基于双侧训练理论的对侧控制功能性电刺激对脑卒中上肢偏瘫患者运动功能的影响

目的:分析脑卒中上肢偏瘫患者应用基于双侧训练理论的对侧控制功能性电刺激对上肢运动功能、腕关节活动度及表面肌电的影响.方法:择取鹤壁市人民医院于 2020年 8 月至 2022 年 8 月期间收治的 114 例脑卒中上肢偏瘫患者作为研究对象,随机分组,各 57 例,对照组给予常规康复训练,实验组增加基于双侧训练理论的对侧控制功能性电刺激.4 w后,对比两组患者上肢运动功能、腕关节活动度、表面肌电图.结果:训练后,实验组患者上肢、腕部、手部分值均高于对照组(P＜0.05);训练后,实验组患者腕关节桡偏、尺偏、背伸、掌屈活动度均高于对照组(P＜0.05);训练后,实验组患者三角肌前束平均肌电值(Averaged electromyography,AEMG)、冈上肌AEMG、斜方肌上部AEMG均高于对照组(P＜0.05).结论:基于双侧训练理论的对侧控制功能性电刺激能够有效提高脑卒中上肢偏瘫患者上肢运动功能,改善腕关节活动度及上肢神经传导速度.     

首发与复发抑郁症患者视觉空间旋转的事件相关电位P500研究

目的:探讨首发与复发抑郁症患者视觉空间旋转的脑电生理特点.方法:对符合精神障碍诊断与统计手册第4版(DSM-Ⅳ)诊断标准的26例首发抑郁症患者和28例复发抑郁症患者,以及28名健康对照进行视觉空间旋转任务的事件相关电位P500检查.测量其波幅和潜伏期,以便评估其视觉空间旋转信息加工认知功能.结果:与健康对照相比,首发抑郁症患者的P500波幅差异无统计学意义[(8.0±2.5) μV vs.(8.8±2.7) μV,P＞0.05],潜伏期较长[(497.2±73.2) ms vs.(447.9±62.8) ms,P＜0.05];复发抑郁症患者的P500波幅较低[(4.5 ±2.0) μV vs.(8.8±2.7)μV,P＜0.05]、潜伏期较长[(54.8.3±82.5)ms vs.(447.9±62.8)ms,P＜0.05].与首发组相比,复发患者的P500波幅较低,潜伏期较长(均P＜0.05).对照组正、镜像P500波幅均与旋转角度呈负线性相关(b=-0.58、-0.59,均P＜0.01);首发组正、镜像P500波幅均与旋转角度呈负线性相关(b=-0.57、-0.58,均P＜0.01);复发组正、镜像P500波幅均与旋转角度无线性相关关系(b=-0.04、-0.02,均P＞0.05).结论:本研究提示首发抑郁症患者视觉空间旋转信息加工自身的电生理机制未见异常,而复发患者视觉空间旋转信息加工的电生理机制受损.     

音乐速度变化感知的失匹配负波

感知速度变化对音乐认知具有重要意义。本研究采用5个鼓点音构成标准等间距序列,再通过调整序列第3个刺激间隔(IOI)的长度引入局部速度扰动(IOI缩短:加速;IOI延长:减速)。从行为实验及被动听觉脑电实验入手,记录被试主动检测三种典型序列速度(快速:IOI=300 ms;中速:IOI=600 ms;慢速:IOI=900 ms)下的局部IOI扰动的行为响应,及自动感知中速序列(IOI=600 ms)局部IOI扰动的脑电响应。行为数据显示:中速的响应精度显著大于快速和慢速;加速与减速的辨别力指数在快速和慢速下均有显著差异,而在中速下无显著差异。脑电数据显示:在额中区电极Fz处,加速的失匹配负波(MMN)比减速的幅度更大、潜伏期更早。实验结果表明,中速序列的局部速度扰动对MMN的影响显著不同;即使在行为无偏差的中等序列速度下,大脑对局部速度扰动的感知加工还是有差异的。     

