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.     

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.     

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。     

人工耳蜗植入术中电刺激中潜伏期听觉诱发电位的检测

目的 建立人工耳蜗植入术中电刺激中潜伏期听觉诱发电位(electrical evoked middle latency response,EMLR)的检测方法,为进一步评估植入者听觉传导通路及高位听觉反应的特点奠定基础.方法 20例人工耳蜗植入者,其中语前聋14例,语后聋6例,全部使用Cochlear公司Nucleus CI24R (CA)人工耳蜗.术中将言语处理器与计算机接口及听觉诱发电位仪触发端口连接,电极植入后,选取第3号电极,先常规进行电刺激听神经复合动作电位(electrically evoked auditory nerve compound active potentials,ECAP)测试初步了解听神经功能状态,然后进行EMLR检测.选择电刺激听性脑干反应(electrical auditory brainstem response,EABR)模式,采用单极刺激,双相交替脉冲电流方波,脉宽50 ～ 100μs,强度(电流级,current leve1,CL)由ECAP阈值上20 CL起,以5 CL为步长递减或递增,听觉诱发电位仪记录EMLR波形.对ECAP阈值与EMLR阈值进行相关性分析.另外选择6名听力正常健康受试者,行声刺激中潜伏期听觉诱发电位(auditory middle latency response,AMLR)测试,作为EMLR波形和潜伏期的声刺激对照.结果 6例听力正常受试者均可记录到AMLR波形,平均反应阈为(12.5±8.6)dBnHL,接近纯音测听阈值(10.8 ±7.3)dBHL.20例人工耳蜗植入者均可记录到EMLR波形,与AMLR波形相似,但各波潜伏期和波间期缩短,波幅变化不大;语前聋较语后聋总体上波幅小,潜伏期长.EMLR平均阈值为(140.55 ±9.92)CL,低于ECAP的平均阈值 ( 160.75±13.34) CL,差异具有统计学意义(t=10.467,P＜0.01);二者阈值之间呈正相关(r=0.763,P＜0.01).结论 人工耳蜗植入术中可成功记录到EMLR波形,其阈值较ECAP低,可以作为判断植入者中枢高位听觉传导功能的客观检查.     

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。     

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。     

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。     

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．     

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。     

电生理测试在力声特人工耳蜗调试中的应用

目的 分析电镫骨肌反射阈值(electrically evoked stapedius reflex threshold, ESRT)、电刺激听性脑干反应(electrically evoked auditory brainstem response, EABR)阈值、电刺激听神经复合动作电位(electrically evoked auditory nerve compound action potentials, ECAP)阈值与人工耳蜗心理物理量测试中的最大舒适阈值(maximum comfort threshold, C值)及最小反应阈值(minimum response threshold, T值)之间的关系，为力声特人工耳蜗植入者调试时参数设置提供参考。方法 选择14例具有一定响度辨别经验及言语交流能力且配合良好的语后聋力声特人工耳蜗植入者，平均年龄22.47±13.37岁，植入体型号为LCI-20PI。在每个患者开机后6±1个月时，选取人工耳蜗低频(1号)、中频(11号)、高频(19号)区域电极各一个，分别测试其T值、C值、ESRT、EABR及ECAP阈值，并进行相关性分...     

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.     

Electrically evoked compound action potential (ECAP) in cochlear implant children: Changes in auditory nerve response in first year of cochlear implant use

AimRecording of the electrically evoked compound action potential (ECAP) of the auditory nerve in cochlear implant (CI) patients represents an option to assess changes in auditory nerve responses and the interaction between the electrode bundle and the neural tissue over time. The aim of the present work is to assess ECAP changes during the first year of cochlear implant for the purpose of predicting thresholds and adjustment of the patients’ programs over time.MethodData were collected from 25 children using Cochlear Nucleus 24 implants. ECAP thresholds were examined at the time of surgery, at initial stimulation, and 3, 6 and 12 months post-stimulation. Five electrodes located at basal, middle, and apical positions in the cochlea were tested at each time interval and ECAP thresholds were analyzed and compared.ResultsThere was a significant decrease in ECAP thresholds between the intraoperative measure and fitting time at all electrode sites. Mean ECAP thresholds measured at 3, 6 and 12 months post-stimulation remained similar to initial stimulation levels. Although there was no significant difference in ECAP thresholds recorded at fitting time and 12 months follow up session, there was significant increase in behavioral T and C levels from initial stimulation to the 12 months’ time point.ConclusionMost electrodes undergo non-significant change in ECAP thresholds over time, and therefore thresholds obtained on the day of initial stimulation can be used to estimate the patients’ map levels at any time. On the other hand, intraoperative thresholds demonstrated significant change relative to postoperative recording times, limiting the ability to use intraoperatively recorded ECAP thresholds to predict postoperative measurements.     

Adaptation of the electrically evoked compound action potential (ECAP) recorded from nucleus CI24 cochlear implant users

OBJECTIVE: This study had three main goals. The first goal was to assess the extent to which neural adaptation varied across cochlear implant users. The second goal was to determine whether adaptation at the level of the auditory nerve was correlated with word recognition ability. The third goal was to determine whether peripheral neural adaptation had an impact on the relationship between the electrically evoked compound action potential (ECAP) thresholds and MAP levels. DESIGN: Neural response telemetry software was used to record the ECAP in 21 Nucleus cochlear implant users. A series of 110 ECAP recordings were made over a 5-min period at three different stimulation rates: 15, 80, and 300 Hz. The stimulation levels used to record this series of responses were held constant at or near the level the subject identified as his or her maximum comfort level (C-level) for the 300-Hz stimulation rate. Consistent decreases in ECAP amplitude as measured from the beginning to the end of the 5-min stimulation interval were interpreted as evidence of neural adaptation. Regression analysis procedures were then used to assess the relationship between neural adaptation and word recognition. RESULTS: Significant levels of adaptation were observed for all 21 subjects at stimulation rates of 80 and 300 Hz. Little or no adaptation was observed over the 5-min recording period when the 15-Hz rate was used. The amount of adaptation was greatest at the 300-Hz rate and varied substantially across cochlear implant users. No relationship between the amount of adaptation and word recognition was found. Neither was the degree of adaptation shown to influence the relationship between ECAP thresholds recorded at low rates and the levels used to program the speech processor. CONCLUSIONS: Cochlear implant users experienced varying degrees of long-term adaptation in response to continuous electrical stimulation. The effects of adaptation on the ECAP were apparent even at stimulation rates as low as 80 Hz. Although variations in the amount of adaptation are likely to reflect cross-subject differences in the status of the auditory nerve, no predictable relationship was found between these physiologic measures of peripheral neural function and either word recognition or the relationship between ECAP thresholds and MAP levels.     

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.     

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.     

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 Nucleus2 4型多导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 2 0例 Nucleus2 4型多导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造成的影响。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显著的是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