KINEMATIC AND KINETIC ASYMMETRIES IN HEMIPLEGIC PATIENTS’ GAIT INITIATION PATTERNS

The effects of combined transcranial brain stimulation and a 4-week visuomotor stepping training on voluntary step initiation in persons with chronic stroke-a pilot study

Purpose

Evidence suggests that transcranial direct current stimulation (tDCS) can enhance motor performance and learning of hand tasks in persons with chronic stroke (PCS). However, the effects of tDCS on the locomotor tasks in PCS are unclear. This pilot study aimed to: (1) determine aggregate effects of anodal tDCS combined with step training on improvements of the neural and biomechanical attributes of stepping initiation in a small cohort of persons with chronic stroke (PCS) over a 4-week training program; and (2) assess the feasibility and efficacy of this novel approach for improving voluntary stepping initiation in PCS.

Methods

A total of 10 PCS were randomly assigned to one of two training groups, consisting of either 12 sessions of VST paired with a-tDCS (n = 6) or sham tDCS (s-tDCS, n = 4) over 4 weeks, with step initiation (SI) tests at pre-training, post-training, 1-week and 1-month follow-ups. Primary outcomes were: baseline vertical ground reaction force (B-vGRF), response time (RT) to initiate anticipatory postural adjustment (APA), and the retention of B-VGRF and RT.

Results

a-tDCS paired with a 4-week VST program results in a significant increase in paretic weight loading at 1-week follow up. Furthermore, a-tDCS in combination with VST led to significantly greater retention of paretic BWB compared with the sham group at 1 week post-training.

Clinical implications

The preliminary findings suggest a 4-week VST results in improved paretic limb weight bearing (WB) during SI in PCS. Furthermore, VST combined with a-tDCS may lead to better retention of gait improvements (NCT04437251) (https://classic.clinicaltrials.gov/ct2/show/NCT04437251).

Effectiveness of mid thoracic spine mobilization on postural balance and gait ability in subacute stroke patients: A randomized clinical trial

BACKGROUND

Although mulligan sustained natural apophyseal glides (SNAG) and maitland mobilization (MM) are common interventions for musculoskeletal disease, no study has directly compared the effectiveness of mid-thoracic spine mobilization in subacute stroke patients.

OBJECTIVE

To investigate the effects of mid-thoracic spine mobilization (SNAG vs. MM) on postural balance and gait ability in subacute stroke patients.

METHODS

Fifty subacute stroke patients were randomly allocated to the SNAG (n= 17), MM (n= 16), and control (n= 17) groups, each receiving a neuro-developmental therapy program for four successive weeks. The SNAG and MM groups additionally received mid-thoracic spine mobilization (T4∼8). The primary outcome measure was postural sway, and secondary outcome measures included the five times sit-to-stand test (FTSST), functional reach test (FRT), 10-m walk test (10MWT), 6-minute walk test (6MWT) and global rating of change (GRC).

RESULTS

Participants reported no adverse events, and there was no loss to follow-up. The SNAG and MM group patients demonstrated significant improvements (p< 0.05) in postural sway, FTSST, FRT, 10MWT, and 6MWT compared with those in the control group, with no between-group differences.

CONCLUSIONS

Mid-thoracic spine mobilization allows significant improvements in postural balance and gait ability in subacute stroke patients, with no differences between the SNAG and MM techniques.

Interlimb Coordination during Double Support Phase of Gait in People with and without Stroke

This study aims to identify differences between participants with and without stroke regarding the ipsilesional and contralesional lower limbs kinematics, kinetics, muscle activity and their variability during double support phase of gait. Eleven post-stroke and thirteen healthy participants performed 10 gait trials at a self-selected speed while being monitored by an optoelectronic motion capture system, two force plates and an electromyographic system. The following outcomes were evaluated during the double support: the time and the joint position; the external mechanical work on the centre of mass; and the relative electromyographic activity. Both, contralesional/ipsilesional and dominant/non-dominant of participants with and without stroke, respectively, were evaluated during double support phase of gait in trailing or leading positions. The average value of each parameter and the coefficient of variation of the 10 trials were analysed. Post-stroke participants present bilateral decreased mechanical work on the centre of mass and increased variability, decreased contralesional knee and ankle flexion in trailing position, increased ipsilesional knee flexion in leading position and increased variability. Increased relative muscle activity was observed in post-stroke participants with decreased variability. Mechanical work on the centre of mass seems to be the most relevant parameter to identify interlimb coordination impairments in post-stroke subjects.

Neurophysiology of cerebellar ataxias and gait disorders

There are numerous forms of cerebellar disorders from sporadic to genetic diseases. The aim of this chapter is to provide an overview of the advances and emerging techniques during these last 2 decades in the neurophysiological tests useful in cerebellar patients for clinical and research purposes. Clinically, patients exhibit various combinations of a vestibulocerebellar syndrome, a cerebellar cognitive affective syndrome and a cerebellar motor syndrome which will be discussed throughout this chapter. Cerebellar patients show abnormal Bereitschaftpotentials (BPs) and mismatch negativity. Cerebellar EEG is now being applied in cerebellar disorders to unravel impaired electrophysiological patterns associated within disorders of the cerebellar cortex. Eyeblink conditioning is significantly impaired in cerebellar disorders: the ability to acquire conditioned eyeblink responses is reduced in hereditary ataxias, in cerebellar stroke and after tumor surgery of the cerebellum. Furthermore, impaired eyeblink conditioning is an early marker of cerebellar degenerative disease. General rules of motor control suggest that optimal strategies are needed to execute voluntary movements in the complex environment of daily life. A high degree of adaptability is required for learning procedures underlying motor control as sensorimotor adaptation is essential to perform accurate goal-directed movements. Cerebellar patients show impairments during online visuomotor adaptation tasks. Cerebellum-motor cortex inhibition (CBI) is a neurophysiological biomarker showing an inverse association between cerebellothalamocortical tract integrity and ataxia severity. Ataxic gait is characterized by increased step width, reduced ankle joint range of motion, increased gait variability, lack of intra-limb inter-joint and inter-segmental coordination, impaired foot ground placement and loss of trunk control. Taken together, these techniques provide a neurophysiological framework for a better appraisal of cerebellar disorders.

