脑卒中偏瘫患者步行速度变化的研究

目的该文通过对脑卒中偏瘫患者步行速度的变化与病程关系的研究,探讨脑卒中偏瘫患者步行速度恢复的规律。方法35例发病后6周内进行步行功能训练的的脑卒中偏瘫患者,连续进行12周的步行速度评测。步行速度测量方法采用10m最大步行速度测定方法。结果脑卒中偏瘫患者最大步行速度的变化与病程呈近似双曲线函数关系Y=A-B/X(R2=0.971)。结论脑卒中偏瘫患者的步行速度恢复的变化是有规律的,而且是可以预测的。     

Determinants of maximum walking speed in hemiparetic stroke patients

The time necessary to walk 10 m with the fastest speed, the sway path of the center of feet pressure in station, and the isokinetic strength for knee extension of each side were examined in 29 hemiparetic stroke patients. The maximum walking speed of the patients was related to the sway path and the isokinetic muscle strength of affected side. The patients could be divided into two groups based on their sway path. The determinants of the maximum walking speed in the unstable group were the sway path and the isokinetic muscle strength of the both sides, whereas that in the stable group was only the isokinetic muscle strength of affected side.     

Functional electrical stimulation-assisted walking for persons with incomplete spinal injuries: longitudinal changes in maximal overground walking speed

This study investigated the changes in maximal overground walking speed (MOWS) that occurred during walking training with a functional electrical stimulation (FES) orthosis by chronic spinal cord injured persons with incomplete motor function loss. The average walking speed over a distance of 10 m was calculated while the participants (n = 14) used their FES orthosis with and without power as well as with the various ambulatory assistive devices available. Within the first year of use, walking with an FES orthosis facilitated use of more advanced ambulatory assistive devices (10/14), improvements in functional mobility (12/14) and increases in the combined (0.26 m/s) and therapeutic (0.25 m/s) MOWS that were correlated (combined: r = 0.57; therapeutic: r = 0.69) with their respective initial MOWS. A longitudinal analysis showed that increases in MOWS followed a pattern of changes best described by either an exponential association (8/12) or a linear (4/12) model. These changes were similar for the combined and therapeutic MOWS (7/11) as well as for the different ambulatory assistive devices (8/9). It is concluded that the increased MOWS during walking training using the FES orthosis is mostly due to a therapeutic effect, implying that mechanisms of plasticity occur during such a training paradigm.     

Walking speed and peak plantar pressure distribution during barefoot walking in persons with diabetes

Background. The impact of walking speed has not been evaluated as a feasible outcome measure associated with peak plantar pressure (PPP) distribution, which may result in tissue damage in persons with diabetic foot complications. The objective of this pilot study was to determine the walking speed and PPP distribution during barefoot walking in persons with diabetes. Methods. Nine individuals with diabetes and nine age–gender matched individuals without diabetes participated in this study. Each individual was marked at 10 anatomical landmarks for vibration and tactile pressure sensation tests to determine the severity of sensory deficits on the plantar surface of the dominant limb foot. A steady state walking speed, PPP, the fore and rear foot (F/R) PPP ratio and gait variables were measured during barefoot walking. Results. Persons with diabetes had a significantly slower walking speed than the age–gender matched group resulting in a significant reduction of PPP at the F/R foot during barefoot walking (p < 0.05). There was no significant difference in F/R foot PPP ratio in the diabetic group compared with the age–gender matched group during barefoot walking (p > 0.05). There was a significant difference between the diabetic and non‐diabetic groups for cadence, step time, toe out angle and the anterior–posterior excursion (APE) for centre of force (p < 0.05). Conclusion. Walking speed may be a potential indicator for persons with diabetes to identify PPP distribution during barefoot walking in a diabetic foot. However, the diabetic group demonstrated a more cautious walking pattern than the age–gender matched group by decreasing cadence, step length and APE, and increasing step time and toe in/out angle. People with diabetes may reduce the risk of foot ulcerations as long as they are able to prevent severe foot deformities such as callus, hammer toe or charcot foot. Copyright © 2011 John Wiley & Sons, Ltd.     

