Robot assisted treadmill training: mechanisms and training strategies

The rehabilitation engineering community is working towards the development of robotic devices that can assist during gait training of patients suffering from neurologic injuries such as stroke and spinal cord injuries (SCI). The field of robot assisted treadmill training has rapidly evolved during the last decade. The robotic devices can provide repetitive, systematic and prolonged gait training sessions. This paper presents a review of the treadmill based robotic gait training devices. An overview of design configurations and actuation methods used for these devices is provided. Training strategies designed to actively involve the patient in robot assisted treadmill training are studied. These training strategies assist the patient according to the level of disability and type of neurologic injury. Although the efficacy of these training strategies is not clinically proven, adaptive strategies may result in substantial improvements. We end our review with a discussion covering major advancements made at device design and training strategies level and potential challenges to the field.     

机器人模式设计对脊髓损伤患者步态的影响

背景：治疗师帮助的减重运动平板训练方法是一种效果较好的步态训练方法,但因其对治疗师体力消耗较大,且人员需要较多,临床应用受到一定限制。机器人帮助的减重运动平板训练受到广泛关注。 目的：总结机器人在脊髓损伤患者步态康复中的作用及其对下肢运动及肌肉活动模式的影响。 方法：由第一作者检索PubMed数据库(http://www.ncbi.nlm.nih.gov/PubMed)1995-01/2010-12涉及机器人、Lokomat、减重运动平板训练及脊髓损伤步态康复内容的文献,英文关键词为“spinal cord injury,gait,walking,locomotor,locomotion,rehabilitation,robot,robotic,Lokomat ”,排除陈旧性、重复性文献,保留30篇文献归纳总结。 结果与结论：虽然到时目前为止还没有证据证明机器人运动训练方法优越于其他方法,但其在脊髓损伤康复领域的应用也有明显的优势。机器人设备对下肢运动的被动引导及固定步行模式的重复训练不利于患者最大自主肌力的发挥及步行循环周期之间的变动,不能做到治疗师那样敏感地感受患者的运动表现。治疗师只有全面了解机器人设备并根据患者的运动能力不断调整训练参数,以致使患者在精确控制环境下最大限度地发挥自主运动能力,才能获得最佳的运动训练效果。     

Robotic assistance that encourages the generation of stepping rather than fully assisting movements is best for learning to step in spinally contused rats

Robotic devices have been developed to assist body weight-supported treadmill training (BWSTT) in individuals with spinal cord injuries (SCIs) and stroke. Recent findings have raised questions about the effectiveness of robotic training that fully assisted (FA) stepping movements. The purpose of this study was to examine whether assist-as-needed robotic (AAN) training was better than FA movements in rats with incomplete SCI. Electromyography (EMG) electrodes were implanted in the tibialis anterior and medial gastrocnemius hindlimb muscles of 14 adult rats. Afterward, the rats received a severe midthoracic spinal cord contusion and began daily weight-supported treadmill training 1 wk later using a rodent robotic system. During training, assistive forces were applied to the ankle when it strayed from a desired stepping trajectory. The amount of force was proportional to the magnitude of the movement error, and this was multiplied by either a high or low scale factor to implement the FA (n = 7) or AAN algorithms (n = 7), respectively. Thus FA training drove the ankle along the desired trajectory, whereas greater variety in ankle movements occurred during AAN training. After 4 wk of training, locomotor recovery was greater in the AAN group, as demonstrated by the ability to generate steps without assistance, more normal-like kinematic characteristics, and greater EMG activity. The findings suggested that flexible robotic assistance facilitated learning to step after a SCI. These findings support the rationale for the use of AAN robotic training algorithms in human robotic-assisted BWSTT.     

