Hemiparetic Gait Parameters in Overground Versus Treadmill Walking

Objective: Hemiparetic gait is characterized by high stride-cycle variability, di minished stance time, single-limb stance time, and stance/swing ratio in the paretic limb. Recent studies suggest treadmill (TM) training may improve the motor control underlying these variables, but supporting evidence is sparse. Methods: This study compared gait patterns of untrained chronic hemiparetic stroke patients (n = 18; mean, 39.5 months poststroke) during overground (OG) and TM walking at matched velocities. Variables included relative stance time, relative single-limb stance time, stance/swing ratio, peak force, and impulse. Within-subject variability of these meas ures (CV) was used to assess gait pattern stability. Results: OG and TM cycle dura tions were similar, but CVs differed (TM < OG, p < 0.05). In the paretic limb, dif ferences were seen in relative stance time, relative single-limb stance time, and stance/swing ratio, respectively (TM > OG, p < 0.05). These variables decreased in the nonparetic limb during TM walking (p < 0.05 for all). Improved interlimb sym metry and coordination were evidenced by decreased between-limb differences and improved relative temporal phasing, respectively, in the TM condition (p < 0.05). Conclusions: Collectively, these results demonstrate that the TM induces an imme diate alteration toward a more consistent and symmetric gait pattern. Further inves tigation is needed to determine whether TM training leads to motor relearning and neuroplasticity in chronic hemiparetic subjects. Key Words: Stroke—Rehabilitation— Hemiparetic gait-Treadmill-Gait symmetry.

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A Unilateral Robotic Knee Exoskeleton to Assess the Role of Natural Gait Assistance in Hemiparetic Patients

10.21203/rs.3.rs-1070568/v1 ◽

2021 ◽

Author(s):

Julio Salvador Lora-Millan ◽

Francisco José Sanchez-Cuesta ◽

Juan Pablo Romero ◽

Juan C. Moreno ◽

Eduardo Rocon

Keyword(s):

Control Strategies ◽

Gait Pattern ◽

Lower Limbs ◽

Motor Deficits ◽

Compensatory Mechanisms ◽

Gait Symmetry ◽

Paretic Limb ◽

Hemiparetic Gait ◽

Preliminary Validation ◽

Technical Validation

Abstract Background: Hemiparetic gait is characterized by strong asymmetries that could severely affect the quality of life of stroke survivors. This asymmetry is due to motor deficits in the paretic leg and the resulting compensations in the non-paretic limb. In this study, we aim to evaluate the effect of actively promoting gait symmetry in hemiparetic patients by assessing the behavior of both paretic and non-paretic lower limbs. This paper introduces the design and validation of the REFLEX prototype, a unilateral active Knee-Ankle-Foot Orthosis able to naturally assist the paretic limb of hemiparetic patients during gait.Methods: REFLEX uses an Adaptive Frequency Oscillator to estimate the continuous gait phase of the non-paretic limb. Based on this estimation, the device synchronically assists the paretic leg following two different control strategies: (1) Replicating the movement of the sound leg or (2) Inducing a healthy gait pattern on the paretic leg. Technical validation of the system was implemented on three healthy subjects, while the effect of the generated assistance was assessed in three stroke patients. Results: Preliminary results proved the feasibility of the REFLEX prototype to assist gait by reinforcing symmetry. They also pointed out that the assistance of the paretic leg resulted in a decrease of the compensatory strategies developed by the non-paretic limb to achieve a functional gait. Notably, better results were attained when the assistance was provided according to a standard healthy pattern, which initially might suppose a lower symmetry but enabled a healthier evolution of the motion of the non-paretic limb.Conclusions: This work presents the preliminary validation of the REFLEX prototype, a unilateral knee exoskeleton for gait assistance in hemiparetic patients. The experimental results indicate that assisting the paretic leg of hemiparetic patients based on the movement of their non-paretic one is a valuable strategy for reducing the compensatory mechanisms developed by their sound limb.

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Persons post-stroke improve step length symmetry by walking asymmetrically

10.21203/rs.2.21659/v2 ◽

2020 ◽

Author(s):

Purnima Padmanabhan ◽

Keerthana Sreekanth ◽

Shivam Gulhar ◽

Kendra M. Cherry-Allen ◽

Kristan A. Leech ◽

...