Effectiveness of Repetitive Transcranial Magnetic Stimulation Combined with Visual Feedback Training in Improving Neuroplasticity and Lower Limb Function after Chronic Stroke: A Pilot Study

After a stroke, sustained gait impairment can restrict participation in the activities listed in the International Classification of Functioning, Disability, and Health model and cause poor quality of life. The present study investigated the effectiveness of repetitive transcranial magnetic stimulation (rTMS) and visual feedback training (VF) training in improving lower limb motor performance, gait, and corticospinal excitability in patients with chronic stroke. Thirty patients were randomized into three groups that received either rTMS or sham stimulation over the contralesional leg region accompanied by VF training groups in addition to the conventional rehabilitation group. All participants underwent intervention sessions three times per week for four weeks. Outcome measures included the motor-evoked potential (MEP) of the anterior tibialis muscle, Berg Balance Scale (BBS) scores, Timed Up and Go (TUG) test scores, and Fugl–Meyer Assessment of Lower Extremity scores. After the intervention, the rTMS and VF group had significantly improved in MEP latency (p = 0.011), TUG scores (p = 0.008), and BBS scores (p = 0.011). The sham rTMS and VF group had improved MEP latency (p = 0.027). The rTMS and VF training may enhance the cortical excitability and walking ability of individuals with chronic stroke. The potential benefits encourage a larger trial to determine the efficacy in stroke patients.

Repeatability and Temporal Consistency of Lower Limb Biomechanical Variables Expressing Interlimb Coordination during the Double-Support Phase in People with and without Stroke Sequelae

Reliable biomechanical methods to assess interlimb coordination during the double-support phase in post-stroke subjects are needed for assessing movement dysfunction and related variability. The data obtained could provide a significant contribution for designing rehabilitation programs and for their monitorisation. The present study aimed to determine the minimum number of gait cycles needed to obtain adequate values of repeatability and temporal consistency of lower limb kinematic, kinetic, and electromyographic parameters during the double support of walking in people with and without stroke sequelae. Eleven post-stroke and thirteen healthy participants performed 20 gait trials at self-selected speed in two separate moments with an interval between 72 h and 7 days. The joint position, the external mechanical work on the centre of mass, and the surface electromyographic activity of the tibialis anterior, soleus, gastrocnemius medialis, rectus femoris, vastus medialis, biceps femoris, and gluteus maximus muscles were extracted for analysis. Both the contralesional and ipsilesional and dominant and non-dominant limbs of participants with and without stroke sequelae, respectively, were evaluated either in trailing or leading positions. The intraclass correlation coefficient was used for assessing intra-session and inter-session consistency analysis. For most of the kinematic and the kinetic variables studied in each session, two to three trials were required for both groups, limbs, and positions. The electromyographic variables presented higher variability, requiring, therefore, a number of trials ranging from 2 to >10. Globally, the number of trials required inter-session ranged from 1 to >10 for kinematic, from 1 to 9 for kinetic, and 1 to >10 for electromyographic variables. Thus, for the double support analysis, three gait trials were required in order to assess the kinematic and kinetic variables in cross-sectional studies, while for longitudinal studies, a higher number of trials (>10) were required for kinematic, kinetic, and electromyographic variables.

Bilateral ankle deformities affects gait kinematics in chronic stroke patients

Objectives

Stroke patients suffer from ankle joint deformities due to spastic ankle muscles. This study evaluated the viability of using 3D scanned surface images of the feet of stroke victims to visually assess the deformities of a hemiparetic foot and investigated the influences of deformed ankle joints on gait kinematics.

Methods

A total of 30 subjects with stroke-induced hemiparesis and 11 age-matched healthy controls completed the clinical assessments. We analyzed their feet's morphometric characteristics using a 3D scanner, identified convenient anthropometric measurements, and conducted gait trials on even and uneven terrains. The 3D foot morphometric characteristics were evaluated using the geometric morphometrics method (GMM).

Results

Results showed that there were significant differences in bilateral foot shapes between the chronic stroke patients and healthy controls and between the paretic and non-paretic sides in the chronic stroke patients. In stroke patients, those with the smaller medial malleoli's vertical tilt angles showed significantly different ankle ranges of motion of dorsi-/plantar flexion during gaits on uneven terrains (p = 0.009). In addition, those with the greater medial malleoli's vertical tilt angles showed significantly different ankle ranges of motion of inversion/eversion during gaits on even and uneven terrains (p < 0.05).

Conclusion

Using 3D scanning technology, bilateral morphometric changes in the feet of chronic stroke patients were shown by GMM and the simple anthropometric measurements identified its shape deformities in the feet. Their possible effects on gait kinematics while walking on uneven terrains were investigated. Current methodology can be potentially useful in applying conventional productions of clinically manufactured, patient-fitted ankle-foot-orthosis in orthotics and prosthetics, and in detecting various unidentified pathological deformities in the feet.

(A)symmetry during gait initiation in people with Parkinson's disease: A motor and cortical activity exploratory study

Background

Gait asymmetry and deficits in gait initiation (GI) are among the most disabling symptoms in people with Parkinson's disease (PwPD). Understanding if PwPD with reduced asymmetry during GI have higher asymmetry in cortical activity may provide support for an adaptive mechanism to improve GI, particularly in the presence of an obstacle.

Objective

This study quantified the asymmetry of anticipatory postural adjustments (APAs), stepping parameters and cortical activity during GI, and tested if the presence of an obstacle regulates asymmetry in PwPD.

Methods

Sixteen PwPD and 16 control group (CG) performed 20-trials in two conditions: unobstructed and obstructed GI with right and left limbs. We measured, through symmetry index, (i) motor parameters: APAs and stepping, and (ii) cortical activity: the PSD of the frontal, sensorimotor and occipital areas during APA, STEP-I (moment of heel-off of the leading foot in the GI until the heel contact of the same foot); and STEP-II (moment of the heel-off of the trailing foot in the GI until the heel contact of the same foot) phases.

Results

Parkinson's disease showed higher asymmetry in cortical activity during APA, STEP-I and STEP-II phases and step velocity (STEP-II phase) during unobstructed GI than CG. However, unexpectedly, PwPD reduced the level of asymmetry of anterior-posterior displacement (p < 0.01) and medial-lateral velocity (p < 0.05) of the APAs. Also, when an obstacle was in place, PwPD showed higher APAs asymmetry (medial-lateral velocity: p < 0.002), with reduced and increased asymmetry of the cortical activity during APA and STEP-I phases, respectively.

Conclusion

Parkinson's disease were not motor asymmetric during GI, indicating that higher cortical activity asymmetry can be interpreted as an adaptive behavior to reduce motor asymmetry. In addition, the presence of obstacle did not regulate motor asymmetry during GI in PwPD.

