基于肌电信号与肌肉形变信号的手语识别

针对手语手势识别问题,提出一种基于肌电信号与肌肉形变信号的手语识别架构。首先,设计信号采集系统;然后,采集肌电信号与肌肉形变信号,利用滤波及小波降噪等方法对原始数据进行降噪处理。采用基于能熵比的双门限端点检测法提取信号有效活动段;分别提取肌电信号以及肌肉形变信号特征,将所提取的信号特征融合组成特征向量;最后,采用基于网格搜索的支持向量机识别模型对所采集手语动作进行识别。信号融合后手语识别正确率达到97.2%,相对于仅采用肌电信号的手语识别方法,融入肌肉形变信号后识别率提高9.3%。结果表明,基于肌电信号和肌肉形变信号的手语识别框架对动态手语手势具有良好的识别效果。     

小波变换在表面肌电信号分类中的应用

针对肌电信号的非平稳特性,采用小波变换方法对表面肌电信号进行分析。通过奇异值分解有效地提取信号特征进行模式识别,能够成功地从掌长肌和肱桡肌采集的两道表面肌电信号中识别展拳、握拳、前臂摧旋、前壁外旋四种运动模式。实验表明,基于小波变换的奇异值分解方法是一种稳定、有效的特征提取方法、为非平稳生理信号的分析提供了新的手段。     

基于低频电刺激诱发表面肌电信号的肌肉疲劳度研究

目的 通过对肌肉疲劳过程中非诱发表面肌电(surface electromyography,sEMG)信号和诱发表面肌电信号的研究分析,寻找有效评价肌肉疲劳的分析测量方法.方法 对7名受试者进行自主运动和电刺激两种致肌疲劳的实验,并在两组实验中分别记录电刺激诱发与非诱发肌电信号,然后对每组信号进行傅里叶变换求取功率谱和近似熵.结果 随着疲劳的产生,两组实验诱发信号的频谱曲线左移效果优于非诱发信号,近似熵分析中电刺激组诱发信号出现先上升后下降的变化,自主运动组诱发信号则呈现单调递减的趋势.结论 低频电刺激诱发表面肌电信号更适于测量肌疲劳的动态变化.相对于传统功率谱,近似熵分析方法更适于处理电刺激诱发的表面肌电信号.     

基于双谱分析表面肌电信号特征的提取与模式识别

背景:肌电信号在本质上是一种具有非平稳、非高斯特性的生理信号。目前基于高阶累积量的高阶谱技术广泛应用于非高斯、非平稳、非线性等问题。目的:基于非高斯AR参数模型,将双谱分析和fisher线性判别分析方法相结合进行表面肌电信号特征提取。方法:针对表面肌电信号特点,从信号高阶统计处理角度,基于"非高斯AR参数模型"进行双谱分析,提取有效特征,用fisher线性判别分析降维方法构造特征向量,然后利用支持向量机实现不同动作模式的准确分类。并与多种常用表面肌电信号特征的识别准确率进行对比研究。结果与结论:利用多类支持向量机分类器对8种前臂动作进行分类,8种动作的平均识别率达到97.6%以上。通过比较发现,基于短数据的双谱特征在分类性能上优于AR模型系数、小波包系数等构造的特征,能够提高肌电假肢的实时控制的性能。     

经穴位电刺激下的表面肌电信号特征分析

目的:探究人体穴位电刺激与相关肌肉活动的关系,通过对经穴刺激诱发的表面肌电信号进行特征分析,阐明经穴电刺激下的肌电信号时域、频域特征参数变化与肌肉的激活程度、疲劳程度之间的定量关系,为康复工程和运动医学研究提供参考依据。方法:以8名健康青年志愿者为研究对象,设计穴位电刺激和自主收缩两种实验模式,采集记录两种模式下对应的指伸肌和尺侧腕屈肌的表面肌电信号,提取表面肌电信号均方根值、平均功率频率、中值频率等特征值,并分析其功率谱变化。通过配对t检验,分析经穴电刺激和自主动作模式的肌电信号特征差异。结果:在经穴电刺激模式下,对应的表面肌电信号均方根幅度增大,且经穴电刺激后,肌电信号的谱分布向高频方向移动,肌电的平均功率频率和中值频率随着刺激时间的延长保持稳定。结论:表明对曲池穴和内关穴位电刺激,能够激活对应的指伸肌和尺侧腕屈肌更多的快肌纤维,使肌肉激活程度提高,对缓解肌肉疲劳具有一定作用。     

