16例Nucleus 24导弯电极人工耳蜗植入体会

目的 通过总结16例Nucleus24导弯电极人工耳蜗植入体会,比较其与24导直电极手术方法的不同,就其临床手术植入中有关情况做出评价。方法 所有患者均于耳后切口经面神经隐窝入路植入电极,术中均进行电极阻抗测试和听神经遥测反应(NRT)测试。结果 所有患者电极全部顺利植入蜗内,阻抗测试均正常。术中均引出满意NRT反应。结论 Nucleus24导弯电极人工耳蜗由于其独特的设计和性能,使得人工耳蜗植入手术适用年龄更小,手术更安全,操作更简便、更容易。术后并发症更少。     

直电极与弯电极人工耳蜗植入患者神经兴奋分布空间的比较

目的 比较Nucleus 24M型直电极与Nucleus 24Contour型弯电极人工耳蜗植入患者的神经兴奋分布空间的宽度,评估电极类型和电极位置对于电极问刺激干扰程度的影响.方法 18名人工耳蜗植入患儿分为两组,其中24M和24Contour植入患者各9名,年龄1.3～7.9岁.按照病因、病程、植入年龄、电极植入角度4个因素将两组患者进行配对.使用NRT3.1测试软件分别对每名患者的5、10、15三个电极进行听神经电诱发复合动作电位(electrically evoked compound action potential,ECAP)测试.测试时,探测脉冲固定加在测试电极,掩蔽脉冲按顺序分别加到1至22号电极,得出一系列的ECAP波形,将ECAP波形幅度从最高降到70.7%所覆盖的电极范围定义为神经兴奋分布空间的宽度.分析电极类型、电极位置这两个因素对神经兴奋分布空间宽度的影响.结果 电极类型、电极位置对神经兴奋分布空间宽度有显著影响.弯电极的兴奋空间分布宽度在5、10、15号三个电极位置均显著窄于直电极组.5、10号电极的兴奋空间窄于15号电极,但5号和10号电极之间无统计学差异.结论 在耳蜗的底部和中部,Nucleus24 Contour弯电极的电极间刺激干扰小于直电极,有助于提高患者中、高频的电极分辨能力.     

Nucleus人工耳蜗弯电极和直电极植入后的心理物理指标比较

目的对比Nucleus CI 24导Contour弯电极与Nucleus CI 24导直电极植入后的电阻阻抗、刺激阈值和舒适阈。方法植入澳大利亚NucleuS人工耳蜗的患者分为2组,1组（19例）植入Nucleus CI 24导Contour电极阵列（弯电极）,另1组（11例）植入CI 24M电极阵列（直电极）。所有患者耳蜗植入术后15天开机调试,并于开机时及开机后1周、1月、3月分别记录各电极的电阻、刺激闽值和最大舒适阈。结果开机后由于Nucleus 24直电极的刺激阈值呈上升趋势,3月和6月时弯电极的阈值明显低于直电极阈值,且差异有统计学意义（P〈0．05）。开机1周、1月和6月2组的舒适阈接近。开机后弯电极和直电极的电阻值接近。结论Nucleus CI 24导Contour弯电极的刺激阈值稳定,刺激阈和舒适阈之间动态范围较宽。     

神经反应遥测技术在人工耳蜗手术中的应用

目的 通过分析神经反应遥测(neural response telemetry, NRT)技术在人工耳蜗手术中的应用,帮助电极定位及预测术后效果。方法 受试对象为使用Nucleus CI24M型多导人工耳蜗系统的患者10例,其中2名患者的耳蜗发育畸形。选取10名患者的13个电极进行NRT测试。结果 NRT波形检出率为100% (n=13)。13个电极的NRT阈值为190.4±21.6CL。两名耳蜗畸形患者均记录到了NRT波形,其中一名阈值较高,为225 CL 。结论 术中10名患者的13个电极均记录到了NRT反应波形,提示NRT技术可有效地用于人工耳蜗植入患者的术中监测,特别为耳蜗畸形患者植入电极的定位提供帮助。     

