基于线性和非线性分析的人体站立稳定调控策略

目的 从线性和非线性两个角度探究人体站立稳定调控策略。 方法 招募 16 名健康男性受试者,在平衡台完成 30 s 正常站立、闭眼站立以及在泡沫垫上睁眼和闭眼站立,通过时空参数、轨迹近似熵和小波变换分析不同干扰因素站立时足底压力中心(center of pressure, COP)轨迹的线性及非线性特征,采用视觉×本体感觉重复测量方差分析比较干扰情况下(视觉干扰、本体感觉干扰和视觉、本体感觉共同干扰)与正常站立情况下 COP 轨迹线性及非线性特征差异。 结果 在线性指标中,闭眼站立、不稳定站立和闭眼不稳定站立相比于正常站立时 COP 轨迹长度、轨迹速率和 C90 面积均增加( P < 0. 05),3 种干扰方式下的 C90 偏角以及前后( anteroposterior,AP)、内外(mediolateral,ML)方向平均偏移量相比于正常站立无明显变化(P>0. 05)。 在非线性指标中,在 ML 和 AP 两个方向,闭眼站立、不稳定站立和闭眼不稳定站立相比于正常站立 COP 轨迹的近似熵差异均无差异(P>0. 05);频域指标的 ML 方向,视觉干扰使中频、低频和次低 3 个频段的能量权重升高(P<0. 05),超低频能量权重降低(P<0. 05);本体感觉干扰时 3 个频段的能量权重相比于正常站立无差异(P>0. 05);在视觉、本体感觉共同干扰时,中频、低频和次低频能量权重增加(P<0. 05),超低频能量权重降低(P<0. 05);在频域指标的 AP 方向,视觉干扰后相比于正常站立次低频能量下降(P<0. 05)、超低频能量上升(P<0. 05);本体感觉干扰和视觉、本体感觉共同干扰中频、低频和次低频能量权重均上升(P<0. 05),超低频能量权重下降(P<0. 05)。 结论 对于健康人群,站立时人体以较低频段的闭环控制机制为主导,外界信号输入受到干扰并不会改变站立 COP 轨迹的复杂性,其中视觉信息干扰对 ML方向影响较为明显,本体感觉信息干扰对 AP 方向影响较为明显。 站立受到干扰时,开环控制机制的较高频段能量权重增加,身体的晃动幅度和速度变大。     

视觉对人体姿势控制影响的脑功能网络连接机制

目的 研究视觉对人体姿势控制影响及其脑功能网络连接机制。方法 以15名健康青年为研究对象,要求受试者分别进行30 s睁眼、闭眼的双腿站立平衡,采集平衡过程中身体压力中心(center of pressure, COP)和脑电。对COP进行样本熵(SampleEn)计算;对脑电θ、α和β频段,计算相位滞后指数(phase lag index, PLI)构建大脑功能网络,并基于图论计算集聚系数(C)、特征路径长度(L)及小世界网络属性(σ)。结果 人体在双腿站立平衡过程中,闭眼COP_Y样本熵显著高于睁眼(P<0.05)。闭眼α频段PLI平均值显著高于睁眼(P<0.05);闭眼α频段C、σ显著高于睁眼,L显著低于睁眼(P<0.05)。闭眼时α频段额区-中央区-顶区之间的网络连接以及中央区和顶区内连接强度显著高于睁眼(P<0.05)。闭眼时α频段PLI平均值以及C值与COP_Y样本熵中度呈中度负相关(P<0.05)。睁眼时左前额区、左顶区、左枕区α频段PLI平均值与COP_Y样本熵呈中度负相关;闭眼时左...     