Bilateral robots for upper-limb stroke rehabilitation: State of the art and future prospects

Robot-assisted bilateral upper-limb training grows abundantly for stroke rehabilitation in recent years and an increasing number of devices and robots have been developed. This paper aims to provide a systematic overview and evaluation of existing bilateral upper-limb rehabilitation devices and robots based on their mechanisms and clinical-outcomes. Most of the articles studied here were searched from nine online databases and the China National Knowledge Infrastructure (CNKI) from year 1993 to 2015. Devices and robots were categorized as end-effectors, exoskeletons and industrial robots. Totally ten end-effectors, one exoskeleton and one industrial robot were evaluated in terms of their mechanical characteristics, degrees of freedom (DOF), supported control modes, clinical applicability and outcomes. Preliminary clinical results of these studies showed that all participants could gain certain improvements in terms of range of motion, strength or physical function after training. Only four studies supported that bilateral training was better than unilateral training. However, most of clinical results cannot definitely verify the effectiveness of mechanisms and clinical protocols used in robotic therapies. To explore the actual value of these robots and devices, further research on ingenious mechanisms, dose-matched clinical protocols and universal evaluation criteria should be conducted in the future.     

Optimizing Heart Rate Regulation for Safe Exercise

Safe exercise protocols are critical for effective rehabilitation programs. This paper aims to develop a novel control strategy for an automated treadmill system to reduce the danger of injury during cardiac rehabilitation. We have developed a control-oriented nonparametric Hammerstein model for the control of heart rate during exercises by using support vector regression and correlation analysis. Based on this nonparametric model, a model predictive controller has been built. In order to guarantee the safety of treadmill exercise during rehabilitation, this new automated treadmill system is capable of optimizing system performance over predefined ranges of speed and acceleration. The effectiveness of the proposed approach was demonstrated with six subjects by having their heart rate track successfully a predetermined heart rate.     

下肢外骨骼康复机器人在膝关节活动受限康复治疗中的应用*

背景：下肢外骨骼康复机器人以持续主被动活动联合为理论基础,通过模拟人体运动,刺激机体的自然复原力,发挥组织代偿作用。 目的：动态观察并了解下肢外骨骼康复机器人在膝关节活动受限患者功能锻炼中的康复作用。 方法：将20例术后早期膝关节活动受限患者随机等分为实验组与对照组,实验组采用下肢外骨骼康复机器人行肢体功能锻炼,对照组采用被动训练装置CPM机行功能锻炼,治疗间隙2组均采用心理疏导、低频脉冲电疗和红外线等物理治疗。 结果与结论：治疗2个月后,实验组与对照组患者膝关节后屈、前伸活动度均较治疗前明显改善(P < 0.01),同时实验组股四头肌肌力较治疗前明显改善(P < 0.01)。2个月后的后续治疗,实验组患者膝关节后屈、前伸活动度有了进一步的改善(P < 0.05),对照组上述指标无明显改善。说明早期采用下肢外骨骼康复机器人或CPM机配合心理疏导、低频脉冲电疗和红外线等治疗均能明显提高膝关节活动受限患者膝关节活动度,同时下肢外骨骼康复机器人具有恢复患者股四头肌肌力的作用。     

融合功能性电刺激的助行康复外骨骼机器人混合控制策略研究进展

运动康复有助于促进脊柱损伤的恢复或脑卒中患者神经可塑,这对患者受损运动功能的恢复有着非常重要的作用。近年来,功能性电刺激(FES)技术与外骨骼机器人的结合,发挥了这两种康复技术的优势,同时互补了各自缺陷,从而促进实现了更有效的康复辅助模式,目前已逐渐成为本领域的研究热点。综述融合FES与下肢康复机器人混合控制策略的研究现状,并分别就FES结合被动矫形器的单向控制方法和融合主动外骨骼的协同控制方法,剖析其相关技术与难点;讨论构建人机信息交互环路的关键问题,以及如何设计出合理高效混合控制策略,从而实现动态控制分配和患者最大程度主动参与康复训练的目标。对未来的混合康复技术发展方向进行了总结与展望。     