多导人工耳蜗植入后电极阻抗的初步研究

目的研究多导人工耳蜗植入后电极阻抗变化的特点,对比直电极和弯电极的阻抗差异,为人工耳蜗植入术后的调试提供参考。方法在Nucleus多导人工耳蜗编程调试界面上,应用R126V1.3和NRTV3.0软件,测试11例语前聋儿童在不同时期的阻抗值,并进行分析比较。结果CI24M和CI24Rcontour两种植入体阻抗随时间变化的基本规律是:术中较低,开机时最高,以后随时间推移逐渐降低。CI24Rcontour阻抗高于CI24M。结论人工耳蜗植入体阻抗开机后随时间推移而逐渐降低,新型CI24Rcontour植入体与CI24M相比,其阻抗值在术中至开机后3周内明显要高。     

人工耳蜗植入术后神经反应遥测技术的参数设置

澳大利亚Cochlear公司的Nucleus24型多层人工耳蜗系统首次提供了直接测量电诱发听神经复合动作电位（electrically evoked compound action potential,ECAP)的技术手段－－神经反应遥测（neural response telemetry,NRT)技术。本文对20例Nucleus24型多层人工耳蜗植入患者进行NRT反应波形采集，选取反应波形较清晰的电极作为测试电极。每次只改变一个测试参数，观察波形的变化，总结出不同测试参数的改变对波形赞成的影响。其中对波形影响较大的有电流强度（current level,CL)，刺激脉宽（stimulation pulse width)、延迟时间（delay)、增益（gain)、掩蔽刺激间期（masker advance)等。对波形采集时间影响垢刺激速率和叠加次数。在此基础上设计出优化的参数调整顺序，用于快速采集反应波形，提高临床工作效率。     

人工耳蜗植入电极插入技巧对蜗内电极位置的影响

目的　观察不同手术技巧对多导人工耳蜗植入术后蜗内电极位置的影响。方法　采用澳大利亚Nu cleus 2 4M (直电极 )、Nucleus 2 4Contour(弯电极 )以及不同的手术技巧 ,术后以改良斯氏位X线拍片 ,测量、比较蜗内电极插入的深度。结果　 59例人工耳蜗植入病例中 ,3 2例Nucleus 2 4M型人工耳蜗常规手术的电极X片显示电极在平面图上的深度为 2 68°～ 3 53° ,平均 2 78.6° ;15例Nucleus 2 4M型人工耳蜗采用改进的电极插入方法 ,术后耳蜗电极X片在平面上显示弯成 3 60°～ 445° ,平均深度 3 91.7° ;12例Nucleus 2 4Contour型人工耳蜗植入采用标准术式 ,术后蜗内电极X片在平面上显示电极弯成 3 80～ 455° ,平均 42 3°。结论　澳大利亚Nucleus 2 4M型人工耳蜗通过改良的手术技巧可使电极插入的深度更大 ,部分病例可与弯电极相似 ,Nucleus 2 4Contour型人工耳蜗的电极则更靠近蜗轴     

人工耳蜗植入术后神经反应遥测阈值与行为阈值及舒适阈的比较

目的 通过对人工耳蜗植入术后不同患者神经反应遥测（neural response telemetr,NRT)阈值与行为反应阈值（T-level,T级）及舒适阈（C-level,C级）的比较，试图为小年龄或不能给予准确反应的患者客观估算人工耳蜗植入术后行为反应T、C级提供依据。方法 受试对象为使用Nucleus CI24M型多导人工耳蜗系统的70例患者。共测试329个电极。测试软件为NRT2.04版本。NRT阈值的测试采用单极刺激方式（monopolar stimulation mode)，分别测试每一位患者的第3、5、10、15、20号电极。T级和C级的测试均于NRT测试同日进行。结果 70例患者的329个电极的NRT波形检出率为92.7%。同一患者不同编号电极的NRT反应幅值和阈值及不同患者同一编号电极的NRT反应幅值和阈值均存在差异。NRT阈值的均值介于行为反应T级和C级的均值之间。NRT阈值及T、C级的数值自蜗底至蜗顶呈下降趋势。结论 NRT阈值、T级和C级的个体差异较大，尚不能根据NRT阈值对T级和C级进行准确的判断。但NRT技术可为不能配合术后调试的儿童患者的行为反应T、C级的估算提供客观的方法。NRT这一新技术仍有待于改进。     

