In this text, the authors recall the main principles and data ruling cochlear implants. Then, a first circle of technical equipment for assistance is presented. This circle includes: device setting (DS), Electrically ...In this text, the authors recall the main principles and data ruling cochlear implants. Then, a first circle of technical equipment for assistance is presented. This circle includes: device setting (DS), Electrically evoked Auditory Brainstem Responses (EABR), Neural Response Telemetry (NRT), Stapedial Reflex (SR) and Electrodogram Acquisition (EA). This first cycle becomes more and more important as children are implanted younger and younger; the amount of data available with this assistance makes necessary the use of models (implicit or explicit) to handle this information. Consequently, this field is more open than ever.1 Introduction1 1.1 About Hearing Mechanisms The hearing function in human beings is something very specific and difficult to understand because it uses the brain highest functions. Basically, we can say (figure 1) that several stages are involved [1]: It is not easy to give a unique interpretation to each one of these stages, as most of the involved processes overlap at all levels. Nevertheless, as a brief summary, let us assume that [2]: l The ear transmits the air vibrations and transforms them into electric stimuli compatible with nerve excitation, l Auditory pathways carry the electric pulses; exchanges take place, through decussation and information goes up using left and right channels. Also, specific features in the signal are detected and encoded before reaching the brain (phonetic features), l Brain interpretation matches input cues with the previously stored data into the memory and make association at different levels of language. In this text, we will come back on some ear features, mostly on the transformation of acoustical vibrations into electrical information transmitted to the brain. We will focus on the technical circle, but people fitted with a cochlear implant (CI) must be seen at all levels of language [3] and a typical team is composed of: l a E.N.T. (Ear Nose Throat) practitioner, l the surgeon performing the implantation, l a psychologist (a strong will and a good surrounding will favour good results), l a speech therapist, because the patient must be evaluated and taught the new language he has to adapt with, l an audiologist who have to set the implant and to take care of the technical details, l a manufacturer contact as modifications and improvement must be passed to the team, and, also, assistance may be needed, l a research group because this technique is under deep scrutiny, l some financial structure, as implants are not free. Cochlear implant is a multidisciplinary science and one must keep it in mind in order to understand the gist of this subject. 1.2 Electrical Rehabilitation Conversion of acoustical vibration into electrical stimulus takes place in the ear, and specifically in the inner ear. The organ of Corti is in charge of this transformation. In the organ of Corti, the inner hair cells (IHC) are moved toward a membrane (the membrana tectoria) and the hair is bent. IHC discharge toward the auditory nerve ends and the stimulus is carried toward the brain [4]. Obviously, when the organ of Corti is destroyed, a total cophosis takes place, and it becomes useless to amplify the signal as no conversion will occur. To beat this handicap, William House and Blair Simmons had, in the sixties, the idea to replace the organ of Corti by a direct electrical stimulation delivered by an electrical device. CI general organisation is indicated on figure 2. Acoustical Wave Ear Auditory Pathways Brain Interpretation Message Figure 1 Main stages of hearing Acoustical Vibration Speech Processor Transmission Cochlear Implant Distribution to Nerve Ends Figure 2 General organisation of a cochlear展开更多
