Matching walking speed of controls affects identification of gait deviations in patients with a total knee replacement

BackgroundThe assessment of functional recovery of patients after a total knee replacement includes the quantification of gait deviations. Comparisons to comfortable gait of healthy controls may incorrectly suggest biomechanical gait deviations, since the usually lower walking speed of patients already causes biomechanical differences. Moreover, taking peak values as parameter might not be sensitive to actual differences. Therefore, this study investigates the effect of matching walking speed and full-waveform versus discrete analyses.MethodsGait biomechanics of 25 knee replacement patients were compared to 22 controls in two ways: uncorrected and corrected for walking speed employing principal component analyses, to reconstruct control gait biomechanics at walking speeds matched to the patients. Ankle, knee and hip kinematics and kinetics were compared over the full gait cycle using statistical parametric mapping against using peak values.FindingsAll joint kinematics and kinetics gait data were impacted by applying walking speed correction, especially the kinetics of the knee. The lower control walking speeds used for reference generally reduced the magnitude of differences between patient and control gait, however some were enlarged. Full-waveform analysis identified greater deviating gait cycle regions beyond the peaks, but did not make peak value analyses redundant.InterpretationMatching walking speed of controls affects identification of gait deviations in patients with a total knee replacement, reducing deviations confounded by walking speed and revealing hidden gait deviations related to possible compensations. Full-waveform analysis should be used along peak values for a comprehensive quantification of differences in gait biomechanics.     

Strength, postural and gait changes following rehabilitation in multiple sclerosis: a preliminary study]

OBJECTIVE: To evaluate the impact of rehabilitation on balance, gait and strength in inpatients with multiple sclerosis (MS). METHODS: Twenty-one in patients with MS benefited from a program of rehabilitation with evaluation before and after rehabilitation. Balance was assessed by stabilometry, walking speed with use of a locometer device and maximal peak torque of knee extensor and flexor with use of an isokinetic dynamometer at 60 degrees /s speed. The functional independence measure (FIM) was also applied before and after rehabilitation. RESULTS: After rehabilitation, patients showed significant improvement in balance with opened and closed eyes, velocity gait, strength of the lower quadriceps and the higher hamstrings and FIM values. Absolute values of gait speed and strength parameters were related as were improvement in velocity speed and the higher hamstrings. CONCLUSION: The results are encouraging and confirm the interest and tolerance of a program of rehabilitation among patients with MS.     

Gait velocity and walking distance to predict community walking after stroke

Gait speed and walking distance were evaluated as predictors for levels of community walking after stroke. In this study, 103 stroke survivors were identified as limited (n = 67) or independent community walkers (n = 36). Ten meter and six min walk tests were used to measure gait speed and walking distance, respectively. The discriminative properties of gait speed and walking distance for community walking were investigated using receiver operating characteristic curves. Cut‐off values of 0.87 m/s for community walking gait speed for walking distance had positive predictive values of 65% and 55%, respectively. The negative predictive value ranged from 89% for gait speed to 79% for walking distance. Gait speed and walking distance showed significant differences between limited and independent community walking. Gait speed was more significantly related to community walking than walking distance. The results of this study suggest that gait speed is a better predictor for community walking than walking distance in moderately affected post‐stroke survivors.     

双小腿截肢者假肢辅助下行走能力的评价

目的比较双小腿截肢者穿戴假肢的行走能力与正常人的差别,制定双小腿截肢者穿戴假肢行走能力参考指标。方法选择11 例双小腿截肢者作为截肢组,12 名健康成年人作为对照组,分别进行室内步态分析测试、室外行走1 km所用时间及能量消耗测试、静态站立平衡能力测试。结果室内步态分析测试中,截肢组自我感觉最舒适平均速度为1.07 m/s,对照组为1.29m/s。当受试者以自我感觉最舒适的速度行走时,截肢组部分步态时空参数与对照组存在显著性差异(P<0.05);室外行走1 km所用时间及能量消耗与对照组存在显著性差异(P<0.05);静态站立平衡与对照组比较无显著性差异(P>0.05)。结论双小腿截肢者与正常人的行走能力存在差异,对截肢者行走能力定量的评价能够为截肢者的康复提供更准确的参考。     

膝上截肢患者穿戴假肢后的功能评定

20例膝上不同水平截肢患者穿戴假肢后,利用步态分析、步行能力及假肢的悬吊能力三项指标进行功能评定。结果综合评定优秀率以膝离断假肢为最佳达89％,依次为大腿中下1/3截肢、大腿中段截肢、大腿中上1/3截肢,髋离断假肢功能评定优秀率最低。提示骨科医师应重视截肢平面的选择。同时步态分析、步行能力及假肢悬吊能力三项评定指标为完善下肢假肢功能的评定提供了有益的参考指标。本组20例膝上不同水平截肢患者的假肢代偿功能总优良率达76.6％。     

