内耳畸形小儿人工耳蜗植入术后电极阻抗测试的研究

目的探讨内耳畸形小儿人工耳蜗植入手术后,植入体电极阻抗值的变化特点及规律。方法对36例澳大利亚Cochlear Nucleus 24型内耳畸形小儿人工耳蜗植入手术患儿,测试手术中及手术后1年阻抗值,并分析其特点及变化规律。结果患儿术中及开机后1年内高中低频段电极阻抗值变化趋势相同。电极阻抗值术中自开机显著增大,术中阻抗值最低,开机达到最大值,其后呈下降趋势,于开机3月后趋于平稳。结论内耳畸形小儿人工耳蜗植入手术后电极阻抗值开机3个月内变化明显,故需多次调机,以使患者语言感知达到最佳状态。     

人工耳蜗植入术后电极阻抗特性分析

目的对使用人工耳蜗系统患者的电极阻抗数值进行分析,总结电极阻抗的变化规律,为临床制定合理的术后调试计划提供依据。方法对152位使用澳大利亚Cochlear Nucleus24M型人工耳蜗系统的患者于术后4周左右安装体外设备并进行测试,使用澳大利亚Cochlear公司提供的R116或R126软件进行电极阻抗测试。结果患者电极阻抗数值自术中至术后开机时呈显著增加的趋势,在开机时达到最大,其后随开机时间的增长显著降低,至开机3个月后趋于稳定,不同部位的电极显示了相同的变化趋势。结论电极阻抗数值随术后使用时间及电极部位的变化而变化。在开机3个月内需多次进行调试,从而为患者提供最适合的程序,使患者的言语感知达到最佳状态。     

Nucleus 24CA型人工耳蜗植入后电极阻抗及T/C值变化分析

目的观察Nucleus 24CA型人工耳蜗植入后电极阻抗、行为反应阈值(T-level,T级)及最大舒适级(C-level,C级)的变化规律,分析其内在联系,探讨其对术后调机的指导意义。方法对81例植入Nucleus 24CA型人工耳蜗患儿,分别在术中、术后1、2、6个月进行电极阻抗阈值测试,收集术后对应T、C值,并对其变化规律及相关性进行统计学分析。结果电极阻抗值术中检测最低,术后1月开机最高,此后逐渐减低(P<0.01);自蜗顶至蜗底各通道间电极阻抗值无显著差异(P>0.05)。各电极通道T值、C值随术后时间延长逐渐增高(P<0.05),并与电极阻抗值呈线性相关。结论测定电极阻抗值是评估人工耳蜗刺激电极状态的有效手段;术后2月应同时调试T值及C值,此后则应对C值进行重点调试。     

经耳道皮下径路人工耳蜗植入术

目的:探讨经耳道皮下径路爱益声人工耳蜗植入手术的可能性.方法:40例双耳重度或极重度聋患儿采用经耳道皮下径路行爱益声人工耳蜗植入,术中行电极阻抗测试和电诱发听性脑干反应,术后拍耳蜗位X线片,术后4周开机验证电极植入位置及工作情况.结果:所有患儿电极全部顺利植入耳蜗内,人工耳蜗装置工作状态正常,术后随访6个月无电极脱出或...     

经耳道皮下径路人工耳蜗植入术

目的:探讨经耳道皮下径路爱益声人工耳蜗植入手术的可能性.方法:40例双耳重度或极重度聋患儿采用经耳道皮下径路行爱益声人工耳蜗植入,术中行电极阻抗测试和电诱发听性脑干反应,术后拍耳蜗位X线片,术后4周开机验证电极植入位置及工作情况.结果:所有患儿电极全部顺利植入耳蜗内,人工耳蜗装置工作状态正常,术后随访6个月无电极脱出或其它严重并发症发生.结论:爱益声人工耳蜗可以安全地经耳道皮下径路植入.     

