Application of Bedside Lower Extremity Rehabilitation Robots in Stroke Rehabilitation: A Randomized Controlled Trial

Summary

This protocol aims to evaluate the clinical efficacy and patient comfort of using bedside lower limb rehabilitation robots for post-stroke hemiplegia rehabilitation, comparing outcomes with those of traditional manual therapy through randomized controlled trials.

Abstract

Stroke remains one of the leading causes of disability worldwide. Bedside lower limb rehabilitation robots are increasingly applied to enhance early motor recovery. This randomized controlled trial compared the clinical efficacy and patient comfort of robot-assisted therapy versus conventional manual therapy in post-stroke hemiplegia. Forty inpatients with first-onset stroke and lower limb muscle strength ≤ grade 2 were randomly allocated (1:1) to a robot-assisted therapy group or a conventional manual therapy group using SAS 9.4 (SEED = 12345). This randomized controlled trial compared the clinical efficacy and patient comfort of robot-assisted therapy versus conventional manual therapy in post-stroke hemiplegia, with primary outcomes including the General Comfort Questionnaire (GCQ), Fugl-Meyer Assessment for lower extremities (FMA-LE), Modified Ashworth Scale (MAS), and Modified Barthel Index (MBI). Robot-assisted therapy achieved similar early motor gains, superior comfort scores, and greater later functional improvements compared to conventional manual therapy. Integrating bedside rehabilitation robots into early stroke care is feasible, safe, and may enhance patient experience and functional recovery. This protocol describes a two-stage intervention design, where the robot-assisted group received a combination of robot training and artificial therapy in the later stage.

Introduction

Stroke is a leading cause of death and long-term disability globally, with ischemic stroke accounting for 70-80% of cases^1,2. The resulting cerebral hypoperfusion leads to irreversible neuronal damage, often causing permanent motor impairment that severely impacts quality of life^3,4. Early rehabilitation initiation within 48 hours of symptom stabilization significantly improves functional outcomes in patients with post-stroke lower limb paralysis⁵. However, conventional early rehabilitation (e.g., manual passive joint mobilization) faces inherent limitations: therapist workload constraints often limit training frequency, and manual operation variability compromises treatment consistency⁶. These gaps are particularly pronounced during the acute bedridden phase, when patients require continuous, standardized mobility support that traditional care struggles to deliver.

Rehabilitation robotics has emerged as a solution to address these unmet needs, with growing integration into clinical practice over the past decade⁷. Compared with conventional therapies, rehabilitation robots reduce therapist workload and ensure treatment consistency through expert-derived algorithms, while their repetitive, task-specific training enhances neural pathway reconstruction⁸. Notably, bedside-specific robotic systems are uniquely tailored to the acute care context-unlike clinic-based robots that require patient transfer (a barrier for bedridden individuals), bedside devices deliver intervention directly at the patient's bed, aligning with the "early mobility at bedside" principle of modern stroke care. Prior studies confirm that such systems significantly improve motor function (as measured by Fugl-Meyer Assessment) and reduce spasm incidence in early stroke patients, outperforming manual therapy in standardization and safety.

Haptic-Walker⁹ and Bo¹⁰ et al. have proved that motor rehabilitation training of the patient's ankle was performed using a parallel robotic platform, and it was confirmed that the lower limb rehabilitation robot significantly improves both motor function and brain function in stroke patients^{11,12,13,14,15}. As a device specifically designed to address lower limb dysfunction, the bedside lower limb rehabilitation robot can assist therapists in performing manual operations to a certain extent. In some aspects, it even surpasses manual therapy in terms of treatment standardization⁷, offering effective support for daily rehabilitation training and promoting the recovery of lower limb function. Bedside lower limb rehabilitation robots have proven their effectiveness and safety in the early rehabilitation of stroke patients¹⁶. A recently published work in the International Journal of Advanced Robotic Systems reported a two-link planar robot model to simulate both the robot and human lower limbs^17,18. The robot allows for the flexion and extension movements of the hip, knee, and ankle joints, as well as the adduction and abduction movements of the ankle. Furthermore, the incorporation of two degrees of freedom in the ankle joint further allows the system to serve as a wearable device for ankle-specific rehabilitation, contributing to a more comprehensive and effective lower extremity rehabilitation program^19,20.

This protocol focuses on a bedside lower limb rehabilitation robot capable of providing passive and assisted movements with built-in safety features, including spasm detection. The system allows customization of parameters such as speed, torque, and session duration to meet individual needs. The primary objective is to investigate the clinical value of lower limb rehabilitation robots in the treatment of post-stroke hemiplegia, with particular attention to their practical efficacy and patient comfort, in order to provide a reference for their broader clinical application.