The effect of treadmill training on the ambulation of stroke survivors in the early stages of rehabilitation: a randomized study

The objective of this study was to compare the effects of conventional over-ground gait training with treadmill training on the restoration of gait in people with hemiparesis following a stroke. Twenty-five individuals in the early stages of rehabilitation were alternately assigned to one of two treatment groups. In addition to conventional physical therapy, the experimental group participated in 15 treadmill-training sessions in which a handrail was used for external support. The control group received the same number of equal length sessions of over-ground ambulation. Treatment effects were established by pre- and posttreatment assessment of: 1) functional walking ability, 2) walking speed, 3) stride length, 4) temporal characteristics of gait, and 5) electromyographic activity of calf muscles. Normal values were obtained from eight healthy individuals of approximately the same age as the stroke survivors. The study demonstrates that individuals following a stroke are well able to tolerate treadmill training in the early stage of their rehabilitation process without the use of a weight support apparatus. Furthermore, the findings suggest that treadmill training may be more effective than conventional gait training for improving some gait parameters such as functional ambulation, stride length, percentage of paretic single stance period, and gastrocnemius muscular activity.     

不完全性脊髓损伤患者与健康人步态变异性、对称性和协调性的对照研究

目的：通过观察不完全性脊髓损伤患者的步态变异性、对称性和协调性，更加全面了解脊髓损伤患者的步态特点。方法：选取22例不完全性脊髓损伤患者（观察组）及健康人（对照组），健康人按正常歩速及匹配患者速度行走分为（对照组A）及（对照组B），采用三维运动采集系统及足底压力采集系统进行步态测试。用步态变异值、对称值和相位协调指数表示步态变异性、对称性和协调性，比较3组受试者步态变异性、对称性和协调性的差异及与步行功能相关性。结果：观察组的步长变异值、站立相变异值及迈步相变异值均高于对照组A，观察组的步长对称值、站立相对称值、迈步相对称值和相位协调指数均低于对照组，且差异有统计学意义（P＜0.05）。观察组的步态变异值、对称值和相位协调指数与脊髓损伤步行能力负相关。多元线性回归分析显示站立相变异值、站立相对称值和PCI对WISCI-II步行指数均有显著负影响，PCI对FIM步行指数有显著负相影响。结论：不完全性脊髓损伤患者的步态变异性、对称性和协调性均低于健康人，在为不完全性脊髓损伤患者制定康复训练方案时，应考虑步态变异性、对称性和协调性等指标对步行功能的影响。     

Active robotic training improves locomotor function in a stroke survivor

ABSTRACT: BACKGROUND: Clinical outcomes after robotic training are often not superior to conventional therapy. One key factor responsible for this is the use of control strategies that provide substantial guidance. This strategy not only leads to a reduction in volitional physical effort, but also interferes with motor relearning. METHODS: We tested the feasibility of a novel training approach (active robotic training) using a powered gait orthosis (Lokomat) in mitigating post-stroke gait impairments of a 52-year-old male stroke survivor. This gait training paradigm combined patient-cooperative robot-aided walking with a target-tracking task. The training lasted for 4-weeks (12 visits, 3 [MULTIPLICATION SIGN] per week). The subject's neuromotor performance and recovery were evaluated using biomechanical, neuromuscular and clinical measures recorded at various time-points (pre-training, post-training, and 6-weeks after training). RESULTS: Active robotic training resulted in considerable increase in target-tracking accuracy and reduction in the kinematic variability of ankle trajectory during robot-aided treadmill walking. These improvements also transferred to overground walking as characterized by larger propulsive forces and more symmetric ground reaction forces (GRFs). Training also resulted in improvements in muscle coordination, which resembled patterns observed in healthy controls. These changes were accompanied by a reduction in motor cortical excitability (MCE) of the vastus medialis, medial hamstrings, and gluteus medius muscles during treadmill walking. Importantly, active robotic training resulted in substantial improvements in several standard clinical and functional parameters. These improvements persisted during the follow-up evaluation at 6 weeks. CONCLUSIONS: The results indicate that active robotic training appears to be a promising way of facilitating gait and physical function in moderately impaired stroke survivors.     