小儿耳蜗植入后电诱发复合动作电位的阈值及其临床应用

目的：研究应用神经反应遥测（neural response telemetry,NRT)技术，测试电诱发复合动作电位（electrically-evoked compound action potential,ECAP)阈值以指导小儿人工耳蜗映射调图的策略与时机。方法：应用NRT3．0软件对辐值增长函数进行线性拟合，确定ECAP阈值。比较6例儿童植入者在术后1、2、3个月ECAP阈值的变化，同时比较了7例儿童术中、术后ECAP阈值的差异。结果：ECAP幅值增长函数在接近阈值或进入饱和时不再呈线性。术后ECAP阈值保持稳定。各导电极的术中ECAP阈值比术后阈值平均高约15CL，二者有显著性相关（R2＝0．9154）。结论：应选取幅值增长函数的直线段部分进行拟合以确定ECAP阈值。术后应用ECAP阈值指导小儿映射调图时，测试一次ECAP阈值即可。术中ECAP阈值可用作开机时映射图的C值。     

20例Med—EL Combi 40＋人工耳蜗术后电极阻抗和检测阈值及最大舒适阈值变化的观察

目的：观察Med—ELCombi40＋人工耳蜗植入后电极阻抗、检测阈值（THR）、最大舒适阈（MCL）、动态范围的变化规律,分析其内在联系,探讨其对术后调机的指导意义。方法：回顾性分析连续的20例植入Med—ELCombi40＋人工耳蜗患儿,对术中、术后1、3、6、12、24、36个月的电极阻抗值,以及对应时间点的THR、MCL值、动态范围进行分析,探讨其变化规律及相关性。结果：总体而言,各电极阻抗值术中检测最低,术后1个月时电阻较术中有明显升高（P〈0．01）,术后3个月时电阻略有下降（P〈0．01）,随后蜗顶组和中间组电极电阻基本趋于平稳,但蜗底的电极电阻呈逐年升高。各电极通道THR值基本随术后时间延长逐渐增高（P〈0．05）,MCL值术后早期呈显著上升（P〈0．05）,但第2年起趋于平稳。蜗底组电极的动态范围术后早期呈上升,但1年后出现下降趋势。各组电极电荷量术后3个月升高显著（P〈0．05）,术后1年起趋于稳定（P〉0．05）。电极电阻与动态范围的相关性较THR值、MCL值高,且呈负相关。术后3个月、6个月时的电极电阻与术后3年时的动态范围呈强负相关,均以蜗顶组最明显（r=-0．618,r=-0．636,均P〈0．01）。结论：电极电阻的变化规律会因电极的位置不同而异,测定电极阻抗值能有效评估人工耳蜗刺激电极状态;术后电极THR、MCL值与电极电阻的关联性小,可能受众多因素影响所致,但电极的动态范围与电阻呈负相关;术后3个月或6个月时的电极电阻具有预测动态范围大小的意义。     

儿童人工耳蜗植入术后电诱发复合动作电位分析

目的 应用神经反应遥测(NRT)技术,观察人工耳蜗植入后不同时间段的电诱发复合动作电位(ECAP)阈值变化,探讨其对人工耳蜗术后调机的指导意义。方法 对33例使用Nucleus CI24R(CA)型人工耳蜗植入的患儿,于术中及术后1、1.5、2、4、6个月进行ECAP 阈值测试,统计分析其变化规律。结果 33例165个电极的波形检出率为93.3%。电极1、7、11、17、22的术中ECAP阈值与术后30d开机时的ECAP阈值的差异有统计学意义。同一测试电极,随术后开机时间的增长,ECAP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ECAP阈值差异有统计学意义。结论 ECAP检出率高,术中可用于检测神经反应;术后可协助估算患者的行为反应T、C级,指导调机,尤其对儿童患者更为重要。     

