Abstract
Objectives:
To assess the effect of a home-based over-ground robotic-assisted gait training program using the AlterG Bionic Leg orthosis on clinical functional outcomes in people with chronic stroke.
Design:
Randomized controlled trial.
Setting:
Home.
Participants:
Thirty-four ambulatory chronic stroke patients who recieve usual physiotherapy.
Intervention:
Usual physiotherapy plus either (1)10-week over-ground robotic-assisted gait training program (n = 16), using the device for ⩾30 minutes per day, or (2) control group (n = 18), 30 minutes of physical activity per day.
Measurements:
The primary outcome was the Six-Minute Walk Test. Secondary outcomes included: Timed-Up-and-Go, Functional Ambulation Categories, Dynamic Gait Index and Berg Balance Scale. Physical activity and sedentary time were assessed using accelerometry. All measurements were completed at baseline, 10 and 22 weeks after baseline.
Results:
Significant increases in walking distance were observed for the Six-Minute Walk Test between baseline and 10 weeks for over-ground robotic-assisted gait training (135 ± 81 m vs 158 ± 93 m, respectively; P ⩽ 0.001) but not for control (122 ± 92 m vs 119 ± 84 m, respectively). Findings were similar for Functional Ambulation Categories, Dynamic Gait Index and Berg Balance Scale (all P ⩽ 0.01). For over-ground robotic-assisted gait training, there were increases in time spent stepping, number of steps taken, number of sit-to-stand transitions, and reductions in time spent sitting/supine between baseline and 10 weeks (all P < 0.05). The differences observed in all of the aforementioned outcome measures were maintained at 22 weeks, 12 weeks after completing the intervention (all P > 0.05).
Conclusion:
Over-ground robotic-assisted gait training combined with physiotherapy in chronic stroke patients led to significant improvements in clinical functional outcomes and physical activity compared to the control group. Improvements were maintained at 22 weeks.
Introduction
Robotic devices provide high-intensity, repetitive, task-specific therapy and have been shown to improve gait quality (i.e., stride length, step length), functional outcomes (i.e. walking speed and walking capacity) and motor performance in stroke patients.1 Stroke patients with greater functional ability may benefit more from over-ground robotic-assisted gait training opposed to treadmill-based robotics (e.g., Lokomat and LOPES) and end effector devices, which moves the patients in a gait like pattern driven by two movable footplates (e.g., G-EO).
Over-ground robotic-assisted devices allow the patient to walk in a real-world environment,2 encourages trunk and balance control,3 and allows for substantial kinematic variability while still ensuring successful task execution. A small number of training case series4–6 and a single randomized controlled trial7 have found modest functional benefits7 and improvements in gait speed, endurance, and balance after completing an over-ground robotic-assisted gait training intervention, lasting ⩽ six weeks.4–6 However, interventions which last greater than eight weeks may accelerate walking gains and improve functional capacity.8 It is plausible that longer programs may elicit greater functional improvements in stroke patients.
The primary use of robotic devices is within a clinical setting, as many available systems are not yet developed for a home-based environment and/or require a trained therapist to operate them. Robotic devices are expensive and research is needed to establish the benefit to cost ratio, and potential risk of harm associated with a device if used within a home-based environment. The “at home” potential, however, of an over-ground robotic-assisted gait training device could potentially improve the efficiency of therapy treatments enabling physiotherapists to implement rehabilitation without being physically present.9 Home-based settings may also be efficacious as patients could use such devices more frequently in a familiar context10 contributing to the formation of habits leading to long-term behavior change.11 Further research is needed to investigate the feasibility, efficacy and application of over-ground robotic-assisted gait training in a home-based environment.
The purpose of this study was to assess the effect of a 10-week home-based rehabilitation program using a lower limb dynamic over-ground robotic-assisted gait training device, in combination with usual care physiotherapy, in ambulatory stroke patients on clinical functional outcomes. It was hypothesized that regular participation in a 10-week over-ground robotic-assisted gait training program would improve functional outcomes in individuals living with stroke. A secondary hypothesis was that over-ground robotic-assisted gait training would increase physical activity and reduce sedentary behavior.