Quantitative analysis of gait in the visually impaired

In this comparative study concerning characteristics of independent walking by visually impaired persons, we used a motion analyser system to perform gait analysis of 15 late blind (age 36–54, mean 44–3 years), 15 congenitally blind (age 39–48, mean 43–8 years) and 15 sighted persons (age 40–50, mean 44–4 years) while walking a 10-m walkway. All subjects were male. Compared to the sighted, late blind and congenitally blind persons had a significantly slower walking speed, shorter stride length and longer time in the stance phase of gait. However, the relationships between gait parameters in the late and congenitally blind groups were maintained, as in the sighted group. In addition, the gait of the late blind showed a tendency to approximate the gait patterns of the congenitally blind as the duration of visual loss progressed. Based on these results we concluded that the gait of visually impaired persons, through its active use of non-visual sensory input, represents an attempt to adapt to various environmental conditions in order to maintain a more stable posture and to effect safe walking.     

Spastic paretic stiff-legged gait: biomechanics of the unaffected limb.

A concern for individuals with hemiparesis affecting their gait, which heretofore has never been studied, is the possibility that various compensations occurring in the unaffected limb may strain or fatigue the muscles or ligaments and/or predispose to joint injury in that limb. We studied the biomechanics of the unaffected limb during walking in 20 subjects with hemiparesis who had stiff-legged gait as a result of stroke. An optoelectronic motion analysis and force platform system was used to estimate torques in all three planes about the hip, knee, and ankle. Sagittal plane joint motion and power about the unaffected hip, knee, and ankle were also studied. Data were compared with control walking data collected from 20 able-bodied controls. On average, peak torques and powers were all either reduced or the same compared with controls, even though in some instances values were >2 standard deviations (SD) above the control means. Our findings suggest that on average the probability of excessive muscular-tendon effort and the risk for biomechanical injury in the unaffected limb are minimal compared with able-bodied, walking controls. However, given individual variability, we recommend routine clinical gait analysis for all people with stiff-legged gait to eliminate excessive values in certain biomechanical parameters, which could, if not addressed, predispose to muscle-tendon strain or joint or ligamentous injury.     

The effect of cognitive dual tasks on balance during walking in physically fit elderly people

OBJECTIVE: To evaluate the effect on balance of 3 different cognitive dual tasks performed while walking without and with standardization for gait velocity, and measured with both foot placements and trunk movements. DESIGN: Cross-sectional study. SETTING: Community. PARTICIPANTS: Fifty-nine physically fit elderly people (mean age, 73.5y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Stride length and time variability measured with an electronic walkway, body sway measured with an angular velocity instrument, and gait velocity. RESULTS: Overall, dual tasks resulted in decreased gait velocity (1.46 to 1.23m/s, P<.001), increased stride length (1.4% to 2.6%), and time variability (1.3% to 2.3%) (P<.001), and had no significant effect on body sway. After standardization for gait velocity, the dual tasks were associated with increased body sway (111% to 216% of values during walking without dual task, P<.001) and increased stride length and time variability (41% to 223% increase, P<.001). CONCLUSIONS: In physically fit elderly people, cognitive dual tasks influence balance control during walking directly as well as indirectly through decreased gait velocity. Dual tasks increase stride variability with both mechanisms, but the increase in body sway is only visible after standardization for gait velocity. The decreased gait velocity can be a strategy with which to maintain balance during walking in more difficult circumstances.     

Gait training of patients after stroke using an electromechanical gait trainer combined with simultaneous functional electrical stimulation

BACKGROUND AND PURPOSE: This case report describes the implementation of gait training intervention that used an electromechanical gait trainer with simultaneous functional electrical stimulation (FES) for 2 patients with acute ischemic stroke. CASE DESCRIPTION: Two individuals with post-stroke hemiplegia of less than 6 weeks' duration participated in a 4-week gait training program as an adjunct to physical therapy received at a hospital. After the 4-week intervention, both patients were discharged from the hospital, and they returned after 6 months for a follow-up evaluation. OUTCOMES: By the end of the 4-week intervention, both patients had shown improvements in scores on the Barthel Index, Berg Balance Scale, Functional Ambulation Categories Scale, 5-m timed walking test, and Motricity Index. In the 6-month follow-up evaluation, both patients continued to have improvements in all outcome measures. DISCUSSION: This case report shows that, following the use of an electromechanical gait trainer simultaneously with FES, patients after acute stroke had improvements in gait performance, functional activities, balance, and motor control in the long term.     

