 12 to 8 to 6 to 4 to achieve stimulation rates of 1200, 1800, 2400, to 3600 pps. RESULTS: Results showed that mean Chinese tone recognition scores with the ACE and CIS strategies were significantly higher than those with the SPEAK strategy. For the ACE strategy, there was no significant difference in performance among the various stimulation rates (for the ACE processing conditions, the stimulation rate was varied while keeping the number of stimulating electrodes constant). For the CIS strategy, there was no significant difference among the various stimulation rates and electrode configurations (for the CIS processing conditions, the stimulation rate was varied by changing the number of stimulating electrodes). There was also a significant correlation between Chinese tone recognition and the recognition of everyday sentences. CONCLUSIONS: The latest-generation speech processing strategies were able to provide cochlear implant users with considerable amounts of tonal information. However, Chinese tone recognition was significantly affected by the choice in speech processing strategy. Relatively higher stimulation rates (>900 ppspe) may improve Chinese tone recognition. Furthermore, it may be necessary to develop speech processing strategies to specifically improve tone recognition, which is critical for understanding tonal languages.     

语前聋儿童人工耳蜗植入患者的电极极间辨差阈与声调识别的初步研究

OBJECTIVE: To investigate tone recognition and electrode discrimination in prelingually deafened children with the Nucleus device, and to develop guidelines for customized mapping in the implant users. METHODS: Fourteen prelingually deafened children with cochlear implants participated in this study. Tone recognition was measured with a four-alternative, forced choice procedure from 25 consonant-vowel syllables, each of which had four tonal variations. Electrode discrimination was measured using a same-difference procedure on 7 pairs of electrodes covering the entire electrode array. RESULTS: Tone recognition ranged from 35% to 99% correct with a mean of 62.8% and standard deviation of 14.7% in these users. Electrode discrimination had the mean threshold of 3.4 +/- 0.9, with the best performance from the middle electrodes (E 14 and E 17) at 2.6 and the followed performance at the most apical electrode (E 20). CONCLUSION: The results showed significant individual differences from both tone recognition and electrode discrimination, but there is significant correlation between them.     

Accuracy of cochlear implant recipients on pitch perception, melody recognition, and speech reception in noise

OBJECTIVE: The purposes of this study were to (a) examine the accuracy of cochlear implant recipients who use different types of devices and signal processing strategies on pitch ranking as a function of size of interval and frequency range and (b) to examine the relations between this pitch perception measure and demographic variables, melody recognition, and speech reception in background noise. DESIGN: One hundred fourteen cochlear implant users and 21 normal-hearing adults were tested on a pitch discrimination task (pitch ranking) that required them to determine direction of pitch change as a function of base frequency and interval size. Three groups were tested: (a) long electrode cochlear implant users (N = 101); (b) short electrode users that received acoustic plus electrical stimulation (A+E) (N = 13); and (c) a normal-hearing (NH) comparison group (N = 21). Pitch ranking was tested at standard frequencies of 131 to 1048 Hz, and the size of the pitch-change intervals ranged from 1 to 4 semitones. A generalized linear mixed model (GLMM) was fit to predict pitch ranking and to determine if group differences exist as a function of base frequency and interval size. Overall significance effects were measured with Chi-square tests and individual effects were measured with t-tests. Pitch ranking accuracy was correlated with demographic measures (age at time of testing, length of profound deafness, months of implant use), frequency difference limens, familiar melody recognition, and two measures of speech reception in noise. RESULTS: The long electrode recipients performed significantly poorer on pitch discrimination than the NH and A+E group. The A+E users performed similarly to the NH listeners as a function of interval size in the lower base frequency range, but their pitch discrimination scores deteriorated slightly in the higher frequency range. The long electrode recipients, although less accurate than participants in the NH and A+E groups, tended to perform with greater accuracy within the higher frequency range. There were statistically significant correlations between pitch ranking and familiar melody recognition as well as with pure-tone frequency difference limens at 200 and 400 Hz. CONCLUSIONS: Low-frequency acoustic hearing improves pitch discrimination as compared with traditional, electric-only cochlear implants. These findings have implications for musical tasks such as familiar melody recognition.     

