神经反应遥测技术应用于婴幼儿人工耳蜗植入的作用和体会

目的探讨应用神经反应遥测技术（NRT）在人工耳蜗植入术中监测，术后调机中的作用和经验体会。方法回顾性分析38例经历人工耳蜗植入的婴幼儿的临床资料，收集每例患者在术中、术后开机、调机应用NRT测试电诱发听神经复合动作电位（ECAP）的阈值数据，应用听觉整合量表（IT MAIS）评估行为听觉言语功能。结果38例婴幼儿在术中植电极进入耳蜗后均实施NRT测试，每例测试5个电极，分别为1、6、11、16、22号电极，共测试了190个电极，其中163个电极（85.8%）引出了ECAP，其平均阈值为（163.8±21.2）CL。近端1号电极ECAP阈值显著高于远端22号电极（P<0.05）。从开机到开机后12个月，各电极ECAP阈值无显著变化。3岁以下患儿中，25例患儿在各次NRT测试时所有电极都能引出ECAP，而8例患儿存在1~5个电极不能引出ECAP，在开机12个月后，后者的IT MAIS积分与前者比较差异无统计学意义（P>0.05）。结论人工耳蜗植入后NRT测试的ECAP阈值在近端电极显著高于远端电极，耳蜗内数个电极引不出ECAP不影响术后的听觉言语康复。     

人工耳蜗植入前电刺激听神经复合动作电位检测方法的建立和初步应用

目的 建立术中利用探测电极施行电刺激听神经复合动作电位(electrically evoked auditory nerve compound active potentials,ECAP)检测的方法,在植入人工耳蜗装置前评估患者耳蜗听神经功能状况.方法 选择20例人工耳蜗植入患者,其中耳蜗形态发育正常12例,5例双侧前庭导水管扩大,3例双侧耳蜗Mondini畸形.测试完成后全部使用Cochlear人工耳蜗.全麻后常规人工耳蜗手术进路,行标准耳蜗鼓阶开窗,将自制测试用多通道试验电极置入鼓阶,电极连接Cochlear公司体外言语处理器及自制电刺激发生器,连接电脑,采用Custom Sound EP 2.0软件,调整优化刺激参数进行神经反应遥测(neural responsetelemetry,NRT)初步了解听神经功能状态;刺激强度以5 CL为步长递减或递增至反应阈值给予电刺激脉冲,同时自动记录ECAP波形和阈值.植入人工耳蜗后常规进行NRT检测,记录ECAP波形和阈值;术后1个月患者开机后采集T、C值,将两种电极测试所得阈值和开机C值进行相关性研究,并进行数据统计分析.结果 试验电极ECAP引出率为90%,商业电极ECAP引出率为90%,平均阈值分别为(160.50±15.12)CL和(160.00±11.27)CL,两者经统计学检验没有显著性差异(P>0.05);和开机后C值(177.40±10.61)有明显相关性(R2=0.844,r=0.919).结论 成功建立了术中植入人工耳蜗装置前的ECAP检测方法,为内耳和/或听觉通路发育异常及无残余听力患者提供有效的听神经反应信息,对了解听觉系统发育程度及初步预测术后患者康复情况提供客观依据.     

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 (neuralresponsetelemetry ,NRT)技术 ,测试电诱发复合动作电位 (electrically evokedcompoundactionpotential,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软件对幅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 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 =0 915 4)。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     

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、准确地判断人工耳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(neuralresponsetelemetry,NRT)监测6个电极的电诱发听神经复合动作电位(electricallyevokedauditorynervecompoundactionpotentials,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反应阈值和较高的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.     

