国内外人工腿(假肢)研究的进展及发展趋势

人工腿(假肢)一直是机器人学和生物医学工程领域 的一个前沿性研究课题．在这方面的研究中,英、日两国于90年代中期研制成功的智能型 人工腿反映了该研究的最新进展．本文共分五个部分,第一部分是引言;第二部分重点介绍 国外在90年代初以前人工腿的研究概况;第三部分重点介绍国外从90年代初至今人工腿 的研究概况,特别是智能人工腿的研究情况;第四部分重点介绍国内人工腿的研究现状;最 后一部分介绍人工腿研究的发展趋势．     

Weight distribution symmetry during the sit-to-stand movement of unilateral transtibial amputees

This study characterises weight distribution symmetry between the intact and amputated limbs of unilateral transtibial amputees during a sit-to-stand movement. A total of 12 amputees and 12 age-matched, non-amputees performed the activity for two conditions – rising with and without chair arm-rest assistance. The sit-to-stand movement was divided into five events: Pre-Ascent; Ascent Initiation; Seat-Off; Deceleration; Standing. Symmetry in ground reaction forces between limbs was calculated at each event together with the rise time. Results indicate that during the course of the movement, amputees increased loading of the intact limb by approximately 27%, resulting in a significant asymmetry at seat-off and deceleration events. Non-amputees loaded the dominant limb more than the non-dominant limb throughout the activity but did not exhibit substantial weight shifts. Weight distribution symmetry was not significantly different between the two rising conditions in either population. Amputees had significantly longer rise times than non-amputees only while rising without arm-rest assistance.

Statement of Relevance: Sit-to-stand movements are performed frequently every day. Incorrect movement biomechanics caused by musculoskeletal impairments can lead to reduced functional independence and secondary co-morbidities. This study defines five events of a sit-to-stand cycle and is the first to address asymmetries of transtibial amputees, providing ergonomic insights for clinical assessment and intervention.     

上肢经肱骨截肢神经功能重建研究

表面肌电信号是一种安全、非侵入的电生理信息,作为实现直觉控制多功能肌电假肢系统的信息源而被广泛应用。由于经肱骨截肢者截肢的程度较高,残留的肢体肌肉少,缺乏足够的肌电信息源,无法实现多功能肌电假肢的直觉控制。目前现有技术是通过采用靶向肌肉神经功能重建的方法重建缺失肌电信息源。但目前国内尚未有关于截肢者残端神经功能重建方法的相关研究。因此,文章提出一种新型的神经吻合技术——目标神经功能替代术：采用靶向肌肉神经功能重建术与目标神经功能替代术相结合的方法,首次在国内对经肱骨截肢者成功实施了神经功能重建手术,成功建立了经肱骨截肢者神经功能重建模型,重建了因截肢而丧失的肌电信息。并采用高密度肌电技术对术前和术后的手-腕-肘部动作进行肌电信号采集,通过动作分类识别的准确率验证了该手术后肌电信息源重建的可靠性。这些结果初步验证了该方法可以为经肱骨截肢者残肢重建缺失肢体神经功能,并为直觉控制多功能肌电假肢提供潜在的信息源。     

Leg stiffness of sprinters using running-specific prostheses

Running-specific prostheses (RSF) are designed to replicate the spring-like nature of biological legs (bioL) during running. However, it is not clear how these devices affect whole leg stiffness characteristics or running dynamics over a range of speeds. We used a simple spring–mass model to examine running mechanics across a range of speeds, in unilateral and bilateral transtibial amputees and performance-matched controls. We found significant differences between the affected leg (AL) of unilateral amputees and both ALs of bilateral amputees compared with the bioL of non-amputees for nearly every variable measured. Leg stiffness remained constant or increased with speed in bioL, but decreased with speed in legs with RSPs. The decrease in leg stiffness in legs with RSPs was mainly owing to a combination of lower peak ground reaction forces and increased leg compression with increasing speeds. Leg stiffness is an important parameter affecting contact time and the force exerted on the ground. It is likely that the fixed stiffness of the prosthesis coupled with differences in the limb posture required to run with the prosthesis limits the ability to modulate whole leg stiffness and the ability to apply high vertical ground reaction forces during sprinting.     

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。     

Robotic hip-disarticulation prosthesis: evaluation of prosthetic gaits in a non-amputee individual

This is the first report regarding the application of a robotic prosthesis for hip-disarticulation amputees. Hip-disarticulation prostheses (HDPs) are used by amputees with either an amputation or anomaly at or close to the hip joint. Robotics can be beneficial in such cases, as these individuals have reduced levels of motor function compared to other amputees and have limited mobility. We developed a robotic HDP, and analysed the gaits of a non-amputee using the robotic and non-powered dummy HDPs. The results imply that a robotic HDP may induce proper gait and maintain the burdens of the prosthetic and non-prosthetic limbs symmetrically.