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Flexion reflex modulation during stepping in human spinal cord injury
Maria Knikou1, Claudia A Angeli, Christie K Ferreira
1Health Sciences Doctoral Programs, The Graduate Center, City University of New York, 2800 Victory Boulevard, Staten Island, NY 10314, USA. knikou@mail.csi.cuny.edu
Experimental Brain Research
|May 27, 2009
Summary
Spinal cord injury patients exhibit phase-dependent modulation of the flexion reflex during treadmill stepping. Training targeting extensor muscles may enhance sensorimotor recovery.
Area of Science:
- Neuroscience
- Motor Control
- Rehabilitation Science
Background:
- Spinal cord injury (SCI) disrupts sensorimotor pathways, affecting reflexes crucial for locomotion.
- Understanding reflex modulation during assisted stepping is vital for developing effective rehabilitation strategies.
Purpose of the Study:
- To investigate the phase-dependent modulation of the flexion reflex during treadmill stepping in individuals with chronic SCI.
- To explore the relationship between flexion reflex activity and extensor muscle activity during assisted locomotion.
Main Methods:
- Nine individuals with chronic SCI participated, undergoing body-weight supported treadmill stepping with therapist assistance.
- The flexion reflex was elicited via sural nerve stimulation, with responses analyzed across the gait cycle.
- Electromyography (EMG) data were collected, processed, and statistically analyzed to determine reflex modulation patterns.
Main Results:
- A long-latency flexion reflex was consistently present, showing facilitation in late stance and swing-to-stance transitions.
- Reflex depression was observed from heel strike to mid-stance and during swing-to-stance transitions.
- Short and medium-latency reflexes were depressed in mid-stance and facilitated during stance-to-swing transitions, coinciding with decreased extensor activity.
Conclusions:
- The flexion reflex is modulated in a phase-dependent manner during assisted stepping in SCI patients.
- Targeted training of spinal reflex circuits involving extensor muscles is proposed to optimize sensorimotor recovery in SCI.
- These findings highlight the potential for specific interventions to enhance functional recovery after spinal cord injury.
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