Interactive Exoskeleton Robot for Walking

Study Overview
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Brief Summary
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A new lower-limb training system is introduced to enhance the clinical service for post-stroke lower limb rehabilitation and to assist the establishment of public clinical trial in different settings and share experiences on the robot-assisted functional training.

Detailed Description
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Stroke is caused by intracranial haemorrhage or thrombosis, which cuts off arterial supply to brain tissue and usually damages the motor pathway of the central nervous system affecting one side of the body. Reduced descending neural drive to the affected side could lead to hemiplegia, which significantly influences the activity of daily living (ADL) of stroke survivors (Singam, Ytterberg, Tham & von Koch, 2015). While the upper-limb motor impairment could be compensated using the contralateral side for picking up or manipulating objects, the loss of motor functionality on the lower limb would substantially limit the mobility and body balance. Many stroke survivors are dependent on walking aids or manual support from caregivers for standing and walking, otherwise they would have great risk of falling with serious consequences (Tasseel-Ponche, Yelnik & Bonan, 2015). Recent studies suggest stroke patients could relearn walking ability by developing alternative neural circuitries through long-term adaptation process, known as neuroplasticity. High-intensity, repetitive, and task-specific gait training is the key to enhance gait recovery of hemiplegic stroke patients (Kreisei, Hennerici & Bäzner, 2007; Kleim & Jones, 2008). The development of robot-assisted lower-limb exoskeleton devices has great clinical potential in stroke rehabilitation. Many lower-limb exoskeleton robots are clinically-available for non-ambulatory stroke patients to practice walking with passive assistance on body-weight-supported treadmill training (BWSTT) (Morone, et al., 2017). Existing robot-assisted gait training (RAGT) such as Lokomat and electromechanical Gait Trainer provide automatic, rhythmic, and repetitive powered assistance to major lower-limb joints at hips and knees bilaterally (Poli, Morone, Rosati & Masiero, 2013). Large-scale randomized controlled trials (RCT) of these RAGT in combination with conventional therapies show significantly more chronic stroke patients improved functional gait independency and ADL than receiving conventional therapies alone (Pohl, et al., 2007; Schwartz, et al., 2009; Hidler, et al., 2009; Mehrholz, et al., 2013). However, Hesse, Schmidt, Werner & Bardeleben (2003) suggest the integration of robots into gait rehabilitation could merely be an auxiliary tool for therapists to enhance training intensity and safety without increasing their workload. Most clinically-available RAGT are bounded to treadmill with passive assistance (van Peppen, et al., 2004; Morone, et al., 2017), but researches show task-variations and active participation in gait training could improve retention of newly-learnt skills and could promote generalization of training effects (Salbach, et al., 2004; Kwon, Woo, Lee & Kim, 2015). Portable RAGT that allows active over-ground gait training would be more promising especially for ambulatory stroke patients. Robot-assisted ankle foot orthosis (AFO) and knee brace are good candidates of portable exoskeleton devices for RAGT of hemiplegic stroke patients (Duerinck, et al., 2012; Zhang, Davies & Xie, 2013; Mehrholz, et al., 2017). Conventional AFO is mainly designed for treating foot drop gait abnormality with passive support in ankle dorsiflexion for foot clearance in swing phase and shock absorption in loading response. Conventional knee brace is mainly designed for body support in stance phase. The integration of robot assistance in the affected ankle and/or knee joint could provide active power assistance that synchronises to patients' voluntary residual ankle and/or knee movement. Long-term active power assistance might stimulate experience-driven gait recovery or develop compensatory gait pattern to facilitate gait (Kleim & Jones, 2008). In order to translate robotic rehabilitation research into clinical application, evidence-based clinical research should be carried out to test the safety and effectiveness of the new devices or interventions on stroke patients (Backus, Winchester & Tefertiller, 2010). Many designs of robot-assisted AFO and knee braces have been proposed by different research groups, but most of them reported only the results of feasibility tests, mainly on healthy subjects with small sample sizes (Dollar & Herr, 2008; Shorter, et al., 2013; Alam, Choudhury & Bin Mamat, 2014). Majority of previous studies concerned about the immediate effects of wearing the robot-assisted AFOs and knee braces during walking, but few studies investigated the long-term therapeutic effects of wearing the devices for RAGT of stroke patients (Lo, 2012). In particular, systematic review by Mehrholz, et al. (2017) shows only one RCT has evaluated the efficacy of ankle training using robot-assisted AFO but in seated position, no RCT evaluated gait training using robot-assisted AFO on both over-ground walking and stair ambulation. In this study, the Exoskeleton Ankle Robot and Knee Robot have been proposed and evaluated as a robot-assisted AFO and knee brace for gait training of stroke patients with foot drop gait abnormality. Clinical application of robot-assisted AFO and knee brace on stroke patients has to overcome some important challenges, such as to reduce weight loading on the leg, and to achieve portability and adaptability to various walking environments. The Exoskeleton Ankle Robot and Knee Brace aims: (1) to provide synchronised active ankle and/or knee power assistance to facilitate walking, (2) to develop accurate and reliable method to classify user walking intention in over-ground walking and stair ambulation, (3) to deliver training protocol for RAGT of stroke patients with foot drop gait abnormality. The feasibility tests and RCT of the Exoskeleton Ankle Robot and Knee Brace could validate the clinical value of this new rehabilitation robot, and could potentially establish a new intervention of gait rehabilitation for stroke patients.