Effects of implicit visual feedback distortion on human gait

Gait rehabilitation after stroke often utilizes treadmill training delivered by either therapists or robotic devices. However, clinical results have shown no benefit from this modality when compared to usual care. On the contrary, results were inferior; perhaps, because in its present form it is not interactive and at least for stroke, central pattern generators at the spinal level do not appear to be the key to promote recovery. To enable gait therapy to be more effective, therapy must be interactive and visual feedback appears to be an important option to engage patients’ participation. In this study, we tested healthy subjects to see whether an implicit “visual feedback distortion” influences gait spatial pattern. Subjects were not aware of the visual distortion nor did they realize changes in their gait pattern. The visual feedback of step length symmetry was distorted so that subjects perceived their step length as being asymmetric during treadmill training. We found that a gradual distortion of visual feedback, without explicit knowledge of the manipulation, systematically modulated gait step length away from symmetry and that the visual distortion effect was robust even in the presence of cognitive load. This indicates that although the visual feedback display used in this study did not create a conscious and vivid sensation of self-motion (the properties of the optical flow), experimental modifications of visual information of subjects’ movement were found to cause implicit gait modulation. Nevertheless, our results indicate that modulation with visual distortion may require cognitive resources because during the distraction task, the amount of gait modulation was reduced. Our results suggest that a therapeutic program involving visual feedback distortion, in the context of gait rehabilitation, may provide an effective way to help subjects correct gait patterns, thereby improving the outcome of rehabilitation.     

Oxygen consumption, oxygen cost, heart rate, and perceived effort during split-belt treadmill walking in young healthy adults

During split-belt treadmill walking the speed of the treadmill under one limb is faster than the belt under the contralateral limb. This unique intervention has shown evidence of acutely improving gait impairments in individuals with neurologic impairment such as stroke and Parkinson’s disease. However, oxygen use, heart rate and perceived effort associated with split-belt treadmill walking are unknown and may limit the utility of this locomotor intervention. To better understand the intensity of this new intervention, this study was undertaken to examine the oxygen consumption, oxygen cost, heart rate, and rating of perceived exertion associated with split-belt treadmill walking in young healthy adults. Fifteen participants completed three sessions of treadmill walking: slow speed with belts tied, fast speed with belts tied, and split-belt walking with one leg walking at the fast speed and one leg walking at the slow speed. Oxygen consumption, heart rate, and rating of perceived exertion were collected during each walking condition and oxygen cost was calculated. Results revealed that oxygen consumption, heart rate, and perceived effort associated with split-belt walking were higher than slow treadmill walking, but only oxygen consumption was significantly lower during both split-belt walking than fast treadmill walking. Oxygen cost associated with slow treadmill walking was significantly higher than fast treadmill walking. These findings have implications for using split-belt treadmill walking as a rehabilitation tool as the cost associated with split-belt treadmill walking may not be higher or potentially more detrimental than that associated with previously used treadmill training rehabilitation strategies.     

基于视频图像边缘检测的人体下肢运动步态

背景：步态规律主要应用人体行走的运动学、动力学等参数进行描述。目前在运动医学、康复工程和仿生学等领域,步态分析可为确定疾病诊断、康复和治疗方案提供重要依据。 目的：应用基于人体运动图像的测量装置系统,采集人体在跑步机上行走的下肢运动步态视频,分析人体步态运动规律。 方法：采用基于双摄影机的人体运动图像捕捉系统,在人体的左右髋关节、膝关节、踝关节及脚板设置标识点,对人体在跑步机上行走的下肢运动步态视频进行采集。应用图像边缘检测的原理,对测量数据进行了图像处理和分析,得到人体正常步速行走时,左右大腿与竖直方向夹角、小腿与竖直方向夹角、脚板与竖直方向夹角及膝关节、踝关节标识点的关节角度变化规律。 结果与结论：基于视频图像边缘检测人体下肢的运动步态,成本相对低廉,数据误差较小,精度与进口设备较接近。应用该测量结果初步构建了人体步态行走数据库,为建立步态评定标准、异常步态判别以及进一步的康复治疗提供了依据。     

Biomechanical effects of body weight support with a novel robotic walker for over-ground gait rehabilitation

Body weight support (BWS) promotes better functional outcomes for neurologically challenged patients. Despite the established effectiveness of BWS in gait rehabilitation, the findings on biomechanical effects of BWS training still remain contradictory. Therefore, the aim of this study is to comprehensively investigate the effects of BWS. Using a newly developed robotic walker which can facilitate pelvic motions with an active BWS unit, we compared gait parameters of ten healthy subjects during a 10-m walk with incremental levels of body weight unloading, ranging from 0 to 40 % at 10 % intervals. Significant changes in joint angles and gait temporospatial parameters were observed. In addition, the results of an EMG signal study showed that the intensity of muscle activation was significantly reduced with increasing BWS levels. The reduction was found at the ankle, knee, and hip joints in the sagittal plane as well as at the hip joint in the frontal plane. The results of this study provide an important indication of increased lateral body balance and greater stabilization in sagittal and frontal plane during gait. Our findings provide a better understanding of the biomechanical effects of BWS during gait, which will help guide the gait rehabilitation strategies.     

