EMG-Controlled Prosthetic Ankle for Below Knee Amputation

Overseen By Ming Liu, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: North Carolina State University

Disqualifiers: Congenital amputees, Powered prosthetic users, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 18

50 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a new method for controlling prosthetic ankles using muscle signals, potentially helping below-knee amputees move more naturally and improve balance. Participants will train to use a powered prosthetic ankle that responds to direct electromyographic signals. Researchers aim to determine if this new prosthetic can reduce the mental effort required for walking and improve coordination. The trial seeks individuals who have used a prosthetic leg for over a year, had an amputation over two years ago, and regularly use their prosthesis. Participants must be willing to travel to NC State University's Centennial Campus for the study. As an unphased trial, this study offers a unique opportunity to contribute to groundbreaking research that could enhance mobility for many.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that the dEMG-controlled prosthetic ankle is safe for transtibial amputees?

Research has shown that using direct electromyographic (dEMG) control for a powered prosthetic ankle is safe and promising. In previous studies, this method helped people improve their balance and posture. No major safety issues were reported, indicating it is well-tolerated.

For those considering joining a trial, it's important to know that dEMG control offers a new way to manage a prosthetic ankle, potentially making movement feel more natural. Although the trials are ongoing, results so far indicate that participants have adapted well to this technology. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores a new way to improve mobility for individuals with below-knee amputations. Unlike traditional passive prosthetic ankles, the direct EMG-controlled prosthetic ankle uses electrical signals from the body's muscles to actively adjust and power movements, offering a more dynamic and responsive experience. This method has the potential to enhance balance and walking efficiency significantly. By comparing this innovative approach to conventional prosthetic training, researchers hope to discover how much more it can improve the quality of life for amputees.

What evidence suggests that the dEMG-controlled prosthetic ankle is effective for improving balance and neuromuscular control in transtibial amputees?

Research shows that direct electromyographic (dEMG) control for a powered prosthetic ankle can improve balance and stability in people with amputations. In this trial, participants in the dEMG group will use the direct EMG-controlled powered prosthetic ankle. Studies have found that this technology can make controlling the prosthetic feel more natural, potentially leading to better coordination of muscles and movements. Users could move more smoothly and steadily. Additionally, dEMG control might make walking feel easier by making the prosthetic feel more intuitive. Overall, early findings suggest that dEMG-controlled prosthetics could offer significant benefits compared to traditional prosthetic ankles that don't move on their own, which participants in the passive group will use. ^{1 2 5 6 7}

Who Is on the Research Team?

He Huang, PhD

Principal Investigator

NC State University

Are You a Good Fit for This Trial?

This trial is for individuals with below-knee amputations. Participants should be able to undergo physical therapy (PT) and use a direct electromyographic (dEMG) controlled prosthetic ankle. Specific inclusion or exclusion criteria are not provided.

Inclusion Criteria

Are willing to come to NC State University's Centennial Campus to participate in research and be photographed while doing research activities

I can walk with some assistance.

I've used my current prosthetic socket for 6+ months without major skin problems or changes.

Exclusion Criteria

I can understand and follow simple instructions.

Congenital amputees

Weight more than 300lbs

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

1 visit (in-person)

Baseline Evaluation

Initial evaluation with both powered and passive prostheses to establish baseline measurements

2 weeks

4 visits (in-person)

Training

Participants undergo training to use the powered prosthetic ankle, focusing on muscle coordination and integration with full body motion

5 weeks

7 visits (in-person)

Post-training Evaluation

Evaluation of the impact of the training program on participants' performance with both prosthetic types

2 weeks

4 visits (in-person)

Follow-up

Participants are monitored for long-term effects of the training program on balance and postural control

4 weeks

2 visits (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• direct EMG controlled prosthetic ankle
• PT guided prosthetic training

Trial Overview

The study tests if using dEMG control of a powered prosthetic ankle improves balance, neuromuscular coordination, and reduces cognitive load in transtibial amputees compared to those using passive prostheses.

How Is the Trial Designed?

Group I: dEMG group Experimental Treatment 2 Interventions

Patients go through the training procedure with the direct EMG controlled powered prosthetic ankle.

Group II: Passive group Active Control 1 Intervention

Patients go through the training procedure with their own passive prosthetic ankles

direct EMG controlled prosthetic ankle is already approved in United States for the following indications:

Approved in United States as dEMG-controlled prosthetic ankle for:

• Transtibial amputation rehabilitation
• Balance and postural stability improvement
• Neuromuscular control and coordination enhancement

Who Is Running the Clinical Trial?