脑卒中偏瘫患者步行速度与步长和步频的关系

目的探讨脑卒中偏瘫患者步行速度与步长和步频之间的相互关系。方法30例恢复步行能力的脑卒中偏瘫患者,测定在自由状态的10m步行速度,求得患者的步行速度、步长和步频等时间-距离因子。对步行速度、步长和步频间进行Pearson和Spearman相关分析及回归分析和逐步回归分析。结果30位患者的步行速度为35.45(4.10～67.40)m/min,平均步长为34.41cm,平均步频为91.59steps/min,步长步频比为0.0038(0.0020～0.0054)犤m/(steps·min)犦。患者的步行速度与步长和步频之间呈高度正相关(r=0.957和r=0.874,P<0.001);步长和步频之间也呈正相关(r=0.781,P<0.001);步长步频比与步行速度之间的相关性差(r=0.280,P>0.05)。回归分析发现步行速度与步长和步频之间存在线性回归关系(R2=0.915和R2=0.763,P<0.001),步长与步频之间也存在线性回归关系(R2=0.610,P<0.001)。逐步回归分析发现步长对步行速度的影响最为显著(R2=0.878,P<0.001)。结论脑卒中偏瘫患者自由步行速度与时间-距离因子步长和步频之间存在规律性的关系,研究结果有助于优化患者的步行训练。     

Balance impairment limits ability to increase walking speed in individuals with chronic stroke

Purpose Determine the relationship between balance impairments and the ability to increase walking speed (WS) on demand in individuals with chronic stroke. Methods WS and Berg Balance Scale (BBS) data were collected on 124 individuals with chronic stroke (>6 months). The ability to increase WS on demand (walking speed reserve, WSR) was quantified as the difference between participants’ self-selected (SSWS) and maximal (MWS) walking speeds. Correlation, regression and receiver operating characteristic (ROC) analyses were performed to investigate the relationship between balance and the ability to increase WS. Results Of sample, 58.9% were unable to increase WS on demand (WSR?r_s=0.74, 0.65–0.81) and were predictive of ‘able/unable’ to increase WS [odds ratio (OR)?=?0.75, 0.67–0.84]. The AUC for the ROC curve constructed to assess the accuracy of BBS to discriminate between able/unable to increase WS was 0.85 (0.78–0.92). A BBS cutscore of 47 points was identified [sensitivity: 72.6%, specificity: 90.2%,?+likelihood ratio (LR): 7.41, ?LR: 0.30]. Conclusions The inability to increase WS on demand is common in individuals with chronic stroke, and balance appears to be a significant contributor to this difficulty. A BBS cutscore of 47 points can identify individuals who may benefit from balance interventions to improve the ability to increase their WS.

• Implications for Rehabilitation

• A majority of individuals with chronic stroke may be unable to increase their walking speed beyond their self-selected speed on demand.

• This may limit functional ambulation, as these individuals are walking “at capacity”.

• Balance impairments contribute to the inability to increase walking speed.

• A Berg Balance Scale score <47 points can be used to identify individuals with chronic stroke walking “at capacity” due to balance impairments.

     

Relations between 6 minute walking distance and 10 meter walking speed in patients with multiple sclerosis and stroke

Dalgas U, Severinsen K, Overgaard K. Relations between 6 minute walking distance and 10 meter walking speed in patients with multiple sclerosis and stroke.ObjectiveTo investigate the relationship between a short walking test and a long walking test in patients with walking disability due to multiple sclerosis (MS) or stroke.DesignCross-sectional observational study.SettingUniversity hospital and sport science department.ParticipantsPatients with MS (n=38), patients with stroke (n=48), and healthy subjects (n=46). Patients were participants in other clinical trials.InterventionsNot applicable.Main Outcome MeasureWalking speed in a 10m walk test and a 6 minute walk test was compared.ResultsDespite differences in absolute walking speed between long and short tests, strong correlations were found between both the tests in patients with MS (r=.95) and in patients with stroke (r=.94), whereas a more moderate correlation was found in healthy controls (r=.69–.70).ConclusionsOur findings show that walking speeds of a short walking test and a long walking test are strongly correlated in both patients with MS and patients with stroke, whereas correlations in healthy subjects are weaker.     

Changes in muscle group work associated with changes in gait speed of persons with stroke

BACKGROUND: Knowledge of associations between changes in muscle work with changes in gait speed could assist gait training in persons with stroke. The purpose of the study was to determine changes in the work of major muscle groups during gait that were associated with increases in walking speed of persons with stroke following training. METHODS: The gait of 28 subjects (14 males, 14 females) with mean age of 64.2 (SD 11.7) years, at 4.8 (SD 6.9) years post stroke was studied using two-dimensional motion analysis before and after a strength training program. Outcome variables were changes in gait speed and changes in work associated with the hip flexors and extensors, knee flexors and extensors and ankle plantar flexors bilaterally. A stepwise linear regression analysis determined best positive work predictors of changes in gait speed. FINDINGS: Hip extension work in early stance and ankle plantarflexion work in late stance of the affected side accounted for 74.9% of the variance in change of gait speed; a second model showed that hip extension work in early stance of the affected and less-affected sides accounted for 74.3%, a similar amount of variance. INTERPRETATION: This work is the first to explore the changes in muscle work during gait that are associated with speed increases in persons with stroke. Augmenting hip extensor work in early stance on both sides, as well as ankle plantarflexion thrust on the affected side may be particularly beneficial in increasing the speed of walking of persons with stroke.     