Mandarin tone recognition in cochlear-implant subjects

This study examined tone recognition in five cochlear-implant subjects who were native speakers of Mandarin and used a Nucleus-22 device. Psychophysical experiments were conduced to measure rate discrimination in individual electrodes from the most apical to the most basal electrodes. The rate range was from 100 to 200 Hz, which corresponded to the range of variation in fundamental frequency for the tonal tokens used in this study. Speech recognition experiments were also conducted to measure tone recognition as function of the number of electrodes from a 1-electrode map to a 20-electrode map. Large individual variability was observed for both rate discrimination and tone recognition result: Average rate discrimination ranged between 0.2 and 1.2 (Weber's fraction) whereas tone recognition ranged between 30% and 70% correct. A highly significant correlation was found between rate discrimination and tone recognition with the 20-electrode map, but a non-significant correlation was observed with the 1-electrode map due to a floor effect in tone recognition. The present result supports the hypothesis that both spectral and temporal cues contribute to tone recognition. In addition, the present result shows that current cochlear-implant subjects produced significantly lower performance than acoustic simulations in normal-hearing subjects, suggesting that neither temporal nor spectral cues have been adequately and appropriately extracted and encoded in current cochlear implants. New designs are discussed to improve tone recognition in cochlear implant subjects.     

An investigation into the effect of limiting the frequency bandwidth of speech on speech recognition in adult cochlear implant users

The purpose of this study was to investigate the effect of the limited-frequency bandwidth employed by telephones (300-3400 Hz) on speech recognition in adult cochlear implant users. The Four Alternative Auditory Feature (FAAF) test was used in four conditions: unfiltered and in three filtered conditions of 300-4500 Hz, 300-3400 Hz and 300-2500 Hz. Ten subjects implanted with the Nucleus CI24M device and 10 normal-hearing listeners were assessed to examine differences between word discrimination scores in each condition. Scores obtained from the 300-3400-Hz and 300-2500-Hz filtered conditions were significantly worse than those with unfiltered speech for the cochlear implant subjects, decreasing by 17.7% and 21.4%, respectively, from scores with unfiltered speech. By contrast, the normal-hearing listeners did not experience difficulties in discriminating between words in any of the conditions. Analysis of the word errors demonstrated that the reduction in implant subject scores with bandwidth arose from errors in place of articulation. Filtering speech in this way has a significant effect on speech recognition for cochlear implant subjects but not normal-hearing listeners. Hence, the limitations of the normal telephone bandwidth can be expected to have a negative effect on speech recognition for cochlear implant users using the telephone.     

An investigation into the effect of limiting the frequency bandwidth of speech on speech recognition in adult cochlear implant users

The purpose of this study was to investigate the effect of the limited-frequency bandwidth employed by telephones (300-3400Hz) on speech recognition in adult cochlear implant users. The Four Alternative Auditory Feature (FAAF) test was used in four conditions: unfiltered and in three filtered conditions of 300-4500Hz, 300-3400Hz and 300-2500Hz. Ten subjects implanted with the Nucleus C124M device and 10 normal-hearing listeners were assessed to examine differences between word discrimination scores in each condition. Scores obtained from the 300-3400-Hz and 300-2500-Hz filtered conditions were significantly worse than those with unfiltered speech for the cochlear implant subjects, decreasing by 17.7% and 21.4%, respectively, from scores with unfiltered speech. By contrast, the normal-hearing listeners did not experience difficulties in discriminating between words in any of the conditions. Analysis of the word errors demonstrated that the reduction in implant subject scores with bandwidth arose from errors in place of articulation. Filtering speech in this way has a significant effect on speech recognition for cochlear implant subjects but not normal-hearing listeners. Hence, the limitations of the normal telephone bandwidth can be expected to have a negative effect on speech recognition for cochlear implant users using the telephone.     

Cochlear implant speech processor frequency allocations may influence pitch perception.