Keyword(s):

Center Of Mass ◽

Metabolic Cost ◽

Step Length ◽

Gait Pattern ◽

Future Research ◽

Cost Of Transport ◽

Post Stroke ◽

Paretic Limb ◽

Gait Parameters ◽

The Many

Abstract Background Restoration of step length symmetry is a common rehabilitation goal after stroke. Persons post-stroke often retain the ability to walk with symmetric step lengths ("symmetric steps") at an elevated metabolic cost relative to healthy adults. Two key questions with direct implications for rehabilitation have emerged: 1) how do persons post-stroke generate symmetric steps, and 2) why do symmetric steps remain so effortful? Here, we aimed to understand how persons post-stroke generate symmetric steps and explored how the resulting gait pattern may relate to the metabolic cost of transport. Methods We recorded kinematic, kinetic, and metabolic data as nine persons post-stroke walked on an instrumented treadmill under two conditions: preferred walking and symmetric stepping (using visual feedback). Results Gait kinematics and kinetics remained markedly asymmetric even when persons post-stroke improved step length symmetry. Impaired paretic propulsion and abnormal movement of the center of mass were evident during both preferred walking and symmetric stepping. These deficits contributed to diminished positive work performed by the paretic limb on the center of mass in both conditions. Within each condition, decreased positive paretic work correlated with increased metabolic cost of transport and decreased walking speed across participants. Conclusions It is critical to consider the mechanics used to restore symmetric steps when designing interventions to improve walking after stroke. Future research should consider the many dimensions of asymmetry in post-stroke gait, and additional within-participant manipulations of gait parameters are needed to improve our understanding of the elevated metabolic cost of walking after stroke.

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Persons post-stroke improve step length symmetry by walking asymmetrically

10.21203/rs.2.21659/v3 ◽

2020 ◽

Author(s):

Purnima Padmanabhan ◽

Keerthana Sreekanth ◽

Shivam Gulhar ◽

Kendra M. Cherry-Allen ◽

Kristan A. Leech ◽

...

Keyword(s):

Center Of Mass ◽

Metabolic Cost ◽

Step Length ◽

Gait Pattern ◽

Future Research ◽

Cost Of Transport ◽

Post Stroke ◽

Paretic Limb ◽

Gait Parameters ◽

The Many

Abstract Background Restoration of step length symmetry is a common rehabilitation goal after stroke. Persons post-stroke often retain the ability to walk with symmetric step lengths ("symmetric steps"); however, the resulting walking pattern remains effortful. Two key questions with direct implications for rehabilitation have emerged: 1) how do persons post-stroke generate symmetric steps, and 2) why do symmetric steps remain so effortful? Here, we aimed to understand how persons post-stroke generate symmetric steps and explored how the resulting gait pattern may relate to the metabolic cost of transport. Methods We recorded kinematic, kinetic, and metabolic data as nine persons post-stroke walked on an instrumented treadmill under two conditions: preferred walking and symmetric stepping (using visual feedback). Results Gait kinematics and kinetics remained markedly asymmetric even when persons post-stroke improved step length symmetry. Impaired paretic propulsion and aberrant movement of the center of mass were evident during both preferred walking and symmetric stepping. These deficits contributed to diminished positive work performed by the paretic limb on the center of mass in both conditions. Within each condition, decreased positive paretic work correlated with increased metabolic cost of transport and decreased walking speed across participants. Conclusions It is critical to consider the mechanics used to restore symmetric steps when designing interventions to improve walking after stroke. Future research should consider the many dimensions of asymmetry in post-stroke gait, and additional within-participant manipulations of gait parameters are needed to improve our understanding of the elevated metabolic cost of walking after stroke.