Rehabilitation after stroke in older people

Stroke is a leading cause of disability and therefore rehabilitation is a major part of patient care. Most interventions do not target aged patient but there is unequivocal evidence to promote rehabilitation in multidisciplinary stroke units or integrated care of a multidisciplinary team in the community. Most research has focused on the effect of interventions on recovery in different forms of impairment and disability. The most promising options for motor recovery of the arm include constraint-induced movement therapy and robotic-assisted strategies. Interventions to improve postural stability and gait include fitness training, high-intensity therapy, and repetitive-task training. However, information about the clinical effect of various strategies of cognitive rehabilitation and strategies for aphasia and dysarthria is scarce. Several large trials of rehabilitation practice are underway to test these interventions in the elderly, either alone or in combination with early mobilisation, cardiorespiratory fitness training and physical exercise.     

ROAD: domestic assistant and rehabilitation robot

This study introduces the concept design and analysis of a robotic system for the assistance and rehabilitation of disabled people. Based on the statistical data of the most common types of disabilities in Spain and other industrialized countries, the different tasks that the device must be able to perform have been determined. In this study, different robots for rehabilitation and assistance previously introduced have been reviewed. This survey is focused on those robots that assist with gait, balance and standing up. The structure of the ROAD robot presents various advantages over these robots, we discuss some of them. The performance of the proposed architecture is analyzed when it performs the sit to stand activity.     

基于人体骨盆运动轨迹的康复辅助机构设计

针对临床康复医师提出在下肢行走障碍患者康复训练过程中,患者身体重心缺乏在左右两脚之间的横向移动能力,从而影响行走甚至导致跌倒的问题,本文通过健康人步态行走过程的骨盆运动特征,对复杂的骨盆运动学和运动轨迹进行分析,提炼出骨盆侧向移动的轨迹和范围。根据人体工学分析,设计辅助骨盆侧向移动的机构,配合康复机器人应用在下肢行走训练,使得康复训练更接近健康人的自然状态,有利于训练过程中机械设备和人的相互作用。此方法获得医生和治疗师们的高度评价,并通过仿真试验做出了验证。     

A robotic system to train activities of daily living in a virtual environment

In the past decade, several arm rehabilitation robots have been developed to assist neurological patients during therapy. Early devices were limited in their number of degrees of freedom and range of motion, whereas newer robots such as the ARMin robot can support the entire arm. Often, these devices are combined with virtual environments to integrate motivating game-like scenarios. Several studies have shown a positive effect of game-playing on therapy outcome by increasing motivation. In addition, we assume that practicing highly functional movements can further enhance therapy outcome by facilitating the transfer of motor abilities acquired in therapy to daily life. Therefore, we present a rehabilitation system that enables the training of activities of daily living (ADL) with the support of an assistive robot. Important ADL tasks have been identified and implemented in a virtual environment. A patient-cooperative control strategy with adaptable freedom in timing and space was developed to assist the patient during the task. The technical feasibility and usability of the system was evaluated with seven healthy subjects and three chronic stroke patients.     

Comparing the efficacy of metronome beeps and stepping stones to adjust gait: steps to follow!

Acoustic metronomes and visual targets have been used in rehabilitation practice to improve pathological gait. In addition, they may be instrumental in evaluating and training instantaneous gait adjustments. The aim of this study was to compare the efficacy of two cue types in inducing gait adjustments, viz. acoustic temporal cues in the form of metronome beeps and visual spatial cues in the form of projected stepping stones. Twenty healthy elderly (aged 63.2 ± 3.6 years) were recruited to walk on an instrumented treadmill at preferred speed and cadence, paced by either metronome beeps or projected stepping stones. Gait adaptations were induced using two manipulations: by perturbing the sequence of cues and by imposing switches from one cueing type to the other. Responses to these manipulations were quantified in terms of step-length and step-time adjustments, the percentage correction achieved over subsequent steps, and the number of steps required to restore the relation between gait and the beeps or stepping stones. The results showed that perturbations in a sequence of stepping stones were overcome faster than those in a sequence of metronome beeps. In switching trials, switching from metronome beeps to stepping stones was achieved faster than vice versa, indicating that gait was influenced more strongly by the stepping stones than the metronome beeps. Together these results revealed that, in healthy elderly, the stepping stones induced gait adjustments more effectively than did the metronome beeps. Potential implications for the use of metronome beeps and stepping stones in gait rehabilitation practice are discussed.     

