基于AAA-ICM技术的视觉闪光诱发电位单次提取新方法的仿真研究

目的:利用计算机仿真人体脑电背景信号和人视觉诱发电位信号,验证基于自参考、自相关、自适应干扰对消理论(AAA-ICM)的诱发电位单次提取新方法。材料与方法:用Delphi语言编程仿真脑电背景信号与视觉闪光诱发电位信号,实现AAA-ICM算法提取诱发电位信号,用信号的功率值及相关系数衡量提取效果。结果:仿真结果表明使用该方法,可以从带有强的自发脑电干扰信号中单次提取出诱发电位信号。结论:与传统的叠加平均提取方法相比,简化了提取方法,改善了提取质量。     

基于自参考自相关自适应干扰对消技术听觉皮层诱发电位单次提取

目的：为实现人体的听觉皮层诱发电位（auditory cortical evoked potential，ACEP）单次提取。方法：将当前流行的计算机应用于生物医学，通过多媒体音频技术产生适合诱发人体听见诱发电位的声音刺激，刺激人体，在电脑皮层提取诱发电位，在大脑皮层提取诱发电位，采用自参考、自相关、自适应干扰对消技术（auto—reference，auto—correlative and adaptive interference cancellation theories and techniques，AAA-ICT）实现听觉皮层诱发电位的单次提取。结果：通过AAA—ICT技术。成功提取出了人体的听觉皮层诱发电位。结论：通过结果可以得出：AAA—ICT技术能够很好地提取人体的听觉皮层诱发电位。而且其自参考思想的创新性明显。     

复合自适应滤波器用于体感诱发电位信噪比的提高

本研究以可靠、快速提取体感诱发电位为目标,试图解决相干叠加方法既费时又不能反映体感诱发电位时变特征的缺点。运用以自适应噪声减法器和自适应增强器为基础构造的复合自适应滤波器提取体感诱发电位。仿真实验表明,运用复合自适应滤波器可实现从强噪声背景中快速提取体感诱发电位,能更快地识别体感诱发电位的潜伏期及幅值,并且系统性能稳定。     

基于多分辨分析与连续小波变换提取和分析兔体感诱发电位

研究单次提取兔体感诱发电位,并定位和分析诱发电位波形成分。麻醉兔,以0.5Hz频率电脉冲刺激兔下肢隐神经,3764Hz采样率收集兔头皮电位。采用一维多分辨分析提取兔体感诱发电位,并用连续小波变换定位和分析诱发电位波形成分。单次诱发电位的小波变换与叠加平均诱发电位比较,表明Daubechies小波多分辨分析可以单次提取诱发电位。连续小波变换能够精确定位诱发电位中波形成分,并可采用连续小波变换分析诱发成分的频域特性。连续小波变换技术把一维时域信号投影到二维时频空间研究将成为医学信号处理的一个有用方法。     

皮层诱发电位潜伏期测量的改进

目的 确定清晰的皮层诱发电位起始点,改进皮层诱发电位潜伏期的测量。方法 利用动物实验提取皮层诱发电位信号。将一种新的基于中值滤波的方法应用于皮层诱发电位潜伏期的测量。结果 广泛使用的叠加平均法对脑皮层诱发电位信号有平滑作用,使皮层诱发电位起始点难以确定。而提出的新的基于中值滤波的方法与传统的叠加平均法相比。能够得到清晰的皮层诱发电位起始点。对大鼠脑皮层诱发电位潜伏期的定量分析表明,不同的检测者应用新的基于中值滤波的方法测量的潜伏期比叠加平均方法得到的潜伏期明显一致。结论 新的基于中值滤波的方法能得到清晰的诱发电位起始点,从而避免了皮层诱发电位潜伏期测量中的人为误差。     

认知诱发电位动态提取的研究进展

认知诱发电位是评价脑认知功能的重要指标。目前临床上应用的平均认知诱发电位由于平均而丧失了大量的动态信息;尤其是认知诱发电位潜伏期(相位)变化大,平均方法将使其波形和波幅严重失真。因此认知诱发电位的单次(少次)动态提取是近年来诱发电位提取技术研究的热点与难点。动态提取认知诱发电位的关键之一在于如何使提取方法适于每个单次诱发电位相位变化大的问题。以三类典型的动态认知诱发电位单次提取方法为例,介绍了近年来在该领域中的研究动向。这三种方法是:B样条小波变换去噪声法、基于三阶相关的滤波法和小波神经网络法。     

认知诱发电位动态提取的研究进展

认知诱发电位是评价脑认知功能的重要指标。目前临床上应用的平均认知诱发电位由于平均而丧失了大量的动态信息；尤其是认知诱发电位潜伏期(相位)变化大，平均方法将使其波形和波幅严重失真。因此认知诱发电位的单次(少次)动态提取是近年来诱发电位提取技术研究的热点与难点。动态提取认知诱发电位的关键之一在于如何使提取方法适于每个单次诱发电位相位变化大的问题。以三类典型的动态认知诱发电位单次提取方法为例，介绍了近年来在该领域中的研究动向。这三种方法是：B样条小波变换去噪声法、基于三阶相关的滤波法和小波神经网络法。     

