双任务介入对社区脑卒中患者步态参数及其对称性的影响

目的 对比社区脑卒中患者单任务步行与不同类型和不同负荷双任务步行时步态参数及其对称性的差异。方法 利用 Simi Motion 三维动作分析系统采集 20 名处于慢性恢复期的社区脑卒中患者在单任务步行及不同负荷认知双任务步行和运动双任务步行时步态参数,并间接计算出其对称指数。 采用单因素重复测量方差分析对比单任务步行与不同双任务步行时步态参数及其对称性差异。 结果 与单任务步行相比,社区脑卒中患者在高低负荷认知任务介入时步速、患侧步长、健侧摆动相占比均降低,困难认知任务介入时健侧步宽和健侧、患侧支撑相占增加、健侧步长和患侧摆动相占比降低,摆动相占比对称指数减小(P<0. 05)。 结论 社区脑卒中患者主要通过降低步速、缩减步长、降低摆动相占比、增加步宽和支撑相占比,改变步态模式来应对认知任务干扰,对于步态稳定性,高负荷认知任务的介入,会增加社区脑卒中患者摆动相占比的不对称性程度,降低其步态稳定性。     

青年期和老年期抑郁症患者抑郁自评量表的对照研究

目的探讨青年与老年抑郁症患者的临床症状学特征。方法以Zung氏抑郁自评量表为工具,对199名青年抑郁症和218名老年抑郁症进行测试。结果在SDS的20个项目中青年组和老年组间有12个存在显著性统计学差异(t=6.27~-8.29,P<0.001 or P<0.05)。青年组与老年组在项目得分≥3的人数百分比上,有显著性统计学差异的项目有9个(χ2=58.64~6.92,P<0.01)。在因子分析中,取特征值大于1,青年组和老年组各获6个因子,各自解释累积总变异的61.16%和60.91%,各因子的构成则不相同。结论青年期和老年期抑郁症患者的临床症状表现形式各具特点。     

不同任务介入对青年行走动态稳定性及 双任务成本的影响

目的 对比不同双任务行走时动态稳定性及双任务稳定性成本的差异。方法利用三维运动捕捉系统采集40名受试者不同双任务行走时的运动学数据,并间接计算相关动态稳定性指标。采用单因素重复测量方差分析对比单任务行走与不同双任务行走步态参数及动态稳定性差异,采用双因素重复测量方差分析双任务类型（认知任务和运动任务）和任务负荷（简单任务和困难任务）对人体双任务稳定性成本的影响以及两者之间的交互作用。结果 与单任务相比,不同双任务介入时步速均降低（P<0.05）,步频和动态稳定性均增加（P<0.05）,在2倍运动负荷介入时步长小于单任务步行（P<0.05）,1倍认知任务和2倍认知任务介入时步宽大于单任务步行（P<005）。简单认知双任务稳定性成本大于简单运动双任务稳定性成本（P<0.05）,困难认知双任务稳定性成本小于困难运动双任务（P<005）,简单运动双任务稳定成本小于困难运动双任务（P<0.05）。结论 与单任务行走相比,不同双任务的介入均会增加人体动态稳定性;对于双任务稳定性成本,不同任务类型以及不同任务负荷之间存在交互效应。当任务负荷较高时,认知任务的双任务成本较低,即认知任务的负向干扰幅度增大,会损害机体的动态姿势控制能力。当第2任务为运动任务时,较低负荷下对人体动态稳定性的负向干扰幅度增大,降低动态姿势控制能力。     

