Gait initiation with electromyographically triggered electrical stimulation in people with partial paralysis

Area of Science:

• Neuroscience
• Rehabilitation Engineering
• Biomechanics

Background:

• Functional electrical stimulation (FES) aids walking in paralysis by activating leg muscles.
• Individuals with incomplete spinal cord injury (iSCI) have partial muscle control, requiring FES integration with voluntary movement.
• Current FES triggering methods include autotrigger, switch-trigger, and electromyogram (EMG)-trigger.

Purpose of the Study:

• To investigate if EMG-triggered FES provides better coordination and stability during gait initiation in individuals with iSCI compared to autotrigger and switch-trigger methods.
• To compare EMG-triggered FES with other FES activation methods for natural gait control.

Main Methods:

• Two volunteers with iSCI and four able-bodied volunteers participated in over-ground FES-assisted gait initiation.
• Gait initiation was assessed using autotrigger, switch-trigger, and EMG-trigger FES systems.
• Coordination and dynamic stability were evaluated for each triggering condition.

Main Results:

• EMG-triggered FES-assisted gait initiation demonstrated superior coordination compared to autotriggered and switch-triggered methods.
• The EMG-triggered system also showed enhanced dynamic stability during gait initiation.
• These findings suggest EMG is a more natural command interface for FES.

Conclusions:

• Surface EMG shows significant potential as a natural command interface for FES-assisted gait.
• EMG-triggered FES can improve coordination and stability, facilitating better integration of stimulated and volitional movements in individuals with iSCI.
• This approach may enhance ambulatory function and walking efficiency after spinal cord injury.