兔皮层体感诱发电位时频特征分析

分析兔皮层体感诱发电位的时域和频域特性。兔麻醉开颅，从大脑体感运动皮层引导诱发电位。连续多次刺激，以3800Hz采样率采样。测量每次诱发电位各个波形成分的峰潜伏期。分析诱发电位的功率谱。比较单次和叠加平均电位的时频特性。结果显示诱发成分时域变异性在一个刺激周期内随时间逐渐增大，诱发电位的频谱包括3个主要频谱包。叠加平均技术使信号产生波形融合，新波形产生，后发放成份消失等多种畸变。     

径向基函数网络在体感诱发电位实时监测中的应用

目的 针对体感诱发电位(SEP)的特征,设计基于径向基函数网络的复合自适应滤波器,实现体感诱发电位的快速提取.方法通过径向基函数网络的关键参数优化选择,对基于径向基函数网络的复合自适应滤波器与以自适应信号增强器和自适应噪声消除器为基础构造的复合自适应滤波器提取体感诱发电位的性能进行比较分析.结果仿真实验表明:基于径向基...     

基于独立分量分析体感诱发电位仪的设计与测量

体感诱发电位技术是术中神经监护的主要技术,由于诱发信号的信噪比一般很低,临床上普遍采用相干平均技术提取体感诱发信号。本文基于独立分量分析算法,设计实现的体感诱发电位仪,除了能对各刺激参数可调外,通过大鼠实验,发现还具有所需刺激次数少、细节信息明显和实时显示提取波形等特点,因而有着很好的医学应用前景。     

Topography and dipole analysis of reafferent electrical brain activity following the Bereitschaftspotential

 The cerebral events related to limb movements can be studied noninvasively with the method of evoked potentials. In this study, a brain potential is analysed that follows the onset of a simple finger movement. Because this potential occurred after active as well as after passive movements, its previously alleged reafferent somatosensory nature is confirmed in this study. Detailed topographic analysis revealed that this potential has the same polarity and merges with the preceeding Bereitschaftspotential (BP; in the active movement) at central electrodes, whereas at parietal electrodes polarity is opposite to the BP. In individual subjects, the maximum of the BP and the peak of the reafferent potential are separated by a small gap, previously described as pre-motion positivity. A comparison with the N20 potential of the electrically evoked somatosensory potential showed similar potential topography, albeit opposite polarity. The dipole analysis supported the view that the reafferent and the electrically evoked potentials are likely to arise from the same cortical area, namely the primary somatosensory cortex. Received: 18 April 1996 / Accepted: 18 October 1996     

基于CNN算法的稳态体感诱发电位的特征识别

脑-机接口研究可为瘫痪病人的康复带来一种新的治疗方法。已有研究表明对手指或者正中神经施加一定频率的体感刺激,会引发相同频率且具有空间特异性的稳态体感诱发电位。为优化基于稳态体感诱发电位的脑-机接口的性能,通过快速傅里叶变换寻找12个健康被试的个人左手特定共振频率,采用事件相关谱扰动进行时频分析,检测其稳态体感诱发电位信号。基于共振频率对实验诱发的脑电信号进行1 Hz带通滤波,获得特定频带的数据,采用卷积神经网络(CNN)学习算法对其进行分类,并与采用共空间模式和支持向量机的特征提取及特征分类的方法(CSP+SVM)进行比较。所有被试的结果显示:基于共振频率滤波方法,采用CNN学习算法获得的离线分类准确率均高于85%,并且CNN学习算法的分类准确率显著性优于CSP+SVM的分类准确率(91.8%±5.9% vs 77.4%±8.5%,P<0.05)。因此,在基于稳态体感诱发电位的脑机接口的特征识别中,CNN学习算法相比传统使用的机器学习分类算法(如共空间模式+支持向量机)能够显著提升分类准确率,提高脑机接口的整体性能。     

Diagnostic utility of somatosensory and motor evoked potentials in a patient with thoracic outlet syndrome

OBJECTIVE: To evaluate the utility of somatosensory and motor evoked potentials in the diagnosis of neurogenic thoracic outlet syndrome (TOS). MATERIALS AND METHODS: In a female patient with progressive weakness and sensory disturbance, ulnar nerve somatosensory evoked potentials (SSEP), and intraoperative motor evoked potential (MEP) were performed. RESULTS: The SSEPs demonstrated no significant change in latency of major peaks at rest and after abduction of the shoulder. Diminishment of amplitude was noted after dynamic position of the arm. The MEPs demonstrated no significant change in latency after dynamic position. Diminishment of amplitude was noted after the dynamic position. The amplitude returned to normal after repositioning the arm. CONCLUSIONS: Electrophysiologic study is helpful in the diagnosis of neurogenic TOS. Reduced amplitude of cortical SSEP and myogenic MEP is expected during dynamic position of the affected arm.     

