Direct Myoelectric Control Modifies Lower Limb Functional Connectivity: A Case Study.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Rehabilitation Science

Background:

• Direct electromyography (EMG) control in prosthetic limbs aims to restore biomechanics and residual muscle function.
• Current systems primarily use feedforward control, leaving neuromuscular coordination mechanisms during training unclear.

Purpose of the Study:

• To investigate neuromuscular control mechanisms coordinating residual and intact muscles in unilateral lower-limb amputees using EMG-controlled prosthetic ankles.
• To determine how these mechanisms change with guided training.

Main Methods:

• Functional connectivity analysis was applied to surface EMG data from eleven lower-limb muscles.
• Data were collected from an individual with unilateral lower-limb amputation during postural sway tasks across three training sessions.

Main Results:

• Functional connectivity networks showed significant reshaping following training.
• A stronger connection between residual and intact below-knee muscle modules was observed, indicating improved bilateral symmetry.
• Functional connectivity patterns remained largely preserved nine months post-training.

Conclusions:

• Guided training with direct EMG control of prosthetic ankles can lead to adaptive changes in neuromuscular control.
• Improved coordination and bilateral symmetry suggest enhanced motor learning and adaptation.
• The findings provide insights into neuromechanic changes following extended prosthetic use and may inform future prosthetic design and rehabilitation strategies.