人工耳蜗植入编程中NRT值和行为测试T值比较分析

目的:了解人工耳蜗植入编程中神经反应遥测(NRT)阈值与行为反应阈值的差别,寻找更好的编程方法。方法:对77例进行澳大利亚24型人工耳蜗植入的患儿在调试时对1、6、11、16、20号电极进行NRT值测试和行为T值测试,在能获得可靠的NRT和行为T值的时候收集数据,并进行统计学分析。结果:各个电极的vNRT值和行为T值的相关系数范围为0.40～0.54。各个电极vNRT的最小值为135μV,最大值为215μV。行为值的最小值为120CL,最大值为190CL。1,6,11,16,20号电极的vNRT和行为T差值的均值为27±14,24±13,31±14,26±13,20±13。vNRT和行为T值的最大差值为65,最小差值为-15。从20号电极到1号电极,平均T值幅度范围为148～159CL,平均vNRT值幅度范围为168～186μV,而且从低频电极到高频电极,vNRT值和行为T值呈上升趋势。结论:用vNRT阈值推测行为T值指导调机编程,个体差异较大,推测结果不是非常可靠,仅用于不能配合行为测试的患者。为了保证编程的准确性,最好对所有进行耳蜗编程的患者用行为T值来编程。     

儿童人工耳蜗植入术后神经反应遥测阈值的变化

目的:通过对儿童患者术后神经反应遥测 (NRT) 阈值的分析,总结其变化规律,为儿童人工耳蜗植入术后调试提供帮助.方法:测试40例接受Nucleus CI24R 型多导人工耳蜗单侧植入术的患儿.测试使用澳大利亚Cochlear公司提供的便携式调试系统及NRT3.1版本软件.采用削减算法提取NRT反应波形,分别测试每位患者的第1、5、10、15、20号电极,NRT阈值使用NRT软件计算.分别在开机时、开机3、6和12个月时进行测试.结果:在术后同一测试时间,位于耳蜗不同部位电极的NRT阈值存在差异.耳蜗底部和顶部电极的NRT阈值较低,而位于耳蜗中部的电极NRT阈值较高.经单因素方差分析,不同部位NRT阈值均差异有统计学意义.同一测试电极,随术后开机时间的增长,NRT阈值呈逐渐增加的趋势.经单因素方差分析,术后不同测试时间NRT阈值均差异有统计学意义.结论:术后开机1年内,NRT阈值呈逐渐增加的趋势.若人工耳蜗植入术后调试需要NRT进行辅助,每次均应测试NRT阈值,以便更准确估算患者的行为反应T、C级,尤其对植入术后1年内的儿童患者更为重要.     

Summary of results using the nucleus CI24M implant to record the electrically evoked compound action potential

OBJECTIVE: This study outlines a series of experiments using the neural response telemetry (NRT) system of the Nucleus CI24M cochlear implant to measure the electrically evoked compound action potential (EAP). The goal of this investigation was to develop a protocol that allows successful recording of the EAP in a majority of CI24M cochlear implant users. DESIGN: Twenty-six postlingually deafened adults participated in this study. A series of experiments were conducted that allowed us to examine how manipulation of stimulation and recording parameters may affect the morphology of the EAP recorded using the Nucleus NRT system. RESULTS: Results of this study show consistent responses on at least some electrodes from all subjects. Cross-subject and cross electrode variations in both the growth of the response and the temporal refractory properties of the response were observed. The range of stimulus and recording parameters that can be used to record the EAP with the Nucleus NRT system is described. CONCLUSIONS: Using the protocol outlined in this study, it is possible to reliably record EAP responses from most subjects and for most electrodes in Nucleus CI24M cochlear implant users. These responses are robust and recording these responses does not require that the subject sleep or remain still. Based on these results, a specific protocol is proposed for measurement of the EAP using the NRT system of the CI24M cochlear implant. Potential clinical implications of these results are discussed.     

