Between-limb synchronization for control of standing balance in individuals with stroke

Background

During standing, forces and moments exerted at the feet serve to maintain stability in the face of constant centre-of-mass movement. These actions are temporally synchronized in healthy individuals. Stroke is typically a unilateral injury resulting in increased sensori-motor impairment in the contra-lesional compared with the ipsi-lesional lower-limb, which could lead to reduced between-limb synchronization for control of standing balance. The purpose of this study is to investigate between-limb synchronization of standing balance control in individuals with stroke; a potentially important index of control of upright stability.

Methods

Twenty healthy controls and 33 individuals with unilateral stroke were assessed. Stability was assessed during a 30-second quiet standing trial by measuring data from two force plates (one per foot). Limb-specific centre of pressure was calculated. Between-limb synchronization was defined as the coefficient of the correlation between the left and right foot for both the antero-posterior and medio-lateral centre of pressure time series. Synchronization, weight-bearing symmetry, and root mean square of the total centre of pressure excursion were compared between controls and stroke participants.

Findings

Stroke participants swayed more, were more asymmetric, and had less between-limb synchronization than healthy controls. Among individuals with stroke, reduced between-limb synchronization was related to increased postural sway in the medio-lateral direction and increased weight-bearing asymmetry.

Interpretation

Individuals with stroke have reduced temporal synchronization of centre of pressure fluctuations under the feet when controlling quiet standing. The clinical significance of reduced synchronization remains to be determined, although it appears linked to increased medio-lateral sway and weight-bearing asymmetry.     

Maximum voluntary weight-bearing by the affected and unaffected legs in standing following stroke

OBJECTIVE: To compare stroke patients to control subjects for ability to transfer body weight onto the affected and unaffected leg in standing; to investigate intra-session reliability. DESIGN: Comparative clinical study conducted within a single session. BACKGROUND: There is a paucity of quantitative data about maximum voluntary weight-bearing in patients during rehabilitation following stroke. METHODS: A Kistler force platform was used to quantify maximum amount of body weight transferred to a single limb in the lateral and forward directions during weight-shifting. Twelve control subjects matched by gender and age (median 64 years) were compared to 12 inpatient stroke patients after a median of 37 days post-onset. RESULTS: The median score for control subjects was approximately 95% of body weight to each leg in both directions. In contrast, stroke patients transferred less body weight (P<0.01) to the affected leg (65.5% lateral; 54.9% forward) and also to the unaffected leg (85.0% lateral; 80.1% forward). For the stroke patients, transfer of body weight was more challenging in the forward direction than the lateral direction on the affected leg (P<0.05). Relative to individual differences in the stroke group, error due to the repeated measurement process was low. CONCLUSION: The testing procedure was found to discriminate between stroke patients and control patients and had high retest reliability within a single session.     

The effect of immediate decreasing of weight bearing asymmetry on quiet standing postural control in individuals with chronic stroke

The main patterns characterizing standing posture of hemiparetic patients include: weight-bearing asymmetry (WBA), larger postural sway, asymmetrical contribution of lower limbs to balance control, and increased visual dependency to balance control. The aim of this study was to evaluate the effect of decreasing WBA with the use of a shoe lift, on quiet standing postural control in patients with chronic stroke. Twenty-seven patients participated in this study. Patients completed two tests: 1) quiet standing; and 2) quiet standing while a lift was placed under the non-paretic limb. The following tests were completed on force plates for evaluation: asymmetry of the balance measures (weight bearing, root mean square (RMS) of anterior-posterior (AP) and medial-lateral (ML) center of pressure (COP) velocity), RMS of total AP and ML COP velocity, and AP and ML Romberg quotients. Paired t-tests were used to analyze the data. The mean value of WBA index decreased significantly after using a lift (p < 0.05). However, the changes of the mean value of other postural control parameters were not significant (p > 0.05). The results indicate that there may not be an association between decreased WBA and improved postural control during quiet standing in patients with stroke.     

Repeated split-belt treadmill walking improved gait ability in individuals with chronic stroke: A pilot study

This study investigated the effects of repeated split-belt treadmill (SBT) walking on gait ability in individuals poststroke. Twelve individuals with a first unilateral cerebral stroke (10 males; mean age 53 (SD 8.74); mean time poststroke 25 months (SD 23.5); 9 left-sided stroke) and initial step length (SL) asymmetry (ratio = 1.10–2.05) volunteered for the study. They were trained by physiotherapists from an outpatient rehabilitation center six times over 2–3 weeks using a SBT protocol. After only six sessions of training, all participants reduced their SL asymmetry from an average ratio of 1.39 to 1.17 (p = 0.002) and increased walking speed (p = 0.043). Improvements in symmetry and speed were retained over 1 month (p ≤ 0.008). No effect was observed in participants’ endurance, assessed with the 6-min walk test. These findings suggest that the present SBT protocol has potential to be an efficient intervention to improve not only SL symmetry but also gait speed, in individuals poststroke.     