Concurrent validity of the step time and walking speed obtained from the smartphone application CareCoaching in independent,community-dwelling older adults

[Purpose] In this study, we verified the validity of the step time and walking speed obtained from the smartphone gait analysis application CareCoaching. [Participants and Methods] The participants were 66 independent, community-dwelling adults aged 65 years or older who performed a 10-m walking test twice each under preferred- and slow-speed conditions. We concurrently measured gait motions using CareCoaching and the OptoGait system for reference data. Both systems compute walking speed and step time as gait parameters. We examined the concurrent validity of these parameters by using intra-class correlation coefficients (ICCs) and limits of agreement (LOAs) with Bland−Altman analyses. [Results] In the preferred walking speed condition, the ICCs of walking speed and step times between the CareCoaching and the OptoGait system were 0.67 and 0.93, respectively. In the slow walking speed condition, the ICCs for walking speed and step time were 0.78 and 0.97, respectively. In addition, the LOAs for step time were −0.0941 to 0.1160 for preferred walking speed and −0.0596 to 0.0883 for slow walking speed. The LOAs for walking speed were −0.4158 to 0.0568 for preferred walking speed and −0.3348 to 0.0523 for slow walking speed. [Conclusion] CareCoaching showed excellent agreement for step time and moderate-to-good agreement for walking speed in independent, community-dwelling older adults.     

Speed-dependent variations of lower-limb joint angles during walking. A graphic computerized method showing individual patterns

A method for obtaining a synthetic representation of the joint angle time-courses at different walking velocities is presented, based on a computerized procedure. Hip, knee and ankle joint angles are measured by electrogoniometric devices and checked on line for their reliability. One stride only for each walking speed is selected as representative of the adopted cadence. For each joint a tridimensional representation of angle time-course versus stride frequency or versus gait speed is performed so that speed-dependent variations can be analyzed. Ten normal (seven males and three females) and three prosthetized subjects have been tested by this method. In normal as well as in pathological subjects individual features could be easily detected and the method proved to be useful for a functional gait evaluation.     

Clinical correlation between motor evoked potentials and gait recovery in poststroke patients

OBJECTIVE: To evaluate, in patients with a stroke in the area of the middle cerebral artery, whether transcranial magnetic stimulation values from the affected lower limb correlated with the degree of gait recovery. DESIGN: The prognostic evaluation in subjects with complete lower-limb palsy, inability to walk, and dependence in the activities of daily living, 1 month after vascular injury. SETTING: University-affiliated rehabilitation hospital. PARTICIPANTS: Twenty consecutive patients (12 women, 8 men) were enrolled 1 month poststroke (30+/-5 d); all patients concluded the rehabilitation program, which lasted 6 months. INTERVENTION: Barthel Index score, Hemiplegic Stroke Scale (HSS) score, and motor evoked potentials (MEPs) from the tibialis anterior muscle were performed 1, 4, and 7 months poststroke. The Wilcoxon signed-rank test, Mann-Whitney U test, and Spearman rank-order correlation coefficient were employed. MAIN OUTCOME MEASURES: The independence of gait defined as an HSS gait score of 3 or less (ability to walk without assistance apart from a stick or cane). RESULTS: Patients with no recordable MEPs 1 month poststroke never regained walking ability; patients with MEPs of 8% or more (13.11+/-5.95) regained independent gait at discharge. It was not possible to predict walking capacity in patients with MEPs less than 8% (4.0+/-1.41). Four months postinjury, walking capacity was achieved only by the patients with MEPs of 18% or more (23.1+/-6.2). CONCLUSIONS: In the postacute phase of stroke, the lower-limb MEP amplitudes could be a supportive tool for prognosis of lower-limb motor outcome.     

Hypoxia silences the neural activities in the early phase of the phrenic neurogram of eupnea in the piglet

The study of gait variability, the stride-to-stride fluctuations in walking, offers a complementary way of quantifying locomotion and its changes with aging and disease as well as a means of monitoring the effects of therapeutic interventions and rehabilitation. Previous work has suggested that measures of gait variability may be more closely related to falls, a serious consequence of many gait disorders, than are measures based on the mean values of other walking parameters. The Current JNER series presents nine reports on the results of recent investigations into gait variability. One novel method for collecting unconstrained, ambulatory data is reviewed, and a primer on analysis methods is presented along with a heuristic approach to summarizing variability measures. In addition, the first studies of gait variability in animal models of neurodegenerative disease are described, as is a mathematical model of human walking that characterizes certain complex (multifractal) features of the motor control's pattern generator. Another investigation demonstrates that, whereas both healthy older controls and patients with a higher-level gait disorder walk more slowly in reduced lighting, only the latter's stride variability increases. Studies of the effects of dual tasks suggest that the regulation of the stride-to-stride fluctuations in stride width and stride time may be influenced by attention loading and may require cognitive input. Finally, a report of gait variability in over 500 subjects, probably the largest study of this kind, suggests how step width variability may relate to fall risk. Together, these studies provide new insights into the factors that regulate the stride-to-stride fluctuations in walking and pave the way for expanded research into the control of gait and the practical application of measures of gait variability in the clinical setting.     