基于小波变换的肌肉疲劳表面肌电信号特征提取的研究

当前肌肉疲劳表面肌电信号(surface electromgography,sEMG)特征提取方法,忽略了非线性跳错信号的影响,且不能在非平稳状态下进行特征提取,存在特征提取准确度差的问题。提出基于小波变换的肌肉疲劳sEMG特征提取研究,采用小波变换对所采集的样本去噪,结合时域、频域特征分析法,融合傅里叶变换方法对肌电信号中的线性特征进行提取,根据带谱近似熵理论对非线性挑错信号进行特征回归分析,并利用拟态分解函数和希尔伯特变换法对肌电信号进行时频特征的整合提取,最终完成基于小波变换的肌肉疲劳sEMG特征提取研究。实验验证,所提方法具有可行性,且将1000个肌电信号样本分成5组,对其中的跳错信号进行特征提取,所提方法准确度较文献方法高出75%,在非平稳状态下将200个肌电信号样本分成5组进行特征提取,所提方法准确度较文献方法高出33%。由此得出,所提方法优于当前特征提取方法。     

一种评价宫缩强度的小波能量值分析方法

宫缩压力数据是提取子宫收缩状况的信息来源,由于宫缩压力数据中存在着多种干扰成分,因而常用的子宫活动积分法等宫缩强度评价方法不能获取较好结果。利用bior 2.4双正交小波基分解并重构宫缩压力数据,以获取最好的消噪效果,并结合消噪结果提出了小波能量值算法,在此算法基础上计算了小波能量值曲线。该小波能量值曲线能够更好地识别宫缩波形、评价宫缩强度。     

基于最佳小波包的表面肌电信号分类方法

针对表面肌电信号的分类问题，采用最佳小波包分解构造最能体现分类能力的小波包基。用Fisher线性判别分析对肌电信号各个子空间的相对能量特征进行降维处理，然后利用BP神经网络进行分类识别。实验表明该方法能够有效地从伸肌和屈肌采集的两道肌电信号中识别前臂内旋、前臂外旋、握拳和展拳四种运动模式，是一种稳定、有效的特征提取方法，为非平稳生理信号的分析提供了新的手段。     

一种改进的子宫肌电包络提取算法

基于腹部采集的子宫肌电信号(EMG)提取子宫收缩信息被认为是一种最有可能取代分娩力描记法(TOCO)的新方法。传统均方根(RMS)算法对子宫肌电信号中脉冲性噪声的抑制能力有限,为了有效克服上述问题,本文提出一种改进的子宫肌电包络提取算法。新方法先对原始子宫肌电信号进行过零检测,识别出爆发波并分段,再对分段后的信号进行不同窗口宽度的平滑滤波,最后采用均方根法提取子宫肌电强度(IEMG)作为包络。为了评估本算法的性能表现,本文将该算法与两种现有子宫肌电强度提取算法进行比较。结果表明,该算法在抑制子宫肌电信号中存在的脉冲性噪声方面要明显优于对比算法,其测量灵敏度与阳性预测值(PPV)分别为0.952和0.922,不仅明显高于对比算法一中对应参数的0.859和0.847,同时也高于对比算法二中的0.928和0.877。本研究表明了该方法的可靠性与有效性。     