文摘目的探讨电刺激听性脑干反应(electrical stimulation-induced auditory brainstem response,EABR)监测在听神经瘤手术中对蜗神经通路的保护作用。方法回顾性分析36例听神经瘤患者手术资料,手术径路均为颅中窝径路,其中18例术中运用EABR监测作为监测组,另18例术中不做监测为对照组。监测组术前听力A级7耳,B级6耳,C级5耳,0.5、1、2、4 kHz平均纯音平均听阈(PTA)为37.60±16.95 dB HL,肿瘤最大直径为13.76±4.37 mm;对照组术前听力A级4耳,B级7耳,C级7耳,PTA为46.80±22.64 dB HL,肿瘤最大直径为13.74±4.26 mm。监测组在手术过程中进行四次EABR监测:第一次在内听道口暴露肿瘤后进行,第二次在到达内听道中段时进行,第三次在内听道底进行,第四次在彻底清除肿瘤及包膜时进行。术后一月复查听力,比较两组结果。结果监测组除了第一次监测时波V引出率为72.22%(13/18),其余三次均为100.00%(18/18);且能引出波V的最小电流刺激强度为0.5 mA,潜伏期为3.97±0.17 ms。术后1个月,监测组听力A级7耳,B级4耳,C级4耳,D级3耳,其中3例患者术后听力丧失,听力保留率为83.33%(15/18),术后PTA为52.20±38.35 dB HL。术后对照组听力A级1耳,B级1耳,C级6耳,D级10耳,其中10例患者术后听力丧失,听力保留率为44.44%(8/18),PTA为90.90±37.28 dB HL。术后监测组PTA、听力分级和听力保留率优于对照组。结论听神经瘤切除术中进行EABR监测,能协助外科医生辨别蜗神经,最大程度上保护了听神经通路的完整性,可提高听力保护率,为日后人工耳蜗植入提供了可能。
文摘In this text, the authors recall the main principles and data ruling cochlear implants. Then, a first circle of technical equipment for assistance is presented. This circle includes: device setting (DS), Electrically evoked Auditory Brainstem Responses (EABR), Neural Response Telemetry (NRT), Stapedial Reflex (SR) and Electrodogram Acquisition (EA). This first cycle becomes more and more important as children are implanted younger and younger; the amount of data available with this assistance makes necessary the use of models (implicit or explicit) to handle this information. Consequently, this field is more open than ever.1 Introduction1 1.1 About Hearing Mechanisms The hearing function in human beings is something very specific and difficult to understand because it uses the brain highest functions. Basically, we can say (figure 1) that several stages are involved [1]: It is not easy to give a unique interpretation to each one of these stages, as most of the involved processes overlap at all levels. Nevertheless, as a brief summary, let us assume that [2]: l The ear transmits the air vibrations and transforms them into electric stimuli compatible with nerve excitation, l Auditory pathways carry the electric pulses; exchanges take place, through decussation and information goes up using left and right channels. Also, specific features in the signal are detected and encoded before reaching the brain (phonetic features), l Brain interpretation matches input cues with the previously stored data into the memory and make association at different levels of language. In this text, we will come back on some ear features, mostly on the transformation of acoustical vibrations into electrical information transmitted to the brain. We will focus on the technical circle, but people fitted with a cochlear implant (CI) must be seen at all levels of language [3] and a typical team is composed of: l a E.N.T. (Ear Nose Throat) practitioner, l the surgeon performing the implantation, l a psychologist (a strong will and a good surrounding will favour good results), l a speech therapist, because the patient must be evaluated and taught the new language he has to adapt with, l an audiologist who have to set the implant and to take care of the technical details, l a manufacturer contact as modifications and improvement must be passed to the team, and, also, assistance may be needed, l a research group because this technique is under deep scrutiny, l some financial structure, as implants are not free. Cochlear implant is a multidisciplinary science and one must keep it in mind in order to understand the gist of this subject. 1.2 Electrical Rehabilitation Conversion of acoustical vibration into electrical stimulus takes place in the ear, and specifically in the inner ear. The organ of Corti is in charge of this transformation. In the organ of Corti, the inner hair cells (IHC) are moved toward a membrane (the membrana tectoria) and the hair is bent. IHC discharge toward the auditory nerve ends and the stimulus is carried toward the brain [4]. Obviously, when the organ of Corti is destroyed, a total cophosis takes place, and it becomes useless to amplify the signal as no conversion will occur. To beat this handicap, William House and Blair Simmons had, in the sixties, the idea to replace the organ of Corti by a direct electrical stimulation delivered by an electrical device. CI general organisation is indicated on figure 2. Acoustical Wave Ear Auditory Pathways Brain Interpretation Message Figure 1 Main stages of hearing Acoustical Vibration Speech Processor Transmission Cochlear Implant Distribution to Nerve Ends Figure 2 General organisation of a cochlear
