基于电刺激的上肢截肢者诱发手指幻肢感初步研究

目前商用假肢缺乏有效的感觉反馈机制,人们通过机械刺激可进行间接的感觉反馈,但仍不 能产生“自然”感觉。一些研究者们通过神经内植入式电刺激可以帮助使用者获取“自然”感觉,这种有创的方式需要进行手术且对电极材料的要求很严格。相比之下,经皮电刺激更易实现,然而目前的研究还缺乏有效的控制策略来主动调控电刺激参数。因此,该文对经皮电刺激诱发手指幻肢感进行了初步研究,并结合脑电信号(EEG)特征,探究了一种客观的方法来评价电刺激参数与所诱发的手指幻肢感觉的关系,使得实现电刺激参数的主动调控成为可能。结果初步表明了通过经皮电刺激可以诱 发上臂截肢患者幻肢手指收缩的感觉;并且,通过分析脑电地形分布可建立刺激的位置与所诱发感觉的位置之间的关系;通过提取事件相关电位并分析其曲线特征,可判断所施加的电刺激强度是否足够诱发明显的幻肢感觉。该研究有助于在电刺激诱发幻肢感的研究中实现刺激参数的自动调控。     

针对上肢高位截肢者的肌电假肢设计

给出了一种基于人体表面肌电信号控制的上肢假肢系统,服务于基于靶向肌肉神经移植术的高位截肢者.通过解析人体肌电信号包含的动作意图控制假肢的运动.系统包括假肢的机械结构、控制系统的硬件和算法.假肢的机械结构包括肘关节、腕关节和手部.控制系统的硬件包括主控板、驱动板和肌电采集模块.模式识别算法采用基于贝叶斯原理的线性分类器,通过在线实时训练,得到需要的线性分类器参数.根据得到的分类器模型,对采集到的肌电信号进行在线实时识别,并根据识别的结果实时控制相应假肢关节的运动.系统样机在健康受试者身上进行了测试,效果良好.     

Development of an upper-limb neuroprosthesis to voluntarily control elbow and hand

This work reports on the research and development of a lightweight neuroprosthesis that can control impaired motion using voluntary biological signals. The total weight of the developed neuroprosthesis is 900?g, which is the weight of 40% of the defective limb. Further, it is lighter than commercially available models. For a transhumeral amputee who had targeted muscle reinnervation (TMR) surgery, we attempted pattern classification using an artificial neural network (ANN) of a surface electromyogram (s-EMG) extracted from an innervated muscle. The result shows that classification of only five motions was possible using an s-EMG extracted from four dry electrodes. However, seven motion classifications were possible using eight wet-gel electrodes. The transhumeral amputee who had TMR surgery could thus successfully perform pick-and-place tasks using the neuroprosthesis.     

下肢截肢者行走意图识别方法研究进展

直立行走是人类独立生活和正常参与社会活动的基本功能之一.人因遭受工伤、交通事故、战争、自然灾害（地震等）、疾病（糖尿病、癌症等）、先天出生缺陷等意外和不幸造成下肢截肢,从而部分或全部丧失行走能力,严重影响正常生活和参与社会活动.下肢假肢是下肢截肢者恢复行走功能的唯一手段,其技术发展吸引了众多研究者的关注.为使下肢假肢使用者能像正常腿一样或接近的步态行走,关键是实现截肢者行走意图的自动精确识别.本文首先探索了行走意图识别的内涵;然后从信号源的角度分析了不同截肢者行走意图识别方法的特点,尤其是神经功能重建作为补充的肌电信号（Electromyography,EMG）源的方法,并简述其研究进展,提出了一种融合生物力学信号和生物电信号的截肢者行走意图识别方法;最后对下肢截肢者行走意图识别方法发展趋势进行了总结和展望.     

Exploring the mechanism of neural-function reconstruction by reinnervated nerves in targeted muscles

A lack of myoelectric sources after limb amputation is a critical challenge in the control of multifunctional motorized prostheses. To reconstruct myoelectric sources physiologically related to lost limbs, a newly proposed neural-function construc- tion method, targeted muscle reinnervation （TMR）, appears promising. Recent advances in the TMR technique suggest that TMR could provide additional motor command information for the control of multifimctional myoelectric prostheses. However, little is known about the nature of the physiological functional recovery of the reinnervated muscles. More understanding of the under- lying mechanism of TMR could help us fine tune the technique to maximize its capability to achieve a much higher performance in the control of multifunctional prostheses. In this study, rats were used as an animal model for TMR surgery involving transferring a median nerve into the pectoralis major, which served as the target muscle. Intramuscular myoelectric signals reconstructed following TMR were recorded by implanted wire electrodes and analyzed to explore the nature of the neural-fimction recon- struction achieved by reinnervation of targeted muscles. Our results showed that the active myoelectric signal reconstructed in the targeted muscle was acquired one week after TMR surgery, and its amplitude gradually became stronger over time. These pre- liminary results from rats may serve as a basis for exploring the mechanism of neural-function reconstruction by the TMR tech- nique in human subjects.     