ECAP检出与否的人工耳蜗植入患者的EABR表现

目的比较分析ECAP检出与否的耳蜗植入患者EABR特点,探讨EABR检测的意义。方法对26例人工耳蜗植入患者分别行神经反应遥测neural response telemetry,NRT）检测评估ECAP,并进行电诱发听洼脑干反应（electrically auditory evoked response,EABR）检测,将第20、10、3号电极均引出ECAP波形的14例患者纳入A组,未检出ECAP波形的12例患者纳入B组。对A、B两组患者的EABR阈值、V波潜伏期进行比较分析。结果A、B两组患者20、10、3号电极EABR阈值之间的差异有统计学意义（P〈0．001）,V波潜伏期之间的差异无统计学意义（P〉0．05）。结论ECAP波形引出与否人工耳蜗植入患者的EABR阈值有显著差异,v波潜伏期无明显差异。     

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。     

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。     

人工耳蜗植入的术中检测

目的　评估人工耳蜗植入术中的电极阻抗测试、神经反应遥测的临床意义 ,探讨术中检测的方式。方法　对 6 5例植入NucleusCI2 4人工耳蜗的患者在术中进行电极阻抗测试 ,其中 37例进行了神经反应遥测 (neuralresponsetelemetry ,NRT)对测试步骤及注意事项进行了分析。结果　 9.2 %的患者术中电极阻抗测试显示个别电极出现短路或开路 ;5 .4 %的患者 ,术中NRT测试得不到分化良好的ECAP。结论　电极坏损与植入过程中的重复插拔有一定的因果关系。不应把ECAP引出与否作为衡量手术成功的唯一指征 ,即使ECAP引不出 ,也不要多次插拔电极序列 ,以免出现电极坏损     

神经反应遥测技术在人工耳蜗植入术中的应用

目的 探讨人工耳蜗植入术中神经反应遥测(neural response telemetry，NRT)技术的应用情况。方法 对10例Nucleus CI24M及4例Nucleus CI24R(CS)人工耳蜗植入术的患儿在术中及术后一个月进行NRT检测，比较两者术中和术后的电诱发复合动作电位(electrically-evoked compound action potential，ECAP)阈值差异，并利用术中ECAP阈值指导首个言语处理器映射图。结果 14例患儿术中各电极的ECAP平均阈值均高于术后一个月开机时相应电极的ECAP平均阈值，CI24M植入体各电极的术中ECAP阈值比术后相应电极的ECAP阈值平均高11CL；术中10个电极相应的ECAP波形采集只需5分钟；术后开机整个过程约1小时。结论 术中应用NRT技术可快捷地了解植入体安置的情况，指导术后首个映射图的调试，明显节省了术后开机调试的时间，操作简单、方便，值得推广。     

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。     

Nucleus24型人工耳蜗使用者电诱发听神经复合动作电位的测定

目的 :探讨电诱发听神经复合动作电位 (ECAP)的特点及在人工耳蜗临床中的应用价值和意义。方法 :应用NRT(neuralresponsetelemetry)软件 ,通过体外言语处理器和耳蜗内的植入电极系统 ,采用单极模式电极刺激和近场记录方法 ,对 37例NucleusCI2 4M装置使用者进行ECAP的记录。对其中 12例使用者做了行为测试。结果 :87.6 %的使用者记录到ECAP波形。分析了有行为阈值的 12例测试者的ECAP阈值和行为阈值的关系 ,二者之间存在显著的相关性。结论 :ECAP的检出率高且波形稳定可靠 ,在临床人工耳蜗装置的调试中可作为对行为测试的补充 ;对于年幼儿童和首次开机的患者的调试尤其重要     

Toward a battery of behavioral and objective measures to achieve optimal cochlear implant stimulation levels in children