OBJECTIVE: To investigate the effects of assigning cochlear implant speech processor frequencies normally associated with more apical cochlear locations to the shallow insertion depths of the Iowa/Nucleus Hybrid electrode. STUDY DESIGN: Subjects using the Hybrid implant for more than 1 year were tested on speech recognition with Consonant-Nucleus-Consonant words and consonant stimuli. Pitch sensations of individual electrodes were also measured electrically through the implant and acoustically in the contralateral ear. SETTING: Tertiary care center. RESULTS: Most subjects showed large improvements in speech recognition within 12 months after implantation. Furthermore, after longer periods of 24-plus months, some individuals were able to achieve high levels of consonant discrimination with electric-only processing comparable to long-electrode patients with deeper electrode insertions. Pitch perceptions obtained from individual electrodes in these subjects were closer to the frequency map assigned an electrode than the place-frequency predicted from cochlear location. CONCLUSION: These results suggest that over time, pitch sensations may be determined more by the implant map than by cochlear location. In other words, the brain may adapt to spectral mismatches by remapping pitch. Furthermore, patients can perform well with shifted frequency allocations for speech recognition. The successful application of shifted frequency allocations also supports the idea of shallower insertions and greater preservation of residual hearing for all cochlear implants, regardless of the patient's frequency range of usable residual hearing.     

Correlations Between Pitch and Phoneme Perception in Cochlear Implant Users and Their Normal Hearing Peers

This study examined correlations between pitch and phoneme perception for nine cochlear implant users and nine normal hearing listeners. Pure tone frequency discrimination thresholds were measured for frequencies of 500, 1000, and 2000 Hz. Complex tone fundamental frequency (F0) discrimination thresholds were measured for F0s of 110, 220, and 440 Hz. The effects of amplitude and frequency roving were measured under the rationale that individuals who are robust to such perturbations would perform better on phoneme perception measures. Phoneme identification was measured using consonant and vowel materials in quiet, in stationary speech-shaped noise (SSN), in spectrally notched SSN, and in temporally gated SSN. Cochlear implant pure tone frequency discrimination thresholds ranged between 1.5 and 9.9 %, while cochlear implant complex tone F0 discrimination thresholds ranged between 2.6 and 28.5 %. On average, cochlear implant users had 5.3 dB of masking release for consonants and 8.4 dB of masking release for vowels when measured in temporally gated SSN compared to stationary SSN. Correlations with phoneme identification measures were generally higher for complex tone discrimination measures than for pure tone discrimination measures. Correlations with phoneme identification measures were also generally higher for pitch perception measures that included amplitude and frequency roving. The strongest correlations were observed for measures of complex tone F0 discrimination with phoneme identification in temporally gated SSN. The results of this study suggest that musical training or signal processing strategies that improve F0 discrimination should improve consonant identification in fluctuating noise.     

The Role of Spectral and Temporal Cues in Voice Gender Discrimination by Normal-Hearing Listeners and Cochlear Implant Users

The present study investigated the relative importance of temporal and spectral cues in voice gender discrimination and vowel recognition by normal-hearing subjects listening to an acoustic simulation of cochlear implant speech processing and by cochlear implant users. In the simulation, the number of speech processing channels ranged from 4 to 32, thereby varying the spectral resolution; the cutoff frequencies of the channels envelope filters ranged from 20 to 320 Hz, thereby manipulating the available temporal cues. For normal-hearing subjects, results showed that both voice gender discrimination and vowel recognition scores improved as the number of spectral channels was increased. When only 4 spectral channels were available, voice gender discrimination significantly improved as the envelope filter cutoff frequency was increased from 20 to 320 Hz. For all spectral conditions, increasing the amount of temporal information had no significant effect on vowel recognition. Both voice gender discrimination and vowel recognition scores were highly variable among implant users. The performance of cochlear implant listeners was similar to that of normal-hearing subjects listening to comparable speech processing (4–8 spectral channels). The results suggest that both spectral and temporal cues contribute to voice gender discrimination and that temporal cues are especially important for cochlear implant users to identify the voice gender when there is reduced spectral resolution.     

The benefits of combining acoustic and electric stimulation for the recognition of speech, voice and melodies

Fifteen patients fit with a cochlear implant in one ear and a hearing aid in the other ear were presented with tests of speech and melody recognition and voice discrimination under conditions of electric (E) stimulation, acoustic (A) stimulation and combined electric and acoustic stimulation (EAS). When acoustic information was added to electrically stimulated information performance increased by 17-23 percentage points on tests of word and sentence recognition in quiet and sentence recognition in noise. On average, the EAS patients achieved higher scores on CNC words than patients fit with a unilateral cochlear implant. While the best EAS patients did not outperform the best patients fit with a unilateral cochlear implant, proportionally more EAS patients achieved very high scores on tests of speech recognition than unilateral cochlear implant patients.