Foot placement in a body reference frame during walking and its relationship to hemiparetic walking performance (original) (raw)
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Gait & Posture, 2011
Post-stroke hemiparetic subjects walk with asymmetrical step lengths that are highly variable between subjects and may be indicative of the underlying impairments and compensatory mechanisms used. The goal of this study was to determine if post-stroke hemiparetic subjects grouped by step length asymmetry have similar abnormal walking biomechanics compared to nonimpaired walkers. Kinematic and ground reaction force data were recorded from 55 hemiparetic subjects walking at their self-selected speed and 21 age and speed-matched non-impaired control subjects. Hemiparetic subjects were grouped by paretic step ratio, which was calculated as the paretic step-length divided by the sum of paretic and nonparetic step-lengths, into high (>0.535), symmetric (0.535-0.465) and low (<0.465) groups. Non-parametric Wilcoxin signed-rank tests were used to test for differences in joint kinetic measures between hemiparetic groups and speedmatched control subjects during late single-leg stance and pre-swing. The paretic leg ankle moment impulse was reduced in all hemiparetic subjects regardless of their paretic step ratio. The high group had increased nonparetic leg ankle plantarflexor and knee extensor moment impulses, the symmetric group had increased hip flexor moment impulses on both the paretic and nonparetic leg and the low group had no additional significant differences in joint moment impulses. These results suggest that the direction of asymmetry can be used to identify both the degree of paretic plantarflexor impairment and the compensatory mechanisms used by post-stroke hemiparetic subjects.
Archives of Physical Medicine and Rehabilitation, 2007
Objective: To understand the relationship between step length asymmetry and hemiparetic walking performance. Design: Descriptive. Setting: Gait analysis laboratory. Participants: Convenience sample of 49 subjects with chronic hemiparesis. Interventions: Not applicable. Main Outcome Measures: Subjects walked at their selfselected walking speed over both an instrumented mat and forceplates to collect spatiotemporal parameters and ground reaction forces, respectively. Step length asymmetry was quantified by using a step length ratio (SLR) defined as paretic step length divided by nonparetic step length. Paretic leg propulsion, selfselected walking speed, hemiparetic severity (assessed by Brunnstrom stages of motor recovery), and some spatiotemporal walking parameters quantified the hemiparetic walking performance. Paretic leg propulsion was quantified by the paretic propulsion (P P) ratio, calculated as the percentage contribution of paretic leg to the total propulsive impulse. Results: Significant negative correlation (rϭϪ.78) was revealed between SLR and P P , indicating that subjects generating less propulsive force with the paretic leg walked asymmetrically with longer paretic steps than nonparetic steps. SLR and self-selected walking speed revealed a weaker correlation (rϭϪ.35), whereas hemiparetic severity correlated strongly with SLR (ϭϪ.53). Conclusions: Step length asymmetry is related to propulsive force generation during hemiparetic walking. Subjects generating least paretic propulsion walk with relatively longer paretic steps. This suggests that one of the mechanisms for the longer paretic step may be the relatively greater compensatory nonparetic leg propulsion. Further, those with more severe hemiparesis (those dependent on abnormal flexor and extensor synergies) walk with the longest paretic steps relative to non-paretic. Finally, our results indicated that asymmetrical step lengths may not necessarily limit the self-selected walking speed, likely due to other compensatory mechanisms.
Journal of NeuroEngineering and Rehabilitation
Background: The effects of a stroke, such as hemiparesis, can severely hamper the ability to walk and to maintain balance during gait. Providing support to stroke survivors through a robotic exoskeleton, either to provide training or daily-life support, requires an understanding of the balance impairments that result from a stroke. Here, we investigate the differences between the paretic and non-paretic leg in making recovery steps to restore balance following a disturbance during walking. Methods: We perturbed 10 chronic-stage stroke survivors during walking using mediolateral perturbations of various amplitudes. Kinematic data as well as gluteus medius muscle activity levels during the first recovery step were recorded and analyzed. Results: The results show that this group of subjects is able to modulate foot placement in response to the perturbations regardless of the leg being paretic or not. Modulation in gluteus medius activity with the various perturbations is in line with this observation. In general, the foot of the paretic leg was laterally placed further away from the center of mass than that of the non-paretic leg, while subjects spent more time standing on the non-paretic leg. Conclusions: The findings suggest that, though stroke-related gait characteristics are present, the modulation with the various perturbations remains unaffected. This might be because all subjects were only mildly impaired, or because these stepping responses partly occur through involuntary pathways which remain unaffected by the complications after the stroke.