Spatial spread of neural excitation in cochlear implant recipients: comparison of improved ECAP method and psychophysical forward masking

This study introduces and evaluates a method for measurement of the longitudinal spread of electrically evoked neural excitation in the cochlea, using the Neural Response Telemetry system (NRT) available with the Nucleus((R)) 24 cochlear implant system. The recently released version of the NRT software (version 3.0) enables presentation of the 'masker' and 'probe' on different electrodes. In the present method the probe position was fixed, while the masker position was varied across the electrode array. The amplitude of the response to the partially masked probe provides a measure of the amount of masking, which is dependent on the extent of overlap of the excitation regions of the masker and probe. These measurements were performed in seven subjects implanted with the Nucleus 24 cochlear implant system (four with straight and three with Contour electrode arrays), for basal, middle and apical probe electrodes. Similar excitation profiles were obtained using either the standard NRT subtraction paradigm or an alternative 'Miller' method. The excitation profiles were compared with those obtained from psychophysical forward masking and good agreement was found. The widths of electrically evoked compound action potential (ECAP) and forward masking profiles did not differ significantly. Whereas the width of the ECAP measure was significantly correlated with both the maximum comfortable level and the distance of the electrode band from the modiolus, the width of the forward masking profile was not.     

Neural response telemetry with the nucleus CI24M cochlear implant

OBJECTIVES: To review our intraoperative and postoperative testing protocol for cochlear implant patients. This study describes the methodologies and applications of a new technique called neural response telemetry (NRT) for the Nucleus CI24M cochlear implant system. NRT uses radiofrequency telemetry technology to measure the action potentials of the auditory nerve. STUDY DESIGN: We have developed a specific protocol for intraoperative testing of the implant device before, during, and after implantation. This includes device integrity tests, visual detection of electrical stapedius muscle reflexes (VESR), and NRT. METHODS: Our methodologies use the commercial software (Windows-based Diagnostic and Programming System [WIN-DPS] and NRT) for the Nucleus CI24M. We describe the details of our protocol used on all of the patients (14 adults and 14 children) who received CI24M implants at Mayo Clinic (Rochester, MN). Our protocol correlates the NRT threshold with the behavioral responses for each patient on at least four electrodes. RESULTS: From August 1, 1998, to December 31,1998, we completed electrode integrity tests, NRT, and VESR testing intraoperatively on 12 patients with the Nucleus CI24M. We have measured normal implant function on all 28 of our CI24M patients with one exception. One of our children had a device failure after approximately 4 months as a result of head trauma. We have also obtained NRT results from an additional 10 patients postoperatively. CONCLUSIONS: The measurement of device and electrode array function is quite simple with the CI24M software. These measurements can be obtained intraoperatively as well as postoperatively. We conclude that VESR and NRT measurements can be very helpful in programming for patients with cochlear implants, especially children, because they provides us with target settings for the speech processor.     

Accuracy of intraoperative electrophysiological testing in confirming correct cochlear implant electrode positions

Objective: To investigate the accuracy of intraoperative electrophysiological studies in detecting incorrectly positioned electrodes in cochlear implant surgery.

Study design: A retrospective chart review.

Setting: Tertiary referral centre.

Patients: In total, 104 consecutive patients with a mean age of 5 years underwent cochlear implant surgery at our centre between January 2012 and December 2013. All patients were implanted with Cochlear Nucleus Freedom implants.

Method: A retrospective study to compare intraoperative neural response telemetry (NRT), impedance and electrode position using Stenver’s transorbital plain X-ray view.

Results: Intraoperative electrophysiological tests for patients with Cochlear Nucleus Freedom implants showed 97% sensitivity and 100% specificity compared with postoperative X-ray imaging.

Conclusion: NRT results for the position of cochlear implants were very accurate when checked by X-ray imaging showing that this technique is sufficient in most cases. Stenver’s plain X-ray view is needed in complicated cases with abnormal NRT testing or difficult electrode insertion.     

