耳蜗电极的发展概况

电子耳蜗是一种可以使全聋患恢复听觉的医学装置。20多年来，耳蜗电极的设计一直是研究的焦点。本首先介绍了耳蜗电极从最初的单一电极到目前的电极组的发展概况，然后介绍了影响耳蜗电极刺激效果的因素，最后简单介绍了几种目前常见的电极组。     

耳蜗植入术的发展和展望

耳蚋植入术又称电子耳蜗或人工耳蜗,是目前唯一可以使全聋患者恢复听力的装置。本文首先介绍了耳蜗植入术的概况和基本结构与原理,然后介绍了其关键技术及今后的研究方向,最后对我国耳蜗植入的发展作了展望。     

耳蜗植入术的发展和展望

耳蜗植入术又称电子耳蜗或人工耳蜗,是目前唯一可以使全聋患者恢复听力的装置。本文首先介绍了耳蜗植入术的概况和基本结构与原理,然后介绍了其关键技术及今后的研究方向,最后对我国耳蜗植入的发展作了展望。     

基于Bark域的电子耳蜗频带划分分析和拟合研究

目前电子耳蜗主流的言语处理策略是基于滤波器组的言语处理算法,该算法通过分频带进行信号处理并把参数传递到对应的电极上。电子耳蜗滤波器组的频带划分不是等分的,而是按一定规律进行并且符合人耳听觉特性的,其中,Bark域的频带划分是重要的参考。本研究基于Bark域的电子耳蜗频带划分方法,探讨Bark域频带划分的特性并结合目前的电子耳蜗滤波器组的频带划分进行分析,进而探讨频带划分中的曲线拟合方法,为电子耳蜗滤波器组中的频带划分提供重要的方法和参数。     

人工电子耳蜗语音编码策略的发展

人工电子耳蜗是一种利用功能性电刺激恢复重度或完全失聪患者部分听力的医学装置.目前大部分人工电子耳蜗的使用者都可以在安静的环境下进行顺畅的电话交谈.本文简单介绍了人工电子耳蜗的基本原理,然后着重阐述了其语音编码策略及其发展趋势.     

电子耳蜗在医学中的应用

一、电刺激的种类 电刺激可分为三类:①功能性电刺激:指借电刺激恢复人体的某些收缩功能,如心脏起搏器,步态矫正器,瘫痪肢体刺激器等。1997年美国FDA批准了一种叫“自由臂”的手臂刺激器,将刺激电极植入瘫痪的手臂中,利用异侧肩部传感器控制臂和手指运动。又如美国研制一种“VOCARE”刺激器,将电极植入在骶骨下的神经节,可使脊柱损伤后大、小便失禁患者     

电子耳蜗实现方案及其信号处理算法研究进展

介绍了当前主要的电子耳蜗实现方案、语音信号处理策略以及现有的电子耳蜗植入芯片。旨在描述和评价电子耳蜗实现过程中的关键所在，并结合我们在这方面的工作，对该领域的发展方向和前沿课题提出了一些看法。     

对人工耳蜗植入患儿的家长实施健康教育的体会

电子耳蜗植入术成为帮助深度耳聋和重聋患者重获听力和语言分析能力、提高与人沟通能力的一种特殊技术，而家长是小儿最亲近、最容易接受和最信任的人，更是聋儿的第一任教师。对家长实施健康教育，对患儿术后的听觉言语康复效果有直接的影响。我科对2003年7月至2004年6月收治的11例人工耳蜗植入患儿的家长实施健康教育，取得了满意效果。现汇报如下。     

人工电子耳蜗语音信号处理方法的研究进展

人工电子耳蜗是全聋人健康的一项新技术。我们从系统角度出发，首先简单阐述了其原理及系统设计，在此基础上重点综述了目前人工电子耳蜗中所涉及的语音信号处理方法的研究进展状况，并对未来的研究提出了设想。     

联合使用助听器和增强电子耳蜗的使用者的中文语音识别

目的使用电子耳蜗与助听器联合的声学模拟考察在语音成形噪声中的中文语音识别.方法使用1增/1减的信噪比自适应变化过程,测试了6个具有正常听力、使用中文语言的被试者在语音成形噪声中的中文句子识别门限(speech recognitionthresholds,SRT).结果中文语音识别门限SRT随模拟系统中助听器的低通滤波截止频率变化的曲线呈现与低通滤波的幅频响应相似的形状.结论只要助听器恢复的残存低频声学听力覆盖了说话人的基频范围,这些低频信息就能显著地帮助电子耳蜗使用者在语音成形噪声中识别中文语音,无论电子耳蜗的整体输入频率范围与助听器恢复的频率范围是否交叠.     

电子耳蜗双麦克风信号采集及不同参数波束形成特征研究

为了提高噪声环境下的电子耳蜗言语识别率,麦克风阵列语音增强的方法逐渐应用在电子耳蜗前端信号采集中。由于电子耳蜗尺寸的限制,双麦克风阵列信号采集是常见的模式,其形成的系统波束指向可用于特定方位的干扰信号的抑制。延迟、权重、频率和间距等参数影响着双麦克风系统的极性图。本文研究基于双麦克风模式的电子耳蜗信号采集和不同参数条件下的波束形成特点,为双麦克风模式的语音增强算法研究提供支持。     

骨科内植物多功能涂层研究进展

无菌性松动和植入物周围感染是骨科内固定术失败的两个主要原因,随着手术数量的日益增长,如何降低此类手术失败风险变得格外重要。在这个领域中,近期大量的研究工作致力于研制各种各样的内植物涂层,而这些涂层大多只具有抗感染作用而无骨整合作用;或者只具有骨整合作用而不具备抗感染作用。但是要使内植物长期有效,理想的涂层应兼顾骨整合和抗感染这两个功能。本文将对同时具有骨整合性和抗感染性的多功能涂层近期的研究进展和未来研究方向进行综述。     