Impact of Constraint-Induced Movement Therapy (CIMT) on Functional Ambulation in Stroke Patients-A Systematic Review and Meta-Analysis

Constraint-induced movement therapy (CIMT) has been delivered in the stroke population to improve lower-extremity functions. However, its efficacy on prime components of functional ambulation, such as gait speed, balance, and cardiovascular outcomes, is ambiguous. The present review aims to delineate the effect of various lower-extremity CIMT (LECIMT) protocols on gait speed, balance, and cardiovascular outcomes. Material and methods: The databases used to collect relevant articles were EBSCO, PubMed, PEDro, Science Direct, Scopus, MEDLINE, CINAHL, and Web of Science. For this analysis, clinical trials involving stroke populations in different stages of recovery, >18 years old, and treated with LECIMT were considered. Only ten studies were included in this review, as they fulfilled the inclusion criteria. The effect of CIMT on gait speed and balance outcomes was accomplished using a random or fixed-effect model. CIMT, when compared to controlled interventions, showed superior or similar effects. The effect of LECIMT on gait speed and balance were non-significant, with mean differences (SMDs) of 0.13 and 4.94 and at 95% confidence intervals (Cis) of (-0.18-0.44) and (-2.48-12.37), respectively. In this meta-analysis, we observed that despite the fact that several trials claimed the efficacy of LECIMT in improving lower-extremity functions, gait speed and balance did not demonstrate a significant effect size favoring LECIMT. Therefore, CIMT treatment protocols should consider the patient's functional requirements, cardinal principles of CIMT, and cardiorespiratory parameters.

Asymmetric Influence of Dual-Task Interference on Anticipatory Postural Adjustments in One-Leg Stance

This study investigated the differences of anticipatory postural adjustments (APAs) in a one-leg stance (OLS) that appear according to lower-extremity dominance and dual-task interference. Thirteen young, healthy, male volunteers performed the OLS task under the following six conditions: (1) dominant leg (DL), single-task; (2) DL, dual-task, with a low level of cognitive load (DT1/2); (3) DL, dual-task, with a high level of cognitive load (DT + 1); (4) non-dominant leg (NDL), single-task; (5) NDL, DT1/2; and (6) NDL, DT + 1. In order to measure the subjects' APA, we used the medial-lateral displacement of their centers of pressure and gravity from the force plate and the time-series data of joint angular motions, recorded using a 3D motion analysis system. In the NDL under the dual-task condition, the onset of APA was delayed and the amplitude declined, which resulted in an increase in the duration of the APA period. The number of components identified by principal component analysis differed according to the dominant foot, and the change caused by cognitive load was found only in the NDL. As the cognitive load increased, the variance of the principal component decreased. These findings show that dual-task interference asymmetrically influences APA according to limb dominance, which reorganizes the coordination strategy of joints' angular motion.

Differences in mediolateral dynamic stability during gait initiation according to whether the non-paretic or paretic leg is used as the leading limb

We investigated mediolateral dynamic stability at first foot off and first initial contact during gait initiation according to whether the paretic or non-paretic leg was used as the leading limb. Thirty-eight individuals with stroke initiated gait with the paretic and non-paretic legs as the leading limb, and their movements were measured using a 3D motion analysis system. Margin of stability (i.e., the length between the extrapolated center of mass and lateral border of the stance foot) was used as an index of dynamic stability, with a large value indicating dynamic stability in the lateral direction. However, an excessively large margin of stability value (i.e., when the extrapolated center of mass is outside the medial border of the stance foot) indicates dynamic instability in the medial direction. Differences in the margin of stability between tasks were compared using the Wilcoxon signed-rank test. The minimum margin of stability was observed just before first foot off. When the non-paretic leg was used as the leading limb, the margin of stability tended to be excessively large at first foot off compared with when the paretic leg was used (p < 0.001). In other words, the extrapolated center of mass was outside the medial border of the paretic stance foot. In conclusion, lateral stability was achieved when using the non-paretic leading limb because the extrapolated center of mass was located outside the medial border of the stance foot. However, medial dynamic stability was lower for the non-paretic leading limb compared with the paretic leading limb.

Effects of limited knee flexion movement in intra-limb gait coordination

This study aimed to investigate intra-limb coordination in non-disabled individuals walking with and without a constrained knee and in individuals with stroke. We hypothesized that a constrained knee would modify the intra-limb coordination of non-disabled individuals and that non-disabled individuals walking with a constrained knee would present coordination patterns similar to those presented by individuals with stroke. Twelve individuals with chronic stroke (age: 54.1 ± 9.9 years) and 12 age- and sex-matched individuals (age: 54.8 ± 9.2 years) with no known gait impairment (non-disabled individuals) participated in this study. Non-disabled individuals walked with and without an orthosis on one of their knees, limiting flexion to 40°, which was the average maximum knee flexion presented by the participants with stroke. Lower limb coordination was assessed on the basis of vector coding for the thigh-shank and shank-foot couplings during stance and swing periods of gait. Constrained knee flexion in non-disabled individuals mainly affected the thigh-shank coupling but not the shank-foot coupling of the constrained limb. There was reduced anti-phase coordination during the stance and swing periods and a marked increase in in-phase coordination during the swing period. Non-disabled individuals presented most changes toward the coordination pattern presented by individuals with stroke, except for the thigh-phase mode during the swing period, which was lower than that in individuals with stroke. Reduced knee flexion movement caused similar alterations in the intra-limb coordination pattern in non-disabled individuals compared to those observed in individuals with stroke. Therefore, diminished knee flexion movement, which is presented by individuals with stroke, can be considered a key disturbance that leads to impairment in lower extremity intra-limb coordination.

Predictive simulation of post-stroke gait with functional electrical stimulation

Post-stroke patients present various gait abnormalities such as drop foot, stiff-knee gait (SKG), and knee hyperextension. Functional electrical stimulation (FES) improves drop foot gait although the mechanistic basis for this effect is not well understood. To answer this question, we evaluated the gait of a post-stroke patient walking with and without FES by inverse dynamics analysis and compared the results to an optimal control framework. The effect of FES and cause-effect relationship of changes in knee and ankle muscle strength were investigated; personalized muscle–tendon parameters allowed the prediction of pathologic gait. We also predicted healthy gait patterns at different speeds to simulate the subject walking without impairment. The passive moment of the knee played an important role in the estimation of muscle force with knee hyperextension, which was decreased during FES and knee extensor strengthening. Weakening the knee extensors and strengthening the flexors improved SKG. During FES, weak ankle plantarflexors and strong ankle dorsiflexors resulted in increased ankle dorsiflexion, which reduced drop foot. FES also improved gait speed and reduced circumduction. These findings provide insight into compensatory strategies adopted by post-stroke patients that can guide the design of individualized rehabilitation and treatment programs.

Neurologic Conditions Associated with Cavus Foot Deformity

The cavus foot deformity is an often less understood deformity within the spectrum of foot and ankle conditions. The hallmark concern is the possibility of an underlying neurologic or neuromuscular disorder. Although a proportion of these deformities are idiopathic, a significant majority do correlate with an underlying disorder. The appropriate evaluation of this deformity, in coordination within the multidisciplinary scope of health care, allows for a timely diagnosis and understanding of the patient's condition. We provide an abbreviated survey of possible underlying etiologies for the patient with the cavus foot deformity as a reference to the foot and ankle surgeon.