衰弱状态和步行速度对老年人下肢关节运动学特征的影响

目的 研究衰弱状态和步行速度对老年人步行时下肢关节运动学特征的影响。 方法 招募 59 名 60 岁及以上老年人,根据衰弱指数清单将受试者分为非衰弱组、衰弱前组和衰弱组,采用 Xsens MVN 运动捕捉惯性传感器采集 3 组老年人慢速、习惯速度、快速行走时的运动学数据,应用双因素重复测量方差分析比较不同衰弱状态和步速下老年人行走时的下肢关节运动学特征差异。 结果 衰弱组老年人的年龄显著高于非衰弱组(P<0. 01),膝关节最大屈角、膝关节和踝关节活动范围(range of motion,ROM)显著低于非衰弱组和衰弱前组(P<0. 05);同时,衰弱组老年人踝关节最大跖屈角显著低于非衰弱组(P<0. 05);随着步速增加,衰弱组老年人的单支撑相时间显著增加(P<0. 05),3 组老年人髋关节矢状面最大角及其 ROM、膝关节最大屈角、踝关节最大跖屈角及其 ROM 显著增加(P<0.05),双支撑相时间、踝关节最大背屈角度和膝关节 ROM 显著减小(P<0. 05);所有关节角度中只有髋关节最大伸角及其 ROM、膝关节最大屈角在慢速与习惯速度之间出现显著差异(P<0. 05)。 相关性分析显示,衰弱前组和衰弱组老年人不同速度步行时髋、膝关节 ROM 均显著正相关(P<0. 01),衰弱组老年人在习惯速度和快速行走时膝、踝关节 ROM 显著正相关(P<0. 05)。 结论 随着衰弱程度的进展,老年人下肢关节矢状面角度持续降低,主要集中于膝、踝关节。 在行走时两个关节间同步性增强,自由度降低,但在提高步行速度时,衰弱状态基本不影响老年人的步行策略。 研究结果有助于对衰弱老年人群进行筛查及康复指导。     

腰椎后部结构的运动学分析

以人体完整腰椎作为实验标本，设计和应用平行光三维运动测量系统，获得各向运动时腰椎后部结构特定点的三维运动参数。通过载荷－位移曲线分析，发现腰椎后部结构重要部位的立体运动规律。右旋时右侧腰４下关节突的相对运动是后移０．６ｍｍ；上移１．０ｍｍ和右移３．０ｍｍ，扩大了腰５神经根管的容积。前屈时，无论那一个腰椎节段，均发生向前、上方的运动，侧向移位较。老年腰椎标本不同节段的主运动轴在Ｘ和Ｚ轴不规律更换，加载过程中位移量变化较中青年标本大，这与标本的退变和稳定性变化有关。     

部分钩突切除对颈椎稳定性影响的有限元分析

目的建立颈椎(C4-C6)三维有限元模型,研究钩突切除前后对颈椎稳定性的影响。方法根据健康志愿者的颈椎断层CT扫描序列图像,采用Mimics13.1和Solid Works2012软件进行三维重建和造型,利用ANSYS15.0软件,对颈椎及周围组织赋予不同的材料属性,建立颈椎(C4-C6)三维有限元模型。在建立的模型上加载,模拟脊柱的前屈、后伸、左右侧曲、左右旋转6种工况下的生理活动,获取位移、应力等数值云图,并进行分析验证。在C5节段左侧钩突上分别切除钩突高度的25%、50%和60%,获得不同范围钩突切除时的左侧弯状态下颈椎各部位的位移、应力等数值云图,分析不同范围钩突切除对颈椎稳定性的影响。结果本研究建立了三个椎体运动节段的三维有限元模型,模型高度模拟颈椎结构与材料特性,研究了不同范围钩突切除后,颈椎稳定性受到的影响。钩突切除高度的25%后的左侧弯状态与未切除时对比分析,位移云图变化不大,最大等效应力减小。钩突切除高度的50%、60%后的左侧弯状态下的位移继续增大,最大等效应力逐渐减小。结论切除钩突高度的25%时对颈椎稳定性影响不大,随着切除钩突范围的增加,颈椎的稳定性逐渐降低。     

脊柱融合内固定致邻近节段退变的生物力学机制

目的：从生物力学角度了解融合内固定对腰椎邻近节段的影响。方法：9具新鲜腰1～骶椎尸体标本分别近、远端固定，在脊柱三维运动实验机上施以8Nm纯力偶矩模拟人体行屈伸、左右侧弯及旋转活动，观察L3～4、L4～5、L5～Sl节段运动范围(ROM)；随后进行各种模拟手术并安装内固定，依次测定CD内固定(CD)、CD加椎体间植骨(CD-骨块)、CD加TFC(CD—TFC)状态下各节段ROM值并进行统计学分析。结果：①各融合术式均可使固定节段达到即刻稳定性，L4～5节段ROM值明显减小；②L3～4节段在屈伸、侧弯和旋转时有明显位移增加，L5S1节段在旋转时ROM值明显增加，屈伸和侧弯时ROM值改变无统计学意义。结论：脊柱融合内固定术后，相邻节段位移增加、运动模式改变，易继发不稳和退变。     