基于脑肌电融合的混合脑机接口研究

动作模式识别是脑机接口技术的核心内容之一。针对目前脑机接口动作识别模式单一、识别率低等问题,基于混合脑机接口思想,提出一种脑电和肌电特征融合策略,可实现单侧肢体不同动作模式的有效分类,进而可用于脑机接口技术。同步采集9名健康受试者单侧手腕屈/伸两种动作模式下的脑电信号和表面肌电信号,分别提取脑电信号事件相关去同步化特征和表面肌电信号的积分肌电值特征,构建基于支持向量机和粒子群优化算法的脑肌电融合及运动模式识别模型,通过调整“特征融合系数”来实现动作模式最优分类,从而提高模式识别的准确率;进一步通过递降健康人的肌电信号幅值来模拟患者和运动疲劳状态下的肌电信号,验证所提出方法对动作模式识别的有效性。实验结果表明,基于脑肌电融合特征的动作模式识别率(98%)比单纯依靠脑电特征的识别率(73%)提高25%;在运动疲劳状态下,基于脑肌电融合特征的识别率稳定在80%以上,比单纯依靠肌电特征的识别率提高14%。可见,脑肌电融合策略能提高动作模式识别的准确性和鲁棒性,为混合脑机接口技术提供条件。     

健康人手部不同动作的脑电-肌电相干性分析

运动皮层和肌肉之间的功能连接直接关系到上肢功能障碍者的康复,神经肌肉的活动状态可以通过脑电-肌电(EEG-EMG)相干性来分析。本文通过在进行手抓、握及手腕屈、伸4组动作时,采集皮层运动区的9导联EEG信号和前臂4导联的EMG信号,进行相干性分析处理。结果表明在β频段,右手做屈指、伸指动作时相应的右前臂指屈肌(FD)、指伸肌(ED)与大脑左侧C3导联相干系数值较大(P0.05);右手做屈腕、伸腕动作时相应的尺侧腕屈肌(FCU)、桡侧腕伸肌(ECR)与大脑左侧C3导联相干系数值较大(P0.01)。研究结果为探索基于皮层肌肉相干性(CMC)的手部运动信息解码提供了依据。     

平山病的临床与神经电生理学特点分析

目的：分析平山病的临床与神经电生理学特点,以提高对平山病的诊断水平。方法：对21例确诊为平山病的患者进行运动和感觉传导速度、肌电图（EMG）、F波及交感皮肤反应（SSR）等神经电生理学检查。结果：对126条神经进行检测,神经传导速度（NCV）测定总异常率为16．7％（21／126）,主要表现为远端运动潜伏期（DML）延长及复合肌肉动作电位（CMAP）波幅下降,感觉神经传导速度均正常。F波平均最小潜伏期为（28．70±3．10）ms,平均出现率为47．70％,总异常率为76．2％。患者患侧上肢及对侧上肢远端肌（不包括肱桡肌）EMG呈神经原性改变者分别为1000及90．5％,主要异常表现为出现自发电位运动单位电位（MUP）时限延长、波幅增宽、多相波增多及募集相等异常。上肢远端肌EMG异常率为91．5％,明显高于上肢近端肌的8．0％及下肢肌的3．5％。结论：平山病可出现神经电生理上的亚临床改变,神经电生理检查对其有较高的诊断价值。     

刺激家兔面神经核腹内侧区对颏舌肌肌电活动的抑制效应

本研究在 2 6只氨基甲酸乙酯麻醉、断双侧迷走神经的健康成年家兔上观察了电、化学刺激面神经核腹内侧区 (vMNF)对颏舌肌肌电活动的影响。结果如下 :(1)长串电脉冲刺激vMNF导致颏舌肌肌电活动明显被抑制 ;(2 )在vMNF内微量注射谷氨酸钠 ,颏舌肌肌电活动出现明显的抑制效应 ;(3)单脉冲电刺激vMNF引起颏舌肌抑制反应的潜伏期为 (2 0 6± 0 4)ms。结果表明 :vMNF的兴奋能降低颏舌肌的肌电活动 ,从而提示其具有增强上呼吸道阻力的作用。     