Effect of robotic-assisted gait training on objective biomechanical measures of gait in persons post-stroke: a systematic review and meta-analysis

BACKGROUND

Robotic-Assisted Gait Training (RAGT) may enable high-intensive and task-specific gait training post-stroke. The effect of RAGT on gait movement patterns has however not been comprehensively reviewed. The purpose of this review was to summarize the evidence for potentially superior effects of RAGT on biomechanical measures of gait post-stroke when compared with non-robotic gait training alone.

METHODS

Nine databases were searched using database-specific search terms from their inception until January 2021. We included randomized controlled trials investigating the effects of RAGT (e.g., using exoskeletons or end-effectors) on spatiotemporal, kinematic and kinetic parameters among adults suffering from any stage of stroke. Screening, data extraction and judgement of risk of bias (using the Cochrane Risk of bias 2 tool) were performed by 2-3 independent reviewers. The Grading of Recommendations Assessment Development and Evaluation (GRADE) criteria were used to evaluate the certainty of evidence for the biomechanical gait measures of interest.

RESULTS

Thirteen studies including a total of 412 individuals (mean age: 52-69 years; 264 males) met eligibility criteria and were included. RAGT was employed either as monotherapy or in combination with other therapies in a subacute or chronic phase post-stroke. The included studies showed a high risk of bias (n = 6), some concerns (n = 6) or a low risk of bias (n = 1). Meta-analyses using a random-effects model for gait speed, cadence, step length (non-affected side) and spatial asymmetry revealed no significant differences between the RAGT and comparator groups, while stride length (mean difference [MD] 2.86 cm), step length (affected side; MD 2.67 cm) and temporal asymmetry calculated in ratio-values (MD 0.09) improved slightly more in the RAGT groups. There were serious weaknesses with almost all GRADE domains (risk of bias, consistency, directness, or precision of the findings) for the included outcome measures (spatiotemporal and kinematic gait parameters). Kinetic parameters were not reported at all.

CONCLUSION

There were few relevant studies and the review synthesis revealed a very low certainty in current evidence for employing RAGT to improve gait biomechanics post-stroke. Further high-quality, robust clinical trials on RAGT that complement clinical data with biomechanical data are thus warranted to disentangle the potential effects of such interventions on gait biomechanics post-stroke.

Ankle and Foot Spasticity Patterns in Chronic Stroke Survivors with Abnormal Gait

Chronic stroke survivors with spastic hemiplegia have various clinical presentations of ankle and foot muscle spasticity patterns. They are mechanical consequences of interactions between spasticity and weakness of surrounding muscles during walking. Four common ankle and foot spasticity patterns are described and discussed through sample cases. The patterns discussed are equinus, varus, equinovarus, and striatal toe deformities. Spasticity of the primary muscle(s) for each deformity is identified. However, it is emphasized that clinical presentation depends on the severity of spasticity and weakness of these muscles and their interactions. Careful and thorough clinical assessment of the ankle and foot deformities is needed to determine the primary cause of each deformity. An understanding of common ankle and foot spasticity patterns can help guide clinical assessment and selection of target spastic muscles for botulinum toxin injection or nerve block.

Can an Observational Gait Scale Produce a Result Consistent with Symmetry Indexes Obtained from 3-Dimensional Gait Analysis?: A Concurrent Validity Study

To investigate whether a simple observational tool may be a substitute to the time-consuming and costly 3-dimensional (3D) analysis, the study applied the Wisconsin Gait Scale (WGS), enabling assessment which is highly consistent with 3D gait parameters in patients after a stroke. The aim of this study was to determine whether, and to what extent, observational information obtained from WGS-based assessment can be applied to predict results of 3D gait analysis for selected symmetry indicators related to spatiotemporal and kinematic gait parameters. Fifty patients at a chronic stage of recovery post-stroke were enrolled in the study. The spatiotemporal and kinematic gait parameters were measured using a movement analysis system. The symmetry index (SI), was calculated for selected gait parameters. The patients’ gait was evaluated by means of the WGS. It was shown that stance % SI, as well as hip and knee flexion-extension range of motion SI can most effectively be substituted by WGS-based estimations (coefficient of determination exceeding 80%). It was shown that information acquired based on the WGS can be used to obtain results comparable to those achieved in 3D assessment for selected SIs of spatiotemporal and kinematic gait parameters. The study confirms that observation of gait using the WGS, which is an ordinal scale, is consistent with the selected aims of 3D assessment. Therefore, the scale can be used as a complementary tool in gait assessment.

Perturbation-Induced Stepping Post-stroke: A Pilot Study Demonstrating Altered Strategies of Both Legs

Introduction: Asymmetrical sensorimotor function after stroke creates unique challenges for bipedal tasks such as walking or perturbation-induced reactive stepping. Preference for initiating steps with the less-involved (preferred) leg after a perturbation has been reported with limited information on the stepping response of the more-involved (non-preferred) leg. Understanding the capacity of both legs to respond to a perturbation would enhance the design of future treatment approaches. This pilot study investigated the difference in perturbation-induced stepping between legs in stroke participant and non-impaired controls. We hypothesized that stepping performance will be different between groups as well as between legs for post-stroke participants.

Methods: Thirty-six participants (20 persons post-stroke, 16 age matched controls) were given an anterior perturbation from three stance positions: symmetrical (SS), preferred asymmetrical (PAS−70% body weight on the preferred leg), and non-preferred asymmetrical (N-PAS−70% body weight on the non-preferred leg). Kinematic and kinetic data were collected to measure anticipatory postural adjustment (APA), characteristics of the first step (onset, length, height, duration), number of steps, and velocity of the body at heel strike. Group differences were tested using the Mann-Whitney U-test and differences between legs tested using the Wilcoxon signed-rank test with an alpha level of 0.05.

Results: Stepping with the more-involved leg increased from 11.5% of trials in SS and N-PAS up to 46% in PAS stance position for participants post-stroke. Post-stroke participants had an earlier APA and always took more steps than controls to regain balance. However, differences between post-stroke and control participants were mainly found when stance position was modified. Compare to controls, steps with the preferred leg (N-PAS) were earlier and shorter (in time and length), whereas steps with the non-preferred leg (PAS) were also shorter but took longer. For post-stroke participants, step duration was longer and utilized more steps when stepping with the more-involved leg compared to the less-involved leg.

Conclusions: Stepping with the more-involved leg can be facilitated by unweighting the leg. The differences between groups, and legs in post-stroke participants illustrate the simultaneous bipedal role (support and stepping) both legs have in reactive stepping and should be considered for reactive balance training.