智能下肢假肢传感器的应用

背景:下肢运动是一种复杂的运动,采用合适的传感器获取人体运动生理信息,成为智能假肢控制的前提。国际上现有的下肢假肢控制信息源为与运动信息有关的物理量,这类信息可以直接反映人体运动的生物力学特性,采集比较简单,非常适合实时控制。现有智能下肢假肢产品根据采用的控制方法不同选择一种或几种传感器测量人体运动信息。目的:研究一种能够采集智能下肢假肢控制所需人体运动信息的传感器系统。方法:对智能下肢假肢带固定式气缸阻尼器的四连杆机械机构进行运动分析,得出四连杆后臂下轴电位计输出信号与膝关节弯曲角度的对应关系,同时,选取合适的霍尔传感器安装位置,解决了其中存在的双值问题。设计了传感器输出信号采集实验,通过跑步机速度调节来保证步行速度完全可控,测量不同步速下脚尖离地时刻膝关节弯曲角度,分析采集结果找到了它们之间的对应关系。结果与结论:脚尖离地时刻膝关节弯曲角度随着步行速度增大而增大,采用二次曲线拟合取得了较好效果。实验结果显示,水平步行状态下,采用电位计和霍尔传感器作为检测手段能够检测下肢假肢的步速,也能区分支撑期和摆动期。     

基于心电图的心肌缺血非线性分析

心电图是心肌缺血检测的一种方便、经济、无创的工具,其主要的临床表现为ST-T段变化.鉴于心脏是一个混沌系统,本文从非线性角度出发,对心电图特征参数序列进行分形维数和最大Lyapunov指数分析,其中特征参数序列包括：心电图RR间期,瞬时心率HR（heart rate）,ST段的平均幅值STmean,ST段最小幅值STmin,STmean与HR的比值STr,T波峰末间期TpTe,R波峰值Ramp,T波峰值Tamp.利用公共数据库Long-term ST database（LTST）中心肌缺血和非心肌缺血心电数据,通过统计t检验分析,除最大分形维数分析中的TpTe与最大Lyapunov指数分析中的Ramp和Tamp特征参数外,其余参数均有显著性差异.基于心电图的非线性分析为心肌缺血检测与诊断提供另一重要依据.     

人体步行运动的关节力学研究

利用角度传感器和步态测力板,本文观察了人体的步行运动,采用Fourier数字滤波拟合出各关节的运动规律,依据多刚体动力变分原理建立了适合作实时计算和模型修改的人体步行动力学方程。对于步行中双脚着地时出现的闭环结构,作者借助测力板测出的脚底反力曲线,提出了由力——位移组成的混合求解法。用文中计算方法编制的软件可用于人体下肢疾病的临床医学诊断。     

Age-related changes in lower trunk coordination and energy transfer during gait

The effects of aging on lower trunk (trunk-low-back joint-pelvis) coordination and energy transfer during locomotion has received little attention; consequently, there are scant biomechanical data available for comparison with patient populations whose upper body movements may be impaired by orthopaedic or neurologic disorders. To address this problem, we analyzed gait data from a cross-sectional sample of healthy adults (n = 93) between 20 and 90 yr old (n = 44 elderly, >50 yr old; n = 49 young, <50 yr old). Gait characteristics of elders were mostly typical: gait speed of elders (1.13 +/- 0.20 m/s) was significantly (P = 0.007) lower than gait speed of young subjects (1.20 +/- 0.18 m/s). Although elders had less low-back (trunk relative to pelvis) range of motion (ROM; P = 0.013) during gait than young subjects, no age-related differences were detected in absolute trunk and pelvis ROM or peak pitch angles during gait. Despite similar upper body postures, there was a strong association between age and pelvis-trunk angular velocity phase angle (r = 0.48, P < 0.001) with zero phase occurring at approximately 55 yr of age; young subjects lead with the pelvis while elderly subjects lead with the trunk. Age related changes in gait speed and low-back ROM were unable to explain the above findings. The trunk-leading strategy used by elders resulted in a sense reversal of the low-back joint power curve and increased (P = 0.013) the mechanical energy expenditure required for eccentric control of the lower trunk musculature during stance phase of gait. These data suggest an age-related change in the control of lower trunk movements during gait that preserves upper body posture and walking speed but requires a leading trunk and higher mechanical energy demands of lower trunk musculature-two factors that may reduce the ability to recover from dynamic instabilities. The behavioral and motor control aspects of these findings may be important for understanding locomotor impairment compensations in aging humans and in quantifying falls risk.     