Recovery of forward stepping in spinal cord injured patients does not transfer to untrained backward stepping

Six spinal cord injured (SCI) patients were trained to step on a treadmill with body-weight support for 1.5–3 months. At the end of training, foot motion recovered the shape and the step-by-step reproducibility that characterize normal gait. They were then asked to step backward on the treadmill belt that moved in the opposite direction relative to standard forward training. In contrast to healthy subjects, who can immediately reverse the direction of walking by time-reversing the kinematic waveforms, patients were unable to step backward. Similarly patients were unable to perform another untrained locomotor task, namely stepping in place on the idle treadmill. Two patients who were trained to step backward for 2–3 weeks were able to develop control of foot motion appropriate for this task. The results show that locomotor improvement does not transfer to untrained tasks, thus supporting the idea of task-dependent plasticity in human locomotor networks.R. Grasso died on 6 October 2000     

腕功能康复机器人按需辅助控制策略研究

在康复机器人辅助脑卒中患者进行康复训练时,为激发患者的主动参与意识,康复机器人应按照患者康复需求提供其所需的辅助力矩。本文针对腕功能康复机器人提出一种按需辅助控制策略:首先制定能力评估规则,并依据该规则评估患者能力;然后设计控制器,控制器可基于评估结果求解出患者完成康复训练任务所需的辅助力矩,并下发指令至电机;最后控制电机输出指令值,辅助患者完成康复训练任务。将该控制策略应用于腕功能康复机器人,不仅实现了按需辅助的训练模式,而且能够避免辅助力矩激增,同时康复治疗师可在线调节能力评估规则中的多个参数,为不同康复状态的患者定制任务难度。本文所提方法不依赖于力学传感器信息,降低了开发成本且易于实现,具有一定的工程应用价值。     

下肢外骨骼康复机器人的研究与进展

背景：如何提高脑血管疾病所致中枢神经系统损伤患者的日常活动能力是康复医学亟待解决的问题,而外骨骼康复机器人的发展为解决这一问题提供了可能。 目的：回顾下肢外骨骼康复机器人的研究进展,对下肢外骨骼康复机器人的设计与开发提出新的展望。 方法：由第一作者检索1990/2008 PubMed数据库(http://www.ncbi.nlm.nih.gov/PubMed)及万方数据库(http://www.wanfangdata.com.cn)有关医用下肢外骨骼康复机器人的文献,英文检索词为“exoskeletons robot,central nerve damage,passive rehabilitation training,the man-machine integration interaction interface”,中文检索词为“外骨骼机器人,中枢神经损伤,主被动康复训练,人机一体化交互接口”。排除重复性研究。 结果与结论：共纳入26篇文献归纳总结。外骨骼康复机器人研究报道较多,但如能解决体积小、轻便、低功耗、大功率输出等问题,同时具有响应快、低惯性、高精度和高安全性等性能,必将使神经损伤患者下肢功能最大化地恢复成为可能。     

电子耳蜗言语训练及发音模拟系统

听力障碍患者可根据听力障碍程度选择佩戴助听器或植入电子耳蜗，其中重度耳聋患者需要植入电子耳蜗以恢复听力感知能力。电子耳蜗手术植入后，患者仍需要大量的言语康复训练，以适应电子耳蜗和日常言语交流。目前，训练的主要方式是人工训练，不利于提高听力康复训练的效率。本研究开发了一套基于电子耳蜗常用言语处理策略的言语训练及发音模拟系统。该系统可用于语音信号的采集，并进一步将采集到的信号转换成特定的言语处理策略。它可以帮助医生对患者进行听力训练，也可以用于开发新的言语处理策略和算法评估，该系统采集和合成的康复训练信号能准确地反映电子耳蜗言语处理策略的特点，GUI界面简单易用，便于在临床推广应用。