大腿截肢患者的残肢肌电运动识别

目的研究利用大腿残肢肌电信号进行下肢运动模式识别的方法,探讨肌电信号控制下肢假肢的可能性。方法采集15名大腿截肢者残肢侧股直肌、股外侧肌、阔筋膜张肌、股二头肌、半腱肌、臀大肌6块肌肉的表面肌电信号,提取肌电信号的6种时域、频域特征,利用支持向量机对平地行走、上楼梯、下楼梯、坐下、起立5种下肢运动模式进行识别。结果利用残肢肌电信号可以实现5种下肢运动模式的在线识别,对同一受试者同次测试数据识别率为94%,同一受试者的多次混合数据识别率为85%,对不同受试者混合数据识别率为74%。通过特征优化,仅利用3块肌肉的2个特征,对同一受试者的同次测试数据识别率仍可达92%。对平地行走、上楼梯、下楼梯3种动作的识别,同一受试者同次测试数据识别率为100%,同一受试者的多次混合数据识别率为98.33%,对不同受试者混合数据识别率为93.33%。结论仅仅利用残肢肌电信号能够实现运动意图的在线识别,通过对同一患者使用前的多次数据训练,有望达到较高的识别率。研究结果为肌电运动识别用于下肢假肢控制奠定了基础。     

Traitement de l'électromyogramme utérin pour la caractérisation des contractions pendant la grossesse

The uterine electrohysterogram (EWG) has been recorded on the abdomen of pregnant women, from 19 to 37 weeks of gestation (WG), and processed in order to detect preterm delivery. The EHG being corrupted by different electromagnetic noises, we have developed specific algorithms, based on wavelet decomposition, for the denoising of the EHG. Classical parameters, extracted from the spectral and temporal representations and from the instantaneous frequency of the EHG, have permitted us to follow the solution of the signals during pregnancy, Furthermore, a discriminant analysis permitted us to evidence a difference between contractions leading to term or preterm deliveries, as soon as 30 WG Non-stationary parameters have then been computed from EHG signals, in order to follow the two electrical waves that are known on animal recordings to be related to contraction efficiency. The extraction and characterization of these waves are made by extracting the ridges of the scalogram, computed from the continuous wavelet transform. The instrumental part development has started with the analysis of maternal movement artifacts, and with the comparison of different kinds of electrodes, suitable for 24 hours recording. A first portable recorder prototype is presently under development.     

Comparison of non-invasive electrohysterographic recording techniques for monitoring uterine dynamics

Non-invasive recording of uterine myoelectric activity (electrohysterogram, EHG) could provide an alternative to monitoring uterine dynamics by systems based on tocodynamometers (TOCO). Laplacian recording of bioelectric signals has been shown to give better spatial resolution and less interference than mono- and bipolar surface recordings. The aim of this work was to study the signal quality obtained from monopolar, bipolar and Laplacian techniques in EHG recordings, as well as to assess their ability to detect uterine contractions. Twenty-two recording sessions were carried out on singleton pregnant women during the active phase of labour. In each session the following simultaneous recordings were obtained: internal uterine pressure (IUP), external tension of abdominal wall (TOCO) and EHG signals (5 monopolar and 4 bipolar recordings, 1 discrete approximation to the Laplacian of the potential and 2 estimates of the Laplacian from two active annular electrodes). The results obtained show that EHG is able to detect a higher number of uterine contractions than TOCO. Laplacian recordings give improved signal quality over monopolar and bipolar techniques, reduce maternal cardiac interference and improve the signal-to-noise ratio. The optimal position for recording EHG was found to be the uterine median axis and the lower centre-right umbilical zone.     