Transtibial Amputee Joint Motion has Increased Attractor Divergence During Walking Compared to Non-Amputee Gait

The amputation and subsequent prosthetic rehabilitation of a lower leg affects gait. Dynamical systems theory would predict the use of a prosthetic device should alter the functional attractor dynamics to which the system self-organizes. Therefore, the purpose of this study was to compare the largest Lyapunov exponent (a nonlinear tool for assessing attractor dynamics) for amputee gait compared to healthy non-amputee individuals. Fourteen unilateral, transtibial amputees and fourteen healthy, non-amputee individuals ambulated on a treadmill at preferred, self-selected walking speed. Our results showed that the sound hip (p = 0.013), sound knee (p = 0.05), and prosthetic ankle (p = 0.023) have significantly greater largest Lyapunov exponents than healthy non-amputees. Furthermore, the prosthetic ankle has a significantly greater (p = 0.0.17) largest Lyapunov exponent than the sound leg ankle. These findings indicate attractor states for amputee gait with increased divergence. The increased attractor divergence seems to coincide with decreased ability for motor control between the natural rhythms of the individual and those of the prosthetic device. Future work should consider the impact of different prostheses and rehabilitation on the attractor dynamics.     

Gait adaptations to simultaneous cognitive and mechanical constraints

Previous studies have shown that walking is not a purely automatic motor task but places demands on sensory and cognitive systems. We set out to investigate whether complex walking tasks, as when walking down a steeper gradient while performing a concurrent cognitive task, would demand gait adaptation beyond those required for walking under low-challenge conditions. Thirteen healthy young individuals walked at their self-selected speed on a treadmill at different inclinations (0, −5 and −10%). Gait spatio-temporal measures, pelvis angular excursion, and sacral centre of mass (CoM) motion were acquired while walking or while walking and performing a mental tracking task. Repeated-measures ANOVAs revealed that decreasing treadmill inclination from 0 to −10% resulted in significant decreased walking speed (P < 0.001), decreased stride length (P < 0.001), increased pelvis tilt (P = 0.006) and obliquity variability (P = 0.05), decreased pelvis rotation (P = 0.02), and increased anterio-posterior (A-P) CoM displacement (P = 0.015). Compared to walking alone, walking under dual-task condition resulted in increased step width (P < 0.001), and increased medio-lateral (M-L) CoM displacement (P = 0.039) regardless of inclination grade, while sagittal plane dynamics did not change. Findings suggest that gait adapts differently to cognitive and mechanical constraints; the cognitive system is more actively involved in controlling frontal than sagittal plane gait dynamics, while the reverse is true for the mechanical system. Finally, these findings suggest that gait adaptations maintain the ability to perform concurrent tasks while treadmill walking in healthy young adults.     

Habituation to treadmill walking

The use of a treadmill to evaluate gait patterns makes it possible to analyze many gait cycles and stride to stride variations. The objective of this study was to assess the time required for a subject to habituate to walking on a treadmill. The evolution of knee kinematics and spatio-temporal parameters were analyzed to measure habituation to walking on the treadmill. To obtain this information, data were recorded on 10 healthy subjects for about 45 minutes as they walked on a treadmill. A steady state was attained for knee kinematics and most spatio-temporal parameters at the time the treadmill had attained its maximal speed (approximately 30 seconds). However, 10 minutes were necessary for stride length to become reproducible. Time for habituation to walking on a treadmill must be considered when kinematics are evaluated during gait of healthy and disabled subjects. We have shown that, at least for young, healthy individuals who are non-na?ve to walking on a treadmill, a 10-minute warm-up is enough before three-dimensional knee kinematics and spatio-temporal data can be recorded.     

慢跑的速度对青年女性下肢关节及肌肉的影响

目的 探讨合理的慢跑速度对体形和步姿的影响,使人在慢跑健身的同时兼得柔美的体态。方法 根据相关测量选择5种慢跑速度。利用运动捕捉系统采集研究对象(15位青年女性志愿者)在慢跑速度下的运动学数据,同时对下肢8块主要肌肉的肌电信号进行采集。计算获得在不同慢跑速度下髋、膝及踝关节矢状面的关节角度变化的均值。选择数据最接近均值的对象作为研究对象并进行运动学分析。结果 计算获得了该研究对象在不同慢跑速度下髋、膝及踝关节矢状面的关节角度以及下肢8块主要肌肉的激活度曲线。运用打分的方法,本文给出了研究对象慢跑速度、慢跑阶段、肌肉激活度与关节角度之间的关系。结论 各关节角的变化范围和各肌肉最大激活度并不随慢跑速度的变化而单调变化。本文为青年女性健身时选择适合自己的慢跑速度提供了参考。     