常用锻炼方式对老年女性静态平衡能力的影响

目的探讨长期从事太极拳、广场舞和健步走锻炼老年女性的静态平衡能力差异。方法选取128名健康老年女性为受试者,根据日常的主要健身项目分为太极拳组、广场舞组、健步走组和对照组;采用平衡测试仪分别测试闭眼双足站立和睁眼右足站立状态下的4个平衡指标值(摆动速度、摆动角度、外周面积和摆动总轨迹长),测试时间为10 s。结果在闭眼双足站立和睁眼右足站立两种状态下,太极拳组、广场舞组和健步走组各平衡指标值分别与对照组间的差异均具有统计学意义(P0.05);太极拳组与广场舞组相比,两组受试者在两种状态下的摆动速度、摆动总轨迹长以及睁眼右足站立下的外周面积具有统计学差异(P0.05);在两种状态下,太极拳组4个平衡指标值均显著低于健步走组(P0.05);广场舞组与健步走组比较,两组受试者在两种状态下的外周面积、摆动总轨迹长以及睁眼右足站立下的摆动速度具有统计学差异(P0.05)。结论长期从事太极拳、广场舞和健步走锻炼的老年女性的静态平衡能力要优于无锻炼者,且长期从事太极拳锻炼的老年女性的静态平衡能力要优于广场舞和健步走锻炼者,长期从事广场舞锻炼的老年女性的静态平衡能力要优于健步走锻炼者。     

支撑面稳定度在不同视觉输入条件下对轻度认知障碍老年人平衡能力的影响

背景：支撑面稳定度与视觉输入是影响静态平衡的重要因素，但目前对轻度认知障碍老年人平衡能力的研究大多集中在稳定的硬支撑面，对其在不同视觉输入条件下不稳定支撑面上的静态平衡控制尚未可知。目的：探讨轻度认知障碍老年人不同视觉输入条件下在软、硬支撑面上的静态平衡能力。方法：选择21名轻度认知障碍老年人和19名认知正常老年人为研究对象，使用Kistler三维测力台分别对其进行睁眼双脚硬支撑面站立、睁眼双脚软支撑面站立、闭眼双脚硬支撑面站立、闭眼双脚软支撑面站立4种测试，每次测试站立持续时间为30 s，采集2组人群不同视觉条件下在软、硬支撑面站立时的足底压力中心数据，并进行对比。结果与结论：(1)有视觉输入条件下，轻度认知障碍老年人在软、硬支撑面上足底压力中心的总摇摆路径(软支撑面：P=0.003)、内外总摇摆路径(软支撑面：P=0.001，硬支撑面：P <0.001)和95%椭圆置信面积(软支撑面：P=0.001，硬支撑面：P <0.001)显著高于认知正常老年人；(2)无视觉输入条件下，轻度认知障碍老年人在软支撑面上足底压力中心的均方根距离(P=0.014)、内外均方根距离(P=0...     

肥胖儿童短时间静态平衡特征

目的 通过比较肥胖和非肥胖儿童6种站立情况下的压力中心（center of pressure, COP）偏移,研究肥胖儿童短时间静态平衡特征。方法 应用Footscan人体平衡系统获取47名肥胖儿童和50名非肥胖儿童分别双足、单足睁眼和闭眼站立10 s时COP摆动参数。结果 在双足闭眼站立时,肥胖儿童前后方向上的最大动摇径显著大于非肥胖儿童。在左足睁眼站立时,肥胖男孩COP摆动速度、左右方向上的最大动摇径显著小于非肥胖男孩,肥胖女孩左右方向上的最大动摇径显著大于非肥胖女孩。在左足闭眼站立时,男孩的COP摆动速度显著大于女孩。结论 短时间内,双足闭眼站立时,肥胖儿童前后方向上的平衡能力比非肥胖儿童差;肥胖对不同性别儿童的静态平衡影响不同。左足睁眼站立时,肥胖男孩平衡能力优于非肥胖男孩,肥胖女孩平衡能力差于非肥胖女孩;左足闭眼站立时,女孩的平衡能力优于男孩,其他情况下男女无显著差异。由于肥胖及性别因素会影响儿童短时静态平衡能力,建议对于不同性别肥胖儿童减重采取不同的运动模式。     

