电诱发听性脑干反应在人工耳蜗植入的研究及临床应用

【作者】 张志利；

【导师】 曹克利； 魏朝刚； 王轶；

【作者基本信息】 中国协和医科大学 ， 耳鼻咽喉头颈外科学， 2009， 博士

【摘要】 【目的】探索和研究人工耳蜗植入术前/中针电极刺激鼓岬或圆窗龛记录电诱发听性脑于反应(EABR)。【方法】42例不同病因(包括耳蜗畸形、内听道狭窄、脑白质异常、前庭导水管扩大综合征等)、不同年龄的施行人工耳蜗植入的重度及极重度感音神经性耳聋患者,在全身麻醉下手术前/中进行电诱发听觉脑干反应测试。电刺激仪采用人工耳蜗体外言吾处理器连接改装的人工耳蜗植入体。刺激电极包括铂铱合金球电极、鼓岬刺激针电极和神经刺激套管针电极三种。实验分为三组(或三个阶段):第一组(阶段),共17例患者,使用球电极进行圆窗膜电刺激和鼓岬刺激针电刺激圆窗龛和/或鼓岬,球电极刺激作为对照,优化针电极的刺激和记录参数;第二组(阶段),共20例患者,在参数、方法等探索稳定后,进行术中鼓岬刺激针和神经刺激套管针刺激鼓岬和圆窗龛记录EABR;第三组(阶段),共5例患者,在第二组方法及刺激位置均摸索较成熟后,于术前鼓岬刺激针或神经刺激套管针经(跨)鼓膜刺激鼓岬或圆窗龛记录EABR,同时于手术中开放面隐窝后同一刺激针刺激同一位置,再次记录EABR,并同经鼓膜结果作对照。由人工耳蜗处理器连接植入体给予电刺激,Bio-logic Navigator Pro诱发电位仪记录电诱发听觉脑干反应。刺激电极放置方式和位置:1)手术中开放面隐窝后(植入人工耳蜗前),在直视下用球电极刺激圆窗膜、鼓岬刺激针或神经刺激套管针刺激圆窗龛和鼓岬;2)手术开始前,用针电极经鼓膜在其圆窗龛投映区处穿刺,刺激圆窗龛或鼓岬。术中直视下的电刺激位置包括圆窗龛底、圆窗龛上缘、前缘,并根据刺激位置将圆窗龛底分为一组,圆窗龛前缘、上缘分为一组,分别进行统计。植入后再次常规记录EABR。摸索参数,建立方法,对比植入前与植入后获得的波形特点,同时对比两种刺激针所引出波形的特点及规律,并在部分特殊病例进行初步临床应用。得到结果应用SPSS11.5统计软件进行统计学分析。【结果】第一组17例病人中,使用脉宽为50或75us的电脉冲,对所有病人分别进行球电极刺激圆窗膜和针电极刺激圆窗龛或鼓岬,其中在球电极电刺激圆窗膜中17例全部引出波形,针电极刺激圆窗龛或鼓岬17例中仅有4例引出EABR波形。在此基础上,我们对17例中的9例分别使用脉宽为50、75和200us的电脉冲,再行圆窗龛或鼓岬针电极刺激,在50/75us脉宽下,能引出EABR波形的为2例,而在200us的脉宽下9例均引出EABR波形。实验发现,不同电极形式和刺激部位诱发的EABR结果存在差异,其中球电极诱发的EABR:V波潜伏期平均为4.30±0.25ms,阈值为189.20±25.80CL,200us脉宽下针电极诱发的EABR:V波潜伏期为4.50±0.39ms,阈值为170.23±13.50CL。V波的引出率最高,其次是Ⅲ波,其余各波引出率不稳定。