Efficacy of Split Gait in the Treatment of Dynamic Asymmetries in Subjects With Pathologic Claudication

Study Overview
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Brief Summary
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Walking on a split-belt treadmill (each of the two belts running at a different speed) imposes an asymmetrical gait, mimicking limping that has been observed in various pathologic conditions. This walking modality has been proposed as an experimental paradigm to investigate the flexibility of the neural control of gait and as a form of therapeutic exercise for hemi-paretic patients. However, the scarcity of dynamic investigations both for segmental aspects and for the entire body system, represented by the centre of mass, challenges the validity of the available findings on split gait. Compared with overground gait in hemiplegia, split gait entails an opposite spatial and dynamic asymmetry. The faster leg mimics the paretic limb temporally, but the unimpaired limb from the spatial and dynamic point of view. These differences suggest that a partial shift in perspective may help to clarify the potential of the split gait as a rehabilitation tool. The aim of the present study is to investigate the dynamic asymmetries of lower limbs in adults with unilateral motor impairments (e.g. hemiplegia post-stroke, Parkinson's disease, multiple sclerosis, unilateral amputation, surgical orthopedic interventions) during adaptation to gait on a split-belt treadmill. The sagittal power provided by the ankle and the total mechanical energy of the centre of mass will be thoroughly studied. The time course of phenomena both during gait when the belts are running at different speed and when the belts are set back to the same speed (i.e. the after-effect) will be investigated. A greater dynamic symmetry between the lower limbs is expected after split gait. The question whether this symmetry will occur when the pathological limb is on the faster or the lower belt will be disclosed. Some alterations of the motion of the centre of mass during split gait are also expected.

Official Title
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Efficacy of Split Gait in the Treatment of Dynamic Asymmetries in Subjects With Pathologic Claudication

Conditions
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Multiple Sclerosis, Poststroke/CVA Hemiparesis, Parkinson Disease, Amputation, Knee Impairment

Intervention / Treatment
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* Other: Pathologic group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age between 18 and 70 years old; ability to walk for at least 20 meters without support; ability to wittingly sign the informed consent form; ability to understand the instructions and to complete the motor task; visual acuity > 10/20 on the worse side, with optical correction; unilateral motor impairments of one lower limb as a consequence of various pathologic conditions, such as (not exhausting list): post-stroke hemiparesis, Parkinson's disease with lateral asymmetry in the motor symptoms, multiple sclerosis with lateral asymmetry in the motor symptoms, unilateral amputation with prosthetic correction, surgical orthopedic interventions, unilateral lesions of peripheral nerves. Exclusion Criteria: systemic neurologic pathologies; orthopedic surgical interventions, other than those determining the inclusion criteria; symptomatic pathologies of rachis; other sensory or neurological pathologies with impact on balance and gait; pregnancy.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Pathologic group<br>At least 20 participants with various orthopaedic or neurologic conditions (for example, post-stroke hemiparesis, Parkinson's disease, multiple sclerosis, unilateral amputation, surgical orthopedic interventions) will be enrolled. | Other: Pathologic group<br>* Participants will walk on a split-belt treadmill mounted on force sensors with the belts running at the same or at different velocities. They will walk freely without hanging to any support. The test sequence will be the following: Baseline phase. 3 minutes walking at increasing speed from 0.2 m s-1 to 0.6 m s-1, speed will be increased of 0.1 m s-1 every 30 s. A brief pause of around 1 minute will follow. Habituation phase. 30 seconds walking at 0.2 m s-1. Adaptation phase. The velocity of the belt under the non-affected lower limb will be increased to 0.6 m s-1, while the other belt will maintain its velocity of 0.2 m s-1 for 6 minutes. Post-adaptation phase. Belts' velocities will be restored at 0.2 m s-1 for 6 minutes. Participants will be informed before the changes in belts' velocities with a verbal warning. Participants will repeat the same protocol with the affected lower limb on the fast belt after one week.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ankle Joint Power | Joint kinematics will be recorded through an optoelectronic method as per the Davis anthropometric model. The 3D displacement of the markers will be captured using 10 near-infrared stroboscopic cameras. Joint power will be computed through the spatiotemporal synchronization of ground reaction force vectors and the joint centers of rotation. Only the sagittal plane will be considered for the analysis. Joint power will be computed as the product of joint torque and joint rotation speed. Power will be defined as positive or generated when the joint moment and rotation speed shared the same directions (i. e., when agonist muscles are contracting while shortening), as negative or absorbed otherwise. Positive work will be computed as the integral of the generated (positive) power over time. | Two assessments, at one week-interval | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Step Length | The sagittal distance between the markers put on the lateral malleolus of the posterior and anterior feet at the ground strike of the anterior foot. The side of step will be defined as the side of the posterior foot during double stance . | Two assessments, at one week-interval | 
| Single Stance Time | For each lower limb, the time interval during which the limb determines vertical ground reactions equal to or exceeding 30 N. | Two assessments, at one week-interval | 
| Double Stance Time | The time interval during which, under both lower limbs, vertical ground reactions equal or exceed 30 N. The side of the double stance time will be defined as the side of the posterior foot. | Two assessments, at one week-interval | 
| Parameters of the center of mass motion | The changes in kinetic energy due to the forward (Ekf), lateral (Ekl) and vertical (Ekv) velocity; the changes of gravitational potential energy (Ep); the changes of the mechanical energy due to the vertical motion, Ev = Ekv+Ep; the changes of the total mechanical energy (Etot = Ekf+Ekl +Ev). The amount of recovery of mechanical energy, R, due to the passive exchange between Ekf, Ev and Ekl, will be calculated according to the equation R = (Wf + Wv + Wl - Wext)/(Wf + Wv + Wl) × 100, where Wf for Ekf, Wv for Ev, Wl for Ekl and Wtot for Etot represents the corresponding work values calculated as the sum of the positive increments of these energy values during one step. | Two assessments, at one week-interval | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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walking, split-belt treadmill, motor adaptation, after-effect, dynamic symmetry, rehabilitation