Assessment of spatio-temporal parameters during unconstrained walking

This paper presents an analysis of spatio-temporal gait parameters during overground walking based upon a method that needs only lower trunk accelerations. Twenty-six healthy young subjects and 15 healthy elderly subjects participated in an experiment where overground walking was studied at different speeds. Accelerations of the lower trunk were measured by a tri-axial accelerometer connected to a portable data logger carried on the body. An analysis of trunk acceleration data produced temporal gait parameters (duration of subsequent stride cycles and left/right steps) and convincing estimations of spatial parameters (step length and walking speed). Typical differences in spatio-temporal gait parameters between young and elderly subjects could be demonstrated, i.e. a limited range of walking speeds, smaller step lengths, and a somewhat higher variability of temporal parameters in elderly subjects. It is concluded from these results that essential spatio-temporal gait parameters can be determined during overground walking using only one tri-axial accelerometer. The method is easy-to-use and does not interfere with regular walking patterns. Both the accelerometer and the data logger can be miniaturised to one small instrument that can be carried on the trunk during hours of walking. Thus, the method can easily be incorporated in current activity monitors so that 24-h monitoring of postures and activities can be combined with assessment of gait characteristics during these monitoring periods. In addition, the presented method can be a basis for more sophisticated gait analyses during overground walking, e.g. an analysis of kinematic signals or muscle activity within subsequent stride cycles.     

利用步态分析研究楔形鞋垫对膝关节载荷的影响

目的研究足底不同位置的楔形鞋垫对膝关节承载及运动特征的影响。方法利用三维动捕捉系统与测力台对10名健康成年女性受试者步态中的关节动力学变化特点进行分析研究。实验状态分为对照组和6组楔形鞋垫测试组。利用单因素方差分析评价楔形足底支撑对膝关节动力学参数的影响。结果相对于对照组,前内侧楔形鞋垫组显著减小了膝内翻力矩第1峰值(P<0.05);使用前外侧楔形鞋垫和外侧全长楔形鞋垫的两组显著减小了膝内翻力矩第2峰值(P<0.05,P<0.05)。结论使用楔形鞋垫可有效地减小站立相的膝关节内翻力矩,这将有助于设计适合的鞋垫以减轻由骨性关节炎所带来的疼痛。     

正走和倒走的膝关节生物力学特征比较

目的 比较正走和倒走两种不同行走模式时膝关节的生物力学特征。方法 采用三维运动捕捉系统Vicon T40和测力台AMTI OR6-7采集并比较13名健康青年男性志愿者正走和倒走时的时间、空间、运动学和动力学参数。结果 与正走相比,倒走时的步速、步频和步幅均显著减小,跨步周期和支撑相所占百分比显著增加;在矢状面上,倒走时膝关节活动度、最大屈伸力矩较正走小;在冠状面上,倒走时膝关节内翻外展活动范围也较正走小,内翻力矩峰值在支撑早期较正走小,但在支撑晚期较正走大;地面反作用力在支撑早期较正走大,但在支撑晚期较正走小。结论 倒走和正走膝关节生物力学特征差异明显。与正走相比倒走在支撑相早期能减轻膝关节内侧间室的负荷,而倒走在支撑相晚期对膝关节负荷的影响则尚须进一步研究。     

老年人上下楼梯的步态特征以及下肢关节运动功能特点

目的 探讨老年人上下楼梯的步态特征以及下肢关节运动的力学性能。 方法 通过17名青年人、15名老年人自然速度上下5个台阶的楼梯测试与分析,并结合红外高速运动捕捉系统和三维测力台获取步态参数、下肢关节角度以及地面反作用力,通过逆向动力学方法计算关节力矩和功率,采取独立样本 t 检验分析年龄对上述参数的影响。 结果 与青年人相比,老年人上下楼梯步态周期较长,步速和步频则明显较低(P<0. 05);同时,老年人上下楼梯支撑相和摆动相分别明显延长和缩短(P<0. 05)。 不论是青年人还是老年人,上下楼梯过程中下肢关节角度、力矩和功率的变化趋势较为一致。 但老年人上楼主要是通过踝、膝关节功率的产生来维持,而青年人则是通过近端肢体的能量,特别动用了较多的膝关节功率。 下楼过程中的能量吸收,两者皆是以膝关节为主。 结论 随着年龄的增长,下肢机能下降和肌力不足,老年人害怕在上下楼梯时发生跌倒,试图通过减少摆动时间来弥补身体的不稳定。 研究结果为临床上老年患者群体的康复管理以及预测跌倒的功能性评估提供参考。