中老年人静态平衡能力与认知、焦虑的相关性分析

目的探讨中老年人静态平衡能力与认知、焦虑之间的相关性。方法选择北京市海淀区中老年受试者57例,其中女性28例,男性29例;年龄50~70岁,平均年龄59.70岁;平均身高164.49 cm,平均体质量69.51 kg,平均体质量指数25.63 kg/m~2。受试对象分别在睁眼双足、睁眼单足、闭眼双足、闭眼单足4种站立状态下测试10 s平衡能力。用简单反应时(SRT)和空间记忆广度(VMT)测试受试者的认知功能。用贝克焦虑量表和状态-特质焦虑问卷进行焦虑状态评估。分析平衡能力与认知、焦虑之间的相关性。结果睁眼双足状态下,VMT与线形图总长度(L-SKG)有显著的相关性(r=-0.43,P=0.01)。睁眼单足状态下,SRT与轨迹长度(LFS)有显著的相关性(r=0.44,P=0.01),T-AI与x轴上摆动幅度(SM_x)的平均值呈正相关系(r=0.35,P=0.04)。闭眼双足状态下,VMT与L-SKG有显著的相关性(r=-0.42,P=0.01)。闭眼单足状态下SRT与y轴上摆动幅度(SMy)的平均值有相关性(r=-0.34,P=0.04),BAI与MD呈负相关关系(r=-0.33,P=0.04)。结论对于50~70岁健康中老年人来说,静态平衡能力与认知、焦虑之间有一定的相关性。     

下肢运动链协同训练对慢性踝关节外侧不稳患者髋膝肌群肌力及平衡能力的影响价值探讨

目的:探究下肢运动链协同训练对慢性踝关节外侧不稳定患者髋膝肌群肌力及平衡能力的影响.方法:选我科2020年10月至2022年2月收治的87例慢性踝关节外侧不稳患者为研究对象,随机分为两组,对照组43例给予常规训练,观察组44例联合下肢运动链协同训练,在干预前及干预1 m后应用坎伯兰踝关节不稳(Cumberland Ankle instability rating,CAIT)评分、星形偏移平衡测试(Star offset balance test,SEBT)、单腿站立试验(One leg standing test,OLS)检测患者的踝关节稳定性;应用等速肌力检测仪检测患者的髋、膝周围肌力;应用平衡检测仪检测患者睁眼-硬地面、闭眼-硬地面、睁眼-软地面条件下的重心晃动指数;在患者住院期间统计患者出现关节僵硬、关节疼痛及其他不良反应的发生率.结果:干预后,观察组CAIT评分、SEBT高于对照组,OLS低于对照组(P<0.05);观察组髋后伸肌群、髋外展肌群、膝伸直肌群峰力矩高于对照组(P<0.05);观察组睁眼-硬地面、闭眼-硬地面、睁眼-软地面条件下的重心晃动指数低于对照组(P<0.05);两组不良反应发生率无明显差异(P>0.05).结论:下肢运动链协同训练可提高踝关节稳定性,改善髋膝肌群肌力水平及踝关节平衡能力.     

功能性踝关节不稳者的静态平衡能力

背景：目前国内对功能性踝关节不稳者平衡能力的研究较少,并且其平衡能力的缺失也可能是导致踝关节反复损伤的一个重要原因,对其研究能有效地降低损伤概率。 目的：分析功能性踝关节不稳者的静态平衡能力特征。 方法：选取10名男性患有单侧功能性踝关节不稳的受试者为实验组,匹配10名无踝关节伤病的受试者作为对照组。采用win-pod平衡功能检测系统对受试者进行双足和单足的静态平衡能力的测试,双足测试30 s,单足测试10 s,获得评价平衡能力各指标的数值。 结果与结论：双足测试时,无论是睁眼还是闭眼状态下,实验组的各项指标与对照组之间差异无显著性意义(P > 0.05),但双足站立时各指标的值明显都小于单足站立时各指标值,说明在双足站立时,功能性踝关节不稳者的静态平衡能力与正常人差异没有显著性意义,而双足的静态平衡能力比单足的要好。而在患侧足单足测试时,观察发现功能性踝关节不稳者的静态平衡能力略差于正常人,尤其在闭眼状态下。再通过组内X轴平均摆幅与Y 轴平均摆幅的对比发现,在维持平衡姿势的过程中,身体重心的摆动方向基本上以前后方向为主。     