Changes in cerebral blood flow before,during, and after forward and backward walking in stroke patients trained using virtual reality walking videos with deliberately induced inaccuracies in walking speed estimations

[Purpose] The aim of this study was to examine the effects of virtual reality (VR) training, with deliberately induced inaccuracies in walking speed estimations, on brain activity. [Participants and Methods] The study participants were 21 stroke patients, and the walking tasks involved forward and backward walking. While the VR walking speed was set at 3 km/h, estimation errors were induced by using an actual walking speed of 1 km/h during the walking tasks. Cerebral blood flow was measured using two functional near-infrared spectroscopy (fNIRS) channels located over the left and right prefrontal cortices, to determine changes in oxyhemoglobin levels from the resting state. Cerebral hemodynamics were compared during and after the VR training. [Results] The backward walking task induced a significant increase in cerebral blood flow in the right prefrontal cortex during and after the VR training. No significant changes were observed during the forward walking task. [Conclusion] In the backward walking condition, greater activation of the right prefrontal cortex was observed during and immediately after the VR training. Watching VR may have led to inaccurate walking-speed estimations, necessitating postural control (which may be attributed to the activation of the prefrontal cortex) during walking.     

脑卒中偏瘫患者步行速度临床决定因素的分析

目的 判别决定脑卒中偏瘫患者步行速度最重要的临床变量。方法 32例恢复步行能力的脑卒中偏瘫患者，测定在自然舒适状态下的10m步行速度，用Fug1—Meyer评价法评测下肢运动功能，用Motricity指数评测下肢肌力，用Berg平衡量表评定平衡功能，用改良Ashworth评定法评定足跖屈肌张力。对步行速度和临床变量进行Pearson相关分析，然后进行逐步回归分析。结果 患者的步行速度与下肢运动功能、平衡功能和下肢肌力之间呈高度正相关(r＝0．781—0．834，P＜0．001)；下肢运动功能与步行速度之间的相关性更高(r＝0．834)；步行速度与足跖屈肌张力痉挛程度呈负相关(r＝-0．461，P＜0．05)。进一步回归分析分析发现，下肢运动功能对步行速度有显著性影响(R^2＝0．696，P＜0．001)。结论 下肢运动功能是决定脑卒中偏瘫患者步行速度最重要的临床因素。     

脑卒中患者患侧下肢肌力与步行速度和步行独立性的关系

目的研究脑卒中偏瘫患者的患侧下肢肌力与步行速度和步行独立性之间的相互关系,明确下肢肌力在影响步行功能恢复上的决定因素,为制定更为有效的康复治疗程序提供指南。方法37例恢复步行能力的脑卒中偏瘫患者,用Motricity指数评测患侧下肢肌力,测定在自然舒适状态下的10m步行速度,用FIM中的步行项目测量步行的独立性。对患侧下肢肌力与步行速度和步行独立性之间进行Pearson相关分析,然后进行逐步回归分析。结果患者患侧下肢肌力与步行速度和步行独立性之间呈高度正相关(r=0.738和0.695,P<0.001);患侧髋屈曲肌力是步行速度和步行独立性最重要的决定因素(R2=0.331和0.479,P<0.001)。结论脑卒中患者的患侧下肢肌力在步行速度和步行独立性恢复方面具有重要的作用。     

Changes in cerebral blood flow during forward and backward walking with speed misperception generated by virtual reality

[Purpose] The purpose of this study was to investigate the effect of speed misperception on brain activity, created by a speed difference between actual walking and virtual reality walking videos. [Participants and Methods] The participants were 20 healthy young people. The walking speed in the video was set to 3 km/h to induce an error, while the actual walking speed was 1 km/h. Cerebral blood flow was measured using an optical imaging brain function measurement device. Left and right prefrontal cortices were analyzed using two channels and oxyhemoglobin level change from rest was used as a cerebral blood flow index. A t-test compared the cerebral blood flow dynamics before, during, and after the virtual reality video viewing under forward and backward walking conditions. [Results] Regarding changes in oxyhemoglobin levels during walking after watching the virtual reality video, cerebral blood flow increased especially in the backward walking state, where the difference was large in the right prefrontal cortex. [Conclusion] The backward walking that caused misperception by virtual reality is an extraordinary movement compared to forward walking. Thus, it is necessary to voluntarily adjust the movement by the cerebral cortex, and it is thought that activation of the prefrontal cortex occurs.     