Effect of ankle-foot orthosis on weight bearing of chronic stroke patients performing various functional standing tasks

[Purpose] This study examined how an ankle-foot orthosis (AFO) influences the weight-bearing of chronic stroke patients during the performance of five functional standing tasks. [Subjects and Methods] Sixteen patients with stroke participated in this experiment. The subjects performed functional standing tasks with or without the AFO and weight bearing was measured during the tasks. [Results] Patients showed increased weight-bearing ability on the affected side during wearing the AFO in all tasks, and there were significant differences among Tasks 1, 2, and 3. Patients showed a small amount of increased weight bearing on the unaffected side while wearing the AFO in all tasks except for Task 2. [Conclusion] ADL-related functional standing tasks with AFO increased the weight bearing.Key words: Ankle-foot orthosis, Weight bearing, Functional standing tasks     

Discriminant ability of the Trunk Impairment Scale: A comparison between stroke patients and healthy individuals

PURPOSE: The Trunk Impairment Scale (TIS) is a standardized scale to evaluate the trunk function in stroke patients. It was the aim of this study to determine the discriminant ability of the TIS by comparing stroke patients with healthy individuals. Further, the variables that had an influence on obtaining a high score on the TIS in healthy subjects were examined. METHOD: Forty stroke patients and 40 age- and sex-matched healthy individuals were included in the study. TIS scores from the stroke patients and healthy individuals were compared using the Wilcoxon ranked sum test. RESULTS: Sub-scale and total TIS scores showed significant differences between stroke patients and healthy individuals (P < 0.0001). Univariate analysis and logistic regression analysis further revealed that younger persons, women and people who are more active in daily life have a higher chance of obtaining a high score on the TIS. CONCLUSIONS: The TIS discriminates between stroke patients and healthy individuals. A submaximal score on the TIS was found in 45% of the healthy subjects suggesting that a lower score on the TIS still indicates normal trunk function and full participation in daily life.     

Effect of dual tasks on balance ability in stroke patients

[Purpose] The purpose of this study was to determine the effects of training using dual tasks on balance ability in stroke patients. [Subjects] Forty stroke patients were divided into a dual-task training group (N = 20) and a single task training group (N = 20) randomly. [Methods] The subjects in the single-task traing group stood in a comfortable position, faced a therapist, then threw a Swiss ball back and forth. They then performed balance training in which they raised and lowered their ankles while facing forward or moved objects from one table to another. The DTG performed dual tasks, which involved performing a task on an unstable surface using a balance pad. Both groups received training 30 min per day, five times per week, for eight weeks. [Results] The DTG showed significant increases in weight distribution rate, anterior limit of stability, posterior limit of stability, and BBS scores compared with the STG. [Conclusion] According to the results of this study, dual-task training and single-task training were effective in improving balance in stroke patients, dual task training is more effective for increasing balance ability.Key words: Stroke, Dual-task training, Balance     

Reliability of mental chronometry for assessing motor imagery ability after stroke

Malouin F, Richards CL, Durand A, Doyon J. Reliability of mental chronometry for assessing motor imagery ability after stroke.

Objective

To examine the reproducibility of 2 chronometric tests: time-dependent motor imagery (TDMI) screening test and temporal congruence test.

Design

Test-retest 10 to 14 days apart.

Setting

Laboratory of a university-affiliated center for research in rehabilitation.

Participants

Twenty persons post cerebrovascular accident (CVA) and 46 healthy persons (controls).

Intervention

The reproducibility of the TDMI screening test, wherein the number of stepping movements (performed in sitting) imagined over 15, 25, and 45 seconds is recorded, and of the temporal congruence test wherein the duration of physically executed (E) and imagined (I) stepping movements is recorded, was evaluated.

Main Outcome Measures

The test-retest reliability of the number of imagined movements (TDMI screening test), movement duration and I/E time ratios (temporal congruence test), and intrasession reliability of the temporal congruence test were assessed by using intraclass correlation coefficients (ICCs).