Anticipatory Postural Adjustments During Gait Initiation in Stroke Patients

Prior to gait initiation (GI), anticipatory postural adjustments (GI-APA) are activated in order to reorganize posture, favorably for gait. In healthy subjects, the center of pressure (CoP) is displaced backward during GI-APA, bilaterally by reducing soleus activities and activating the tibialis anterior (TA) muscles, and laterally in the direction of the leading leg, by activating hip abductors. In post-stroke hemiparetic patients, TA, soleus and hip abductor activities are impaired on the paretic side. Reduction in non-affected triceps surae activity can also be observed. These may result in a decreased ability to execute GI-APA and to generate propulsion forces during step execution. A systematic review was conducted to provide an overview of the reorganization which occurs in GI-APA following stroke as well as of the most effective strategies for tailoring gait-rehabilitation to these patients. Sixteen articles were included, providing gait data from a total of 220 patients. Stroke patients show a decrease in the TA activity associated with difficulties in silencing soleus muscle activity of the paretic leg, a decreased CoP shift, lower propulsive anterior forces and a longer preparatory phase. Regarding possible gait-rehabilitation strategies, the selected studies show that initiating gait with the paretic leg provides poor balance. The use of the non-paretic as the leading leg can be a useful exercise to stimulate the paretic postural muscles.

Gait initiation and partial body weight unloading for functional improvement in post-stroke individuals

BACKGROUND

To better understand gait initiation in individuals with stroke and suggest possible training strategies, we compared the gait initiation of individuals with stroke and age-matched controls, and we examined the influence of different amounts of body weight support (BWS) during the execution of gait initiation in individuals with stroke.

MATERIALS AND METHODS

Twelve individuals with stroke and 12 age-matched controls initiated gait after a verbal command at a self-selected and comfortable speed, and individuals with stroke also initiated gait wearing a harness with 0%, 15%, and 30% of BWS. Length and velocity of the first step, distance between heels, and weight bearing in both lower limbs in the initial position were calculated. We also assessed the displacement and average velocity of the center of pressure (CoP) in the medial-lateral (ML) and anterior-posterior (AP) directions in 3 distinct sections during gait initiation, which correspond to the CoP position toward the swing limb, stance limb and progression line, respectively.

RESULTS

Individuals with stroke presented shorter and slower step, shorter and slower CoP-ML and CoP-AP toward swing limb and Cop-ML towards stance limb, and longer and faster CoP-AP toward stance limb compared to their peers. The BWS lead individuals with stroke to decrease step length and to increase CoP-ML displacement and average velocity toward stance limb.

CONCLUSION

Individuals with stroke present impairments in executing gait initiation mainly during the preparation period and the employment of an overground BWS system promotes a better performance. These results suggest that BWS is a functional strategy that enables individuals with stroke to modulate gait initiation and it could be adopted for gait intervention.

Progressive intervention strategy for the gait of sub-acute stroke patient using the International Classification of Functioning, Disability, and Health tool

BACKGROUND

The International Classification of Functioning, Disability, and Health (ICF) provides models for functions and disabilities. The ICF is presented as a frame that enables organizing physical therapists' clinical practice for application.

OBJECTIVE

The purpose of the present study was to describe processes through which stroke patients are assessed and treated based on the ICF model.

METHODS

The patient was a 65-year-old female diagnosed with right cerebral artery infarction with left hemiparesis. Progressive interventions were applied, such as those aiming at sitting and standing for the first two weeks, gait intervention for the third and fourth weeks, and those aiming at sitting from a standing position for the fifth and sixth weeks.

RESULTS

The ICF model provides rehabilitation experts with a frame that enables them to accurately identify and understand their patients' problems. The ICF model helps the experts understand not only their patients' body structure, function, activity, and participation, but also their problems related to personal and environmental factors.

CONCLUSIONS

The experts could efficiently make decisions and provide optimum treatment at clinics using the ICF model.

Effect of ankle foot orthosis on gait parameters and functional ambulation in patients with stroke

Objectives

This study aims to investigate the effect of ankle foot orthosis (AFO) on temporospatial parameters, ankle kinematics, and functional ambulation level in patients with stroke.

Patients and methods

Records of 286 adult patients with stroke assessed in the gait and motion analysis laboratory between April 2005 and January 2013 were reviewed. The data of 28 patients (16 males, 12 females; mean age 43.2±15.9 years; range 20 to 72 years) who were analyzed with and without AFO during the same session were selected for the study. Temporospatial parameters (walking speed, cadence, opposite foot contact, double support time, single support time, step time, and step length) and ankle kinematics (ankle dorsiflexion at initial contact and midswing) were measured using the Vicon 512 motion analysis system. The video and medical records of patients were examined to determine their ambulation level according to Functional Ambulation Category.

Results

Walking speed, cadence, and ankle dorsiflexion at initial contact and midswing were significantly increased while walking with AFO compared to walking barefoot (p<0.05). There were significant reduction in step time and significant increase in step length and opposite foot contact with AFO on the affected side (p<0.05). Single support time reduced significantly with AFO on the unaffected side (p<0.05). Functional Ambulation Category score improved significantly with use of AFO (p<0.05).

Conclusion

The use of AFO has positive effects on gait parameters and functional ambulation in patients with stroke.

Ultrasonic Measurement of Dynamic Muscle Behavior for Poststroke Hemiparetic Gait

Quantitative evaluation of the hemiparesis status for a poststroke patient is still challenging. This study aims to measure and investigate the dynamic muscle behavior in poststroke hemiparetic gait using ultrasonography. Twelve hemiparetic patients walked on a treadmill, and EMG, joint angle, and ultrasonography were simultaneously recorded for the gastrocnemius medialis muscle. Pennation angle was automatically extracted from ultrasonography using a tracking algorithm reported previously. The characteristics of EMG, joint angle, and pennation angle in gait cycle were calculated for both (affected and unaffected) sides of lower limbs. The results suggest that pennation angle could work as an important morphological index to continuous muscle contraction. The change pattern of pennation angle between the affected and unaffected sides is different from that of EMG. These findings indicate that morphological parameter extracted from ultrasonography can provide different information from that provided by EMG for hemiparetic gait.

Views of physiatrists and physical therapists on the use of gait-training robots for stroke patients

[Purpose] Gait-training robots have been developed for stroke patients with gait disturbance. It is important to survey the views of physiatrists and physical therapists on the characteristics of these devices during their development. [Subjects and Methods] A total of 100 physiatrists and 100 physical therapists from 38 hospitals participated in our questionnaire survey. [Results] The most common answers about the merits of gait-training robots concern improving the treatment effects (28.5%), followed by standardizing treatment (19%), motivating patients about treatment (17%), and improving patients' self-esteem (14%). The subacute period (1-3 months post-stroke onset) was most often chosen as the ideal period (47.3%) for the use of these devices, and a functional ambulation classification of 0-2 was the most selected response for the optimal patient status (27%). The preferred model was the treadmill type (47.5%) over the overground walking type (40%). The most favored commercial price was $50,000-$100,000 (38.3%). The most selected optimal duration for robot-assisted gait therapy was 30-45 min (47%), followed by 15-30 min (29%), 45-60 min (18%), ≥ 60 min (5%), and < 15 min (1%). [Conclusion] Our study findings could guide the future designs of more effective gait-training robots for stroke patients.