How is walking speed related to muscle strength? A study of healthy persons and persons with late effects of polio

OBJECTIVES: To evaluate the relationship between walking speed and muscle strength in the lower extremities in healthy persons and in persons with late effects of polio and to compare the models for these relationships. DESIGN: Retrospective analysis. SETTING: University hospital department. PARTICIPANTS: An urban sample of 144 healthy men and women (age range, 40-79 y) and 234 (146 women, 88 men) subjects with late polio. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Muscle strength in the lower extremities was measured and combined into an index. Walking speed for spontaneous and maximal walking was measured. A nonlinear regression model was developed. RESULTS: Evidence was provided for the nonlinear relationship between walking speed and strength. A specific strength threshold could not be identified. The asymptote of this curve for maximal walking was 2.57 m/s in the healthy group and 2.02 m/s in the subjects with late effects of polio. A high body mass index (>25 kg/m2) lowered the asymptote. CONCLUSIONS: It is important to prevent strength decrease that approaches the critical level where a further reduction affects walking speed more evidently. The difference in the relationship between muscle strength and walking speed for the 2 groups studied may partly depend on biomechanic imbalance between muscle groups.     

Balance and walking performance are improved after resistance and aerobic training in persons with chronic stroke

Purpose: To investigate the effect of different types of physical training on balance performance and whether improved balance correlates with improved walking performance.

Methods: Forty eight participants with chronic stroke were randomly assigned to aerobic training on cycle ergometer (AT-group), resistance training of the lower extremities (RT-group), or sham training of upper extremities (ST-group). Participants exercised 3 d/week for 12 weeks. Balance (Berg Balance Scale), peak oxygen uptake rate, isometric knee extensor strength, maximal gait speed, and 6?minute walk test were measured at baseline and after 12 weeks.

Results: Training specific effects were observed; the AT-group improved peak oxygen uptake rate by 15.5 (6.0–25.0)%, the RT-group improved non-paretic knee extensor strength by 35.1 (18.3–51.9)% and the ST-group improved non-paretic knee extensor strength by 8.9 (0.7–17.1)%. All groups improved balance (6.0 (95% CI: 3.2–8.8)%), maximal gait speed (10.2 (6.5–14.0)%), and 6?minute walk distance (12.4 (8.8–15.9)%) but balance improvements did not correlate with improvements in muscle strength, peak oxygen uptake rate, or walking.

Conclusions: Physical exercise improves balance and walking performance, but improved balance is not a prerequisite for functional improvements in chronic stroke.

• Implications for Rehabilitation

• Aerobic training and progressive resistance training show small significant improvements in balance and walking, indicating a possible clinical relevance of these training modalities.

• Improvements in balance may not be a prerequisite for improvements in walking distance when assistive devices are allowed during walking tests.

     

Effects of walking with loads above the ankle on gait parameters of persons with hemiparesis after stroke

Background

Walking with a load at the ankle during gait training is a simple way to resist lower limb movements to induce functional muscle strengthening. This study investigated the effects of walking with different loads attached above the paretic ankle on biomechanical gait parameters during over ground walking in post-stroke participants.

Methods

Ten participants with moderate chronic hemiparesis were evaluated while walking over ground with three different loads (0.5, 1.0, and 1.5 kg) attached above the paretic ankle. Gait speed, cadence, step lengths as well as hip and knee angular displacements, joint moments and power of the paretic limb were compared while walking with and without loads.

Findings

Walking with a load led to an increased in gait speed (+ 0.03–0.05 m/s), and in step length of the paretic leg (+ 5.6 to 9.4% step length, effect size = 0.49–0.63), but not of the non-paretic leg. The proportion of the stance and swing phases did not change. Maximal joint moments (+ 20 to 48%, effect size = 0.26–0.55) and power (+ 20 to 114%, effect size = 0.30–0.57) increases varied across participants but were mostly affected in early stance at the hip and during the late swing phase at the knee. Mean angular displacement changes were less than 4°.

Interpretation

Post-stroke participants are able to increase hip and knee power bursts to meet the increased mechanical demand of added loads attached to the paretic ankle, while preserving the basic pattern of walking. Further study is needed before using loading to functionally strengthen paretic muscles.     

Rate of isometric knee extension strength development and walking speed after stroke

The relationship between lower-limb weakness and walking speed after stroke is not clear. This may be related to the measurement used to quantify weakness, typically peak strength. This study examined the relationship between two measures of isometric knee extension strength, i.e., peak torque and the rate of torque development and walking speed in adults with stroke. This study had 83 stroke survivors who participated. For the affected lower limb, rate and peak torque explained 12% of the variance in gait speed. Removing rate from the model significantly reduced the explained variance; in contrast, removing peak torque did not reduce the variance. For the less affected lower limb, rate tended to be more predictive of gait speed than peak torque. Diminished ability to rapidly generate knee extension torque contributes more to decreased walking speed after stroke than does maximal strength. Of note, 88% of the variance in gait speed is not explained by rate and peak isometric knee extension strength. Further studies are needed to determine if rehabilitation poststroke can increase the rate of knee strength development and if it results in faster walking speeds.