但针电极刺激诱发出的EABR波形比球电极刺激诱发的波形分化差。在针电极刺激时,尝试改变其它参数,如刺激速率、改用双极刺激模式、叠加次数、增益以及调整高、低通滤波等均未对波形引出率产生明显影响。第二组所有20例患者植入前均记录到明确的电诱发听性脑干反应波形,同一病人分别使用鼓岬针和神经刺激套管针进行电刺激8例,单独使用神经刺激套管针3例,单独使用鼓岬针电刺激8例,单独使用神经刺激套管针的外壳针电极进行刺激1例。V波全部引出,V波潜伏期平均4.70±0.58ms;Ⅲ波有10例引出,潜伏期平均2.91±0.45ms,Ⅲ-V间期2.01±0.38ms,反应平均阈值197.00±20.79CL,约相当于电流540uA。植入后有1例内听道狭窄病人EABR波形分化不典型,但NRT波形分化较好,其余19例植入后均获得明确的电诱发听性脑干反应波形,V波引出19例,平均潜伏期4.65±0.67ms;Ⅲ波引出13例,平均潜伏期2.66±0.61ms,Ⅲ-V间期2.09±0.51ms,平均反应阈值161.32±20.40CL,约相当于电流260uA。经统计学分析,植入前、植入后的Ⅲ波潜伏期、V波潜伏期、Ⅲ-V间期均P＞0.05;术中不同刺激部位之间的V波潜伏期、反应阈值均P＞0.05;植入前鼓岬刺激针和神经刺激套管针电极刺激的反应阈值比较P＞0.05;在植入前和植入后,无残余听力病人和有残余听力病人的V波潜伏期之间分别进行统计分析,均P＞0.05;植入后50us和200us脉宽下分别记录EABR,V波潜伏期相比较,P＞0.05,无统计学差别。植入前的反应阈值和植入后的反应阈值P＜0.05,植入后50us和200us脉宽下分别记录EABR阈值,统计分析结果为P＜0.05,有统计学差别。植入前针电极刺激所需要的神经刺激电流量动态范围较窄,平均约24.6CL,植入后约55CL。第三组,5例患者手术前、手术中植入前、植入后均记录出易于辨认的分化良好的波形,手术中同一位置同一刺激器再次记录诱发出的EABR波形与经鼓膜刺激获得的EABR波形重复性好,波形可靠,经鼓膜刺激的波形分化较手术中植入前同一位置的波形分化好。【结论】1、人工耳蜗植入前,经鼓膜针电极刺激鼓岬或圆窗龛记录EABR的方法是可行的,经鼓膜电刺激的EABR波形比术中植入前同一位置电刺激诱发的波形分化好;2、植入前针电极刺激鼓岬和圆窗龛记录的EABR,波形分化较术后蜗内记录的波形差,但波形引出率相似;3、在人工耳蜗植入前行针电极刺激时,脉宽和刺激点的位置是决定能否引出EABR波形的最重要因素;4、针电极刺激鼓岬或圆窗龛时,不同的位置之间以及同植入后蜗内刺激所引出的EABR波形可能会有差异,但总的阈值和潜伏期在统计学上无明显差别;5、不同脉宽下记录EABR,潜伏期基本相同,但阈值不同,脉宽越大,阈值越低,脉宽越小,波形分化越好,50us的脉宽如果能引出波形,其波形最容易辨认;6、神经刺激套管针和鼓岬针电刺激均能高效的引出EABR,两者之间的阈值和潜伏期无明显差别,但引出的波形在同一刺激参数下,神经刺激套管针分化更好,波形更容易辨认。更多还原