Official Title
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Wearable Interactive Lower-limb Exoskeleton Robotic Device for Gait Training of Post-stroke Patients on Different Walking Conditions

Conditions
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Stroke

Intervention / Treatment
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* Device: Robotic ankle system
* Device: Robotic knee system


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: First episode of stroke, Hemiparesis resulting from a unilateral ischemic or hemorrhagic stroke, Functional Ambulation Category (FAC) > 2 out of 6, i.e. have ability to walk on the ground independently or under supervision, with or without assistive device, Have sufficient cognition to follow instructions and to understand the content and purpose of the study. Exclusion Criteria: Uncontrolled cardiovascular or respiratory disorders, Moderate to serve contractures in the lower extremities, Orthopedic problems or muscle diseases that impair mobility, Difficulty to comply with the study protocol and the gait training schedule, i.e. at least 2 sessions per week.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Robotic ankle system<br>Subjects will wear the Ankle Robot during 20-session gait training, power assistance will be provided from the motor to the ankle joint. | Device: Robotic ankle system<br>* Patients will wear the robotic ankle system and undergo 20-minute over-ground walking and 10-minute stair walking.<br>* Other names: Ankle Robot;|
| Experimental: Robotic knee system<br>Subjects will wear the Knee Robot during 20-session gait training, power assistance will be provided from the motor to the knee joint. | Device: Robotic knee system<br>* Patients will wear the robotic knee system and undergo 20-minute over-ground walking and 10-minute stair walking.<br>* Other names: Knee Robot;|
| Placebo Comparator: Ankle Sham group<br>Subjects will wear the Ankle Robot during 20-session gait training, but no power assistance will be provided from the motor to the ankle joint. | Device: Robotic ankle system<br>* Patients will wear the robotic ankle system and undergo 20-minute over-ground walking and 10-minute stair walking.<br>* Other names: Ankle Robot;|
| Placebo Comparator: Knee Sham group<br>Subjects will wear the Knee Robot during 20-session gait training, but no power assistance will be provided from the motor to the knee joint. | Device: Robotic knee system<br>* Patients will wear the robotic knee system and undergo 20-minute over-ground walking and 10-minute stair walking.<br>* Other names: Knee Robot;|
| No Intervention: Health Control<br>Healthy subjects will wear the Ankle Robot and/or Knee Robot during walking tasks (with or without power assistance), to collect control data for investigating if there are any effects of the robotic assistance on normal gait pattern. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Functional Ambulatory Category (FAC) | Functional Ambulatory Category (FAC) is a reliable measurement of independent walking ability on level-ground walking and stair ambulation, which is a good prediction of independent community walking post-stroke (Mehrholz, et al., 2007). FAC consists of 6-level scale: patients with FAC=4 requires supervision in level ground walking, FAC=5 requires supervision only when walking on non-level surface such as stairs. | Baseline, Post-Training, 3-month follow up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fugl-Meyer Assessment for Lower-Extremity (FMA-LE) | Fugl-Meyer Assessment for Lower-Extremity (FMA-LE), consists of 34-level cumulative scoring system to examine lower-limb functions of hemiplegic stroke patients quantitatively through a set of lower-limb movement tasks in reflex, flexor/extensor synergy, volitional movement, coordination and speed (Fugl-Meyer, et al., 1975). All assessment items are either scoring full, partial, or none functionality in the affected side, which minimizes ceiling and floor effects. FMA-LE demonstrated high internal consistency and a reliable assessment tool for a group of 140 hemiplegic community dwelling patients (Park & Choi, 2014). | Baseline, Post-Training, 3-month follow up | 
| Modified Ashworth Scale (MAS) | Modified Ashworth Scale (MAS), consists of 4-level scale to examine joint spasticity based on muscle tone and resistance detected during passive stretching with good inter-rater reliability (ICC =0.85) (Bohannon & Smith, 1987). | Baseline, Post-Training, 3-month follow up | 
| Berg Balance Scale (BBS) | Berg Balance Scale (BBS), consists of 56-level measures to examine balance ability and to predict falling risk with high reliability (ICC=0.98) (Steffen, Hacker & Mollinger, 2002). Stroke patients were assessed based on their performance on 14 simple mobility tasks, including transfer, standing, and reaching. | Baseline, Post-Training, 3-month follow up | 
| Timed 10-Meter Walk Test (10mWT) | Timed 10-Meter Walk Test (10mWT), measures comfortable and fast walking speeds in short distance. The ability to increase walking speed above a comfortable pace suggests the capability to adapt to varying environments, such as crossing street, with high reliability (ICC=0.90-0.96) (Flansbjer, et al., 2005). Average walking speed of healthy elderly subjects ranges in 0.6m/s-1.4m/s, and can increase to 21%-56% above the comfortable pace for faster walking speed. | Baseline, Post-Training, 3-month follow up | 
| 6-minute Walk Test (SMWT) | Six-Minute Walk Test (SMWT), measures the maximum walking distance covered in fixed duration as a sub-maximal test of endurance and aerobic capacity. The measurement of 6MWT is highly correlated to FAC (Mehrholz, et al., 2007) with good reliability (ICC=0.94-0.96) (Steffen, Hacker & Mollinger, 2002). | Baseline, Post-Training, 3-month follow up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Stroke, Exoskeleton Robot, Rehabilitation, Ankle Foot Orthosis, Knee Brace, Foot Drop