Protocol

The study recruited 40 patients with lower limb dysfunction who were admitted to the rehabilitation ward of the First Affiliated Hospital of Zhejiang University from March to April 2024, and were randomly selected and divided into two groups. This study protocol was approved by the Ethics Committee of the First Affiliated Hospital of Zhejiang University (approval number IIT20210035C-R2), and informed consent was obtained from all participants.

NOTE: Patients diagnosed with their first onset of stroke based on cranial CT or MRI, and had lower limb muscle strength ≤ grade 2 were included in the study. Patients in poor general condition, with unstable medical status, or with unstable vital signs, and patients unable to complete the study due to various reasons were excluded.

1. Study design

1. Randomization and blinding
   1. Randomization:
      1. Generate a random sequence using SAS software (version 9.4) with a fixed seed (SEED = 12345) to assign 40 patients equally to control or observation groups (n = 20 each).
      2. Ensure allocation concealment by using sequentially numbered, opaque, sealed envelopes prepared by an independent statistician not involved in patient recruitment or assessment. Each envelope contained the group assignment. Open each envelope only after the participant meets eligibility criteria and provides informed consent.
   2. Blinding:
      1. Due to the nature of the intervention (robot-assisted vs. manual therapy), participants and therapists could not be blinded. However, blind the outcome assessors to group assignments to minimize detection bias.
2. Observation indicators and evaluation criteria
   1. General Comfort Questionnaire (GCQ)
      1. Administer the 28-item General Comfort Questionnaire (GCQ) (Likert scale 1-4) in a quiet, private room (≤40 dB ambient noise) before and after phase 1 treatment.
         NOTE: The scale evaluates three domains: physical comfort (items 1-12, e.g., "I feel no pain when moving"), psychological comfort (items 13-20, e.g., "I feel calm during therapy"), and environmental comfort (items 21-28, e.g., "The room temperature is comfortable").
      2. Instruct patients to complete all items independently; discard questionnaires with <80% response rate and re-administer within 24 h, if necessary.
         NOTE: Ensure a quiet environment during assessment; discard incomplete responses (<80% items answered).
   2. Fugl-Meyer assessment for lower extremities (FMA-LE)
      1. Conduct the FMA-LE (0-34 points) at three timepoints: pre-treatment, post-phase 1 (week 2), and post-phase 2 (week 4) . Follow standardized scoring:
      2. Reflex activity (items 1-2): Grade ankle plantarflexion and knee extensor reflexes (0 = absent, 1 = hypoactive, 2 = normal).
      3. Voluntary movement (items 3-34): Score hip/knee/ankle movements hierarchically (0 = no movement, 1 = partial movement, 2 = full movement).
      4. Video-record all assessments using a 4K camera (60 fps) for blinded review by two independent raters, with discrepancies resolved via consensus.
   3. Modified Ashworth scale (MAS)
      1. Assess quadriceps spasticity (0-5 scale) pre- and post-phase 2 using a standardized protocol as follows:
      2. Position the patient supine with the knee flexed at 90°.
      3. Passively move the ankle through full dorsiflexion-plantarflexion at a 1 s cycle.
      4. Grade resistance during stretch: 0 = no resistance, 1 = slight resistance (catch), 2 = mild resistance (easily overcome), 3 = moderate resistance (requires effort), 4 = severe resistance (difficult to move), 5 = rigid.
      5. Perform 3 trials and use the mean score if the variability exceeds 1 grade.
   4. Modified Barthel Index (MBI)
      1. Score 10 activities of daily living (ADLs) (e.g., feeding, grooming, walking) using the MBI (0-100 scale) before and after phase 2 treatment.
      2. For patients with cognitive impairment (MMSE < 18), interview primary caregivers to verify ADL performance (e.g., "Can the patient dress independently?"). Higher scores indicate greater independence in daily activities.