Results

For the TDMI screening test, the ICCs ranged from .88 to .93 (CVA, n=20) and from .87 to .92 (controls, n=9). For the temporal congruence test, when the total duration of 2 series of 5 stepping movements was averaged, ICCs ranged from .76 to .97 (CVA, n=20) and from .77 to .93 (controls, n=46), whereas for 1 series the ICCs ranged from .71 to .95 and from .63 to .95 in the CVA and control groups, respectively. The ICCs for intrasession reliability for the CVA (n=20) and control (n=46) groups, respectively, ranged from .90 to .98 and .95 to .97.

Conclusions

The present findings support the reproducibility of both tests in both groups. Mental chronometry can be used reliably for the screening of patients capable of motor imagery or for measuring temporal congruence between real and imagined movements poststroke.     

Gait training with partial body weight support during overground walking for individuals with chronic stroke: a pilot study

Background

It is not yet established if the use of body weight support (BWS) systems for gait training is effective per se or if it is the combination of BWS and treadmill that improves the locomotion of individuals with gait impairment. This study investigated the effects of gait training on ground level with partial BWS in individuals with stroke during overground walking with no BWS.

Methods

Twelve individuals with chronic stroke (53.17 ± 7.52 years old) participated of a gait training program with BWS during overground walking, and were evaluated before and after the gait training period. In both evaluations, individuals were videotaped walking at a self-selected comfortable speed with no BWS. Measurements were obtained for mean walking speed, step length, stride length and speed, toe-clearance, durations of total double stance and single-limb support, and minimum and maximum foot, shank, thigh, and trunk segmental angles.

Results

After gait training, individuals walked faster, with symmetrical steps, longer and faster strides, and increased toe-clearance. Also, they displayed increased rotation of foot, shank, thigh, and trunk segmental angles on both sides of the body. However, the duration of single-limb support remained asymmetrical between each side of the body after gait training.

Conclusions

Gait training individuals with chronic stroke with BWS during overground walking improved walking in terms of temporal-spatial parameters and segmental angles. This training strategy might be adopted as a safe, specific and promising strategy for gait rehabilitation after stroke.

     

Effect of shoulder pain on shoulder kinematics during weight-bearing tasks in persons with spinal cord injury

Nawoczenski DA, Riek LM, Greco L, Staiti K, Ludewig PM. Effect of shoulder pain on shoulder kinematics during weight-bearing tasks in persons with spinal cord injury.ObjectiveTo assess 3-dimensional scapulothoracic and glenohumeral kinematics between subjects with spinal cord injury and disease (SCI/D) with and without shoulder pain during a weight-relief raise and transfer task.DesignCase-control, repeated-measures analysis of variance.SettingMovement analysis laboratory.ParticipantsSubjects (N=43; 23 with clinical signs of impingement and 20 without) between 21 and 65 years of age, at least 1 year after SCI/D (range, 1–43y) resulting in American Spinal Injury Association Impairment Scale T2 motor neurologic level or below, and requiring the full-time use of a manual wheelchair.InterventionsWeight-relief raises and transfer tasks.Main Outcome MeasuresAn electromagnetic tracking system acquired 3-dimensional position and orientation of the thorax, scapula, and humerus. Dependent variables included angular values for scapular upward and downward rotation, posterior and anterior tilt, and internal and external rotation relative to the thorax, and glenohumeral internal and external rotation relative to the scapula. The mean of 3 trials was collected, and angular values were compared at 3 distinct phases of the weight-relief raise and transfer activity. Comparisons were also made between transfer direction (lead vs trail arm) and across groups.ResultsKey findings include significantly increased scapular upward rotation for the pain group during transfer (P=.03). Significant group differences were found for the trailing arm at the lift pivot (phase 2) of the transfer, with the pain group having greater anterior tilt (mean difference ± SE, 5.7°±2.8°). The direction of transfer also influenced kinematics at the different phases of the activity.ConclusionsPotentially detrimental magnitude and direction of scapular and glenohumeral kinematics during weight-bearing tasks may pose increased risk for shoulder pain or injury in persons with SCI/D. Consideration should be given to rehabilitation strategies that promote favorable scapular kinematics and glenohumeral external rotation.     

复合感觉测试在慢性腰痛人群中的信度研究

目的:评估两点辨别测试(TPD)、点对点测试(PTP)和两点距离估算(TPE)三种测试在正常人和慢性腰痛人群(CLBP)中的重测信度和测试者间信度.方法:筛选30例正常人和30例CLBP患者,由两名物理治疗师分别对60例受试者进行TPD、PTP和TPE三种测试评估,测试者间测试间隔时间为10min,其中一人在24h后重...     