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。     

368例人工耳蜗植入手术分析

目的探讨人工耳蜗植入手术的操作程序,以提高手术效率及手术安全性。方法回顾性分析人工耳蜗植入手术368例,手术均采用经后鼓室径路。术中行电极阻抗测试和神经反应遥测,术后拍耳蜗位X线平片判断电极植入情况,术后一个月开机调试及跟踪随访。结果所有患者电极全部顺利植入,人工耳蜗装置工作状态正常。术后3天1例出现迟发型面瘫,用激素保守治疗后逐渐恢复,术后45天1例患儿发生外耳道炎,术后2个月1例出现乳突及耳后骨膜下脓肿,术后7个月1例由于头部外伤致植入体损坏更换植入体,经积极处理后均恢复良好。全部病例术后随访24个月无永久性面瘫、植入体移位及脑膜炎等严重并发症发生,但术后4年3例患儿出现植入体外露合并皮肤感染。结论熟练掌握手术技巧并根据个体特点进行人工耳蜗植入手术对于提高植入成功率、重建听觉、减少手术并发症有着非常重要的意义,术后的长期随访甚至终生随访是必要的。     

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。     

A longitudinal study of electrode impedance, the electrically evoked compound action potential, and behavioral measures in nucleus 24 cochlear implant users.

OBJECTIVE: The primary goal of this study was to examine changes that may occur in electrode impedance, electrically evoked compound action potential (EAP) threshold and slope of the EAP growth function, and behavioral measures of threshold T-level) and maximum comfort (C-level) over time in both adult and child cochlear implant users. Secondary goals were to determine whether changes in these measures are consistent between children and adults, and to determine whether behavioral measures (MAP T- and C-levels) and electrophysiologic measures (EAP thresholds) exhibit the same trends over time. DESIGN: Thirty-five children and 33 adults implanted with the Nucleus CI24M between November 1996 and August 1999 participated in this study. Subjects were included in this study if 1) they had used their implant for at least 1 yr after device connection, and 2) they had participated in the necessary data collection at a minimum number of the time intervals assessed in this study. EAP threshold, slope of the EAP growth function, and common ground electrode impedance measures were collected intraoperatively, at initial stimulation, and at several subsequent visits up to 2 yr post initial stimulation. MAP T- an d C-levels weremeasured at initial stimulation and at the same time intervals as described above. RESULTS: Changes in electrode impedance, EAP thresholds, and slope of the EAP growth function from measures made intraoperatively, at initial stimulation, and at 1 to 2 mo post initial stimulation were similar in both children and adults. Beyond the 1- to 2-mo visit, children exhibited significant increases in electrode impedance, EAP thresholds, slope, and MAP T-levels, whereas these samemeasures in adults remained relatively stable. EAP thresholds in children stabilized by the 3- to 8-mo visit, and electrode impedance stabilized by the 6- to 8-mo visit, while slope of the EAP growth function, MAP T-levels,and MAP C-levels werestable by 1 yr post initial stimulation. C-levels in adults increased up to 1 yr post initial stimulation; however, the amount of increase was much smaller than that seen in children. In both children and adults, longitudinal trends in EAP thresholds mirrored T-level more closely than C-level. CONCLUSIONS: The results of this study suggest that peripheral changes occur in many children that do not generally occur in adults within the first year of cochlear implant use. One implication of these results is that if EAP thresholds are to be used to assist in programming the speech processor for children, it is best to make those measures at the same time interval as device programming rather than using measures made intraoperatively or at the initial programming session to set MAP levels at later visits.     

Electrode impedance changes over time in MED El cochlear implant children recipients: Relation to stimulation levels and behavioral measures

Objective: Electrode impedance measures resistance encountered by electric current passing through wires, electrodes and biological tissue. This study was designed mainly to evaluate changes in electrode impedance values and psycho-electric parameters changes (i.e. threshold levels, comfortable levels, and dynamic range) in cochlear implant patients over time.

Methods: It was a prospective study encompassing 20 patients implanted by MED-EL device programd using behavioral programs. Electrical stimulation levels and electrode impedance values were examined at 0, 1, 3 and 6 months after the first fitting session.

Results: Electrode impedance values were reduced from the time of activation to the 6 months visit. Most comfortable levels increased and dynamic range widened until the 6 months visit. There was an inverse correlation between impedance values and most comfortable level as well as dynamic range, over time.

Conclusion: Frequent monitoring of electrode impedance (for device and electrodes problems) and electric stimulation levels (for better performance, mapping and habituation) during the first 6 months of implant use is recommended.     