Methods
This study was a dual-center, parallel group, randomized controlled clinical trial, reported in accordance with CONSORT (Consolidated Standards of Reporting Trials) guidelines.12 The study protocol received institutional ethical approval from the University of Winchester (Approval number BLS/16/16) and was registered with the Clinical Trials.gov Protocol Registration and Results System (NCT03104127). The study was funded by the University of Winchester. AlterG Bionic Leg orthoses were provided freely by AlterG (Bionic Leg orthosis, Fremont, CA, USA) who had no input or influence on the data analysis or manuscript preparation. Recruitment started in April 2017 and ended in July 2019.
Participants with chronic stroke (> three months since stroke diagnosis) were identified, screened for eligibility, which included a health history questionnaire, and recruited from a single neuro-physiotherapy practice (Hobbs Rehabilitation, Winchester, UK). All participants were diagnosed with stroke by a specialist neurologist/stroke consultant from a UK National Health Service (NHS) Trust and had undertaken normal inpatient and outpatient rehabilitation in accordance with recommended guidelines.13 Eligible participants were contacted by telephone and invited to attend a baseline assessment at the University. Written informed consent was obtained from all participants prior to the commencement of the study.
Study inclusion criteria were: individuals who were between 3 months and 5 years post-stroke at the time of study enrolment, who were community-dwelling, medically stable, and cognitively capable, able to stand and step with an aid or with assistance (defined as a Functional Ambulation Categories between 2 and 5),14 and who were either currently receiving physiotherapy or attending a community-based, stroke support group. Exclusion criteria were: Unresolved deep vein thrombosis, unstable cardiovascular conditions, open wounds, active drug resistant infection, recent fractures of involved limb, peripheral arterial disease, incontinence, severe osteoporosis, and/or non-weight bearing.
Participants completed a baseline assessment and follow-up assessments at 10 and 22 weeks after baseline. On completion of the baseline assessment, participants were randomized to either:
- (i) a 10-week home-based over-ground robotic-assisted gait training program, including weekly “usual care” physiotherapy (O-RAGT).
- (ii) a 10-week “usual care” physiotherapy only program (CON).
Web-based randomization was prepared by an independent researcher with no clinical involvement in the trial, using covariate adaptive randomization.15 In this study, participants were sequentially assigned to over-ground robotic-assisted gait training or control by taking into account the following covariates:
- (i) Baseline postural sway (only able to stand with an aid versus able to stand unaided; able to stand ⩽two minutes versus able to stand > two minutes).
- (ii) Age (age ⩾ 70 years vs <70 years).
The independent researcher informed the participant of group allocation at the end of the baseline assessment. Although participants and the primary researcher collecting outcome data were aware of the allocated treatment condition, in order to control and minimize investigator bias, data analysts were kept blinded to the allocation using an independent researcher to re-code the original data sets before returning the data to the data analyst. Identical assessments to those implemented at baseline, were administered at 10 and 22 weeks after baseline.
Participants were asked to abstain from any moderate-to-strenuous physical activity 24 hours prior to the baseline assessment. During this assessment, a series of clinical functional outcomes were measured, wherein participants could use walking aids (e.g., canes, orthoses) if necessary. The primary outcome for this study was the Six Minute Walk Test as it provides an overall measure of an individual’s walking ability, indicates physical incapacity, and is sensitive to change as a result of rehabilitation therapy which targets walking performance.16 The Six Minute Walk Test was conducted indoors on a flat walkway. Participants were required to walk between two cones 10m apart for a total of six minutes and were instructed to complete as far a distance as possible. At the end of the Six Minute Walk Test, participants also reported their terminal Ratings of Perceived Exertion (RPE).17
The secondary outcomes included: the Timed-Up-and-Go,18 Dynamic Gait Index,19 Berg Balance Scale,20 Functional Ambulation Categories,14 Modified Rankin Scale21 and accelerometry (ActivPAL3
The over-ground robotic-assisted gait training device (Alter-G, Bionic Leg orthosis, Fremont, CA, USA) is an externally-wearable, battery-operated dynamic device that helps patients and therapists during rehabilitation by providing adjustable and progressive functional mobility training (Figure 1). The device consists of an orthosis shell and an actuation unit. The orthosis shell functions as the user interface that transfers the assistive torque to the human body, while the actuation unit assists the movement of the limb which has been shown to be stable, smooth and similar to biological knee motion during sit-to-stand exercises.6 The over-ground robotic-assisted gait training device acts to supplement existing muscle strength, provide sensory inputs (i.e. auditory and sensory feedback) and mobility assistance for users with impaired lower-extremity function during rehabilitation (see Supplemental Information), and is fitted and worn in a manner similar to an orthopedic knee brace.
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