Neural response telemetry in cochlear implant users

Programming of multichannel cochlear implants requires subjective responses to a series of sophisticated psychophysical percepts. It is often difficult for cochlear implant patients (especially young prelinguistically deaf children) to provide adequate responses for device fitting. However, the neural response telemetry (NRT) system renders possible the measurement of the compound action potential threshold. We performed NRT examinations in 27 cochlear implant users with Nucleus 24-channel cochlear implants. Measurements were obtained from five electrodes (3, 5, 10, 15, and 20) in each patient. Our goal was to look for correlation between behavioral subjective thresholds and compound action potentials. The action potentials could be elicited in 23 patients in all measured electrodes. The NRT threshold values were highly correlated with electrical threshold levels obtained through subjective responses. Our results suggest that the electrically elicited neural responses may yield very important information for device fitting in patients with cochlear implants.     

神经反应遥测技术在人工耳蜗植入术中的监测应用

目的：探讨在人工耳蜗植入术中能快速,准确地判断人工蜗装置的完好性和患者客观听觉反应的监测方法。方法：在40例患儿人工耳蜗植入术中先测定电极阻抗,然后使用神经反应遥测技术（neural response telemetry,NRT)监测6个电极的电诱发听神经复合动作电位（electrically evoked auditory nerve compound action potentials,ECAP)。结果：患儿所有电极阻抗正常,ECAP的检出率分别为97．5％（39例／40例）和92．1％（221个电极／240个电极）,其中33例内耳无畸形的患儿所有198个测试电极中有195个电极测出清晰的ECAP波形（98．5％）,7例内耳Mondini畸形患者共42个测试电极中有26个电极测得ECAP波形（61．9％）,两组之间差异有极显著性,靠近耳蜗底回（高频区）的电极比靠近蜗尖（低频区）的电极具有较高的ECAP反应阈值的ECAP饱和阈值。结论：NRT技术可以简便,快速和准确地判断患者的听神经反应,可望成为术中常规监测方法。内耳Mondini畸形是影响ECAP检出的重要因素。     

Efficacy of using NRT thresholds in cochlear implants fitting,in prelingual pediatric patients

ObjectiveTo evaluate the efficacy of using neural response telemetry (NRT) thresholds in predicting behavioural thresholds during programming of cochlear implant in prelingual children.MethodProspective study of 28 cochlear implants implanted with Nucleus 24 cochlear implant. We recorded NRT-thresholds on electrode numbers 1, 6, 11, 16 and 22 of the electrode array in each patient, the neural response thresholds were correlated with the behavioural map after six months of programming the device.ResultsThe mean neural response telemetry level was significantly higher than the mean threshold level (T-level) but lower than the comfortable level (C-level) in all the electrodes tested. NRT levels could statistically significantly predict T behavioural levels and comfortable behavioural levels, p < 0.01. There was a strong positive correlation between comfortable thresholds and neural response telemetry level measurements and behavioural threshold level and neural response telemetry threshold measurements.ConclusionThere is a useful role for neural response telemetry values in predicting the behavioural threshold and comfortable values in prelingual children. Combining the NRT values with behavioural observations can improve the programming of cochlear implants.     

Correlation between NRT measurement level and behavioral levels in pediatrics cochlear implant patients

Objective

To determine the relationship between the electrically evoked nerve action potential (Neural Response Telemetry [NRT]) and behavioral levels (T- and C-level) for pediatric patients using the Nucleus 24 cochlear implant system.

Method

A hospital based study of pediatric cochlear implant patients in the period between June 2000 and December 2008. At King Abdul-Aziz University Hospital (KAUH) Saudi Arabia the Neural Response Telemetry was administered to 47 children (mean age at implantation: 4 years) with the Nucleus 24 cochlear implants. Four intra cochlear electrodes (numbers 5, 10, 15, and 20) were tested one-month post-implantation, the neural response threshold compared with the behavioral threshold and the maximum comfort level estimated at the same time.

Results

At all the electrode numbers, the mean for NRT level measurements was significantly higher than that for the T-level measurements and the mean for the C-level measurements was significantly higher than that for NRT level measurements The correlation analyses showed positive correlation between C-level and NRT level measurements and T-level and NRT level measurements.

Conclusion

There was a positive correlation between NRT value measurements and both T and C value measurements. Therefore, it is useful to use the NRT values to predict the behavioral T and C values in prelingual children.