Effects of a multichannel dynamic functional electrical stimulation system on hemiplegic gait and muscle forces

[Purpose] The purpose of the study was to design and implement a multichannel dynamic functional electrical stimulation system and investigate acute effects of functional electrical stimulation of the tibialis anterior and rectus femoris on ankle and knee sagittal-plane kinematics and related muscle forces of hemiplegic gait. [Subjects and Methods] A multichannel dynamic electrical stimulation system was developed with 8-channel low frequency current generators. Eight male hemiplegic patients were trained for 4 weeks with electric stimulation of the tibia anterior and rectus femoris muscles during walking, which was coupled with active contraction. Kinematic data were collected, and muscle forces of the tibialis anterior and rectus femoris of the affected limbs were analyzed using a musculoskelatal modeling approach before and after training. A paired sample t-test was used to detect the differences between before and after training. [Results] The step length of the affected limb significantly increased after the stimulation was applied. The maximum dorsiflexion angle and maximum knee flexion angle of the affected limb were both increased significantly during stimulation. The maximum muscle forces of both the tibia anterior and rectus femoris increased significantly during stimulation compared with before functional electrical stimulation was applied. [Conclusion] This study established a functional electrical stimulation strategy based on hemiplegic gait analysis and musculoskeletal modeling. The multichannel functional electrical stimulation system successfully corrected foot drop and altered circumduction hemiplegic gait pattern.

Ankle anticipatory postural adjustments during gait initiation in healthy and post-stroke subjects

BACKGROUND

Anticipatory postural adjustments during gait initiation have an important role in postural stability but also in gait performance. However, these first phase mechanisms of gait initiation have received little attention, particularly in subcortical post-stroke subjects, where bilateral postural control pathways can be impaired. This study aims to evaluate ankle anticipatory postural adjustments during gait initiation in chronic post-stroke subjects with lesion in the territory of middle cerebral artery.

METHODS

Eleven subjects with post-stroke hemiparesis with the ability to walk independently and twelve healthy controls participated in this study. Bilateral electromyographic activity of tibialis anterior, soleus and medial gastrocnemius was collected during gait initiation to assess the muscle onset timing, period of activation/deactivation and magnitude of muscle activity during postural phase of gait initiation. This phase was identified through centre of pressure signal.

FINDINGS

Post-stroke group presented only half of the tibialis anterior relative magnitude observed in healthy subjects in contralesional limb (t=2.38, P=0.027) and decreased soleus deactivation period (contralesional limb, t=2.25, P=0.04; ipsilesional limb, t=3.67, P=0.003) as well its onset timing (contralesional limb, t=3.2. P=0.005; ipsilesional limb, t=2.88, P=0.033) in both limbs. A decreased centre of pressure displacement backward (t=3.45, P=0.002) and toward the first swing limb (t=3.29, P=0.004) was observed in post-stroke subjects.

INTERPRETATION

These findings indicate that chronic post-stroke subjects with lesion at middle cerebral artery territory present dysfunction in ankle anticipatory postural adjustments in both limbs during gait initiation.

Interrater and intrarater reliability and minimal detectable change of the Wisconsin Gait Scale when used to examine videotaped gait in individuals post-stroke

Background

Often, interventions targeting the kinematic and temporal and spatial changes in gait commonly seen after a stroke are based on observations of walking. Having the capacity to objectively identify such changes and track improvements over time using reliable and valid measures is important. The Wisconsin Gait Scale (WGS), which is comprised of 14 items, was developed specifically to examine and document gait changes occurring after a stroke. The purpose of the study was to explore the interrater and intrarater reliability and minimal detectable change (MDC) of the WGS when used by physical therapists to examine gait in adults post-stroke.

Methods

Fourteen physical therapists from 3 different acute inpatient rehabilitation centers rated videotapes of the gait of 6 adults post-stroke using the WGS. To minimize subject variability from fatigue, videotapes created by using 4 cameras provided right and left lateral, anterior, and posterior views of walking on a level surface. One complete ambulation trial from each subject post-stroke, which included 4 views of the same ambulation trial, was examined by the licensed physical therapists using the WGS. An opportunity was provided to review the tool and a practice trial was performed using an additional videotape not included in the analysis. Gait was examined on 2 different occasions separated by a period of approximately 21 days to minimize the effects of recall bias. Intraclass Correlation Coefficients (ICC) were used to examine the interrater and intrarater reliability of the WGS.

Results

Interrater (ICC = 0.83) and intrarater (ICC = 0.91) reliability were both good. The standard error of the measurement (SEM) was 1.47 and the MDC₉₅ was 4.24. There was no statistically significant difference between the scores on the WGS when comparing the 2 different sessions.

Conclusions

The WGS shows promise as an instrument that can make observational gait analysis more reliable. High intrarater reliability and low SEM suggests that the WGS is stable when administered across multiple sessions by the same rater. The ICC for interrater reliability was also good, which suggests that multiple examiners can effectively use the instrument. With minimal training, the physical therapists in the study were able to produce highly reliable results using the WGS to objectively document gait dysfunction.

Stance limb ground reaction forces in high functioning stroke and healthy subjects during gait initiation

BACKGROUND

Following stroke, little is known about ground reaction forces during gait initiation.

OBJECTIVE

To compare stroke patients' with healthy subjects' anterior, medial, and lateral ground reaction forces generated during gait initiation.

METHODS

Patients with left paresis, right paresis, and age-similar healthy subjects were recruited. During gait initiation the average peak anterior, medial, and lateral ground reaction forces acting on each lower limb were calculated when it was the stance limb.

FINDINGS

Anterior ground reaction forces acting on the right and left stance limbs of healthy subjects were greater than anterior forces acting on the nonparetic and paretic limbs of stroke patients. Medial ground reaction forces for the nonparetic and paretic limbs of stroke patients and for the right and left stance limbs of healthy subjects were equivalent. While lateral ground reaction forces acting on the nonparetic and paretic limbs were equivalent for left paretic patients, for right paretic patients lateral forces acting on the nonparetic limb were greater compared to the paretic limb and also greater compared to the left limb of healthy subjects.

INTERPRETATION

An effect of side-of-lesion was revealed in average peak lateral ground reaction force data. Larger lateral ground reaction forces acting on the left nonparetic stance limb of right paretic patients compared to the right nonparetic stance limb of left paretic patients during gait initiation may be an indication of differing adaptations that depend on the side-of-lesion.