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Volume and intramuscular fat content of upper extremity muscles in individuals with chronic hemiparetic stroke

10.1101/687699 ◽

2019 ◽

Cited By ~ 1

Author(s):

Lindsay R. P. Garmirian ◽

Ana Maria Acosta ◽

Ryan Schmid ◽

Jules P. A. Dewald

Keyword(s):

Upper Extremity ◽

Muscle Atrophy ◽

Upper Limb ◽

Intramuscular Fat ◽

Muscle Volume ◽

Contractile Element ◽

Paretic Limb ◽

Hemiparetic Stroke ◽

Chronic Hemiparetic Stroke ◽

Wrist Flexors

AbstractStroke survivors often experience upper extremity deficits that make activities of daily living (ADLs) like dressing, cooking and bathing difficult or impossible. Survivors experience paresis, the inability to efficiently and fully activate muscles, which combined with decreased use of the upper extremity, will lead to muscle atrophy and potentially an increase in intramuscular fat. Muscle atrophy has been linked to weakness post stroke and is an important contributor to upper extremity deficits. However, the extent of upper extremity atrophy post hemiparetic stroke is unknown and a better understanding of these changes is needed to inform the direction of intervention-based research. In this study, the volume of contractile tissue and intramuscular fat in the elbow and wrist flexors and extensors were quantified in the paretic and non-paretic upper limb using MRI and the Dixon technique for the first time. Total muscle volume (p≤0.0005) and contractile element volume (p≤0.0005) were significantly smaller in the paretic upper extremity, for all muscle groups studied. The average percent difference between limbs and across participants was 21.3% for muscle volume and 22.9% for contractile element volume. We also found that while the percent intramuscular fat was greater in the paretic limb compared to the non-paretic (p≤0.0005), however, the volume of intramuscular fat was not significantly different between upper limbs (p=0.231). The average volumes of intramuscular fat for the elbow flexors/extensors and wrist flexors/extensors were 28.1, 28.8 and 19.9, 8.8 cm3 in the paretic limb and 29.6, 27.7 and 19.7, 8.8 cm3 in the non-paretic limb. In short, these findings indicate a decrease in muscle volume and not an increase in intramuscular fat, which will contribute to the reduction in strength in the paretic upper limb.

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Reduction in voluntary activation of elbow and wrist muscles in individuals with chronic hemiparetic stroke

10.1101/689364 ◽

2019 ◽

Author(s):

Lindsay R. P. Garmirian ◽

Julius P. A. Dewald ◽

Ana Maria Acosta

Keyword(s):

Upper Extremity ◽

Voluntary Activation ◽

Force Output ◽

Twitch Interpolation ◽

Paretic Limb ◽

Full Capacity ◽

Muscle Groups ◽

Hemiparetic Stroke ◽

Chronic Hemiparetic Stroke ◽

Wrist Flexors

AbstractAfter a stroke, descending drive is impaired due to the loss of corticospinal and corticobulbar projections which causes a reduction in voluntary activation or an inability of the nervous system to activate muscles to their full capacity, which in turn contributes to weakness of the upper extremity. Voluntary activation has not been quantified at specific joints in the upper extremity, in part because directly assessing changes descending drive is difficult. In this study, voluntary activation of elbow and wrist flexors and extensors was assessed in participants with chronic hemiparetic stroke using twitch interpolation. Twitch interpolation uses electrical stimulation to estimate voluntary activation and relies on the principle that there is an inverse relationship between the amplitude of a twitch evoked by a stimulus and the voluntary force output during stimulation (Taylor, 2009). We measured voluntary activation using twitch interpolation as well as maximum voluntary torque (MVT) of the elbow and wrist flexors and extensors in the paretic and non-paretic limb of ten participants post stroke and the dominant and non-dominant limb of 2 control participants. Results show, MVT interlimb differences were significantly greater for stroke participants compared to control, across muscle groups (p≤0.005). For stroke participants, MVT interlimb differences were significantly greater at the wrist compared to the elbow (P=0.003). Voluntary activation was significantly less in the paretic limb compared to the non-paretic, dominant and non-dominant limbs, across participants and muscle groups (p<0.005 for all four muscle groups). For the stroke participants, the voluntary activation interlimb difference was significantly greater for the wrist muscles compared to the elbow muscles (p<0.005). There was a significant positive correlation (r = 0.39, P = .022) between each participant’s impairment level, as measured by a hand specific subscore of the Fugl-Meyer Assessment, and the wrist extensor voluntary activation in the paretic limb but the relationship was not significant for the other muscle groups.