Neurorehabilitation and Neural Repair, 2011
Background. In hemiplegic gait, step length typically differs in magnitude between paretic and nonparetic sides. However, the direction of step-length asymmetry varies across stroke patients. Objective. The study sought to understand directional variations in step-length asymmetry in terms of asymmetries in forward foot placement relative to the trunk and trunk progression. Methods. A total of 10 hemiplegic stroke patients and 9 healthy elderly controls walked at a self-selected comfortable speed while pelvic and heel marker positions were recorded.
Direction of gait asymmetry following stroke determines acute response to locomotor task
BackgroundGiven the prevalence of gait dysfunction following stroke, walking recovery is a primary goal of rehabilitation. However, current gait rehabilitation approaches fail to demonstrate consistent benefits. Furthermore, asymmetry is a prominent feature of gait dysfunction following stroke. Differential patterns of gait asymmetry may respond differently to gait training parameters.ObjectiveThe purpose of this study was to determine whether differential responses to locomotor task condition occur on the basis of direction of step length asymmetry (Symmetrical, NPshort, Pshort) observed during overground walking.MethodsParticipants first walked overground at their self-selected walking speed. Overground data were compared against three task conditions all tested during treadmill walking: self-selected speed with 0% body weight support (TM); self-selected speed with 30% body weight support (BWS); and fastest comfortable speed with 30% body weight support and nonparetic leg guidance...
Neurorehabilitation and Neural Repair, 2008
Background. In hemiparetic individuals, sit-to-stand (STS) transfer is characterized by asymmetric weight-bearing and altered trunk kinematics that can be improved by positioning the affected foot behind the nonaffected one. Objective. To examine the influence of frontal trunk kinematics on medio-lateral displacements of the center of pressure (CP) during STS performed with the feet placed in 2 different positions, as well as relationships between these parameters, medio-lateral stability, and clinical scores of the participants. Methods. Eighteen patients with chronic stroke and 15 control individuals were evaluated during sit-to-stand transfers either in spontaneous foot position or with their affected or dominant foot placed behind, respectively. Medio-lateral CP, pelvis, and shoulder displacement were analyzed using 3D kinematic and kinetic data recordings of the whole task. Motor and sensory impairment, spasticity, muscle strength, and equilibrium were evaluated by standard scales. The possible time during which a participant could prevent a fall (minimal time-to-contact) was used as a stability index. Results. Spontaneously, the deviation of the CP of stroke participants paralleled the tilt of the trunk toward the nonaffected side, as early as the first third of the task. With the affected foot placed behind, trunk position did not differ from those of control participants who executed the transfer spontaneously. Hemiparetic participants were less stable than control participants. Placement of the feet had no significant effect on the stability of either group. Stability was strongly associated with better motor scores on the Chedoke-McMaster Stroke Assessment. Conclusions. In hemiparetic individuals, improving STS symmetry by positioning the affected foot behind the nonaffected one did not decrease medio-lateral stability, which was associated with the level of stroke-related motor impairments.