North Carolina State University

Lead Sponsor

Trials

38

Recruited

50,000+

University of North Carolina, Chapel Hill

Collaborator

Trials

1,588

Recruited

4,364,000+

Published Research Related to This Trial

Powered foot-ankle prostheses can significantly enhance the natural gait and energy efficiency of amputees, allowing for voluntary control of ankle movements, which aids in daily activities.

A study involving 12 trans-tibial amputees and 5 control subjects demonstrated that accurate real-time control of ankle joint movements can be achieved using electromyographic signals from as few as 4 muscles, with a mean error of only 5.3%.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Myoelectric neural interface enables accurate control of a virtual multiple degree-of-freedom foot-ankle prosthesis. Tkach, DC., Lipschutz, RD., Finucane, SB., et al.[2013]

Using electromyographic (EMG) signals from both native and reinnervated thigh muscles significantly improved the control of a robotic leg prosthesis for a knee-amputated patient.

The integration of EMG signals with sensor data allowed for intuitive movement control, enabling smooth transitions between different walking surfaces and repositioning while seated.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Robotic leg control with EMG decoding in an amputee with nerve transfers. Hargrove, LJ., Simon, AM., Young, AJ., et al.[2022]

The study demonstrated that direct, continuous electromyographic (dEMG) control of a powered ankle prosthesis significantly improved standing postural control in a participant with a transtibial amputation, as evidenced by higher clinical balance scores compared to a passive prosthesis.

Using dEMG control led to synchronized muscle activation and a notable increase in postural stability, with a cross-correlation coefficient of .83 for center of pressure excursions, indicating enhanced control and reduced reliance on intact joints.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Direct continuous electromyographic control of a powered prosthetic ankle for improved postural control after guided physical training: A case study. Fleming, A., Huang, S., Buxton, E., et al.[2021]

A biofeedback training system was developed to assist above-knee amputees in learning to control their prosthetic knee, showing effectiveness in improving knee control for most users.

Out of 15 patients who completed the training program, 13 experienced significant benefits, indicating that while the system is generally effective, individual responses may vary.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Biofeedback training of knee control in the above-knee amputee. Fernie, G., Holden, J., Soto, M.[2022]

A neural network approach using surface electromyography (sEMG) has been successfully developed to control a powered ankle prosthesis, predicting ankle angle and moment during walking with high accuracy using muscle data from healthy individuals.

The study identified optimal combinations of lower extremity muscles for controlling the prosthesis, with the combination of tibialis anterior and medial gastrocnemius showing the best performance, suggesting a pathway for creating more economical and flexible prosthetic devices for amputees.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Development of a neural network based control algorithm for powered ankle prosthesis. Keleş, AD., Yucesoy, CA.[2021]

Using electromyographic (EMG) signals from residual muscles can significantly enhance the control of robotic lower limb prostheses, allowing for more natural and adaptable movement for amputee users.

This review identifies both the potential benefits and challenges of EMG-based control, emphasizing the need for collaboration among researchers and clinicians to develop advanced bionic limbs that improve motor function.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Myoelectric control of robotic lower limb prostheses: a review of electromyography interfaces, control paradigms, challenges and future directions. Fleming, A., Stafford, N., Huang, S., et al.[2021]

Despite advancements in prosthetic technology, no commercially available prosthetic leg currently utilizes electromyography (EMG) signals for control, highlighting a gap in practical application.

A systematic review of 121 studies revealed that while there is significant research interest in using EMG for controlling lower limb prosthetics, challenges remain in signal quality, electrode placement, and control algorithms, indicating the need for further development before widespread use.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Electromyography-Based Control of Lower Limb Prostheses: A Systematic Review. Ahkami, B., Ahmed, K., Thesleff, A., et al.[2023]

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This case study showed the feasibility of this dEMG control paradigm of a powered prosthetic ankle to assist postural control.

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This manuscript aims to provide a comparative overview of EMG-driven control methods for MLLPs, to identify their prospects and limitations,

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This exploratory study examined the biomechanical performance of a bionic ankle prosthesis under direct myoelectric control compared with ...

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This manuscript aims to provide a comparative overview of EMG-driven control methods for MLLPs, to identify their prospects and limitations, and to formulate ...