Recent advances on the development of magnesium alloys for biodegradable implants

In recent years, much progress has been made on the development of biodegradable magnesium alloys as “smart” implants in cardiovascular and orthopedic applications. Mg-based alloys as biodegradable implants have outstanding advantages over Fe-based and Zn-based ones. However, the extensive applications of Mg-based alloys are still inhibited mainly by their high degradation rates and consequent loss in mechanical integrity. Consequently, extensive studies have been conducted to develop Mg-based alloys with superior mechanical and corrosion performance. This review focuses on the following topics: (i) the design criteria of biodegradable materials; (ii) alloy development strategy; (iii) in vitro performances of currently developed Mg-based alloys; and (iv) in vivo performances of currently developed Mg-based implants, especially Mg-based alloys under clinical trials.     

Properties of implanted electrodes for functional electrical stimulation

Implanted wire electrodes are increasingly being used for the functional electrical stimulation of muscles in partially paralysed patients, yet many of their basic characteristics are poorly understood. In this study we investigated the selectivity, recruitment characteristics and range of control of several types of electrode in triceps surae and plantaris muscles of anaesthetized cats. We found that nerve cuffs are more efficient and selective (i.e., cause less stimulus spread to surrounding muscles) than intramuscular electrodes. Bipolar intramuscular stimulation was more efficient and selective than monopolar stimulation, but only if the nerve entry point was between the electrodes. Monopolar electrodes are efficient and selective if located close to the nerve entry point, but their performance declines with distance from it. Nonetheless, for a variety of reasons monopolar stimulation provides the best compromise in many current applications. Short duration pulses offer the best efficiency (least charge per pulse to elicit force) but high peak currents, increasing the risk of electrode corrosion and tissue damage. Electrode size has little effect on recruitment and should therefore be maximised because this minimises current density.     

蝶骨电极对颞叶癫痫致痫灶手术的定位价值

目的探讨蝶骨电极脑电图对颞叶癫痫致痫灶手术的定位价值。方法对５２例颞叶癫痫病人在手术前用常规电极和蝶骨电极描记脑电图，确定癫痫病灶。在手术中描记皮层电图（ＥＣｏＧ）及深部脑电图（ＤＥＥＧ）。结果用蝶骨电极描记者均有痫样放电（１００％），其中９０％局限于颞叶；而常规头皮电极发现有痫样放电４６例（８８％），局限于颞叶者只占４６％。术中ＥＣｏＧ和ＤＥＥＧ证明所有病人的颞叶表面、海马或杏仁核均有痫样放电。结论在诊断颞叶癫痫中蝶骨电极较为可靠，有助于手术前的定位诊断，并且可提高颞叶癫痫脑电图的阳性率４４％。     

Use of Computed Tomography Scans for Cochlear Implants

While 3-dimensional (3D) imaging by computed tomography has long been desirable for research and treatment of cochlear-implant patients, technical challenges have limited its wide application. Recent developments in scanner hardware and image processing techniques now allow image quality improvements that make clinical applications feasible. Validation experiments were performed to characterize a new methodology and its imaging performance.     

Dry electrodes and holder for electro-oculography

The temporal decrease in electrode-subject resistance was measured for dry silver electrodes placed bitemporally to measure the horizontal component of the electro-oculogram. It was found that the electrode-subject resistance decreased exponentially with time. The average time constant for ten determinations was 3·26 min. After about 20 min there was no further reduction in electrode-subject resistance. On average, the ratio of the final to the intial resistance was approximately 0·1.     

Stimulus induced pH changes in cochlear implants: an in vitro and in vivo study

Large pH changes have been shown to be potentially harmful to tissue. The present study was designed to examine stimulus induced changes in pH for a variety of stimulus parameters both in vitro and in vivo, in order to ensure that stimulation strategies for neural prostheses result in minimal pH change. Stimulation using charge balanced biphasic pulses at intensities both within and well above maximum clinical levels for cochlear implants (0.025–0.68 C per phase), were delivered to platinum electrodes in vitro [saline, phosphate buffered saline (PBS), or saline with human serum albumin (HSA)], and in vivo (scala tympani). Stimulus rates were typically varied from 62.5 to 1000 pulses per second (pps), although rates of up to 14,500 pps were used in some experiments. The pH level was recorded using a pH indicator (Phenol red) or pH microelectrodes. While electrical stimulation at intensities and rates used clinically showed no evidence of a pH shift, intensities significantly above these levels induced pH changes both in vitro and in vivo. The extent of pH change was related to stimulus rate and intensity. In addition, pH change was closely associated with the residual direct current (dc) level. As expected, stimulation with capacitive coupling induced little dc and a minimal pH shift. Moreover, no pH shift was observed using alternating leading phase pulse trains at intensities up to 0.68 C per phase and 1000 pps. Saline with HSA or buffered solutions dramatically reduced the extent of pH shift observed following stimulation in unbuffered inorganic saline. Reduced pH shift was also observed following in vivo stimulation. These findings provide an insight into mechanisms of safe change injection in neural prostheses. © 2001 Biomedical Engineering Society. PAC01: 8719Nn, 4366Ts, 4364Nf, 4364Gz, 8714Ee, 8768+z, 8717Nn, 8715Nn, 8719Bb     

A simple method for connecting chronically implanted electrodes

A simple method for connecting chronically implanted electrodes is described, using a classical electronic device. The procedure allows the utilisation of a large number of connections and permits recording from freely moving animals.