The influence of accuracy constraints on EMG and kinetic variables during gait initiation

[Purpose] This study investigated the effects of accuracy constraints (targets) placed on the stepping-limb heel-strike (HS) on the electromyogram (EMG) and ground reaction forces (GRFs) during gait initiation. [Subjects and Methods] Twenty healthy subjects (29.2 ± 2.9 years) were asked to begin walking or stepping over a 10-cm-high obstacle at a fast speed. A 3-cm-diameter target was placed on the ground to dictate the position and accuracy of the stepping-limb HS. [Results] The results showed that the initiation velocity increase in the no-target conditions was due to modulation of the stance- and stepping-limb GRFs and a corresponding increase in the tibialis anterior (TA) activities of both limbs before stepping-limb toe-off. This was achieved by significantly increasing the stepping- and stance-limb TAEMG1 (determined between the onset of movement and time to peak anteroposterior (A-P) GRF of the stepping- and stance- limb) for the no-target conditions. It seems, therefore, that TAEMG1 and the slope to stepping-limb peak A-P GRF contributed to the intended velocity of initiation. [Conclusion] These data indicate that gait initiation and/or stepping over an obstacle may prove to be tasks by which motor control can be measured. The present study provides insight into the working mechanisms of the stepping and stance limbs and shows a clear need to further investigate whether the intact or affected limb should be used to initiate gait during rehabilitation and prosthetic training.

The effects of gait velocity on the gait characteristics of hemiplegic patients

[Purpose] The present study investigated the effects of gait speed on temporal and spatial gait characteristics of hemiplegic stroke patients. [Subjects and Methods] Twenty post-stroke hemiplegic patients participated in the present study. To enhance the reliability of the analysis of the gait characteristics, the assessments were conducted three days per week at the same time every day. Each subject walked maintaining a comfortable speed for the first minute, and measurement was conducted for 30 seconds at a treadmill speed of 1 km/hour thereafter. Then, the subjects walked at a treadmill speed of 2 km/hour for 30 seconds after a 30-minute rest. The differences in the measurements were tested for significance using the paired t-test. [Results] The measures of foot rotation, step width, load response, mid stance, pre-swing, swing phase, and double stance phase showed significant difference between the gait velocities. [Conclusion] The present study provides basic data for gait velocity changes for hemiplegic patients.

Effect of Task Specific Exercises, Gait Training, and Visual Biofeedback on Equinovarus Gait among Individuals with Stroke: Randomized Controlled Study

Background and Purpose. Equinovarus foot is a common sign after stroke. The aim of this study is to investigate the effect of task specific exercises, gait training, and visual biofeedback on correcting equinovarus gait among individuals with stroke. Subjects and Methods. Sixteen subjects with ischemic stroke were randomly assigned to two equal groups (G1 and G2). All the patients were at stage 4 of motor recovery of foot according to Chedoke-McMaster Stroke Assessment without any cognitive dysfunction. E-med pedography was used to measure contact time, as well as force underneath hind and forefoot during walking. Outcome measures were collected before randomization, one week after the last session, and four weeks later. Participants in G1 received task specific exercises, gait training, and visual biofeedback and a traditional physical therapy program was applied for participants in G2 for 8 weeks. Results. Significant improvement was observed among G1 patients (P ≤ 0.05) which lasts one month after therapy termination. On the other hand, there were no significant differences between measurements of the participants in G2. Between groups comparison also revealed a significant improvement in G1 with long lasting effect. Conclusion. The results of this study showed a positive long lasting effect of the task specific exercises, gait training, and visual biofeedback on equinovarus gait pattern among individuals with stroke.

Gait disturbances in patients with stroke

Poststroke hemiplegic gait is a mixture of deviations and compensatory motion dictated by residual functions, and thus each patient must be examined and his/her unique gait pattern identified and documented. Quantitative 3-dimensional gait analysis is the best way to understand the complex multifactorial gait dysfunction in hemiparetic patients. The goals of the present work are to (1) review the temporospatial, kinematic, kinetic, and electromyographic deviations from normal gait that commonly occur after stroke and are of clinical significance, along with the most likely causes of these deviations, and (2) differentiate the departures from normal gait parameters that arise as a direct consequence of poststroke motor problems and those that arise as learned or adaptive compensations for poststroke motor problems.

Acting in perspective: the role of body and language as social tools

We investigated how the reach-to-grasp movement is influenced by the presence of another person (friend or non-friend), who was either invisible (behind) or located in different positions with respect to an object and to the agent, and by the perspective conveyed by linguistic pronouns ("I", "You"). The interaction between social relationship and relative position influenced the latency of both maximal fingers aperture and velocity peak, showing shorter latencies in the presence of a non-friend than in the presence of a friend. However, whereas the relative position of a non-friend did not affect the kinematics of the movement, the position of a friend mattered: latencies were significantly shorter with friends only in positions allowing them to easily reach for the object. Finally, the investigation of the overall reaching movement time showed an interaction between the speaker and the pronoun: participants reached the object more quickly when the other spoke, particularly if she used the "I" pronoun. This suggests that speaking, and particularly using the "I" pronoun, evokes a potential action. Implications of the results for embodied cognition are discussed.

Inter-limb centre of pressure symmetry during gait among stroke survivors

The purpose of the present study was to describe the spatial-temporal parameters of the centre of pressure (COP) trajectory during the single-support phase of gait among stroke survivors and relate these parameters to the severity of sensorimotor impairment. Fifty-seven participants were asked to walk at their preferred and fast speed over a pressure sensitive mat. Outcome measures included anterior-posterior (AP) COP displacement, AP-COP velocity, medial-lateral (ML) COP variability and foot region COP time. The results demonstrated an asymmetrical AP-COP displacement in favour of the non-paretic limb for the majority of participants. The inter-limb difference scores for AP-COP displacement and AP-COP velocity were related to the severity of sensorimotor impairment and greater among gait aid users. ML-COP variability was greater under the non-paretic limb, possibly suggesting difficulty with paretic limb swing phase. Reduced or absent forefoot COP time suggests difficulty with forward progression and modified foot function during push-off. The inter-limb difference in COP parameters highlights the asymmetrical nature of post-stroke gait and the challenge of maintaining single limb support. We view this information as potentially important to clinicians as an outcome measure for gait rehabilitation.