超声测量前置胎盘孕妇子宫颈管长度预测阴道出血与早产

应用超声测量前置胎盘孕妇子宫颈管长度,探讨其与阴道出血和早产的关系。方法 将2005年1月至2010年1月在本院产检并分娩的82例前置胎盘孕妇按孕周28～30周、31～33周、34 ～ 36周分为3组,采用超声测量各组孕妇子宫颈管长度,记录3组前置胎盘孕妇子宫颈管长度＞30 mm和≤30 mm例数,观察各组子宫颈管长度＞30 mm和≤30 mm孕妇出现的阴道出血、下腹痛、宫缩临床症状的例数并统计对比早产率、平均分娩孕周、新生儿出生体质量、新生儿窒息率。分别绘制子宫颈管长度预测阴道出血和早产的ROC曲线,计算曲线下面积和最佳临界点。结果 3组前置胎盘孕妇子宫颈管长度＞30 mm和≤30 mm的例数分别为28～30周组:20例、8例,31～33周组:19例、11例,34～36周组:11例、13例。子宫颈管长度≤30 mm的前置胎盘孕妇阴道出血率、早产率均明显高于子宫颈管长度＞30 mm者(28 ～ 30周组:阴道出血率87.50％比20％,早产率75％比15％;31～33周组:阴道出血率72.73％比26.32％,早产率63.64％比21.05％; 34 ～ 36周组:阴道出血率69.23％比27.27％,早产率38.46％比18.18％;均P＜0.05),3组出现下腹痛和官缩临床症状的比例也是子官颈管长度≤30 mm的前置胎盘孕妇高于子宫颈管长度＞30 mm者;3组子宫颈管长度≤30 mm的孕妇平均分娩孕周、新生儿出生体质量则低于子宫颈管长度＞30 mm者(均P＜0.05),新生儿窒息率在28 ～ 30周、31～ 33周组子宫颈管长度≤30 mm的孕妇高于子宫颈管长度＞30mm者(均P＜0.05),而34～36周组的孕妇均未出现新生儿窒息。子宫颈管长度预测阴道出血及早产的ROC曲线下面积分别为73.4％、65.3％,30.5 mm为预测的最佳临界点。结论 超声测量前置胎盘孕妇子宫颈管长度可作为预测阴道出血与早产的一种方法。     

一种阵列式胎动信号及子宫收缩信号监测腹带

目的胎动信号和子宫收缩信号是胎儿及母体重要的生理信号,为此本文介绍一种孕妇可自行操作、使用方便、测量准确的便携装置.方法本装置通过阵列式压电传感器采集胎动信号和子宫收缩信号,信号经过滤波、放大和 A/D转换后,利用单片机软件进行胎动信号及子宫收缩信号辨别,实现胎动信号和子宫收缩信号的次数累加、持续时长确定、信号发生位置及信号类型的确定,最后将结果显示在数码管上.结果用本装置对3名不同妊娠期孕妇进行胎动信号和子宫收缩信号的监测,并与孕妇自身计数结果对比,测量误差小,能够达到实时显示信号位置、信号类型、信号次数的功能.结论阵列式胎动信号及子宫收缩信号监测腹带可为孕妇提供简单方便的便携监护.     

欣普贝生和缩宫素对足月胎膜早破引产效果比较

目的 比较欣普贝生和缩宫素对足月胎膜早破的临床效果。方法 选择我院2017年12月~2018年5月收治的胎膜早破孕妇200例,其中92例孕妇放置欣普贝生引产的作为欣普贝生组,缩宫素引产的108例孕妇作为缩宫素组,比较两组孕妇用药后引产结局,包括宫颈评分、破膜至用药时间、用药至临产时间、总产程、引产成功率、剖宫产率、产后出血及新生儿结局。结果 两组产后2 h出血量比较,差异无统计学意义（P＞0.05）;欣普贝生组引产前宫颈评分低于缩宫素组,用药至临产时间及总产程少于缩宫素组,差异有统计学意义（P＜0.05）;欣普贝生组、缩宫素组引产成功率分别为81.52%和83.33%,绒毛膜羊膜炎率分别3.26%、3.70%,差异均无统计学意义（P＞0.05）;两组新生儿窒息、羊水粪染及胎儿窘迫发生率比较,差异无统计学意义（P＞0.05）。结论 针对足月胎膜早破,宫颈不成熟的孕妇,欣普贝生诱发宫缩快,宫缩强而协调,是安全有效的引产方式,其剖宫产率、新生儿不良结局、产后出血与使用缩宫素基本一致,不增加风险。     

The effects of intracellular and extracellular alkalinization on contractions of the isolated rat uterus

The effects of changing pH on a spontaneously active smooth muscle, the myometrium, is examined. We show, for the first time in any smooth muscle, that the frequency of contraction is greatly increased when intracellular pH is raised. Three weak bases, trimethylamine, diethylamine and ammonium, were used to raise intracellular pH (pH_i), at constant external pH, in isolated uteri of pregnant and non-pregnant rats. Each base increased spontaneous uterine contractile activity, particularly by raising the frequency, in a concentration-dependent manner. At the highest concentrations (40–50 mM) frequency was so increased that a maintained contraction resulted. Intracellular alkalinization during a high-K-maintained uterine contraction produced a small, but significant, fall in force. When external pH was increased, the results were greatly influenced by gestational state; in uteri from non-pregnant animals there was no effect whereas uteri from pregnant rats were found to be extremely sensitive to a raised external pH above 7.4; spontaneous contractions were reduced. In pregnant uteri, when both internal and external pH were elevated, spontaneous contractions were immediately reduced, thus the effects of external pH predominated. These findings may have significance in labour.     