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Motor Impairment–Related Alterations in Biceps and Triceps Brachii Fascicle Lengths in Chronic Hemiparetic Stroke

Neurorehabilitation and Neural Repair ◽

10.1177/1545968318792618 ◽

2018 ◽

Vol 32 (9) ◽

pp. 799-809 ◽

Cited By ~ 9

Author(s):

Christa M. Nelson ◽

Wendy M. Murray ◽

Julius P. A. Dewald

Keyword(s):

Motor Impairment ◽

Distal Portion ◽

Functional Mobility ◽

Triceps Brachii ◽

Motor Impairments ◽

Fascicle Length ◽

Paretic Limb ◽

Hemiparetic Stroke ◽

Long Head ◽

Chronic Hemiparetic Stroke

Poststroke deficits in upper extremity function occur during activities of daily living due to motor impairments of the paretic arm, including weakness and abnormal synergies, both of which result in altered use of the paretic arm. Over time, chronic disuse and a resultant flexed elbow posture may result in secondary changes in the musculoskeletal system that may limit use of the arm and impact functional mobility. This study utilized extended field-of-view ultrasound to measure fascicle lengths of the biceps (long head) and triceps (distal portion of the lateral head) brachii in order to investigate secondary alterations in muscles of the paretic elbow. Data were collected from both arms in 11 individuals with chronic hemiparetic stroke, with moderate to severe impairment as classified by the Fugl-Meyer assessment score. Across all participants, significantly shorter fascicles were observed in both biceps and triceps brachii ( P < .0005) in the paretic limb under passive conditions. The shortening in paretic fascicle length relative to the nonparetic arm measured under passive conditions remained observable during active muscle contraction for the biceps but not for the triceps brachii. Finally, average fascicle length differences between arms were significantly correlated to impairment level, with more severely impaired participants showing greater shortening of paretic biceps fascicle length relative to changes seen in the triceps across all elbow positions ( r = −0.82, P = .002). Characterization of this secondary adaptation is necessary to facilitate development of interventions designed to reduce or prevent the shortening from occurring in the acute stages of recovery poststroke.

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Effects of Aerobic Treadmill Training on Gait Velocity, Cadence, and Gait Symmetry in Chronic Hemiparetic Stroke: A Preliminary Report

Neurorehabilitation and Neural Repair ◽

10.1177/154596830001400108 ◽

2000 ◽

Vol 14 (1) ◽

pp. 65-71 ◽

Cited By ~ 104

Author(s):

Kenneth H.C. Silver ◽

Richard F. Macko ◽

Larry W. Forrester ◽

Andrew P. Goldberg ◽

Gerald V. Smith

Keyword(s):

Ischemic Stroke ◽

Functional Mobility ◽

Treadmill Training ◽

Assistive Device ◽

Gait Velocity ◽

Gait Symmetry ◽

Before And After ◽

Hemiparetic Stroke ◽

Temporal Measures ◽

Chronic Hemiparetic Stroke

It is widely assumed that only limited improvement in functional mobility is pos sible beyond the subacute period following ischemic stroke. Contrary to this notion, we studied "neurologically plateaued" stroke patients with chronic hemiparesis to as sess whether a "task-oriented" treadmill-training regimen would improve walking speed, cadence, and gait cycle symmetry on a modified "Get-Up and Go" task. Five male patients with a mean age of 60.4 ± 2.7 years (mean ± S.D.) status post ischemic stroke (> 6 months prior) participated in this nonrandomized low-intensity tread mill exercise pilot study three times/week for 3 months. All patients had mild to mod erate gait asymmetries due to residual hemiparesis. Patients were videotaped before and after 3 months of treadmill aerobic exercise (AEX) while performing a functional task consisting of arising from a chair, walking 3.1 m without an assistive device as fast as safely possible, and returning to sit. Gait events were timed using a 2-D Peak Motus™ video analysis system. After 3 months AEX training, times for the overall "get-up and return-to-sit" (GURS) task and the "straight-away walk" (SAW) segment decreased from 8.2 ± 1.4 sec to 6.5 ± 0.8 sec (mean ± SEM) (p < 0.05), and from 3.7 ± 1 sec to 2.8 ± 0.7 sec (p < 0.05), respectively. These data represent improve ments of 21% and 24% for the GURS and 'SAW segments, respectively. Mean veloc ity increased from 0.9 ± 0.2 to 1.2 ± 0.21 m/sec, a 33% improvement (p < 0.01). Mean cadence (steps/min) increased from 89 ± 9 to 97 ± 8, a 9% increase (p < 0.05). Mean stance and swing duration diminished for both paretic (P) and nonparetic (NP) limbs, and the intralimb stance/swing ratio values moved toward normal for both the paretic and nonparetic limbs. However, these latter changes reached significance only for the P limb. Interlimb stance symmetry was unchanged. The more impaired subjects experienced the greatest gains in gait velocity and temporal measures. Collectively, these findings indicate that treadmill exercise improves functional overground mo bility in individuals with chronic, stable hemiparesis. Key Words: Cerebrovascular disease—Hemiplegia—Exercise—Gait.