Use of prolonged standing for individuals with spinal cord injuries

BACKGROUND AND PURPOSE: Prolonged standing in people with spinal cord injuries (SCIs) has the potential to affect a number of health-related areas such as reflex activity, joint range of motion, or well-being. The purpose of this study was to document the patterns of use of prolonged standing and their perceived effects in subjects with SCIs. SUBJECTS: The subjects were 152 adults with SCIs (103 male, 49 female; mean age=34 years, SD=8, range=18-55) who returned mailed survey questionnaires. METHODS: A 17-item self-report survey questionnaire was sent to the 463 members of a provincial spinal cord support organization. RESULTS: Survey responses for 26 of the 152 respondents were eliminated from the analysis because they had minimal effects from their injuries and did not need prolonged standing as an extra activity. Of the 126 remaining respondents, 38 respondents (30%) reported that they engaged in prolonged standing for an average of 40 minutes per session, 3 to 4 times a week, as a method to improve or maintain their health. The perceived benefits included improvements in several health-related areas such as well-being, circulation, skin integrity, reflex activity, bowel and bladder function, digestion, sleep, pain, and fatigue. The most common reason that prevented the respondents from standing was the cost of equipment to enable standing. DISCUSSION AND CONCLUSION: Considering the many reported benefits of standing, this activity may be useful for people with SCI. This study identified a number of body systems and functions that may need to be investigated if clinical trials of prolonged standing in people with SCI are undertaken.     

Weight distribution in standing and sitting positions,and weight transfer during reaching tasks,in seated stroke subjects and healthy subjects

Background and Purpose. The recovery of sitting balance after a stroke is assumed to be essential to obtain independence in other vital functions. The purpose of the present study was to investigate weight distribution while sitting and standing still, and weight transfer during seated reaching tasks performed by stroke subjects and healthy subjects. Method. The study was cross‐sectional. Twenty‐one stroke subjects and 21 healthy subjects, matched by age and gender, participated. Main measures were weight distribution while standing and sitting still, and displacements of centre of pressure (COP) during seated reaching tasks. Data were collected using a balance performance monitor (BPM), including software. Results. Stroke subjects had less symmetrical weight distribution in standing than that of healthy subjects (p < 0.001). No significant differences between the groups were found while sitting still, and no associations between asymmetries in standing still and sitting positions within individual stroke subjects were found. Neither did the degree of weight distribution in sitting correspond to COP displacements in seated reaching tasks. However, COP displacement patterns in reaching tasks in the seated position were different in stroke subjects from those of healthy subjects. Stroke subjects showed more lateral displacement when reaching forwards (p < 0.001), and less lateral displacement when reaching sideways to the unaffected side (p = 0.01). Conclusion. COP displacement patterns in stroke subjects deviate more than those of healthy subjects in seated reaching tasks. The deviating COP displacement patterns are discussed as a possible dysfunction in the ability to make postural adjustments and learn an efficient movement pattern. Copyright © 2007 John Wiley & Sons, Ltd.     

Reliability and validity of step test scores in subjects with chronic stroke

Hong S-J, Goh EY, Chua SY, Ng SS. Reliability and validity of step test scores in subjects with chronic stroke.ObjectivesTo establish (1) the intrarater and interrater reliabilities of step test (ST) scores in subjects with chronic stroke, (2) the ST's known-groups validity and cutoff scores for distinguishing subjects with chronic stroke from healthy adults older than 50 years, and (3) the convergent validity of ST scores with lower-limb muscle strength, coordination, balance performance, and walking speed.DesignCross-sectional study.SettingUniversity-based rehabilitation center.ParticipantsConvenience sample of subjects (N=30): community-dwelling subjects with chronic stroke (n=15) and healthy adults older than 50 years (n=15).InterventionsNot applicable.Main Outcome MeasuresST scores; handheld dynamometer measurements of bilateral lower-limb muscle strength; lower-extremity motor coordination test (LEMOCOT) scores; Berg Balance Scale scores; walking speed as measured by a 5-meter walk test.ResultsST scores showed excellent intrarater reliability, with intraclass correlation coefficients ranging from .981 to .995 and interrater reliability ranging from .996 to .999. A cutoff score of 13 on the paretic side was found to distinguish the healthy adults older than 50 years from subjects with stroke at a sensitivity of 87% and a specificity of 87%. A cutoff score of 11 on the nonparetic side was found to distinguish the healthy adults from subjects with stroke at a sensitivity of 100% and a specificity of 67%. ST scores of the paretic limb demonstrated a significant correlation with muscle strength, the LEMOCOT scores of the paretic leg, and walking speed. ST scores of the nonparetic limb demonstrated a significant correlation with muscle strength and the LEMOCOT scores of the paretic leg.ConclusionsThe ST is a reliable measurement tool when the number of steps is counted by either experienced or inexperienced examiners by viewing videotapes. ST scores with both the paretic limb and the nonparetic limb are sensitive in distinguishing subjects with chronic stroke from healthy adults older than 50 years.     