Influence of smartphone use styles on typing performance and biomechanical exposure

Twenty-seven subjects completed 2-min typing tasks using four typing styles: right-hand holding/typing (S-thumb) and two-hand typing at three heights (B-low, B-mid and B-high). The styles had significant effects on typing performance, neck and elbow flexion and muscle activities of the right trapezius and several muscles of the right upper limb (p < 0.0001 by repeated-measure analysis of variance). The subjects typed the fewest words (error-adjusted characters per minute: 78) with the S-thumb style. S-thumb style resulted in similar flexion angles of the neck, elbow and wrist, but significantly increased muscle activities in all tested muscles compared with the B-mid style. Holding the phone high or low reduced the flexion angles of the neck and right elbow compared with the B-mid style, but the former styles increased the muscle activity of the right trapezius. Right-hand holding/typing was not a preferable posture due to high muscle activities and slow typing speed.

Practitioner Summary: Right-hand holding/typing was not favoured, due to increased muscle activities and slower typing speed. Holding the phone high or low reduced the flexion angles of the neck and right elbow, but the former styles increased the muscle activity of the right trapezius compared with holding the phone at chest level.     

波谱响应函数和波宽对地表温度反演的影响

分析了波谱响应函数和波宽对红外数据反演地表温度的影响。结果表明,波谱响应函数对温度反演的影响与传感器波段设置相关,误差随波宽变大而增加。Landsat、CBERS和环境卫星等宽波段红外数据的通道辐亮度和温度的关系,用有效波长比中心波长代替积分效果更好,但都存在一定误差,针对这些传感器数据的单通道算法须考虑波谱响应的差别。窄波段的MDIS地表温度反演,有效波长比中心波长代替积分效果更好,能满足精度要求。Terra和Aqua的MODIS波谱响应函数差别很小,可相互结合提高地表温度的反演精度。     

一种基于矢量伸缩函数的参数曲面插值变形方法

为了对参数曲面进行精确变形,可通过构造特殊矢量伸缩函数来实现参数曲面的捕值变形.变形时,先在曲面选取变形辅助点,并利用这些辅助点构造矢量伸缩甬数;然后基于矢量叠加原理用此伸缩矢量函数去作用曲面,使曲面发生变形且变形后通过给定的插值点.插值变形结果表明,此方法不仅能够精确控制变形范围,而且在变形与未变形部分之间具有C2连续性.     

基于高密度肌电的对称位置发音肌肉对语音识别 贡献的研究

说话是人类正常生活中最重要的技能之一,是发音相关肌肉在神经中枢的控制下协调运动的 结果。表面肌电图法(Surface Electromyography,sEMG)是目前采集肌肉电信号的常用方法,能检测到 可靠的肌肉电生理信息。用肌电信号进行语音分类时,所选的电极位置对分类精度有重大作用。但目 前基于 sEMG 的语音识别方法选取电极位置及数量时没有一个客观的指标,也不清楚发音相关的面、 颈部左右两侧对称位置电极对肌电语音识别的贡献是否冗余。该文使用 120 通道电极(关于面中、颈 中对称)采集了 8 名发音正常的受试者分别发 5 个中文单词和 5 个英文单词时的面、颈部 sEMG,考察 了面、颈部左右两侧对称位置 sEMG 对语音识别的贡献。结果表明,发音过程中面、颈部左右两侧肌 肉活动有相似的变化规律,但整个活动过程中面部对称位置的相关性比颈部低;使用颈部左侧、右侧 的肌电信号进行语音分类的分类精度区别不大,而使用面部左、右两侧肌电信号的分类结果差异较明 显。因此,颈部对称位置的 sEMG 信号对语音识别贡献程度具有一致性,而面部则不具有,这为后续 研究减少电极数量和选择最佳通道提供了新思路。     

一种基于相关函数法铁磁谐振波形研究

对铁磁谐振波形进行了系统的分类分级,提出了一种基于Matlab的相关函数方法,并且利用大量数据进行对比,已经得到了效果验证,经过桂林市电力电容器责任有限公司认证,具有良好的实际效果。     

基于运动函数的行走识别方法研究

结合人体生理特征与物体运动特点,提出了一种用运动函数表示人体运动的方法,来用于视频图像的运动检测。针对智能监控系统的特点,以人行走视频为例,通过提取实验数据并对其进行分析处理,得到人行走函数方程。在此基础上,进行实验验证人行走函数中各参数的有效性,得到人行走函数关系表达式。     

基于样本相似度曲面重构的核函数构造

根据数据特征构造核函数是当前SVM(支持向量机)的难点，文章采用重构数据样本相似度曲面的方法构造三种新的核函数．证明前两种核是Mercer核，并且讨论了三种核的存在性、稳定性和唯一性．指出核函数的本质是表达相似性的工具，核函数与Mercer条件、正定性、对称性互为非充分非必要条件．仿真研究表明，本核函数对学习样本本身的分类是完美的，而且其泛化能力优于传统核函数的SVM．