膝骨性关节炎患者动态平衡能力变化

背景：膝骨性关节炎患者屈膝肌力及伸膝肌力均有不同程度的下降,进而影响患者的平衡控制能力。 目的：探讨膝骨性关节炎患者动态平衡功能的变化特征。 方法：纳入22例膝骨性关节炎患者(膝骨性关节炎组)和20例健康正常人(正常组),应用动态平衡仪进行动态平衡能力测试,包括总体稳定指数、前后方向稳定指数和左右方向稳定指数;稳定性测试：包括完成稳定性测试全部随机目标跟踪的时间,平均方向控制能力和前、后、右、左、前右、前左、后右、后左8个方向上的控制能力。 结果与结论：膝骨性关节炎组在睁眼双足站立、闭眼双足站立状态下总体稳定指数、前后方向稳定指数、左右方向稳定指数均高于正常组(P < 0.01),平均方向控制能力、前方控制能力、后方控制能力、左方控制能力、后右方控制能力测试值低于正常组,而完成该测试所需时间明显增加(P < 0.01)。说明膝骨性关节炎患者动态平衡能力下降。     

非预期条件下前交叉韧带重建术后运动员侧切动作下肢运动生物力学特征

目的 量化非预期条件下前交叉韧带重建(anterior cruciate ligament reconstruction, ACLR)术后运动员侧切动作中膝关节生物力学特征,探讨运动员前交叉韧带(anterior cruciate ligament, ACL)损伤潜在风险。 方法 应用红外运动捕捉系统和三维测力台同步采集 30 名 ACLR 男性运动员在预期和非预期条件下侧切动作中健侧、患侧下肢运动学和动力学数据。 应用双因素方差分析对关节角度、关节力矩、地面反作用力( ground reaction force, GRF)等测试指标进行统计分析。 结果 患侧肢体的膝关节屈曲角度、外翻力矩和屈曲力矩显著低于健侧肢体,内旋力矩和胫骨前剪切力显著高于健侧肢体。 与预期条件相比,非预期条件下膝关节屈曲角度、内旋力矩、胫骨前剪切力显著增加。 患侧肢体膝关节外旋角度在预期和非预期条件下均显著高于健侧,非预期条件下健侧肢体侧向 GRF 和前后 GRF 显著小于预期条件,患侧肢体侧向 GRF 显著高于预期条件。 结论 ACLR 运动员进行侧切动作时,相比于健侧,患侧表现出较小的膝关节屈曲角度,较大的膝关节内旋力矩和胫骨前剪切力的生物力学特征,可能存在较大的 ACL 潜在损伤风险;在非预期条件下,ACLR 运动员双侧下肢均表现出膝关节内旋力矩增大,侧向 GRF 增大和胫骨前剪切力增大的生物力学特征,提示 ACL 潜在损伤风险不仅限于患侧,健侧下肢也应加强侧切动作中 ACL 损伤预防。     

不同大脑半球损伤脑卒中患者双下肢足底压力参数差异分析

背景:足底压力可有效评估脑卒中后静态站立平衡功能,不同大脑半球损伤可能会造成不同的足底压力表现.目的:探究不同大脑半球损伤脑卒中患者、健康人群静态站立下足底压力参数的差异性.方法:纳入蚌埠医学院第一附属医院收治的11例右脑损伤与15例左脑损伤脑卒中患者,招募蚌埠医学院第一附属医院及其周边的12名健康受试者,采用Foot...     