基于自适应动态特征库的P300诱发脑电单次提取算法研究

目的 诱发电位的单次提取技术一直是脑电信息处理领域的难题之一,为进一步提高单次提取算法的时间准确性和特征精度,针对体感诱发脑电数据信噪比低、试次间参数变化大的特点,研究诱发脑电参数单次提取新算法,保留试次间诱发脑电的动态特性,并提高估计准确率.方法 基于小波滤波和多元线性分析技术,加入自适应动态特征库并由此提出的诱发脑电P300参数单次提取新方法.随机选取4组小波滤波(WF)后诱发脑电数据,分别叠加平均后进行主成分分析(PCA)组成特征库.单次提取时,针对每试次数据从特征库中选择与当次诱发脑电信号相关系数最高的成分作为自变量开展多元线性回归分析,由回归分析结构重构出单次诱发电位信号并自动提取潜伏期和幅值等关键特征.结果 与专家判定的基准数值相比,新算法预测的P300成分潜伏期与幅值参数更准确,两者的平均差值分别为(11.16±8.60) ms和(1.40±1.34)μV;与常用的叠加平均法结果亦更为接近,平均差值分别为(23.26±25.76) ms和(2.52±2.50) μV,新算法相比传统多元线性回归分析算法具有显著优势.结论 将动态更新的诱发脑电数据主成分样本库应用于小波滤波与多元线性回归方法,能有效保留单次诱发脑电数据中的动态特征,从而提升参数估计的准确率.     

中风康复运动中脑电-肌电相干性分析

本文针对中风康复患者运动功能障碍相关的神经肌肉功能评价问题,研究有效的脑电(EEG)信号与肌电(EMG)信号相干性分析及相干显著性判断方法,探索运动功能障碍患者的脑、肌电相干差异性表现。提出一种基于小波分解的脑、肌电相干性分析方法,定义了相干显著性指标定量描述EEG、EMG信号在某频域内的相似性和锁相活动。通过对中风患者和健康人膝关节"屈"、"伸"运动中脑、肌电相干性分析实验,得到以下结论:在相同运动模式下患者健侧的脑、肌电相干性与正常人无明显差异,患者患侧的脑、肌电相干性在gamma频段存在明显缺失;但随着运动功能的康复,患者患侧的脑、肌电相干性与健侧gamma频带脑、肌电相干性的差异会逐渐减小。     

肌力训练对脑卒中恢复期偏瘫患者大腿表面肌电的影响

目的 探讨脑卒中恢复期偏瘫患者肌力训练对大腿肌群表面肌电(sEMG)信号特征的影响,为脑卒中患者的康复治疗提供客观依据.方法 共选取35例脑卒中恢复期偏瘫患者,分为治疗组(n=19)和对照组(n=16),治疗组给予6周的肌力训练,并在治疗前后在患侧膝关节屈伸最大等长收缩(MIVC)时记录股内侧肌、股直肌、股外侧肌、股二头肌、半腱半膜肌的sEMG信号,计算膝关节屈伸力矩值、均方根值(RMS)及其相应协同收缩率;对照组不给予康复训练,仅与治疗组同时进行上述指标测量.结果 治疗组治疗后患者患侧屈膝及伸膝MIVC力矩均较治疗前明显改善[屈膝:(18.02±6.52)nm比(13.12±5.79)nm,伸膝:(45.72±17.21)nm比(34.76±17.19)nm,均P＜0.05],而伸屈膝协同收缩率较治疗前无明显变化.对照组伸屈膝MIVC力矩和协同收缩率治疗前后差异则无统计学意义(均P＞0.05).治疗组治疗后患者患侧大腿股直肌、股外侧肌、半腱半膜肌作为主动肌时的RMS值均较治疗前明显改善[(146.60±60.85)μV比(97.02±57.17)μV,(172.65±60.73)μV比(131.46±52.15)μV,(188.69±89.60)μV比(130.57±73.76)μV,均P＜0.05],而股内侧肌、股二头肌的RMS值在治疗前后无明显变化,对照组治疗前后各肌的RMS值则无变化(均P＞0.05).结论 肌力训练可改善脑卒中恢复期偏瘫患者下肢屈伸肌力,但并不会增强下肢伸屈肌的异常收缩.sEMG结合力矩测量能更全面评估偏瘫肢体功能状态.     