大前庭水管综合征与内耳结构正常患儿人工耳蜗术后心理物理测试比较

目的:探讨大前庭水管综合征患儿人工耳蜗植入术后阈值、舒适阈和电极阻抗的特点,为这类患儿进行人工耳蜗植入术的可行性提供依据。方法:将131例语前聋患儿,根据CT检查结果分为A和B两组,A组111例,内耳结构正常;B组20例,双侧前庭导水管扩大,但不伴有其他内耳结构异常。所有患儿均使用澳大利亚Cochlear公司生产的Nucleus24M型人工耳蜗。术后4周左右安装体外设备并进行心理物理测试,使用与患儿年龄相应的方法进行阈值和舒适阈的测试;使用R116和R126软件自动测试电极阻抗。结果:经独立样本t检验,两组各电极的阈值和舒适阈的差异均无统计学意义(均P>0.05);两组心理物理测试值即阈值和舒适阈,在开机时和开机后1、2、3周,2、3、6、9个月及1年的差异无统计学意义(均P>0.05)。两组各电极阻抗之间的差异无统计学意义(均P>0.05);两组电极阻抗在开机时和开机后1、2、3周,2、3、6、9个月及1年的差异无统计学意义(均P>0.05)。结论:大前庭水管综合征患儿与内耳结构正常患儿人工耳蜗植入术后的差异无统计学意义,为大前庭水管综合征患儿制定术后调试计划及设置各电刺激参数时,均可采用与内耳结构正常患儿相同的方法。     

Electrode impedance in adults and children using the Nucleus 24 cochlear implant system

This study measured changes in electrode impedance over time in 19 adults and 29 children implanted with the Nucleus 24 cochlear implant system, using common ground and three monopolar modes of stimulation, over a series of time intervals. Impedances increased from the intraoperative to the initial fitting session, decreased during the initial fitting session and for the following week, and were then stable. Impedances were lowest for the common ground mode, while for the monopolar modes, impedances were related to the surface area of the return electrode. Impedances for children were higher than those for adults at the initial fitting session and for the following three weeks. The clinically measured impedance values increased in a basal-to-apical direction. When these data were corrected for differences in electrode surface area, impedances decreased in a basal-to-apical direction. Impedances were influenced by whether the electrodes were stimulated or unstimulated. Adults with higher electrode impedances tended to have lower hearing thresholds and comfortable listening levels, but this did not appear to clearly be the case for children.     

Estimation of psychophysical levels using the electrically evoked compound action potential measured with the neural response telemetry capabilities of Cochlear Corporation's CI24M device.

OBJECTIVE: The goal of this study was to estimate psychophysical levels using the electrically evoked compound action potential (EAP), measured with the Neural Response Telemetry capabilities of Cochlear Corporation's Nucleus CI24M cochlear implant system. DESIGN: Twelve postlingually deafened adults with at least 3 mo of implant experience with the CI24M were subjects in this study. EAP growth functions were successfully quantified on each active electrode of every subject. Correlation and regression analyses were performed between EAP measures and cochlear implant fitting psychophysics. Other information including performance, etiology and duration of hearing loss, and individual electrode impedance was considered. RESULTS: EAP thresholds were found to be highly correlated with psychophysical thresholds. The rate of EAP growth with increasing stimulation levels was also found to be correlated with the dynamic range of loudness limits and psychophysical thresholds in some subjects. No relationship was evident between EAP measures and speech perception tests. CONCLUSIONS: Information from EAP growth function measurements may be used to estimate psychophysical information used in cochlear implant fitting but not to predict performance with the device.     

Measurement and analysis of access resistance and polarization impedance in cochlear implant recipients.