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Immediate augmented real-time forefoot weight bearing using visual feedback improves gait symmetry in chronic stroke

Technology and Health Care ◽

10.3233/thc-192016 ◽

2020 ◽

Vol 28 (6) ◽

pp. 733-741

Author(s):

Jihye Jung ◽

Wonjae Choi ◽

Seungwon Lee

Keyword(s):

Visual Feedback ◽

Weight Bearing ◽

Step Length ◽

Gait Pattern ◽

Gait Symmetry ◽

Affected Side ◽

Gait Parameters ◽

Weight Shift ◽

Spatiotemporal Parameters ◽

Single Limb Support

BACKGROUND: Symmetry of gait is an important component of rehabilitation in stroke patients. Insufficient weight-bearing causes gait asymmetry. OBJECTIVE: This study aimed to identify the immediate effects of sufficient weight-bearing on the forefoot during the stance phase using visual feedback. METHODS: Twenty-seven individuals with stroke enrolled in this study. All patients were evaluated for gait parameters with and without visual feedback. Visual feedback was provided through a smart application and a beam projector screen that showed a weight shift as a change in color. Spatiotemporal gait parameters were evaluated, resulting in values for a calculated symmetry index, in addition to heel % and toe % temporal values. RESULTS: Velocity and cadence were significantly decreased when visual feedback was provided (p< 0.05). Spatiotemporal parameters, except for bilateral step length, swing time of affected side, and single-limb support of less affected side, showed significant improvement (p< 0.05). The gait pattern of subjects was more symmetrical with visual feedback compared to non-visual feedback (p< 0.05). The toe-on time significantly improved on the affected side with visual feedback (p< 0.05). CONCLUSION: This study suggests that visual feedback aids in the improvement of gait symmetry, forefoot weight-bearing on the affected side, and spatiotemporal parameters.

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The Effect of Prosthesis Alignment on the Symmetry of Gait in Subjects with Unilateral Transtibial Amputation

Prosthetics and Orthotics International ◽

10.1080/03093640600568617 ◽

2006 ◽

Vol 30 (2) ◽

pp. 114-128 ◽

Cited By ~ 40

Author(s):

Daniel H. K. Chow ◽

Andrew D. Holmes ◽

Christina K. L. Lee ◽

S. W. Sin

Keyword(s):

Knee Flexion ◽

Dynamic Testing ◽

Reaction Force ◽

Step Length ◽

Gait Pattern ◽

Vertical Ground Reaction Force ◽

Gait Symmetry ◽

Prosthetic Alignment ◽

Gait Parameters ◽

Study Results

A high degree of gait symmetry is characteristic of healthy gait. The aim of this study is to examine the symmetry of various gait parameters in subjects with unilateral trans-tibial amputation over a range of acceptable anteroposterior translational and tilt alignments, and further to examine if a consistent alignment of highest symmetry can be found. Acceptable alignments were determined by bench, static and dynamic testing on level and non-level surfaces. A total of 15 kinetic and kinematic parameters were then measured in the seven subjects participating in this study. Results indicate that some parameters show consistently higher symmetries, particularly the vertical ground reaction force parameters and the stance duration, step length and time to full knee flexion during the swing phase. Symmetries in other parameters such as knee flexion at loading response, acceleration impulse, and peak anteroposterior propulsive force seem to have little relevance in determining whether the gait pattern for that prosthetic alignment is acceptable or not. While analysis of the symmetry of more relevant gait parameters may assist the prosthetist in consistently and objectively identifying a most symmetrical alignment within the acceptable range, further clinical study is required before any conclusions can be drawn regarding evaluation of symmetry as a tool in defining any optimum alignment.

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