Hyperthermia up-regulates matrix metalloproteinases and accelerates basement membrane degradation in experimental stroke

We investigated the effects of balance difficulty on contingent negative variation (CNV) and postural preparation against perturbation. Thirteen subjects were perturbed by a backward floor translation (S2) after an auditory warning stimulus. To alter balance difficulty, subjects maintained standing posture from four initial positions before perturbation. The position of the center of pressure in the anteroposterior direction (CoPy) was expressed as a percentage distance of foot length (%FL) from the heel: 10%FL anterior to extreme backward leaning; quiet standing (QS); and 20%FL and 10%FL posterior to extreme forward leaning. CNV, CoPy, and electromyography (EMG) of the lower leg muscles were analyzed. Balance difficulty was represented by the relative distance of the forward peak position of CoPy after S2 from the QS position. Balance difficulty was higher with a more anterior initial position. The late CNV peaked just before S2 (latency: -76 to -306 ms), then started becoming small. CNV peak was earlier and larger with increasing balance difficulty. CoPy backward shift and a continuous EMG increase were observed as the strategy for postural preparation, and were significantly earlier (61 ms and 42 ms, respectively) than the CNV peak. CNV peak time correlated closely with onset times of CoPy backward shift (r=0.78) and continuous EMG increase (r=0.71). These findings suggest that as balance difficulty increases, attentional allocation to sensory information and/or postural preparation starts earlier just before the perturbation.     

Influence of local sensory afference in the calibration of human balance responses

Summary Peripheral sensory modulation of balance behavior may require a calibrated mechanism which would maintain upright standing by a feedback control of torque at the ankle joint. The calibration of human balance was studied using a systematic presentation of perturbation excursions and velocities in normal freely standing subjects. All perturbations (posterior movements of a force platform) induced a forward body sway and were presented by first increasing and then decreasing the magnitude of perturbation. In preselected conditions the stability of the ankle and hence the accuracy of surface orientation inputs was altered using a foam base placed under the subjects feet. Each subject pressed a hand held response key at the moment a postural disturbance was detected. The automatic neuromuscular response (ANR) was recorded from the gastrocnemius muscles bilaterally and the perturbation detection time (DT) was obtained from the onset of thenar muscle discharge. The major findings in this study were: (1) Conscious DT changed as a function of step variations in perturbation excursion and was disassociated from the ANR latency. The ANR latency remained essentially constant in all conditions and did not have any influence on the kinematics of body sway. (2) Normalized peak body sway decreased during unstable ankle conditions and the reduction of body sway could be attributed to an increase in the gain of the ANR across a 200 ms integration period. The ANR 200 ms amplitude also showed higher correlations with perturbation magnitude during unstable (versus stable) ankle conditions. (3) The 200 ms gastrocnemius amplitude was modulated by excursion and velocity of platform displacement but the amplitude integrated over 100 ms was dependent on only the velocity of perturbation. Our results indicate that balance is controlled by a centrally initiated postural response but regulated in amplitude by local sensory information. These results establish that the gain of the ANR is functional, peripherally driven, and occurs subconsciously to alter the kinematics of body sway.     

Perturbed upper limb movements cause short-latency postural responses in trunk muscles

Addition of a load to a moving upper limb produces a perturbation of the trunk due to transmission of mechanical forces. This experiment investigated the postural response of the trunk muscles in relation to unexpected limb loading. Subjects performed rapid, bilateral shoulder flexion in response to a stimulus. In one third of trials, an unexpected load was added bilaterally to the upper limbs in the first third of the movement. Trunk muscle electromyography, intra-abdominal pressure and upper limb and trunk motion were measured. A short-latency response of the erector spinae and transversus abdominis muscles occurred approximately 50 ms after the onset of the limb perturbation that resulted from addition of the load early in the movement and was coincident with the onset of the observed perturbation at the trunk. The results provide evidence of initiation of a complex postural response of the trunk muscles that is consistent with mediation by afferent input from a site distant to the lumbar spine, which may include afferents of the upper limb.     