OBJECTIVES: Children require audible and comfortable stimulation from their cochlear implants immediately after device activation. To accomplish this, a battery of objective measures may be needed that could include the electrically evoked stapedius reflex (ESR), compound action potential from the auditory nerve (ECAP), and/or auditory brain stem response (EABR). In the present study, the following specific research questions were asked: In children using cochlear implants, 1) Can the ECAP, EABR, and ESR be recorded at the time of cochlear implantation? 2) What is the feasibility of measuring the ECAP, EABR, and the ESR repeatedly without the use of sedation over the first year of implant use? 3) Do ECAP, EABR, and ESR thresholds or behavioral measures change over time? 4) What is the relation between ECAP, EABR, and ESR thresholds and behavioral measures of threshold and comfortably loud levels? DESIGN: In 68 children, ECAP, EABR, and ESR responses as well as behavioral measures of stimulation threshold and maximum stimulation were recorded at regular intervals over the first year of implant use. In each child, responses were recorded to electrical pulses provided by three different electrodes along the implanted array. Visual inspections of the stapedius reflex (V-ESR) evoked by activation of the same three electrodes at the time of surgery were performed in an additional 20 children. RESULTS: ECAP and EABR measures were obtained in more than 84% of electrodes tested and 89% of children tested both in the operating room at the time of implant surgery (OR) and after surgery in nonsedated children. ESRs were recorded by using immittance measures in more than 65% of electrodes tested and 67% of children tested by 3 mo of implant use, but this technique was less successful in the OR and during early stages of device use. V-ESRs and ECAP thresholds were higher in the OR than ESRs and ECAPs at postoperative recording times. EABR and ECAP thresholds did not significantly change over the first 6 and 12 mo of implant use, respectively, whereas ESR thresholds increased. Behavioral measures of threshold decreased over time, whereas maximum stimulation levels rose over time. Behavioral measures of threshold and loudness were highly correlated at all test times. ECAP, EABR, and behavioral measures were lower when evoked by an electrode at the apical end of the implanted array than by more basal electrodes. Behavioral thresholds could be predicted mainly by ECAP thresholds, whereas maximum stimulation levels could best be predicted by ESR thresholds; both were significantly affected by the age at implantation. CONCLUSIONS: A combination of nonbehavioral measures can aid in the determination of useful cochlear implant stimulation levels, particularly in young children and infants with limited auditory experience. These measures can be made in the operating room and can be repeated after surgery when needed. Correction factors to predict threshold stimulation levels should be based on ECAP thresholds or EABR thresholds if necessary. Correction factors should be made for at least one apical and mid-array electrode, should take into account the age of the child, and may have to be revised during the first year of implant use. Maximum stimulation levels may be best determined by using the ESR.     

Clinical application of electrically evoked compound action potentials

ECAPs are the summary of multiple neurons’ spikes which could be recorded by a bidirectional stimulation-recording system via the cochlear implant, with the artifact elimination paradigms of forward-masking subtraction paradigm or alternating polarity paradigm. Three kinds of FDA approved cochlear implants support ECAP testing. This article is to summarize the clinical application of ECAP test. ECAP test after insertion of electrode during implant operation has been widely used during cochlear implant surgery. In recent years, ECAP thresholds are also used to estimate the T levels and C levels helping programming. However, correlation between ECAP thresholds and psychophysical thresholds is affected by many factors. So far, ECAPs cannot yet be a good indicator of post-operative hearing and speech performance.     

Assessing the Electrode-Neuron Interface with the Electrically Evoked Compound Action Potential,Electrode Position,and Behavioral Thresholds

Variability in speech perception scores among cochlear implant listeners may largely reflect the variable efficacy of implant electrodes to convey stimulus information to the auditory nerve. In the present study, three metrics were applied to assess the quality of the electrode-neuron interface of individual cochlear implant channels: the electrically evoked compound action potential (ECAP), the estimation of electrode position using computerized tomography (CT), and behavioral thresholds using focused stimulation. The primary motivation of this approach is to evaluate the ECAP as a site-specific measure of the electrode-neuron interface in the context of two peripheral factors that likely contribute to degraded perception: large electrode-to-modiolus distance and reduced neural density. Ten unilaterally implanted adults with Advanced Bionics HiRes90k devices participated. ECAPs were elicited with monopolar stimulation within a forward-masking paradigm to construct channel interaction functions (CIF), behavioral thresholds were obtained with quadrupolar (sQP) stimulation, and data from imaging provided estimates of electrode-to-modiolus distance and scalar location (scala tympani (ST), intermediate, or scala vestibuli (SV)) for each electrode. The width of the ECAP CIF was positively correlated with electrode-to-modiolus distance; both of these measures were also influenced by scalar position. The ECAP peak amplitude was negatively correlated with behavioral thresholds. Moreover, subjects with low behavioral thresholds and large ECAP amplitudes, averaged across electrodes, tended to have higher speech perception scores. These results suggest a potential clinical role for the ECAP in the objective assessment of individual cochlear implant channels, with the potential to improve speech perception outcomes.     