Hemiplegic gait of stroke patients: the effect of using a cane.

OBJECTIVE: To assess the effects of cane use on the hemiplegic gait of stroke patients, focusing on the temporal, spatial, and kinematic variables. DESIGN: Case-control study comparing the effect of walking with and without a cane using a six-camera computerized motion analysis system. SETTING: Stroke clinic of a tertiary care hospital. PARTICIPANTS: Fifteen ambulatory stroke patients were analyzed, including 10 men and 5 women (mean age, 56.9 years; mean time since stroke, 9.8 weeks). Nine age-matched healthy elderly subjects were recruited as a control group. RESULTS: Stroke patients walking with a cane showed significantly increased stride period, stride length, and affected side step length, as well as decreased cadence and step width (p < .05) in comparison with those who walked without a cane. There were no significant differences in the gait phases and the five gait events of hemiplegic gait walking with or without a cane. Cane use thus may have more effect on spatial variables than on temporal variables. The affected-side kinematics of hemiplegic gait with a cane showed increased pelvic obliquity, hip abduction, and ankle eversion during terminal stance phase; increased hip extension, knee extension, and ankle plantar-flexion during preswing phase; and increased hip adduction, knee flexion, and ankle dorsiflexion during swing phase as compared with hemiplegic gait without a cane. A cane thus improved the hemiplegic gait by assisting the affected limb to smoothly shift the center of body mass toward the sound limb and to enhance push off during preswing phase. It also improved circumduction gait during swing phase. CONCLUSION: Stroke patients walking with a cane demonstrated more normal spatial variables and joint motion than did those without a cane.     

Computer algorithms to characterize individual subject EMG profiles during gait.

Three methods of precisely determining onset and cessation times of gait EMG were investigated. Subjects were 24 normal adults and 32 individuals with gait pathologies. Soleus muscle EMG during free speed level walking was obtained with fine wires, and was normalized by manual muscle test (%MMT). Linear envelopes were generated from the rectified, integrated EMG at each percent gait cycle (%GC) of each stride in individual gait trials. Three methods were used to generate EMG profiles for each tested subject. The ensemble average (EAV) was determined for each subject from the mean relative intensity of the linear envelopes. Low relative intensity or short duration EMG was removed from the ensemble average to create the intensity filtered average (IFA). The packet analysis method (PAC) created an EMG profile from the linear envelopes in successive strides whose respective centroid %GC locations were within +/- 15%GC of each other. Control values for onset and cessation times of individual gait trials were calculated after spurious outliers were removed. Mean onset and cessation times across subjects for control values and the experimental methods (EAV, IFA, and PAC) were calculated. Dunnett's test (p less than .05) was performed to compare control and experimental groups in patient and normal trials. EAV differed from control values for onsets (p less than .01), cessations (p less than .01), and durations (p less than .01) in both normal and patient trials. IFA and PAC had no significant differences from control value means. IFA was selected for clinical use as automatic analysis could be performed on all trials and a minimum number of decision rules were needed.     

Walking and balance ability gain from two types of gait intervention in adult patients with chronic hemiplegic stroke: A pilot study

This study examined whether the walking and balance ability of adult patients with chronic hemiplegic stroke are associated differentially with the degree of gain after two types of gait intervention. Twenty-four subjects with hemiplegic stroke were enrolled in this randomized study. Each subject participated in one of two gait intervention strategies: gait training with auditory feedback caused by active weight bearing on the paralyzed side (experimental group; EG), or general gait intervention over the ground (control group; CG). The walking and balance abilities were assessed before and after gait intervention. Significant improvements in the 10-m walking test, functional gait assessment (FGA) score, and center of pressure (COP) path length were observed after gait training in both groups (p < 0.05). The EG showed a larger increase in the 10-m walking test, FGA score, and COP path length in the state of eyes opened and closed than the CG (18.2%, 27.0%, 24.8%, and 18.2%, respectively). The auditory feedback caused by active weight bearing on the paralyzed side appeared to be a more effective approach for improving the walking and balance ability in adult patients with hemiplegic stroke during walking training than general gait intervention.