Gait characteristics of post-stroke hemiparetic patients with different walking speeds
International Journal of Rehabilitation Research, 2019
Hemiparesis resulting from stroke presents characteristic spatiotemporal gait patterns. This study aimed to clarify the spatiotemporal gait characteristics of hemiparetic patients by comparing them with height-, speed-, and age-matched controls while walking at various speeds. The data on spatiotemporal gait parameters of stroke patients and that of matched controls were extracted from a hospital gait analysis database. In total, 130 pairs of data were selected for analysis. Patients and controls were compared for spatiotemporal gait parameters and the raw value (RSI) and absolute value (ASI) of symmetry index and coefficient of variation (CV) of these parameters. Stroke patients presented with prolonged nonparetic stance (patients vs. controls: 1.01 ± 0.41 vs. 0.83 ± 0.25) and paretic swing time (0.45 ± 0.12 vs. 0.39 ± 0.07), shortened nonparetic swing phase (0.35 ± 0.07 vs. 0.39 ± 0.07), and prolonged paretic and nonparetic double stance phases [0.27 ± 0.13 (paretic)/0.27 ± 0.17 (nonparetic) vs. 0.22 ± 0.10]. These changes are especially seen in low-gait speed groups (<3.4 km/h). High RSIs of stance and swing times were also observed (-9.62 ± 10.32 vs.-0.79 ± 2.93, 24.24 ± 25.75 vs. 1.76 ± 6.43, respectively). High ASIs and CVs were more generally observed, including the groups with gait speed of ≥3.5 km/h. ASI increase of the swing phase (25.79 ± 22.69 vs. 4.83 ± 4.88) and CV of the step length [7.7 ± 4.9 (paretic)/7.6 ± 5.0 (nonparetic) vs. 5.3 ± 3.0] were observed in all gait speed groups. Our data suggest that abnormalities in the spatiotemporal parameters of hemiparetic gait should be interpreted in relation to gait speed. ASIs and CVs could be highly sensitive indices for detecting gait abnormalities.
The Association between Spatiotemporal Gait Asymmetry and Walking Balance in People Post Stroke
2019
Background: Falls are a common complication post-stroke and often induce due to poor balance. Given that falls often occur during walking, it is possible that gait patterns influence balance during walking. Walking post-stroke is frequently spatiotemporally asymmetric, which may reduce walking balance. The aim of this study was to determine the relationship between gait asymmetry and walking balance in persons with chronic stroke. Methods: Fifty-four persons with chronic stroke (34 men and 20 women) with the mean age of 57.28 participated in this cross-sectional study.Participants walked at their self-selected speed to calculate gait asymmetry ratios for stance time, swing time, and step length. The data were collected using a conventional camera with a sampling frequency of 60 Hz. Reflective markers were attached to the heel and toe regions. Participants also performed walking balance tests including Functional Gait Assessment (FGA) and Mini Balance Evaluation System Test (Mini-BES...
The link between weight shift asymmetry and gait disturbances in chronic hemiparetic stroke patients
Clinical Interventions in Aging, 2017
Introduction: While the asymmetry of body posture and the asymmetrical nature of hemiparetic gait in poststroke (PS) patients are well documented, the role of weight shift asymmetry in gait disorders after stroke remains unclear. Objective: We examined the association of weight-bearing asymmetry (WBA) between paretic and nonparetic lower limbs during quiet standing with the degree of deviation of hemiplegic gait from normal gait evaluated by the Gillette Gait Index (GGI) incorporating 16 distinct clinically important kinematic and temporal parameters in chronic PS patients. Participants and methods: Twenty-two ambulatory patients with chronic stroke aged between 50 and 75 years were included in this study. Fourteen patients had hemiparesis on the nondominant side and 8 on the dominant side. The mean time PS was 2 years and 6 months. The reference group consisted of 22 students from the University of the Third Age presenting no neurological disorders. The examination consisted of posturographic weight-bearing (WB) distribution and 3-dimensional gait analyses. Results: A significant positive relationship between WBA and GGI was revealed. Moreover, we observed a significant negative association between WBA and paretic step length and walking speed. With regard to kinematic data, the range of motion of knee flexion and peak dorsiflexion in the swing phase of the paretic leg were significantly negatively associated with WBA. Conclusion: Although further research is needed to determine a causal link between postural control asymmetry and gait disturbance in hemiplegics, our findings support the inclusion of WB measurements between paretic and nonparetic body sides in early assessment after stroke.