2. Intervention protocols

1. Control group (Conventional manual therapy)
   1. Phase 1 (Weeks 1-2): Therapist-led passive training
      1. Perform passive range-of-motion exercises (hip/knee flexion-extension, ankle dorsiflexion) for 20 min/day. Maintain joint angles within safe limits (hip ≤ 90°, knee ≤ 120°).
   2. Phase 2 (Weeks 3-4): Therapist-led active training
      1. Guide active resistance training using elastic bands with 20-30 N resistance. The training includes hip abduction-adduction, knee extension-flexion, and ankle dorsiflexion-plantarflexion, with 20 min/day.
   3. Ensure the patient maintains a stable sitting position during training and avoids compensatory movements of the trunk. Terminate session if pain VAS >3/10 or blood pressure >160/100 mmHg.
2. Observation group (Robot-assisted therapy)
   1. Device settings: Set the following parameters:
      Speed: Set to 15°/s (phase 1) or 20°/s (phase 2).
      Torque Limit: 30 Nm (hip/knee), 15 Nm (ankle).
      ROM Limits: Hip 0-90°, knee 0-120°, ankle -10° to +20°.
   2. Phase 1 (Weeks 1-2): Robot-assisted passive training
      1. Secure the patient in the supine position with 30° head elevation. Initiate passive mode; monitor electromyography (EMG) for spasm detection (>50 µV/100 ms triggers auto-pause).
   3. Phase 2 (Weeks 3-4): Combine 20-min therapist-led active training with 20-min robot-assisted passive training
      NOTE: Calibrate force sensors before each session; recalibrate if drift > 5%.

3. Robot operation protocol

1. Bedside consultation
   1. Conduct a comprehensive clinical assessment of the patient, including vital sign monitoring (blood pressure, heart rate, SpO2) to confirm stability; neurological examination to evaluate limb muscle strength (FMA-LE); skin condition inspection to exclude lesions at brace contact sites; functional assessment to determine the patient's ability to cooperate with training (using the Mini-Mental State Examination, MMSE).
   2. Provide functional evaluation and rehabilitation recommendations.
   3. Exclude patients with skin lesions at brace contact sites.
      NOTE: This step is performed by a rehabilitation physician before treatment begins.
2. Brace installation
   1. Position the patient in a supine, lateral, or prone position as needed.
      NOTE: Maintain supine position with 30° head elevation for ≤60 min; reposition if SpO2 drops > 5% from baseline.
   2. Inspect the patient's lower limb to ensure it is suitable for bracing.
   3. Inform the patient about the training procedures.
   4. Install the brace on the patient's lower limb.
      1. Align brace connectors (marked with an upward arrow) with joint axes.
      2. Tighten straps to 2-finger tightness (5-7 N tension).
      3. Confirm no skin pinching or excessive pressure (>30 mmHg via pressure film).
         NOTE: Proper alignment and comfort should be confirmed after installation.
3. Training execution
   1. Passive mode: Select Pre-programmed Trajectory 1 for flexion-extension cycles (10 reps/set). Patients in Phase 1 (Weeks 1-2) of the observation group undergo 20 min of passive mode training daily.
      NOTE: If joint misalignment occurs, reposition the brace and restart.
   2. Assistive mode: Set assistance level to 50% of the patient's maximum voluntary contraction (MVC). Patients in Phase 2 (Weeks 3-4) of the observation group undergo 20 min of assistive mode training daily, combined with 20 min of therapist-led active training.
      NOTE: Reassess MVC weekly using a handheld dynamometer.

4. Critical practical notes

1. Contraindications:
   1. Exclude patients with unstable fractures (X-ray confirmation required) and exclude patients with deep vein thrombosis (D-dimer >500 µg/L).
2. Safety checks:
   1. Test emergency stop button functionality daily and inspect cables for wear monthly.
3. Data recording:
   1. Export session logs in CSV format, which should include joint angles, torque output, and spasm events.

Results

This study adopted a randomized controlled trial design, where 40 participants were randomly assigned to either an observation group (robot-assisted therapy) or a control group (conventional manual therapy) using SAS software. The treatment plans of the two groups were as follows:

For the control group, patients received manual therapy targeting lower limb dysfunction, administered by a physical therapist once daily for 20 min per session. The treatment was divided into two phases: phase 1 (we...

Discussion

The lower limb dysfunction caused by post-stroke hemiplegia has a severe impact on patients' quality of life and even their safety^22,25. Conventional rehabilitation therapy is primarily performed manually by physical therapists, facing challenges such as difficulty in quantifying the treatment process and poor control over treatment intensity. As a result, it is difficult to ensure that each patient receives standardized and equivalent therapy. This protocol demo...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Bedside Lower Limb Rehabilitation Training System, Model: LR-H01-L10	Suzhou Kanglian Medical Technology Co., Ltd.	LR-H01-L10	Robotic device for passive and assisted lower limb movement in post-stroke rehabilitation
SAS software	SAS Institute	version 9.4	https://www.sas.com/en_in/home .html
SPSS software	IBM	version 31	https://www.ibm.com/products/spss-statistics