Stabilization of human standing posture using functional neuromuscular stimulation.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Rehabilitation Technology

Background:

• Functional neuromuscular stimulation (FNS)/functional electrical stimulation (FES) offers potential for restoring limb function in spinal cord injury (SCI) patients.
• A significant barrier to FNS/FES adoption is the lack of efficient control algorithms, with many existing methods relying on oversimplified biomechanical models.

Purpose of the Study:

• To propose and evaluate an innovative control strategy for stabilizing standing posture in paraplegic patients using FNS/FES.
• To develop a control system that generates appropriate musculotendon torque for skeletal motion control.

Main Methods:

• A hybrid control strategy combining a proportional-plus-derivative (PPD) controller for skeletal dynamics and a control action prediction mechanism for musculotendon activation was developed.
• Computer simulations were performed using a detailed skeletal-musculotendon-muscle activation dynamics model of the human body.

Main Results:

• The proposed FNS/FES control approach successfully stabilized the standing posture of a paraplegic patient in simulations.
• Stability was achieved using a minimal number of musculotendon groups.
• The control strategy demonstrated robustness, maintaining stability even with variations in controller parameters.

Conclusions:

• The developed control strategy represents a significant advancement for FNS/FES applications in restoring standing function for individuals with spinal cord injuries.
• This approach offers a more efficient and robust method for controlling FNS/FES systems, potentially overcoming limitations of current methods.