BACKGROUND: Impedance measurements are commonly performed at the end of cochlear implant surgery, not only to confirm that all electrodes are working but also to monitor the impedances of the newly implanted electrodes. The current method of testing allows the determination of only the overall electrode impedance but not its components, access resistance and polarization impedance. To determine whether any longitudinal change in the electrode impedance is caused by a change in the endocochlear environment or rather caused by a change in the surface quality of the electrode, it is necessary to extract access resistance and polarization impedance. METHODS: We applied an impedance model that enabled us to calculate access resistance and polarization impedance after measurement of electrode impedance at three points along the voltage waveform. RESULTS: The results show that the value of the components of electrode impedance varied with time after surgery: access resistance increased slowly over time, whereas polarization impedance increased up to Week 2 but decreased after commencement of electrical stimulation at that stage. These results are consistent with the hypothesis that a layer of fibrous tissue forms around the electrode within the cochlear canal, resulting in a slow increase of access resistance, whereas a layer of proteins forms on the surface of the electrode in the early phase after implantation. Electrical stimulation appears to disperse this surface layer, thereby reducing both the polarization impedance and electrode impedance. CONCLUSION: The method presented enables the extraction of more detailed information about the longitudinal changes in the intracochlear environment after cochlear implantation.     

Long-term electrode impedance changes and failure prevalence in cochlear implants

Objective: This study assessed the prevalence of electrode failures and electrode impedance measures in Nucleus cochlear implants around initial activation (an average of 16 days after surgery) and after 8 to 12 years of device use. Design: Retrospective data from the Melbourne Cochlear Implant Clinic was collated and analysed. Study sample: Included in this study were 232 adults, all of whom were implanted at the clinic between March 1998 and August 2005. Results: Overall 0.5% of electrodes failed over the entire test period, with 5.6% of devices showing one or more electrode failure. The majority of these failures were recorded by initial activation. The numbers of electrode failures have decreased over time with array type, such that no failures were recorded with the currently available Contour Advance array. Array type was shown to affect electrode impedance at both time points, with the Contour and Contour Advance arrays having significantly higher absolute values than the Banded array. However, the Banded array had significantly higher area-normalized impedances at initial and final measures than the Contour and Contour Advance array. Conclusions: A relatively low incidence of electrode failures were recorded for the Nucleus devices of these recipients. Electrode impedance dropped for all array types after 8 to 12 years of device use.     

Effect of age,electrode array,and time on cochlear implant impedances

Objectives: To determine the impact of age, electrode array, and time on impedance patterns in cochlear implant (CI) patients.

Methods: A retrospective case review was performed on 98 patients implanted with the CI24RE perimodiolar (PM) and CI422 lateral wall (LW) arrays between 2010 and 2014 to assess impedances at the 1 week and 3–6 month visit after initial stimulation (IS).

Results: With respect to age, impedances were higher in young patients compared to older patients in the middle and apical turns. With time, there were significant reductions in impedances across most electrodes. Electrode array type also had a significant impact on impedance measurements with PM and LW arrays having higher impedances in the basal turn and apical turns, respectively. Furthermore, PM arrays demonstrated significantly lower impedances in the middle and apical turn with time, when compared to LW arrays.

Conclusions: Age, electrode array, and time can independently affect CI impedances. Moreover, we show that PM arrays may be advantageous to LW arrays, due to demonstrated lower impedances in the middle and apical turns long term. Understanding the impact of impedance on speech discrimination and determining the intracochlear processes that contribute to differences in impedance are future research directions.     

大前庭水管综合征患儿人工耳蜗植入效果分析

目的比较大前庭水管综合征（1arge vestibular aqueduct syndrome,LVAS）和内耳结构正常人工耳蜗植入术后最大舒适阈值（most comfortab lelevel,M值）和神经反应成像阈值（neural response imaging threshold,tNRI值）,为LVAS患者进行人工耳蜗植入术的可行性提供依据。方法将38例耳聋患儿根据CT检查结果分为A、B两组,A组32例,内耳结构正常;B组6例,双侧前庭导水管扩大,但不伴有其他内耳结构异常。所有患儿均植入美国Advanced Bionics公司生产的HiRes90K人工耳蜗系统。术后1个月左右安装体外设备并进行测试,使用与患儿年龄相应的行为测试方法进行舒适阈的测试;同时用SoundWave1．4调机软件行神经反应成像（neural response imaging,NRI）检测,记录tNRI值。结果两组术后1月开机时3、7、11和15号电极的M值和tNRI值的差异均无统计学意义（P〉0．05）。结论LVAS患儿并非人工耳蜗植入的禁忌,且术后调试时各指标的设定可参考内耳结构正常患儿的数值。