Intraoperative findings on ECAP-measurement: Normal or special case?

Objective: This study aimed to investigate the measurability and threshold level of electrically evoked compound action potentials (ECAPs) in order to provide a baseline for the development of diagnostic references to support aftercare procedures. Design: In this retrospective study, cochlear implant patients were grouped according to the electrode array type and preoperative diagnostic findings from radiological imaging. ECAP measurements were performed intraoperatively on 22 electrodes for each patient resulting in two comparisons: (1) normal vs. pathological findings based on imaging with same electrode array, (2) perimodiolar electrode vs. straight electrode array within the normal group. Study sample: The study sample consisted of 218 ears with a Nucleus^® implant. Results: In the group with normal radiological imaging, the percentage of measurable ECAPs was higher than in the pathological group. The ECAP thresholds on 21 electrodes were significantly different between the two groups. Furthermore the thresholds were significantly lower for basal electrodes mainly for the two different electrode types. Conclusion: The pathological changes in the inner ear, the type of electrode array, and the electrode position affect the ECAP threshold. Further consideration suggests that a receiver operating characteristic curve can be derived from the results.     

A comparison of intra- versus post-operatively acquired electrically evoked compound action potentials

The objective of this study was to compare the electrically evoked compound action potentials, intra- versus post-operatively, in cochlear implant patients. In a prospective study twenty-five consecutively implanted adult patients received a multichannel cochlear implant. In all patients, electrically evoked compound action potentials were recorded immediately after cochlear implantation and in a post-operative setting nine months later. The threshold of the electrically evoked compound action potential was determined in both settings. A high success rate (97.4%) was found in the intra-operative setting when recording the electrically evoked compound action potential threshold per patient. The success rate per patient was significantly lower (53.4%) in the post-operative setting. Correlations between the intra- versus the post-operative ECAP thresholds were statistically significant for all electrodes tested. The ECAP thresholds were not significantly different for the two settings. The intra-operative setting is preferable for acquisition of the ECAP threshold.     

A comparison of intra- versus post-operatively acquired electrically evoked compound action potentials

The objective of this study was to compare the electrically evoked compound action potentials, intra- versus post-operatively, in cochlear implant patients. In a prospective study twenty-five consecutively implanted adult patients received a multichannel cochlear implant. In all patients, electrically evoked compound action potentials were recorded immediately after cochlear implantation and in a post-operative setting nine months later. The threshold of the electrically evoked compound action potential was determined in both settings. A high success rate (97.4%) was found in the intra-operative setting when recording the electrically evoked compound action potential threshold per patient. The success rate per patient was significantly lower (53.4%) in the post-operative setting. Correlations between the intra- versus the post-operative ECAP thresholds were statistically significant for all electrodes tested. The ECAP thresholds were not significantly different for the two settings. The intra-operative setting is preferable for acquisition of the ECAP threshold.     

神经反应遥测技术在人工耳蜗术后调试中的应用

目的通过对小儿人工耳蜗植入者术后言语处理器调试中运用NRT（神经反应遥侧）技术效果的分析．探讨NRT在人工耳蜗术后调试中的应用价值。方法选取10例术后主观调试配合欠佳的儿童．用Cochlear公司NRT3．0编程软件进行ECAP波形检测并测定ECAP阈值，利用测试结果判断主观阈值（T-值）和最大舒适阈（C-值），并得出言语处理器映射图（Map）。术后6个月行声场听阈测听。结果86．2％的电极引出ECAP波形，开机调试时反应阈值较小，以后逐渐升高，3～4个月左右闽值逐渐趋于稳定，而且靠近蜗底的阈值比蜗尖高。声场平均听阈为30～40dBSPL。经过言语康复训练，获得良好的效果。结论NRT技术可为术后快速准确地调试言语处理器提供客观依据．