Tactile interference in visually guided reach-to-grasp movements

Stabilometry signals involve irregular and unpredictable components. The purpose of the present study was to investigate these signals with a nonlinear technique to examine how the complexity of the postural control system breaks down under altered visual conditions. We evaluated the dynamical similarities of the postural control system when the eyes were open or closed, or when there was optokinetic stimulation (OKS). A similarity index was calculated by the cross-correlation integral between the two dynamics: eyes open and eyes closed, or eyes open with OKS. Using this technique, dynamical changes were not observed between eyes-open and eyes-closed conditions. This result suggests that the nonvision condition does not produce any striking effect on the postural control system; instead, the eyes-open condition causes a decrease in the stochastic activity of the postural control system, which may originate mainly from the stiffness of the musculoskeletal systems. In contrast, the visual input of OKS affected the dynamics of the postural control system in nearly half of the subjects (group 2) despite showing no significant differences between the eyes-open condition and the other conditions for area as the conventional parameter. However, the other half of the subjects (group 1) did not experience any influence of OKS on their postural dynamics, despite showing significant differences between eyes-open and the other conditions for all traditional parameters. From the results for group 2, we hypothesize that OKS may induce the striking effect on dynamics properties of the multilink network system involving visual and vestibular cortex related to self-motion perception, which acts to decrease the stochastic activity in order to correct disturbed posture. Electronic Publication     

Postural control in response to an external perturbation: effect of altered proprioceptive information

The purpose of the study was to investigate the role of altered proprioception on anticipatory (APAs) and compensatory (CPAs) postural adjustments and their interaction. Nine healthy adults were exposed to external perturbations induced at the shoulder level while standing with intact or altered proprioception induced by bilateral Achilles tendon vibration. Visual information was altered (eyes open or closed) in both the conditions. Electrical activity of eight trunk and leg muscles and center of pressure (COP) displacements were recorded and quantified within the time intervals typical for APAs and CPAs. The results showed that when proprioceptive information was altered in eyes-open conditions, anticipatory muscle activity was delayed. Moreover, altered proprioceptive information resulted in smaller magnitudes of compensatory muscle activity as well as smaller COP displacements after the perturbation in both eyes-open and eyes-closed conditions. The outcome of the study provides information on the interaction between APAs and CPAs in the presence of altered proprioception.     

Parameters of Eyes-Closed Alpha Enhancement

The performance of subjects (Ss) receiving contingent feedback in an eyes-closed alpha enhancement setting was contrasted with changes in alpha of Ss receiving random feedback and no feedback. In addition, comparisons were made between: 1) binary and continuous feedback signals; 2) integrated and criterion alpha as dependent variables; and 3) eyes-open and eyes-closed alpha enhancement tasks. It was found that: 1) Increases in emitted occipital alpha under eyes-closed conditions are related to contingent reinforcement. 2) Proportional feedback was most efficient in the rapid development of eyes-closed training. 3) Larger changes in alpha were seen during eyes-open than during eyes-closed training. 4) Binary feedback appeared to be more efficient in increasing eyes-open alpha response. 5) No relationships between the ability to perform the eyes-open and eyes-closed alpha enhancement tasks were found within Ss.     

内侧开放楔形胫骨高位截骨术治疗膝关节内侧单间室骨关节炎后的足底压力分析

目的 分析内侧单间室膝关节骨性关节炎(knee osteoarthritis, KOA)患者接受内侧开放楔形胫骨高位截骨术(medial opening wedge high tibial osteotomy, MOWHTO)治疗后的足底压力分布情况,为患者的手术治疗和康复提供生物力学参考。方法 选取31例行单侧MOWHTO治疗后的内侧单间室KOA患者作为实验组,同时以35例同年龄健康人群作为对照组,使用Pedomedic 40^?足底压力测试系统进行动态足底压力的测试。通过比较步行状态下实验组(术侧及未术侧)与对照组不同足底分区的峰值压强(p_max)、压力时间积分(force-time integral, FTI)和接触面积(contact area, CA),评估内侧单间室KOA患者MOWHTO术后的足底压力变化。结果 与未术侧和对照组相比,术侧第1跖骨区(MH1)CA和FTI偏高(P<0.05),第4跖骨区(MH4)CA偏小(P<0.001),第5跖骨区(MH5)p_max和FTI偏小(P<0.05)...     