1～14岁儿童正中神经及胫后神经体感诱发电位正常参考值

目的：测量正常儿童正中神经体感诱发电位(MN—SEP)及胫后神经体感诱发电位(PIN—SEP)，探讨儿童SEP正常值。方法：1～14岁正常儿童390名，分13组，每岁为一组，均行双侧正中神经体感诱发电位及胫后神经体感诱发电位检测，取单肢结果统计学处理。结果：儿童SEP波潜伏期随年龄增长先缩短后延长，但不同部位的电位表现并不一致。峰问期没有年龄规律。结论：严密的正常参考值是正确分析儿童SEP结果的有效保证。     

脑梗死患者的运动及体感诱发电位研究

目的：研究脑梗死患者的运动诱发电位（ＭＥＰ）及体感诱发电位（ＳＥＰ）改变。方法：对３０便脑梗死患者在急性期行经颅磁刺激ＭＥＰ检测,对其中２０例同时行电刺激ＳＥＰ检测,１０例患者２月后复查ＭＥＰ,并以３０例健康者作为正常对照组。结果：急性期ＭＥＰ的异常率为９３％,主要表现为皮层ＭＥＰ消失,中枢运动传导时间（ＣＭＣＴ）延长,波形异常及阈刺激强度增高。ＳＥＰ的异常率为３０％,表现为皮层波的缺失及中枢传导时间延长。复查ＭＥＰ有９例明显改善。结论：对于脑梗死的诊断,ＭＥＰ较ＳＥＰ敏感,但将ＭＥＰ与ＳＥＰ联合应用,可从不同的两个侧面反映运动及感觉功能受损的情况,弥补了ＣＴ仅能提供颅内解剖学改变而不能反映功能状态的不足。     

快速检测SEP在手术中脊髓监护的应用

介绍了利用体感诱发电位进行手术中脊髓监护的方法，介绍了手术中脊髓监护的原理及实验系统的构成，给出了利用伪随机序列技术实现快速检测体感诱发电位的算法，实验结果显示，本文的研究较传统方法有一定,值得进一步研究。     

慢性肝病肝硬化的脑干诱发电位的初步研究

在我们嘉兴地区,由于曾是血吸虫病流行区,因此对血吸虫病肝纤维化及混合性肝硬化发病率高,为了解肝硬化患者与脑干诱发电位的关系,我们于1995年1月～1996年12月对100例肝硬化肝功能失代偿患者,其中还包含有32例由于肝硬化门静脉高压并发上消化道大出血的患者进行了脑干听觉诱发电位(BAEP),视觉诱发电位(VEP),体感诱发电位(SEP)进行测试,其结果BAEP阳性率为50％,VEP阳性率为18％,SEP阳性率为12％,本文检测对象年龄从21岁～82岁,平均年龄为51.5岁,所以还必须对年龄因素来进行分析,以便客观和确切的来探讨肝硬化与脑干诱发电位之间的关系。     

A case of acute polyneuropathy with nephrotic syndrome showing transient proximal sensory conduction defects

Acute sensorimotor polyneuropathy that resembles Guillain-Barré syndrome (GBS) is rarely accompanied with nephrotic syndrome, and its underlying immunological mechanisms are unclear. A 56-year-old man presented with simultaneous acute progressive symmetric sensorimotor polyneuropathy and proteinuria. A kidney biopsy revealed focal segmental glomerulosclerosis. Serial electrophysiologic studies showed only a transient proximal conduction block in the median nerve, stimulated somatosensory evoked potential and prolonged terminal latencies of the median and peroneal nerves. The patient's neurologic deficits and kidney dysfunction recovered with corticosteroid treatment. Our case showed that somatosensory evoked potential study can be an important objective tool in the diagnosis of acute polyneuropathy with normal distal nerve conduction and that corticosteroids should be considered in the initial treatment of GBS-resembling polyneuropathy associated with nephrotic syndrome.     

Neurogenic vestibular evoked potentials in the diagnosis of multiple sclerosis

OBJECTIVES: To determine the value of neurogenic vesibular evoked potential (NVESTEP) studies in comparison with other paraclinical tests in demonstrating dissemination in time and space in Multiple Sclerosis (MS) and in identifying clinically silent lesions. METHOD: All patients in whom MS was suspected but the diagnosis of MS was not possible based on the McDonald criteria were included in this study. We studied 14 patients and performed visual, brainstem auditory, somatosensory and neurogenic vestibular evoked potentials in all patients, together with MRI and CSF analysis of oligoclonal bands (OB). RESULTS: Two out of the thirteen patients could be movedfrom the category of "possible MS" to "MS" using the McDonald criteria based on an abnormal NVESTEP result. CONCLUSION: Neurogenic vestibular evoked potentials are potentially useful in identifying clinically silent lesions in patients with possible MS.