The increased foreperiod duration to attain the neutral optimal preparation from sitting to standing

The purpose of the present experiment was to investigate the effects of a neutral preparation during the foreperiod on motor and postural programming processes in a voluntary upper limb movement. The foreperiod duration (300, 500, 700 and 900 ms) and the postural condition (sitting vs standing) were manipulated using a neutral preparation (no advanced information during the preparatory signal). Thirteen subjects performed a raising arm movement with 1 kg load at the wrist. Premotor time, latency of the anticipatory postural adjustments and the vertical torque were calculated. A previous experiment showed that the optimal foreperiod duration (i.e. leading to the shortest premotor time) increased from sitting to standing in a selective preparation (Cuisinier et al. in Brain Res Bull 66(2):163–170, 2005). The present experiment replicated this finding in a neutral preparation. It was found that (1) this optimal foreperiod duration still increased from 500 ms in sitting to 700 ms in standing in a neutral preparation, (2) this increased optimal foreperiod duration resulted from a greater level of alertness necessary to control a more constrained posture in standing than in sitting, and (3) the existence of a temporal modulation in the central organization of the postural and focal commands was according to the foreperiod duration.     

Automatic postural responses in the cat: responses of proximal and distal hindlimb muscles to drop of support from a single hind- or forelimb

Summary Cats respond to drop of the support from beneath a single limb with the diagonal stance response (Coulmance et al. 1979). They load the limbs on the diagonal opposite to the one containing the dropped limb and unload the third supporting limb in the diagonal containing the dropped limb. Characteristic biomechanical delays in limb motion and in vertical force changes imposed upon the limbs are observed. These delays range from 30 to 45 ms, depending upon the location of the dropped limb. This study describes the kinematics of the diagonal stance response and the activation of selected agonist-antagonist muscle pairs acting on the joints of the hindlimb during the response. Proximal and distal hindlimb muscles respond to perturbations in groups that are appropriate to the vertical forces imposed upon the limb. When the hindlimb containing the recording electrodes is loaded by drop of the contralateral hindlimb or the ipsilateral forelimb medium latency (25–45 ms) EMG responses occur in the extensors. This response serves to stiffen the limb against the increased vertical force of loading. A similar response is observed when the hindlimb is reloaded after being dropped. In this case, however, short latency responses precede the medium latency responses in muscles that are passively stretched by the limb drop. When drop of the diagonal forelimb unloads the hindlimb containing the electrodes, medium latency responses are observed in the distal hindlimb flexors, which indicates that the unloading is evoked in part by active lifting of the limb. In most cases, the medium latency responses precede or are coincident with the changes in force imposed on the limb, suggesting that the observed responses are centrally programmed.     

Effect of submaximal isometric wrist extension training on grip strength

Gripping force is produced by co-contraction of forearm flexors and extensors. Activation of extensors is important for stabilizing the wrist during gripping. However, forearm muscle function is complicated and the neurophysiological mechanism responsible for the gain in gripping force is unclear. Therefore, the purpose of this study was to investigate whether increasing forearm extensor activation with isometric wrist extension training has an effect on gripping force. Thirteen healthy subjects participated in this study. Maximal voluntary contraction of gripping was measured using a piezosensor (MVC_grip) and EMG of forearm muscles at every wrist angle (from 70° flexion to 80° extension with 10° intervals) were measured simultaneously at baseline, 4 weeks, and 8 weeks after training. Training consisted of 30 repetitions equal to 70% MVC of isometric wrist extension for 8 weeks (5/week) on the right side. Gripping force was measured on both sides using a grip dynamometer without wrist angle restriction. Gripping force, EMG, maximal wrist extension force, and wrist angle-gripping force curve were investigated after training. After training, maximal wrist extension force increased significantly. Gripping force on the trained side also increased significantly. The training changed wrist angle at peak of MVC_grip. EMG activation of forearm extensors increased and that of flexors decreased during gripping. These results suggest that wrist extension training leads to an increase in gripping force and changes the balance of EMG activation between forearm flexors and extensors during gripping. Therefore, this training method should be useful as a therapeutic strategy for increasing grip strength.     

Automatic postural responses in the cat: Responses to headward and tailward translation

