Mitigating Muscle Fatigue in Upper-Limb Prosthesis Users Through Exoskeletal Weight Compensation

Area of Science:

• Biomedical Engineering
• Rehabilitation Robotics
• Human-Machine Interaction

Background:

• Prosthetic devices can cause muscle fatigue and reduced control, leading to high abandonment rates.
• Soft exoskeletons offer a potential solution to mitigate these issues by providing mechanical assistance.

Purpose of the Study:

• To investigate the impact of a soft exoskeleton integrated with a myoelectric prosthesis on upper-limb muscle fatigue and user experience.
• To assess the effects on muscle activity, perceived exertion, kinematics, workload, and usability.

Main Methods:

• Nine non-disabled participants performed functional tasks with and without the soft exoskeleton-assisted prosthesis.
• Muscle activity was measured using surface electromyography (sEMG).
• Perceived exertion (Borg scale), kinematics (motion capture), workload (NASA-TLX), and usability (System Usability Scale) were also assessed.

Main Results:

• Exoskeleton assistance significantly reduced muscle activation (up to 64% in Deltoid, Biceps, Triceps Lateral Head during lifting) with large effect sizes.
• Perceived exertion slopes decreased across tasks, and kinematic analysis showed minimal impact on shoulder range of motion.
• NASA-TLX scores indicated reduced physical demand, and System Usability Scale scores suggested moderate usability.

Conclusions:

• Soft exoskeletons can effectively unload muscles and reduce fatigue during upper-limb prosthesis use.
• This technology has the potential to enhance endurance, task performance, and user comfort for prosthesis users.
• Further research should involve more joints and testing with amputee users in real-world settings.