Reactivity of alpha rhythms to eyes opening is lower in athletes than non-athletes: A high-resolution EEG study

In the present study, we tested the hypothesis that compared with non-athletes, elite athletes are characterized by a reduction of reactivity of electroencephalographic (EEG) alpha rhythms (about 8–12 Hz) to eyes opening in the condition of resting state, as a possible index of spatially selective cortical activation (i.e. “neural efficiency”). EEG data (56 channels; Eb-Neuro©) were recorded in 18 elite karate athletes and 28 non-athletes during resting state eyes-closed and eyes-open conditions. The EEG data were spatially enhanced by surface Laplacian estimation. Cortical activity was indexed by task-related power decrease (TRPD), namely the alpha power during the eyes-open referenced to the eyes-closed resting condition. Low-frequency alpha TRPD (about 8–10 Hz) was lower in the elite karate athletes than in the non-athletes in frontal (p < 0.00002), central (p < 0.008) and right occipital (p < 0.02) areas. Similarly, high-frequency alpha TRPD (about 10–12 Hz) was lower in the elite karate athletes than in the non-athletes in frontal (p < 0.00009) and central (p < 0.01) areas. These results suggest that athletes' brain is characterized by reduced cortical reactivity to eyes opening in the condition of resting state, in line with the “neural efficiency” hypothesis. The present study motivates future research evaluating the extent to which this general functional brain feature is related to heritable trait or intensive visuo-motor training of elite athletes.     

The effects of visual input on open-loop and closed-loop postural control mechanisms

In an earlier posturographic investigation (Collins and De Luca 1993) it was proposed that open-loop and closed-loop control mechanisms are involved in the regulation of undisturbed, upright stance. In this study, stabilogram-diffusion analysis was used to examine how visual input affects the operational characteristics of these control mechanisms. Stabilogram-diffusion analysis leads to the extraction of repeatable center-of-pressure (COP) parameters that can be directly related to the resultant steady-state behavior and functional interaction of the neuromuscular mechanisms underlying the maintenance of erect posture. Twenty-five healthy male subjects (aged 19–30 years) were included in the study. An instrumented force platform was used to measure the time-varying displacements of the COP under each subject's feet during quiet standing. The subjects were tested under eyes-open and eyes-closed conditions. The COP trajectories were analyzed as one-dimensional and two-dimensional random walks, according to stabilogram-diffusion analysis. Using this technique, it was found that visual input affects the performance of the postural control system in one of two different ways — either it significantly modifies the steady-state behavior of the open-loop postural control mechanisms, or it significantly alters the characteristics of the other closed-loop feedback mechanisms that are involved in balance control. This result is interpreted as an indication that the visual system is integrated into the postural control system in one of two different ways. The experimental population was roughly evenly divided between these two schemes. For the first group (13 of 25 subjects), visual input principally caused a decrease in the effective stochastic activity of the open-loop control mechanisms in both the mediolateral and anteroposterior directions. For the second group (12 of 25 subjects), visual input caused an increase in the effective stochastic activity and uncorrelated behavior of the closed-loop control mechanisms in the anteroposterior direction only. On the basis of these results, it is hypothesized that visual input, in both schemes, serves to decrease the stiffness of the musculoskeletal system. In the former case, this may be accomplished by decreasing the level of muscular activity across the joints of the lower limb, whereas, in the latter case, reduced stiffness may be achieved by reducing the gain(s) of the other postural feedback mechanisms, i.e., the proprioceptive and/or vestibular systems. Using stabilogram-diffusion analysis, it was also found that the two groups of subjects behaved similarly under eyes-closed conditions. This result suggests that the open-loop postural control mechanisms and reflex-based feedback systems, respectively, of healthy, young individuals are organized in functionally equivalent ways.