神经肌肉本体促通技术对偏瘫患者立位平衡极限的影响

目的观察神经肌肉本体促通技术 (PNF)对偏瘫患者立位平衡极限能力的影响。方法 18例脑卒中恢复期患者分为 :治疗组 (9例 )使用PNF手法 ;对照组 (9例 )采用Bobath、运动再学习等康复技术。均治疗 3个月结果治疗组患者立位平衡极限能力优于对照组 (P <0 0 5 -0 0 1)。结论利用PNF技术对提高偏瘫患者平衡极限能力有明显的效果。     

Transcranial doppler monitoring during language tasks in stroke patients with aphasia

Purpose. To investigate the pattern of hemispheric activation, according to cerebral blood flow changes, as measured by Transcranial Doppler Ultrasonography (TCD) during language tasks in stroke patients with aphasia.

Method. Prospective study investigating results of TCD monitoring during language naming and recognition tasks in ischemic stroke patients (n = 32) with and without aphasia and 5 control subjects.

Results. Delta mean flow velocity (MFV) in the left Middle Cerebral Artery (MCA) was found to be much lower in aphasia patients as compared to healthy subjects. Negative statistical correlation was found between the improvement of language ability and the blood flow velocity parameters in the left hemisphere. Aphasia patients with good language ability showed much higher MFV in the right MCA during the first test. Left hemispheric blood flow velocity shift was found to be higher during speech tasks in the patients with poor language ability.

Conclusions. Our study suggests that the performance of language tasks in aphasia patients during early recovery after stroke is associated with relatively high right hemisphere activation. High blood flow velocity in the right MCA of aphasia patients was found to be a good prognostic sign for better language ability. Arterial blood flow that shifted towards the left hemisphere during speech tasks was associated with poor language ability.     

Transcranial Doppler monitoring during language tasks in stroke patients with aphasia

Purpose.?To report some psychometric properties of the functional status assessment of seniors in the emergency department (FSAS-ED) at item level. This 40-item tool addresses the person's functional status prior to and following the decision to consult in ED.

Method.?A sample of 150 community-living elderly individuals who consulted the ED was recruited. Two evaluators administered the FSAS-ED in the ED and scored it independently. Three measurement properties were considered relevant for the item analysis: response distribution, inter-rater reliability and the ability to indicate a change between before and following the decision to consult ED. Criteria related to these properties were established to classify items as being excellent, acceptable or weak.

Results.?The response distributions were excellent or acceptable for 36 items (90%). Results pertaining to inter-rater reliability showed 39 excellent or acceptable items (97.5%). Comparison of the responses between before and following the decision to consult to ED showed 24 (60%) excellent or acceptable items and 16 (40%) weak items; the latter were related to communication and cognitive skills.

Conclusions.?At the item level, the FSAS-ED provides reliable and clinically relevant information about the functional status of older adults consulting ED.     

Transcranial Doppler monitoring during language tasks in stroke patients with aphasia

Purpose. To investigate the pattern of hemispheric activation, according to cerebral blood flow changes, as measured by Transcranial Doppler Ultrasonography (TCD) during language tasks in stroke patients with aphasia.

Method. Prospective study investigating results of TCD monitoring during language naming and recognition tasks in ischemic stroke patients (n = 32) with and without aphasia and 5 control subjects.

Results. Delta mean flow velocity (MFV) in the left Middle Cerebral Artery (MCA) was found to be much lower in aphasia patients as compared to healthy subjects. Negative statistical correlation was found between the improvement of language ability and the blood flow velocity parameters in the left hemisphere. Aphasia patients with good language ability showed much higher MFV in the right MCA during the first test. Left hemispheric blood flow velocity shift was found to be higher during speech tasks in the patients with poor language ability.

Conclusions. Our study suggests that the performance of language tasks in aphasia patients during early recovery after stroke is associated with relatively high right hemisphere activation. High blood flow velocity in the right MCA of aphasia patients was found to be a good prognostic sign for better language ability. Arterial blood flow that shifted towards the left hemisphere during speech tasks was associated with poor language ability.