Prolonged electrical stimulation over hip flexors increases locomotor output in human SCI.

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Biomedical Engineering

Background:

• Locomotor function is often impaired after spinal cord injury (SCI).
• Sensory feedback from muscles plays a crucial role in regulating locomotion.
• The contribution of thigh afferent feedback to SCI locomotion remains an area of investigation.

Purpose of the Study:

• To investigate if enhanced afferent feedback from thigh muscles improves locomotor output in human SCI.
• To determine the effects of electrical stimulation of thigh afferents on gait parameters.

Main Methods:

• Electrical stimulation was applied to the medial thigh (sartorius muscle region) in 10 individuals with incomplete SCI and 3 controls during robotic-assisted treadmill walking.
• Stimulation was delivered bilaterally with 20 pulses at 30 Hz during four distinct gait phases.
• Hip and knee joint torques and leg electromyograms were recorded under baseline, stimulation, and post-stimulation conditions.

Main Results:

• Electrical stimulation significantly enhanced hip and knee extension and flexion torque responses during stance and swing phases, respectively.
• Greater hip extension torque was observed when stimulation occurred during the stance phase and the stance-to-swing transition.
• These findings suggest improved excitability of spinal locomotor circuits.

Conclusions:

• Enhanced afferent feedback via electrical stimulation can modulate spinal cord locomotor circuits in SCI.
• Sensory input from thigh muscles, specifically sartorius afferents, is vital for locomotor control in SCI during treadmill walking.
• This approach holds potential for improving gait rehabilitation strategies in SCI.