【Abstract】 [Objective]To research the method of recording electrically auditory brainstem responses(EABR) evoked by promontorium tympani or round window niche stimulation with needle electrode in/before cochlear implantation.[Methods]42 patients with different causes(including Inner Ear Malformation,abnormal white matter,large vestibular aqueduct Syndrome,etc) and ages were tested with EABR during cochlear implant surgery.The electrical stimulator was a modified Nucleus 24M cochlear implant which connected to a body worn speech processor.Three kinds of stimulating electrodes were used in this study,which included ball-end platinum-iridium wire electrode,promontory needle electrode and insulated nerve block needle for neurostimulation.The patients were divided into three groups(or three stages).The first group includes 17 patients whom were recorded electrically auditory brainstem responses(EABR) evoked,1) by round window membrane stimulation with ball-end electrode,and 2) by promontorium tympani or round window niche stimulation with needle electrode before cochlear implantat electrode insertion.The result of ball-end electrode stimulation was used to contrast.The objective was to optimize stimulating and recording parameters. The second group included 20 patients.After optimization of stimulating and recording parameters and method exploration,we got the EABR results from stimulating promontorium tympani or round window niche with needle electrode or nerve block needle.The third group included 5 patients.We got trans-tympanic electric auditory hrainstem response before the surgery and intra-operative EABR during surgery with promontory needle electrode or insulated nverve block needle.With modified Nucleus 24M cochlear implant connected to a body worn speech processor as the stimulation device,EABR was recorded by Bio-logic Navigator Pro evoked potential instrument.Modality of placement and location for electrodes:1)After opening facial recess and before cochlear implantation,stimulate promontorium tympani or round window niche with needle electrode or insulated nerve block needle,and stimulate round window membrane with ball-end wire electrode.2) Trans-tympanic electric auditory brainstem response before the surgery with promontory needle electrode or insulated nerve block electrode.A stimulating electrode was placed in three different positions:1) the floor of the RW niche round,2) anterior to the RW niche on the promontory and 3 ) superior to the RW niche on the promontory,which were divided into two parts:the first part for the first position and the second part for the last two positions.The results of two parts will be contrasted.Our objective was to explore and optimize the stable parameters for the trans-tympanic electric auditory brainstem response.It has been preliminarily used in some special cases.All the datas were analyzed by SPSS 11.5 statistic software.[Results]For the first group,all the patients received the positive EABR with the pulse width 50/75us.Clear EABR waveforms were recorded in all 17 cases with ball-end electrode stimulation.There were only 4 patients who got the clear EABR waveforms.9 of 17 patients with needle electrode stimulation participated in the further study,the pulse width were 50,75and 200us respectively.With the pulse width 50 or 75us,a clear EABR waveforms were recorded only in 2 cases.But with the pulse width 200us,the positive waveforms could be observed in all 9 cases.For all waveforms,wave V were the most stable to get,and waveⅢwas the second.For spherical electrode stimulation,the average latencies of waveformⅤwere 4.30±0.25ms,the average threshold was 189.20±25.80CL.And for needle electrode stimulation,the average latencies of waveformⅤwere 4.50±0.39ms,the average threshold was 170.23±13.50CL.EABR waveforms differentiation evoked by needle electrode stimulation were less than waveforms differentiation evoked by spherical electrode stimulation.Other parameters,such as rate,No of Sweeps,gain and so on influence waveform obsoletely.For the second group,clear EABR waveforms were recorded in all 20 cases with promontory needle electrode or insulated nverve block needle for neurostimulation intra-operation and before cochlear implants.WaveⅤwere recorded in all 20 cases,and waveⅢwere recorded in 10 of all 20 cases.The average latencies of waveformⅤand waveⅢandⅢ-Ⅴinterval before cochlear implantation were 4.70±0.58ms,2.91±0.45ms and 2.01±0.38ms respectively,and the average response threshold at 197.00±20.79CL,about 540uA.After cochlear implantation there was only one patient with internal acoustic canal who couldn’t get EABR waveform,but neural response telemetry(NRT) was elicited.19 cases get waveⅤand 13 cases get waveⅢwith pulse width at 200us.The average latencies of waveformⅤand waveⅢandⅢ-Ⅴinterval after cochlear implantation were 4.65±0.67ms,2.66±0.61ms and 2.09±0.51ms respectively,and the average response threshold at 161.32±20.40CL,about 260uA.There were no statistic difference in waveⅤlatency,waveⅢlatency andⅢ-Ⅴinterval between before cochlear implantation and after cochlear implantation.There were no statistic difference in average waveⅤlatency and average response threshold in different positions.There was no statistic difference in average response threshold between needle electrode and insulated nverve block needle for neurostimulation.There were no statistic difference in waveⅤlatency between presence of residual hearing group and absence of residual hearing group,and between pulse width in 50us and pulse width in 200us.There were statistic difference in average response threshold between pulse width in 50us and pulse width in 200us.The dynamic current level scope before and after cochlear implantation was 24.6CL and 55C1 respectively.For the third group,clear EABR waveforms were recorded before surgery, intra-operation and after surgery.Waveforms differentiation of trans-tympanic electric auditory brainstem response Were better than waveforms differentiation during intra-operation for the same position.[Conclusion]1.Trans-tympanic electric auditory brainstem response is feasible and stable. Waveforms differentiation of trans-tympanic electric auditory brainstem response were better than waveforms differentiation during intra-operation for the same position.2.The elicitation ratio of EABR evoked by the needle electrode before cochlear implantation was coherent compared with elicitation ratio after cochlear implantation,though the waveforms differentiation were pgorer.3.Average waveⅤlatency and average response threshold in different positions between promontorium tympani or round window niche stimulation with needle electrode before cochlear implantation and EABR after cochear implantation were similar,though there were still some difference.4.Position of needle electrode stimulation and pulse width were the most important reason for elicit good waveform.5.Waveforms latency for different pulse width was similar,but the response threshold was different and waveforms differentiation was better for short pulse width.6. Needle electrode and insulated nerve block neelde for neurostimulation were all efficient for elicit EABR,but the waveform differentiation evoked by insulated nerve block needle for neurostimulation was better than needle electrode.更多还原