妊娠期糖尿病孕妇心率变异性变化

目的:探讨妊娠期糖尿病孕妇心率变异性变化.方法:选取阳春市妇幼保健院2018年1月至2020年4月收治的50例妊娠期糖尿病患者作为观察组,选取同期健康孕检孕妇50例作为对照组,年龄20～36岁,孕周24～40周.所有孕妇给予动态心电图监测,比较两组孕妇平均心率(AHR)、正常窦性RR间期的总体标准差(SDNN)、每5 ...     

The embryo versus endometrium controversy revisited as it relates to predicting pregnancy outcome in in-vitro fertilization-embryo transfer cycles

To evaluate embryonic and endometrial factors for their value in predicting pregnancy outcome in in-vitro fertilization (IVF) and embryo transfer, a retrospective data collection and prospective uterine artery colour Doppler imaging study was performed in a university-based IVF-embryo transfer programme setting. A total of 210 patients were included and grouped as follows: (I) IVF with controlled ovarian stimulation (214 cycles); (II) frozen-thaw cycle of autologous embryos (30 cycles); (III) oocyte donation, no cryopreservation (12 cycles); (IV) frozen-thaw cycle with embryos from donated oocytes (10 cycles). Embryo quality was significantly better in pregnant than non-pregnant cycles (group I, P = 0.0104; groups II-IV, P = 0.0418). The endometrial echo was significantly thicker in pregnant versus non-pregnant patients in group I (P = 0.0059), but not in groups II-IV (P = 0.741). Past uterine surgery or abnormalities had no effect on pregnancy outcome. There were no significant differences in mean uterine artery resistance index or peak systolic velocity in pregnant versus non-pregnant patients in groups II-IV. Thus, embryo quality is the most reliable predictor of pregnancy outcome. Endometrial measurements were significantly thicker in subsequently pregnant patients only in group I, where the endometrium reflects the hormonal environment. Doppler parameters were not useful in predicting pregnancy outcome.      

Pulsatility index of uterine artery in pregnant and non-pregnant women

In 60 infertile women, 73 uterine arterial pulsatility indices(PI) were measured by transvaginal colour Doppler sonography.The aims were to assess uterine perfusion response in infertilewomen during spontaneous ovarian cycles, and to analyse thechange of uterine perfusion in pregnant cases. The mean PI values(± SD) of 67 non-pregnant cycles were 2.30 (±0.78) in the follicular phase, 2.51 (± 1.05) in the ovulatoryphase and 2.50 (± 0.97) in the mid-luteal phase. Themean PI values (± SD) of six pregnant cycles were 1.67(± 0.22), 1.89 (± 0.41) and 2.23 (± 0.69)in the corresponding phases respectively. The difference betweenthe PI values in the follicular phase for the pregnant and non-pregnantgroups was significant (P < 0.05), as well as that betweenthe follicular and mid-luteal phase for the pregnant group (P< 0.05). There was no significant difference between thePI values in the ovulatory or mid-luteal phase of the two groups.     

Uterine electromyogram database and processing function interface: An open standard analysis platform for electrohysterogram signals

The uterine electromyogram or electrohysterogram (EHG) is one of the most promising biophysical markers of preterm labor. At this time no recording parameter standard exists for EHG recordings which can be a problem for the establishment of international multicentric trials. In this paper, we present a management and processing system dedicated to storing and processing EHG signals. This system can process EHG signals recorded in different experimental conditions i.e. different sampling frequencies. The signal management is performed using an easy to use graphical user interface. Other available functions include visualization, preprocessing and analysis of EHG signals. The proposed processing functions provide temporal, spectral and time-scale parameters obtained from the EHG bibliography. The obtained results from real signals recorded in two different hospitals in two different countries are in accordance with the literature and demonstrate the potential of the proposed system. The incorporation of new functions is easy, due to a standardization of the EHG data formats.