EMG responses, vertical and A-P shear forces and kinematics of "automatic postural responses" to unexpected translational perturbations in the headward and tailward directions were studied in cats. Muscles acting on the major joints of the forelimbs and hindlimbs were studied. Movement of the animals in response to perturbation were highly stereotyped and consisted of two phases: (1) motion of the feet during platform movement while the trunk remained relatively stationary followed by (2) active correction of posture by movement of the trunk in the direction of perturbation. Vertical force changes occurred after the perturbation was well underway (latency 65 ms) and were related to the displacement of the center of mass and active correction of trunk position. Shear forces showed both passive (inertial) and active components and suggested that the majority of the torque necessary for postural correction was generated by the hindlimb. EMG responses in forelimb and shoulder muscles were most correlated with increase in vertical force, showing a generalized co-contraction in tailward translation (when these limbs were loaded) and little activity when the forelimbs were unloaded. EMG responses in hindlimb showed reciprocal activation of agonists and antagonists during perturbation with strong synergies of thigh and foot flexors in tailward translation and thigh and foot extensors in headward translation. The forelimb EMG patterns were most consistent with the conclusion that the forelimb is used primarily for vertical support during perturbation. It was concluded that hindlimb EMG responses were appropriate for both vertical support and performance of the postural correction. The hindlimb muscle synergies observed during translation are the "mirror image" of those observed in humans by other workers.     

The interaction of postural and voluntary strategies for stability in Parkinson's disease

This study assessed the effects of stability constraints of a voluntary task on postural responses to an external perturbation in subjects with Parkinson's disease (PD) and healthy elderly participants. Eleven PD subjects and twelve control subjects were perturbed with backward surface translations while standing and performing two versions of a voluntary task: holding a tray with a cylinder placed with the flat side down [low constraint (LC)] or with the rolling, round side down [high constraint (HC)]. Participants performed alternating blocks of LC and HC trials. PD participants accomplished the voluntary task as well as control subjects, showing slower tray velocity in the HC condition compared with the LC condition. However, the latency of postural responses was longer in the HC condition only for control subjects. Control subjects presented different patterns of hip-shoulder coordination as a function of task constraint, whereas PD subjects had a relatively invariant pattern. Initiating the experiment with the HC task led to 1) decreased postural stability in PD subjects only and 2) reduced peak hip flexion in control subjects only. These results suggest that PD impairs the capacity to adapt postural responses to constraints imposed by a voluntary task.     

Cerebral evoked potentials associated with the compensatory reactions following stance and gait perturbation

We have studied the gastrocnemius electromyographic (EMG) responses and the cerebral potentials evoked in normal subjects by perturbations of stance and gait in the form of short treadmill acceleration impulses. In the stance condition a small EMG response (LM1; latency around 40 ms) was followed by a strong muscle activation (LM2; latency 75–90 ms). Following perturbation during gait, LM1 was lacking and LM2 appeared a little earlier (65–75 ms). In the stance condition, the cerebral potentials appeared with shorter latency (42 ms as compared to 83 ms) and a larger amplitude (41 μV as compared to 21 μV) than those seen in the gait condition. These changes can be explained by a presynaptic inhibition of group I afferent signals during gait, which are assumed to be responsible for the early EMG and EEG responses. It is suggested that the LM2 and the cerebral responses evoked by gait perturbation are mediated by signals from group II and III afferents.     

Stance dependence of automatic postural adjustments in humans

Summary This study investigated the effect of initial stance configuration on automatic postural responses in humans. Subjects were tested in both bipedal and quadrupedal stance postures. The postural responses to horizontal translations of the supporting surface were measured in terms of the forces at the ground, movement of the body segments, and electromyographic (EMG) activity. Postural responses to the same perturbations changed with initial stance posture; these responses were biomechanically appropriate for restoring centre of mass. A change in stance configuration prior to platform movement led to a change in both the spatial and temporal organization of evoked muscle activation. Specifically, for the same direction of platform movement, during bipedal stance muscles on one side of the lower limb were activated in a distal to proximal sequence; during quadrupedal stance, muscles on the opposite side of the lower limb were activated and in a proximal to distal sequence. The most significant finding was an asymmetry in the use of the upper limbs and the lower limbs during postural corrections in quadrupedal stance. Whereas antagonists of the upper limb were either co-activated or co-inhibited, depending on the direction of translation, lower limb antagonists were reciprocally activated and inhibited. Human subjects in a quadrupedal stance posture used the lower limbs as levers, protracting or retracting the hips in order to propel the trunk back to its original position with respect to the hands and feet. Postural responses of the subjects during quadrupedal stance were remarkably similar to those of cats subjected to similar perturbations of the supporting surface. Furthermore, the same predominance of lower limb correction is characteristic of both species, suggesting that the standing cat is a good model for studying postural control in humans.