Involvement of the corticospinal tract in the control of human gait

Given the inherent mechanical complexity of human bipedal locomotion, and that complete spinal cord lesions in human leads to paralysis with no recovery of gait, it is often suggested that the corticospinal tract (CST) has a more predominant role in the control of walking in humans than in other animals. However, what do we actually know about the contribution of the CST to the control of gait? This chapter will provide an overview of this topic based on the premise that a better understanding of the role of the CST in gait will be essential for the design of evidence-based approaches to rehabilitation therapy, which will enhance gait ability and recovery in patients with lesions to the central nervous system (CNS). We review evidence for the involvement of the primary motor cortex and the CST during normal and perturbed walking and during gait adaptation. We will also discuss knowledge on the CST that has been gained from studies involving CNS lesions, with a particular focus on recent data acquired in people with spinal cord injury.

Impaired transmission in the corticospinal tract and gait disability in spinal cord injured persons

Rehabilitation following spinal cord injury is likely to depend on recovery of corticospinal systems. Here we investigate whether transmission in the corticospinal tract may explain foot drop (inability to dorsiflex ankle) in persons with spinal cord lesion. The study was performed in 24 persons with incomplete spinal cord lesion (C1 to L1) and 15 healthy controls. Coherence in the 10- to 20-Hz frequency band between paired tibialis anterior muscle (TA) electromyographic recordings obtained in the swing phase of walking, which was taken as a measure of motor unit synchronization. It was significantly correlated with the degree of foot drop, as measured by toe elevation and ankle angle excursion in the first part of swing. Transcranial magnetic stimulation was used to elicit motor-evoked potentials (MEPs) in the TA. The amplitude of the MEPs at rest and their latency during contraction were correlated to the degree of foot drop. Spinal cord injured participants who exhibited a large foot drop had little or no MEP at rest in the TA muscle and had little or no coherence in the same muscle during walking. Gait speed was correlated to foot drop, and was the lowest in participants with no MEP at rest. The data confirm that transmission in the corticospinal tract is of importance for lifting the foot during the swing phase of human gait.

Effects of unilateral robotic limb loading on gait characteristics in subjects with chronic stroke

Background

Hemiparesis after stroke often leads to impaired ankle motor control that impacts gait function. In recent studies, robotic devices have been developed to address this impairment. While capable of imparting forces to assist during training and gait, these devices add mass to the paretic leg which might encumber patients' gait pattern. The purpose of this study was to assess the effects of the added mass of one of these robots, the MIT's Anklebot, while unpowered, on gait of chronic stroke survivors during overground and treadmill walking.

Methods

Nine chronic stroke survivors walked overground and on a treadmill with and without the anklebot mounted on the paretic leg. Gait parameters, interlimb symmetry, and joint kinematics were collected for the four conditions. Repeated-measures analysis of variance (ANOVA) tests were conducted to examine for possible differences across four conditions for the paretic and nonparetic leg.

Results

The added inertia and friction of the unpowered anklebot had no statistically significant effect on spatio-temporal parameters of gait, including paretic and nonparetic step time and stance percentage, in both overground and treadmill conditions. Noteworthy, interlimb symmetry as characterized by relative stance duration was greater on the treadmill than overground regardless of loading conditions. The presence of the unpowered robot loading reduced the nonparetic knee peak flexion on the treadmill and paretic peak dorsiflexion overground (p < 0.05).

Conclusions

Our results suggest that for these subjects the added inertia and friction of this backdriveable robot did not significantly alter their gait pattern.

Control of mediolateral stability during rapid step initiation with preferred and non-preferred leg: is it symmetrical?

During voluntary stepping initiation, postural stability along the mediolateral direction is controlled via "anticipatory postural adjustment" (APA). This study tested the hypothesis that, in young healthy subjects, the biomechanical features of mediolateral APA depend on the leg that initiates stepping. Subjects (N=10) initiated a rapid single step with the preferred (P condition) and the non-preferred leg (NP condition) on a force-plate. Results showed that mediolateral APA duration (P=0.020) and amplitude were higher (as attested by the increase in maximal center-of-gravity velocity (P=0.003) and displacement (P<0.001) during APA), and that mediolateral stability was better (as attested by the attenuation in center-of-gravity velocity at time of swing-foot contact (P=0.007)) in P than in NP. These results support the view that stepping initiation in healthy subjects involves postural asymmetry. This statement may have relevant implications in clinical evaluation where postural asymmetry is generally considered as reflecting postural impairment.

Effects of virtual reality training on gait biomechanics of individuals post-stroke

OBJECTIVE

To evaluate gait biomechanics after training with a virtual reality (VR) system and to elucidate underlying mechanisms that contributed to the observed functional improvement in gait speed and distance.

DESIGN

A single blind randomized control study.

SETTING

Gait analysis laboratory in a rehabilitation hospital and the community.

PARTICIPANTS

Fifteen men and three women with hemiparesis caused by stroke.

INTERVENTIONS

Subjects trained on a six-degree of freedom force-feedback robot interfaced with a VR simulation. Subjects were randomized to either a VR group (n=9) or non-VR group (NVR, n=9). Training was performed three times a week for 4 weeks for approximately 1h each visit.

MAIN OUTCOME MEASURES

Kinematic and kinetic gait parameters.

RESULTS

Subjects in the VR group demonstrated a significantly larger increase in ankle power generation at push-off as a result of training (p=0.036). The VR group had greater change in ankle ROM post-training (19.5%) as compared to the NVR group (3.3%). Significant differences were found in knee ROM on the affected side during stance and swing, with greater change in the VR group. No significant changes were observed in kinematics or kinetics of the hip post-training.

CONCLUSIONS

These findings are encouraging because they support the potential for recovery of force and power of the lower extremity for individuals with chronic hemiparesis. It is likely that the effects of training included improved motor control at the ankle, which enabled the cascade of changes that produced the functional improvements seen after training.

Changes in postural control in hemiplegic patients after stroke performing a dual task

OBJECTIVE

To determine the effects of an attentional task on hemiplegic patients' postural control performances.

DESIGN

Retrospective study.

SETTING

Department of physical and rehabilitation medicine at a university hospital.

PARTICIPANTS

Twenty-three hemiplegic patients and 23 healthy age- and sex-matched control subjects.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Sway area and sway path of the center of pressure were measured during 30 seconds in standing subjects and patients under 3 conditions: eyes open (EO), EO while performing a simple arithmetic task (EO-AT), and eyes closed (EC).

RESULTS

In the hemiplegic patients, the body sway area increased significantly with EC (P<.001) and during the EO-AT task (P<.017) in comparison with EO. Sway area with EO-AT remained, however, significantly smaller than with EC (P<.014). In the healthy subjects, the body sway did not differ significantly between the EO-AT and EO tasks (P<.42). The increase observed in the sway area and path in the hemiplegic population during the EO-AT task correlated significantly with age.

CONCLUSIONS

The postural performances of hemiplegic patients decreased during both the arithmetic task and the EC task. The cognitive task had no effect on healthy subjects' postural performances. This study is the first to show the combined effects of age and dual task on the postural performances of hemiplegic subjects.